【 Weak current College 】 terminal device selection and layout

1 Terminal device select the General principles of

VAV system is the right choice of terminal equipment and the reasonable control of the entire system of energy consumption and the comfort of the rooms, have a very significant impact, a larger capacity of the terminal device, at run time through it generated may lower pressure drop, making the energy consumption of air conditioners in blower can be reduced, however, the capacity is big terminal device minimum air control set-point are relatively high, which in turn will make the operational power consumption increased forced draft fan, also increases the heat again (if you choose to use the reheat-terminal device). On the contrary in the air volume required under the same conditions, select a size too small of a terminal device, in addition to making energy consumption will increase, you may have greater operating noise. However, due to its regulation of air flow control valve, relative to the room's load change reactions are more sensitive to its control stability than select a capacity rate of terminal device will be better.

Terminal device selection is designed according to the room need air, determine terminal device of the type and number. In General, choose a major terminal equipment should review its three performance indicators meets the design requirements: (1) standard air (or the maximum and minimum air); (2) noise value; (3) appliance inlet pressure value or unit maximum pressure drop (i.e. the total pressure drop). Finally, select the number of terminal device, it should be and architectural partition, lighting and ceiling-mounted another device on the harmonization of the layout, this building is very important.

It should be stressed that VAV choice, and control functions are inseparable. Different control on the design requirements, need to use a different type and size of the terminal device matching to obtain satisfactory operating result.

1.1 max air

In the terminal device before, we have been selected according to cooling load in summer maximum seek the maximum design of room air flow. Now concern were the selected terminal device (one or more terminal device maximum air flow) is the biggest air and the maximum air volume of design are the same. If the terminal device size is too large, will cause the entire system running a significant increase in energy consumption, when the Terminal settings using conventional "single maximum" control logic, the situation is even more so. For example, room maximum design flow for 500m3/h, now choose a terminal device for its service, the maximum air-1000m3/h, if it's the smallest air set points to its maximum air 30%, the minimum air as 300m3/h. In this case, because the terminal device maximum air is room maximum design air volume of 2 x, then the device at run time, a truly effective minimum air flow set point (i.e. 300m3/h), not the biggest design air flow (i.e. 500m3/h) 30%, but it's 60%. Thus, in most of the running hour, the terminal device is at its minimum air flow (i.e. 300m3/h), but in fact, a lot of time should be 150m3/h (i.e. 500m3/h 30%), which led to the cold wind quantity sent too much, will definitely need to heat, otherwise the room appears too cold. Of course, this is a waste of energy. This shows that the terminal device capacity selection is too large. Visible, the selected terminal device for maximum air supply and rooms need maximum design matches the amount of wind.
　　
1.2 minimum air

Similarly, at the made before the end of the device selected, for building area, we also have their summer minimum cooling load, evaluated over a minimum of room air flow design, selection of terminal device (one or more terminal device minimum air flow) of minimum air should be the minimum design air match.

As for the building area, its minimum cooling load depends on the terminal device, it's the smallest air to its maximum air 30% ~ 50%. A lower percentage of minimum air, you can provide users a wider range of temperature control set.

Again, the minimum end device air flow set point can be calculated for the value of minimum air flow, you can also calculate values lower than this number, the so-called can have high limit and lower limit of minimum air flow set points, depending on the terminal device of control logic. If you use a maximum value of the "single" control logic, the terminal device of minimum air flow setting can and calculation of the minimum ventilation rate values, is the minimum for high limits of air flow set point. Typically, only the end of the cooling unit with a maximum value of the "single" control logic. Zone reheat coil terminal device that is customary or a maximum value of the "single" control logic. If you use the "double Max" control logic, the terminal device of minimum air flow set point can be calculated the value of minimum air flow is low, low minimum air flow set point. Typically, the zone reheat coil terminal device, the recommended maximum value for the "double" control logic, that is, the smallest volume set point, not only depends on the room minimum ventilation rate requirements also depend on the terminal device is installed in velocity probe measuring accuracy and precision, and can be evaluated by calculating the lower limit of minimum air flow set point.

Visible, the terminal device, the minimum air meets the requirements to see which end device take a control logic. It should be noted that, at present only a minority of DDC control manufacturer can provide the system controller to the "double Max" control program.

1.3 noise

The noise level at the end of the device conforms to the air conditioning room noise level requirements, select the terminal device is another important factor.

Room internal noise level is determined by a variety of individual sound sources of noise in a cumulative, these sound sources include:

External noise— — outdoor generated and transmitted into the noise inside buildings;
Interference noise — — adjacent side will or corridor and passes into the room of noise;
Environmental noise — the room personnel and equipment arising from noise, its characteristics and the use of the room;
> System noise from air conditioning to decency pass into the room, or terminal device is in the room noise.
　　
Should carefully analyse the room personnel may hear voices came from a variety of sound sources. In an environment noise was very high room for a very low noise level, is unrealistic, but also economic. On the contrary, the ambient noise level is low, at the same time, many dispersed and intermittent noise and interference of external noise and can take some measures to shield off, room only from a single noise air-conditioning system, which is the ideal State.

Air tube design, on the effect of room noise level is high, while the terminal device of choice, is even more direct and room noise level. Terminal device noise in the room, spread, its sound energy propagation loss refers to the ceiling on VAV propagation attenuation of sound has, since the existence of this role makes the terminal device and the room between the sound delivery channel has been a degree of isolation. The room effect refers to the officers heard sound energy and sound source device actually issued the difference between the sound energy, it actually reflects the room itself, the sound-absorbing ability, its size and the size of rooms, the room walls of materials, indoor furniture materials relative hardness. All manufacturers of VAV product samples, in citing their standard air volume, will indicate the room effect. Samples can't find these data, a variety of different types of room room effect value can refer to table 1

Table 1 room effect on noise attenuation values

Room type
X band

250
500
1000
2000
4000

Hospital
0.8
2.5
3.5
4.0
4.8

Hotel
6.9
7.5
8.5
8.5
8.6

Office
7.2
10.3
11.0
10.5
10.5


Various sound sources on the combined effects of noise in the room, you cannot simply use digital overlays, and the application log, the added value of the sum method (table 2) plus two sound sources in higher sound energy, be integrated after the sound energy value, and then subtract the room effect, is there room in the actual noise level.
Table 2 noise superimposed when added value
The difference between the two sound sources (dB)
0
2
4
6
8
10

Added value (dB)
3
2
1
1
0
0


In General, as long as the press manufacturer product samples of air terminal device to select the callout, and run by the wind, the room will be able to reach the required level of noise. Product samples of VAV standard air flow is the recommended design flow, which is within the area and North room select terminal device, especially so because these rooms of load changes is relatively small. On the other surrounding area room, because the Sun meets the changing selection of terminal device, the volume should be slightly larger than standard air. Terminal equipment for maximum air flow value is only used on those that allow a very high level of abnormal noise, or the maximum amount of wind, the cavity of the original static value generally 500Pa following. You should understand the cavity pressure higher values in the given amount of wind noise level produced will also. Of course, the terminal device of the air flow reduction, the noise levels are reduced.

VAV manufacturers will usually provide two types of noise data diffusion noise and noise. Diffusion noise means the terminal device box downstream measured noise values, it is basically the box in the upper air pipe-air pressures; radiation noise is means underfloor in triage and in the air valve produced turbulence caused by and through the terminaldevice box body shell entered the room ceiling space of noise values. In fact, if the terminal device during Setup, the entrance to a rigid duct, and export and the straight pipe, hose and air diffusers, and the proliferation of noise will seldom occur. If the terminal device is installed in the standard acoustic ceiling above, then the terminal device-generated noise, generally not less than the noise room allows high 5NC. For example, a typical Office, its design allows the noise value is 30NC, then you can press 35NC radiation noise value to select a terminal device. In other words, the terminal units of radiated noise level is not greater than 35NC, ensures the room noise values within the 30NC.

1.4 total pressure drop

Total pressure drop is also known as the terminal device of maximum pressure drop, it should be equal to the static pressure drop and dynamic voltage drop, it was the air conditioning system design Air conveying blower will be through the terminal device may be required for the actual energy consumption indicators. However, the terminal device manufacturer generally only provide their blood pressure lowering data. It is clearly lower than the total pressure drop values because, in the terminal equipment of the entrance to the exit of the wind speed of the wind speed high number, resulting in a certain number of static regain. Therefore, when the terminal device product catalog does not provide the total pressure drop data, designers need a product sample of the air volume and size of the import, export, calculation of pressure drop of value out, resulting in the total pressure drop.

In the air the same case, you can select various sizes of different end devices. But as already stated, when you select a smaller size of the terminal device, the total running time is relatively high pressure drop, forced draft fan energy consumption will increase, the noise will be relatively high; on the contrary, when you choose a large size ofthe terminal device, the investment will increase at a time, how to determine the minimum air flow set point, will be limited, otherwise, there is likely to increase in a writ of low loadCondition of fan energy consumption and thermal energy again. Typically, you can make the calculation, energy simulation, from best energy-saving needs, considering the total pressure drop and minimum air flow setting limits, and seeking the best value for the total pressure drop. Most of the terminal device used analysis indicates that the total pressure drop of approximately 120 ~ 140Pa to choose more appropriate terminal device.

Obviously, the air supply system of the terminal device by total pressure drop is 120 ~ 140Pa to choose, and in accordance with this overall numerical calculation of pressure drop, the air supply system needs, determine the need for power blowers, close to the blower (from hydraulics sense), because there are remaining pressure can be used, where the terminal device can use larger total pressure loss value and the terminal device size selection a bit smaller?

We know that when the load on all day and all year in changes, most of the air terminal units are changing, you need a larger air and maximum air zone, the entire floor is changing, regardless of the outside area within a zone or situation. Therefore, the maximum air pressure values, in a day is changing. If you set the value of the static pressure blowers and then transferred to just meet the design State need maximum air pressure range of requirements, or if in order to offset the near end of air blower installed devices in design mode of operation, the terminal device may need more air pressure, air pressure and operating power consumption it will increase.

Therefore, because in the floor in the maximum air pressure requirements of the terminal device is over time, in a VAV system all the terminal device is installed, you should press the same total pressure drop (e.g. 120 ~140Pa) to select their size, regardless of its location is close to the blower is installed.
　　
2 several terminal device choice

Single-duct Vav (including zone reheat coil terminal device) can be according to the first section describes the General principles for selection, here no longer. Fan power terminal units, dual-channel terminal device of choice, in addition to the above general principles to be followed, there are also worthy of note in the selection, the following are described separately.
　　
2.1 series fan power terminal device

Except for some special requirements of occasions, are advised to avoid using in-line blower power terminal device, this is because the device installed recycling small fan and motor needs even broken seamlessly, while their efficiency in general are very low, typically better than centralized air conditioning blowers operating efficiency low 15%.
However, in some occasions, it is recommended that you use in-line blower power terminal device:

(1) District rooms: in design mode, the room personnel density is large, but practical in use evolution of the situation of the staff. In design mode, since ventilating and minimum requirements of the new amount of wind, meeting room requirements of the minimum ventilation rate and the maximum air volume of the often very high, even as high as 75 percent, is in the meeting room in the area, the situation is even more so. When the Conference room personnel, consistent with the decreases, such a high minimum design flow, will inevitably lead to the room is too cold. If the room uses ordinary single-duct VAV, except in the cooling will consume additional fan energy consumption, but also have reheat measures against very low room staff experienced cold. Generally, the minimum airflow over cooling with a maximum of 40% of the air flow design, you should consider choosing another type of terminal equipment, in-line blower power terminal device is one of the proposed programme. In this case use of in-line blower power terminal device may show zero set point minimum air flow, it can only send room recycling wind to meet ventilation requirements instead of air handling unit for heat, when the Conference room appears part load, and then tune and reduce primary air flow, increase the introduction of recycling of ceiling space, air and energy from the control's point of view, this is the most simple, is also one of the most effective programmes.

(2) need to have a greater minimum air flow to the maintenance room good mixed state, you can use in-line blower power terminal units, thereby preventing in part load conditions declined air flow. For example, a large entrance hall, or lobby, large space that it itself has two storeys high, usually in the first layer of height installation side sent diffuser outlet, but because of the diffuser outlet air temperature reduction, it is possible to produce the air flow, ventilation is not possible to absorb the entire space of the air volume. In this case, selection of in-line blower power terminal device, it can be used in a variety of load State remained fixed air and fixed air speed, so that space be satisfied with the air mixed state.

When the in-line blower power terminal device, the design of system control programme to be aware of when a problem is that the in-line blower power terminal units and air conditioning blowers chain control in advance, and the former to the latter starts first, preventing once the system is started, from air conditioning blowers sent a wind through the terminal device and into the ceiling space, the terminal device of circulating fan appears inverted.

In-line blower power terminal units in circulation fan, you will be 100% Design air into the room, therefore, when determining the device of the primary air inlet need minimum static value, it is not necessary to its downstream of various resistance losses (such as the air through the terminal device, appliance outlet, ventilation pipes and air diffusers, and reheat coil resistance loss) into account, these resistance loss can rely on circulating fan to overcome. In other words, in the selected in-line blower power terminal device, you should know that the device requires more than the outlet pressure value. It is clear that in determining the overall system of air conditioning blowers of wind pressure, you only need to take to overcome the primary air to a terminal device entry and adopt a secondary air valve of resistance values, so the power blowers can be reduced.

However, this concept must not be abused. Pay attention, do not put in-line blower power terminal installationCycling fans as the entire air supply system booster fan. Because, in the cooling at run time, if not enough due to wind pressure, causing the fan to the terminal device entrance, and through an air valve for primary air flow is not enough to rely on the terminal device of circulating fan from an air duct aspiration in more air flow to meet design requirements, it is impossible, if this happens, circulating fan only from the ceiling in pumping more circulating air into the room because there's resistance far less than a wind blowing tube resistance. As a result, the air temperature will increase, room cooling down, people are not comfortable. Therefore, the air conditioning blowers of wind pressure should ensure adequate primary air flow to the terminal device entry and adopt a secondary air valve.

There is no doubt that the in-line blower power terminal units of air volume in circulation fan, you should press the entire device for maximum air flow value determined.

2.2 parallel fan power terminal device

Use parallel fan power terminal device, usually can reduce, or even cancel the system and then heat requirement, and then heated terminal units compared to its initial investment and maintenance costs are very high. In addition, parallel fan power terminal units in circulation fan is run periodically, it generated noise is detected more easily. However, the loop fan and motor efficiency problems, not like in-line blower power terminal device that looked very prominent, because under normal circumstances, parallel fan power terminal units in circulation fan and motor, only the system is in heating State continuously put into operation, and in-line blower power terminal units in circulation fan and motor you need to run continuously.

If single-duct VAV reheat-terminal device can use the "double Max" control logic, and press to control logic to determine the minimum air flow set point, so that their entire life-cycle cost than parallel fan power terminal device to province. When parallel fan power device with zero set point minimum air flow, it can be completely abolished the system of heat demand, thereby significantly reducing centralized air handling unit's fan energy consumption, their life-cycle cost than single-duct reheat-terminal device to province.

Parallel fan power terminal units in circulation fan only transitional quarter and motivation gap running, it only room ceiling air sucked in and terminal units, therefore, in determining the terminal device of primary air inlet requires a minimum static values, including the air through the entire terminal device, the device outlet and air pipes and air diffuser of resistance losses are to be calculated, if with reheat coil, it should also be calculated reheat coil resistance loss. Air circulating fans are usually designed by heating the air flow required to select, it is usually the largest cooling air flow design when 50% ~ 80%.
　　　　
2.3 double-duct VAV

Select the double-duct VAV, should also follow select Single-duct VAV general principles, each terminal device for maximum air flow design to comply with the maximum air volume of requests, the total pressure drop should be not more than 120 ~ 140Pa noise level should be consistent with the room allows noise level requirements. When this type of terminal equipment with reheat coil will involve how to determine the minimum air flow control set-point, if the dynamic pressure sensitive components installed on the terminal device of Tuyere, accurately determine the calculation that you want to use basal area of the outlet, the end of this class of device is very important. You can control the minimum air flow setting point dynamic pressure sensitive element, to such end devices outlet is very important. You can control the minimum air flow setting point dynamic pressure sensitive element, controller minimum dynamic pressure set point output power, and place the dynamic pressure sensitive element of the basal area of air duct. While, generally the outlet sensitive components installed in a circular air ducts, but double-duct connection pipe end device, usually a larger rectangular duct with flange and terminal device is attached to the end of the output. Often, manufacturers are using this relatively large dimensions of the rectangular duct to measure wind tube static pressure losses. Therefore, in the calculation of the double-duct terminal device of dynamic pressure loss when using rectangular duct of basal area values.

By the end of the double-duct unit of pressure will be distinct, they depend entirely on the type of terminal equipment and the dynamic pressure-sensitive components. For cold and hot air flow can fully mixed and have a mixture of double wind vanes road terminal device, the pressure drop Max. When using hybrid control logic (not meant here in the outlet with separate sensitive element of rapid switch control, because using this control, cold and hot air valve is never in the same moment is open), cold and hot air in full hybrid is only an index, only when the terminal device for multiple supply air temperature requirements are not consistent with the room service, which may disturb the equilibrium will be experiencing this problem. When using a separate outlet dynamic pressure sensitive components, often the outlet of the section size appropriate to reduce, than using the cold, hot-air inlet dynamic pressure-sensitive components of the terminal device outlet section size to small, in this way, you make it through the dynamic pressure-sensitive components of air velocity increases, improved air flow measurement accuracy, resulting in two underfloor blend better, but at the same time, the pressure will increase. It was found that in most double-duct terminal device applications, with a separate outlet air flow sensing element, from the comfort of the room, cold, hot-air mixing control room enough. While installing mixed vanes can significantly increase the initial investment at the end of the installation and run-time total pressure drop, only in the most need this type of terminal device (e.g. hospitals) before use.

【 Weak current College 】 McQuay air conditioning control panel operation manual

I. McQuay air conditioning MAC air cooled modular chillers

1 switch on machine
· Press ON/OFF key on the unit (RUN lights), shutdown (RUN the lights).

2 mode select
· Press "mode" key can be used in cooling/heating mode to switch between, it should be noted that mode switch must be in the shutdown, this compressor can play a protective role.

3 parameter query
· Use the controller to query arbitrary it networking one unit of work status and parameters (which compressor at work, set temperature 35℃，inlet water temperature and the actual water temperature and set water temperature and the actual water temperature, unit of timings, refrigeration and freezing temperatures, anti-freezing defrost temperature, temperature, etc.).
· Press "set" key unit number flashing, press "▲" or the "▼" key to adjust the unit number, view the different units of the current parameter to the query parameter to a unit of work, the Unit found enquiries, press "OK" key to query the unit of work parameters, press the "▲" or the "▼" key to view the set of different parameters.

4 parameter settings
Press the "set" key unit number flashing, press "▲" or the "▼" key to adjust the unit number, found to set parameters of the unit, press the "OK" key to set the unit of work parameters (the parameters can be set are: cooling water inlet temperature, cooling water temperature, heating water temperature, heating water temperature, freezing temperatures, in addition to the dew point temperature, dew point A B temperature, defrost temperature). (password:55)
Press the "▲" or the "▼" key to select a set of parameters, press the "OK" key you can press "▲" or the "▼" key to set the parameter values, set is complete press the "OK" key to save the settings.
Repeat step ② to set other parameters.

5 real time clock settings
· Use needle tool press the "mode" button at the top of the hole, the LCD display on the set of "week" of the words, "▲" or the "▼" key to set the current time is the day of the week, set up, and then press the small weeks set successfully, and at the same time, the monitor displays the words "clock setting", time flashes, press "▲" keys to modify the hours, by modifying the "▼" key, then press the small hole minutes to save the setting of the clock.

6 timing settings
Press the "scheduled" keys simultaneously displayed on the monitor after setting the "week" and "timings" typeface, then press the "▲" or the "▼" keys to select the time you want to set the timing in the week, select the right and press "OK" button, the monitor displays "timings" typeface, then press the "▲" key to select which day you want to set the timing (set of 4, in the "units" above), press the "▼" keys to select the "timed out" or "timer off", press "OK" keys and then pressing "▲" keys to modify the hours, by modifying the "▼" key, set the time in minutes after pressing the "OK" key to save the timings.
Repeat steps ① to set other timing settings. If you want to cancel a scheduled set, just set it's scheduled time is set to 0: 00 in the morning.

Note: the regular boot and regular shutdown is to line controller clock on time, if the clock is not accurate, regular boot and regular shutdown time also will be closed. In the course of timer settings, press the "set" and "mode" and "password" and other key will exit timer setting (don't save settings).

7 defrosting
· Unit in heating State press "▲" or the "▼" key until the "manual defrost" appears, press the "OK" key, i.e. enter manual defrosting. Exit the defrosting of condition: ① defrosting time is greater than 10 minutes walk or ② if you defrost temperature probe detects temperature is greater than the set temperature of defrosting and defrosting time is greater than 1 minute.

8 reset
· Press "▲" keys at the top of the small hole can be reset.

【 Weak current College 】 elevator monitoring and intelligent building technology development trend analysis---Power By 【 China power house network 】

At present, China's intelligent building elevator control and power relations between
　　
Experienced a 100-year history of the elevator is already familiar with important buildings, equipment, modern age with the growing of the tall buildings and the architectural design of grades, enables people to lift the increasingly high demands. Now not limited to, the requirements for the elevator ride fast, comfortable, elegant decoration manufacturing firm,, Elevator Safety and reliability and versatility are made increasingly higher demands for this lift is moving control intelligent direction.

In some developed countries in the world of modern intelligent construction, the people have the elevator into the building automation management system important charged device, using advanced electronic monitoring and control instruments, implementation of the operational status of the elevator, maintenance and management of all aspects of security.

In our country, in recent years with advanced control technology of the growing popularity of elevators, especially in the many new intelligent building is the choice of a variety of upscale elevator, elevator control and power control between organic combination possible. But because of the traditional management idea and the elevator manufacturer and weak electricity supplier of their system of relative independence, making our elevator control and power control of mutual penetration of technology and application is slow in most of the high buildings elevator monitoring are basically elevator suppliers provide a closed system, in building security centre is equipped with elevator vendors elevator Monitoring Board for simple display of elevator operation status and can be used with the elevator car to intercom. Elevator and the building automation management system occurred between most of the following three aspects:

(1) elevator from fire Center about signal, elevator in the fire back to the basestation, use the fire ladder with fire.

(2) in the elevator car built-in video camera, video signal (also with audio signals) to the Security Center, monitor show sedan, there's also the elevator floor signal character generator at the same time displayed in the monitor for security personnel in the elevator when committing the fault or bad guys.

(3) Elevator equipped with loudspeakers, can transmit the contents of the public broadcasting system or into the emergency broadcast.

In addition, there are also some important places into the elevator door access part of the regional control, usually in the elevator Hall door or lift is equipped with a card reader, card determines the identity of passengers, to decide whether to run or elevator elevator dock floor. In short, our present in the elevator control and weak current combination of high technology and applications is still at a relatively low level.

II. application of elevator monitoring technology and development direction

Elevator monitoring is the intelligent construction the building automation management system component, the elevator monitoring technology is the building automation management system standard for a basis. Elevator monitoring technology from long-term goals or short-term objective is to design and from the system of single application level two aspects to be taken into account.

First, from system design perspective, the elevator control better long-term objective is to enter the social model of intensive management, at least a regional management model, the advantage is you can each elevator manufacturing, installation and property vendors of products and services of the standard and quality specifications, to various suppliers in an open, fair and equitable conditions of competition, thus improving the quality of their products and services, and makes the overall efficiency greatly improved, costs significantly reduced. Ultimately provide a cheap, safe and comfortable riding the elevator service. To achieve this goal, the Government, or harmonization norms unemployment departments to each vendor's product and service standards and quality.

From our current situation, the lift must be from a technical specification for each elevator supplier provides a unified communication and communication protocols, and technically should not be a problem, and the current main elevator manufacturer is possible even if the computer is not affected by outside interference, you can use a standard protocol for communication to provide lift for running or receive instructions from an external control. According to China's national conditions, and elevator monitoring implementation of the social intensive management go a long way, its main obstacles from two aspects: one is my current property management model is essentially closed small operation, without the elevator monitoring as social intensive management of demand and cries; the second is my existing elevator between various brands has a unified communication protocol, weak monitoring required software and hardware have not been harmonized specifications, many or even the basic configuration. If you want to make social intensive management, improvement of the existing elevators will be significant workload.

So, now on elevator monitoring for the time intensive management of society is not yet mature, but use weak control of high-tech achievement of elevator monitoring is, after all, the future development trend of elevator monitoring regional or social intensive management in our country is also not very far away, to this end, calls on the Government sector and the elevator industry parties, should pay attention to the development direction of elevator monitoring, research, from the standard specification for the design and manufacture, installation, maintenance and so on each link to do some basic work.

Take the elevator car in case of camera-monitor: from the elevator markets of China, the elevator car camera monitoring device in the elevator supplier does not have as a basic configuration of the elevator or optional configurations to consider, so it is usually in the design or manufacturing process is not considered their best recommended scenarios, often based on the temporary additional requirements. The device has a weak electricity supplier in the elevator after installation, the principal Installer during installation, because there is no good solution to standardize the operation of the parties, the effects of unsatisfactory for many, mainly in the following areas:

(1) camera selection not ideal

Elevator car installation of surveillance cameras should be considered and the car's overall coordination and elegant decoration and the hidden, it is advisable to select a roof installation of elevator dome cameras, this camera with a wide-angle lens compact structure, handsome in appearanceAnd concealment. But most of the elevator car installation of ordinary gun camera, the camera directly installed in the cabin top, top of the car, making a hole in the lens exposed. As a result of improper selection of camera, leading to the top of the lift decorated very inconsistent, if the installation doesn't fit hole is even more is needed.

(2) improper camera video cable selection

Elevator monitoring camera video cable should use elevator soft video cable, guarantees that the impedance matching, the television, cable service life is long, and the video cable, power cord, and so video cameras should be done into the accompanying cables, avoiding the elevator runs up bad cables, thereby improving the reliability and service life. Many projects are using ordinary video cable suitable for cable and cable break life shortening, and film and television effects are generally not good. Moreover, no video and radio-frequency cables, of course, this is not acceptable.

All in all, the current firstresponse involving elevator monitoring of communications technology, cabling, security equipment, automation technology, research, specifications, and by borrowing other weak current industry standards, or by the individual to develop standard, elevator to reach unity, enhance individual single elevator monitoring application level, to standardize the elevator control system design. Thereby the further realization of elevator monitoring design become part of the overall design of the elevator, Elevator monitoring design become part of the design of the building automation. In the elevator manufacturing, installation and maintenance also correspondingly increased, implementation specifications, and elevator monitoring device configurations serialized, standardization, then elevator monitoring device will become a unified standard and unified interface of elevator equipment basic configuration items or matching entries, people need to realize the elevator monitoring of regional management and community management is very easy.

【 Weak current College 】 heat pump water heater problem-based-2

12. do you need regular charging refrigerant?

Do not need. Air-source heat pump unit and the like are sealed parts fridge, when used in the delivery of the user pressed the quantitative filling good refrigerant, users without own charge.

13. why heat pump hot water unit than the electric water heater or gas water heaters more effective?

General heating method is the direct use of energy to heat the water, the water heater efficiency of energy use is approximately 95%, natural gas is about 75% of the heat pump unit is used electric energy to drive the compressor, and not used directly for heating water, the heat actually come from the environment.

14. why from the environment to absorb the heat will make the heat pump has greater efficiency?

Heat pump with 1 power can learn from the environment 2-3 servings of free energy, reuse these heat heating water, consumption of 1 copy of the power is also used for heating and hot water, so ultimately enables the thermal efficiency of up to 300%-500%.

15. do I need to provide room?

No, the heat pump unit can be placed anywhere that you specify, not building beautiful, with little space, without direct lighting, the installation is very easy to open display, also can be placed in the inconspicuous corner or to the library, and can realize unmanned operation, automatic control temperature water.

16. heat pump unit can be used to what place?

The scope of application of the heat pump unit is very extensive, with specially designed for hotels, restaurants, schools, hospitals, sauna, beauty salon, swimming pools, laundry room, and other design of various types of business machine, specially designed for families of various types of household machines, and free access air-conditioned, can realize heating.

17. If using multiple heat pump, one out of the question whether the whole system?

Is not affected. Air-source heat pump unit with modular functionality, using parallel operation, each heat pump unit can be controlled individually, even if one is causing the problem, when the maintenance does not affect the normal operation of the other units.

18. heat pump can use low price?

Can, and is automatically controlled. Air-source heat pump unit are designed according to user's use of hot water quantity disposition appropriate insulation tanks, heat preservation water tank has good thermal insulation effect, while air-source heat pump unit with a scheduled start-stop function, which can in the bottom price stored in the preparation of hot water when warm water tank.

19. each model how the heat pump water tank with?

Because of the heat pump output load is relatively small, slow producing hot water, heat pump unit is the first system of hot water preparation at any time, not only by water, water tank, hot water production is based on the user's daily water design, design capacity is large enough, you can implement a 24-hour continuous water supply.

20. heat pump operation is stable?

Runs very stable and reliable, air-source heat pump is designed with high-voltage protection, anti-freezing protection, exhaust temperatures and excessive protection, water temperature is too high and low temperature protection, water protection, water protection and compressor switch and stop delay protection.

21, household heat pump water heater which features?

Air-source heat pump hot water unit home machine there are many models, it is a specially designed for upper-middle-income families of new high-efficiency, safety, environmental protection, families with superior performance, central water heater as its main features:

1, pressure tank design: hydraulic foot, hot and cold water pressure automatic balance;

2, split-design: easy installation;

3, microcomputer control: automatic operation,

4. any combination of tank host: meet individual needs.

22, household heat pump water heater water tank how selected?

Heat pump water heater water tank according to user actual consumption of water a day, at the user acceptance conditions, advise the user to choose a type of tank, the average family: 1-2 people, with 150 or 200L tank (100L/person); 3-4 people, with 200 or 2 × 150L tank (80L/person); 5-6 people, with 3 or 2 × 200L tank (70L/person).

23, heat pump products and the advantages of a boiler in comparison?

1, high thermal efficiency: the average thermal efficiency of products in more than 300%, and the thermal efficiency of boiler will not exceed 100%.

2. low running cost: with oil, gas boilers, annual average to 70% of the energy section, plus the price lower and fuel price increases, low operating cost advantages have become increasingly prominent.

3. environmental protection: heat pump products without any combustion emissions, refrigerant use environmentally friendly refrigerant R417A, zero pollution, the ozone layer is a better environment-friendly products.

4. run the security without the attendant: compared with fuel boiler runs absolutely safe, and automatic control without the need to staff on duty, saves personnel costs.

Modular Setup, easy to add devices: products using multiple units parallel installation mode, when water consumption increases, the user may at any time add device.

【弱电学院】特种设备培训存在的问题及几点思 --- Power By【中国弱电之家网】

考
特种设备安全培训教育是为普及特种设备安全知识，提高特种设备作业人员安全意识，掌握安全操作规程和技能，消除不安全行为而采取的一种必要手段，同时也是对职工进行有关特种设备的政策、法律、法规和规章等方面知识的教育。
特种设备安全是国家经济安全的重要方面，它直接影响到国家经济安全、可持续发展及社会稳定。作为世界上最大的发展中国家，我国又是一个特种设备生产和消费大国，经济的快速发展与特种设备安全的矛盾一直比较突出。长期以来，如何认识我国特种设备安全的基本问题，采取何种培训方式应对我国的特种设备安全，这是目前安全培训工作者值得思考的问题，本文从以人为本强化特种设备安全培训出发，就我国工厂企业特种设备安全培训中的若干突出问题作些探讨。
　　一、特种设备安全培训教育的主要内容
　　特种设备安全思想教育。主要是通过学习国家有关法律法规，提高管理人员和作业人员的政策水平，充分认识特种设备安全使用的重要意义，在特种设备的使用中严格贯彻执行“安全第一、预防为主”的方针政策，严格执行操作规程，遵守劳动纪律，杜绝违章指挥、违章操作的行为，利用曾经发生的重大事故案例及给社会、给企业、给家庭造成的损失，对职工进行安全意识教育。
　　特种设备安全使用技术知识教育
　　一是一般安全生产、使用技术知识培训教育。这是所有工人包括特种设备作业人员都必须具备的基本安全生产、使用技术知识，主要包括：A.危险设备和区域及其安全防护的基本知识和注意事项；B.有关电器设备的基本安全知识；C.生产、使用现场消防制度和规定；D.环境和职业健康安全知识教育；E.个人防护用品的正确使用以及伤亡事故报告办法；F.发生事故时的紧急救护和自救技术措施、办法等。
　　二是特种设备安全使用专业技术知识培训教育。包括特种设备从业人员必须具备的专业安全使用技术操作规程知识教育，以及在特种设备使用中经常出现或可能发生的事故方面的技能知识教育。
　　特种设备安全使用技能培训教育。包括作业技能、熟练掌握作业安全装置设施的技能，以及在应急情况下进行妥善处理的技能。
　　三是事故案例教育。通过实际事故案例分析和介绍，了解事故发生的原因、过程和现实后果，对认识事故的发生规律、总结经验、吸取教训、防止同类事故的反复发生起着较大的作用。
　　二、特种设备安全培训教育的重要性
　　一是特种设备安全培训教育能够提高特种设备作业人员的责任感和自觉性。特种设备安全培训教育工作是特种设备使用企业实现安全生产的一项基础性工作，是提高特种设备作业人员素质、保证安全生产的重要手段。通过特种设备安全培训教育，不仅能增强各级特种设备管理人员和相关作业人员对“三落实”、“二有证”、“一检验”的认识，提高他们对安全工作的责任感，而且能使他们提高自觉遵守各项安全生产规章制度的自觉性，增强他们的安全生产法制意识。
　　二是特种设备安全培训教育能够增强作业人员的安全知识和技能。对特种设备从业人员进行安全培训教育，保证从业人员具备必要的安全操作知识和安全操作技能，是保证企业安全生产的重要前提和基础。通过安全技术知识的培训教育和安全技术水平的提高，能使广大作业人员掌握各种伤害事故发生发展的客观规律，提高安全操作技术水平，减少人的失误，控制自身的不安全行为，使广大从业人员在安全意识上真正从“要我安全”向“我要安全”、“我会安全”的观念转变，从而达到确保特种设备使用安全，保护自身和他人健康的目的。
三、目前特种设备安全培训管理存在的问题
　　目前对特种设备安全培训的认识有误区。
　　一是重引进轻培训。有人认为企业培训既花钱又占时间,影响企业的生产和效益，还不如花重金从外部挖掘有用之才，能解企业人力资源不足的燃眉之急就可以，所以不愿派人参加培训。二是重成本轻培训。有些企业认为培训是企业出钱，个人长本事，成本投入为别人做嫁衣，所以怕出钱不合算，不愿派人去参加学习。三是重使用轻培训。特种设备安全培训是经常强调的事，你抓紧了我派人应付，你不提了我就不参加。所以企业采用先用人等你查到了再说。这些认识危害极大,使企业特种设备安全培训管理工作无法放在应有的高度以形成正常的培训管理体系和制度。
　　二是对特种设备安全培训的定位不清，导致培训与企业长期发展脱节。
　　特种设备安全培训的首要目的应该是满足企业长期发展的需要，然而现实中往往是企业没有将培训放在一定的高度来考虑，企业生产紧张了不培训，企业效益不好了不培训，安全方面不出事了不培训。与此相应最为明显的是，许多职工也就认为培训就是来应付差事，培训结束了事情也就了结了，培训根本没有与企业发展目标相联系。
　　三是对特种设备岗位安全需求分析不深入，对特种设备安全培训的重视度不够。
　　企业对职工的安全培训应根据生产需求进行科学、细致的分析，更应该对员工的工作岗位进行必要的重大危害性分析和评价，充分认识岗位的危险因素和发生事故的机率。部分企业管理者把日常管理的重点放在企业的重要岗位上（如流水线上），而不是放在危险的岗位上（如锅炉），他们可以聘请高级管理人员管流水线，而不肯花钱培训几个高层次的锅炉工。这就是企业中安全需求和生产需求发生矛盾的时候，片面强调了生产需求而忽视了安全需求，造成了全面的对特种设备安全培训的重视度不够。
　　四是与国外企业相比，我国企业培训投资太少，使培训管理受到严重制约。
　　据有关资料显示：近年来美国公司用于员工培训的投资已占到全美培训投资的一半，且以每年5%的速度递增,每个员工平均每年接受1～2次培训，而我国企业只有5%左右的企业加强了培训经费投入，20%左右的企业培训费人均仅为10～30元，30%的企业只是象征性地拨一点培训费，年人均在10元以下，其他的亏损企业已停止了投资。有些企业现在根本就不存在培训这一块，说是“培训社会化”。然而参加社会培训又是心不甘情不愿，不愿投资出钱，造成了对特种设备安全培训的严重制约。
　　四、特种设备安全培训的几点思考
　　一要把重视人的生命视作为工厂企业特种设备安全培训的第一需要。
　　国务院颁发的《特种设备安全监察条例》第一条就明确定义：特种设备是指涉及生命安全、危险性较大锅炉……设备。为了防止和减少事故，保障人民群众生命和财产，促进经济发展，特制定本条例。
　　因此，我们要时刻注重人的生命，要把重视人的生命视作为工厂企业特种设备安全培训的第一需要。特种设备培训除了要强调设备安全、环境安全、更应该强调人的安全。特种设备的安全培训理念是要把员工的生命安全放在第一位，当人身安全与经济利益或其他的安全发生冲突时要无条件地服从人的生命，所以，特种设备的安全培训的重点在保护人的生命安全。
　　在特种设备安全培训做法上，如介绍电梯，除了介绍电梯的的基本结构外，更应该介绍操作、使用、乘坐电梯时采取哪些措施来保护人的生命安全，采取这些措施（安全装置、安全防护装置、安全报警装置、安全保护措施）为什么能保护人的生命安全，哪些措施失效时会使人的生命安全受到严重威胁，日常运行管理中应重点放在哪几个方面？通过对特种设备安全培训学习，真正使特种设备的作业管理人员懂得尊重人的生命价值，明白设备对人的生命安全威胁的程度，以及采取措施保护人的生命安全的重要性。从而进一步增强自身责任感激发人们对特种设备安全知识学习的重视。
　　二要用人本主义理论和实践指导特种设备的安全培训。
　　按照新颁布的《安全生产法》第三章“从业人员的权利和义务”的规定，生产经营单位的职工(从业人员)享有的安全生产保障权利主要有：(1)知情权，即有权了解其作业场所和工作岗位存在的危险因素、防范措施和事故应急措施；(2)建议权，即有权对本单位的安全生产工作提出建议；(3)批评、检举、控告权，即有权对本单位安全生产管理工作中存在的问题提出批评、检举、控告；(4)拒绝权，即有权拒绝违章作业指挥和强令冒险作业；(5)紧急避险权，即发现直接危及人身安全的紧急情况时，有权停止作业或者在采取可能的应急措施后撤离作业场所；(6)依法向本单位提出要求赔偿的权利；(7)获得符合国家标准或者行业标准的劳动防护用品的权利；(8)获得安全生产培训和培训的权利，等等。那么，我们是否从人本主义观点出发，在工厂企业特种设备安全培训工作中加以讲清、讲明、讲透，让职工真正明确自己在特种设备作业中具有哪些权利，得到哪些权利，需要哪些维权。以便他们在特种设备作业中更安全、更放心。
　　三要将危险隐患识别和评价的知识加入特种设备安全培训中去。
　　俗话说：“授人以鱼，不如授人以渔”。在特种设备的安全培训中要大力宣传对特种设备作业危险隐患进行识别和评价的目的、作用，以及对识别和评价结果的整改活动，提高工厂企业全员的安全意识和安全行为观念；要主张在生产岗位上广泛开展安全检查和危险源预知活动，要发挥员工的积极性，在生产岗位上组织自查。另外，结合公布“危险隐患”，动员工厂企业员工查找自己岗位上可能的危害事故致因根源，或可能发生的伤害。使他们养成：“上岗时不是先急着去完成任务，而应当先看一看、想一想、问一问今天的岗位能否引起对他的伤害，怎样操作才能做到安全生产”。如果每一个员工都能掌握特种设备作业危险源的识别和评价，都能把特种设备安全作业作为主动的行为，这就是特种设备安全培训的真正目的，安全生产才能落到实处。
　　四要审时度势，加快发展，进一步搞好特种设备安全培训工作。
　　目前，各地市特种设备安全教育发展不平衡，或者缺少综观全局的有权威性的战略规划。因此，建议有关机构在进行深入调查研究、科学分析的基础上，加强统筹安排与协调发展，尽快制定出我省特种设备安全教育发展纲要，为工厂企业特种设备安全培训健康发展打下基础。
　　其次要和政府安全教育宣传工作充分融合，利用其他安全管理职能部门的工作平台，积极参与开展特种设备安全教育宣传工作，宣传工作是完善培训工作的一项基础性工作，宣传工作做的好，将会营造出良好的特种设备管理氛围，使特种设备使用单位走上自主管理参与培训的轨道。
　　当然，我们还要结合具体情况注意抓好两个层次上的工作。第一个层次是“面上”的工作，即力求做好发证考核教育。第二个层次是“提高”工作，即在企业的管理层面，要从讲政治，打造平安福建的高度，提高个人对特种设备安全的认识。只有这样，我们特种设备安全培训才能创出特色来。
特种设备安全培训教育是适应安全生产工作的需要,也是加强安全生产监督管理、预防和减少各类伤亡事故的治本措施之一。因此，相关管理、考核、培训教育部门和企业一定要高度重视，用高质量的特种设备安全培训教育为安全生产的稳定提供强有力的保障。

【 Weak current College 】 on central air conditioning system and energy-saving

Summary: with the development of China's economic construction, central air conditioning more Purdue, central air conditioning energy consumption problem is increasingly important. This article from the project "life cycle" perspective, discusses the significance of the central air-conditioning energy saving and status from the engineering, engineering design, project construction and operation of management made a number of energy-saving measures and methods.

Key words: central air conditioning energy consumption and energy saving measures

1 Introduction

In all types of buildings, extensive use of advanced equipment and the appropriate equipment and central air conditioning system has become an important modern construction technology mark of modern architecture to create a comfortable and efficient working and living environment-an essential critical infrastructure. On these devices for the design, installation and operation of management not only directly related to the owners and the interests of users, but also on the Department of environmental protection. For example, in the intelligent construction, the central air conditioning system of monitoring points number often account for floor control point more than 50 per cent of the total, its energy consumption often account for the amount of total energy consumption, 5o%. Thus, the central air conditioning system in modern architecture is extremely important especially in modern intelligent building, central air conditioning system is indispensable. Thus the study of central air-conditioning system power consumption is especially important for significance. On the air conditioning system energy consumption of objectives to be achieved is how to create a good indoor small environment of use of energy, on the external environment of the minimum damage. to achieve the long-term objectives of sustainable development. The research was a very wide range of topics involving many disciplines.. This article from the project "life cycle (circlelife)" point of view, from the project status, engineering design, project construction and operation of the management of the central air conditioning system and energy-saving measures and methods.

2 practical engineering problems
Air conditioning project implementation is a systems engineering, it involves all relevant specialized in design and construction process in close coordination. While air conditioning projects mainly depends on the correctness of HVAC professional design and construction of rationality and air conditioning professionals. But in the more practical engineering, air-conditioning projects exist many problems. About the causes of air conditioning profession itself is not in this for detailed analysis.

This article only on the air conditioning engineering problems in the automatic control system for analysis, because along with the development of intelligent buildings, air conditioning air-conditioning automatic control system is an integral part of the system, and run the air conditioning system plays a key role. Air-conditioning automatic control system while increasing one-time investment, but can maintain good indoor environment on the basis of save operating costs. A design platform and run well-managed automation system can significantly save operating costs, so that the owners in a relatively short period of time to recover control system of an investment-you can substantially reduce the impact of the external environment. But because of the design and operation management reasons, most of the automatic control system, the design goal. Beijing Association have organized to engage in automatic control, computer, communications, air conditioning, and other experts on the development of intelligent buildings and technical connotation research went to Beijing as an example, the statistics user on building automatic control system operation of the evaluation are: satisfaction of only 30 per cent of the average total Pak per cent difference has accounted for 30 per cent. This state of affairs in addition primarily due to the low level of property management, automatic control design and air-conditioning design seriously. Air-conditioning automatic control system of project implementation are generally the following works: by the Design Institute of HVAC design professionals, and air conditioning air-conditioning automatic control requirements, and then submitted to the Institute of automation professionals air-conditioning automatic control design, or by automatic control equipment manufacturers to control part of programme design and construction drawing design, construction units installed debugging. Finally surrender to property management again for operational management. Therefore involves designing, construction unit and automatic control equipment manufacturers and decisions and control of building owners, etc. In these areas should form a close match Tai, but practice shows that the important links are often not very ideal convergence, legacy in the future, to the building automation system uptime and energy-saving effect have serious impact.

3 establish a system of energy-saving concept. Select sound design programme

Realization of the fundamental way air-conditioning energy saving lies clever use of indoor and outdoor conditions, maintenance structure and interactions of air conditioning equipment, select meet building energy efficiency requirements of the programme, both electricity made comfortable, efficient indoor environment, while at the same time the aim of achieving significant energy saving.

3.1 determination of indoor temperature.

The Chongqing, Shanghai, Guangzhou and other areas of practice shows that summer indoor temperature low 1 ° c or 1 ° c, in winter the high investment will increase 6% of energy consumption increased 8 per cent, and increase the indoor and outdoor temperature difference also hygienic requirements inconsistent with Taiwan. Comfort air conditioning in summer ideal indoor temperature is lower than the outdoor temperature 5-8 ° c as well.

3.2 envelope.

Air conditioning cold (hot) load can be divided into the envelope of cold (hot) load and Interior cooling (heat) load. The following terms from energy-saving doors and Windows-. Control window wall ratio: the window heat consumption accounted for the total heat loss in buildings 35%-45%, to ensure good indoor lighting, reasonably determine ratio of the wall is very important. As a general rule all toward the window wall ratio shall not be greater than the following numbers: 25%; in the North to the East and West to 30 percent; South to percent. Improve Windows tightness: room ACH by 0.9/h to 0.6 times the energy consumption of buildings/h, reduces the 8 percent, the design should be airtight good doors and Windows, and an additional seal is improving door air tightness of the important means to seal shall use good elasticity, with strict, received solid durable products, according to the specific situation of doors and Windows, using different seal, such as rubber, plastic or rubber seal on the combination of its shape can be a bar or a flush. Fixed method available paste, packed tight or nail knot.

3.3 air-conditioning heat and cold sources

Central air conditioning energy consumption generally consists of three parts, namely (1) heat source; (2) air conditioner terminal equipment; (3) water or airConveying system. This three-part, heat energy, or about energy consumption, total energy consumption is 50 percent. conditioning of important content. If you are putting their consumption of energy is converted into an energy source, preparation units are available once per time unit energy consumption by energy production volume of Ling or heat. This article uses the "once energy efficiency OEER (W/W) to indicate the energy consumption from units perspective. summer refrigeration: centrifugal and screw chiller O Mong R value maximum. absorption chiller OEER minimum; winter heating: screw, piston-type heat pump chiller OEER Supreme electric hot water unit minimum. i.e. the maximum energy consumption.

3.4 air-conditioning system.

General air conditioning water system of transmission and distribution of electricity, heating in winter period asked about the entire building power electricity 2o%-25%, in summer cooling period accounted for 12 percent to 24 percent of the energy-saving water system therefore has important significance for the present, the air conditioning system designed for a number of questions:

(1) select the pump is the design value find pump sample nameplate parameters, rather than by the pump performance curve selected pump models;

(2) not to carry out each water loops, hydraulic equilibrium calculation for pressure differential vastly circuit did not take effective measures, hydraulic, misadjustment phenomenon seriously;

(3) large capacity, small temperature difference widespread, design temperature for, backwater, but generally take 5cC, as measured in the summer the temperature of the chilled water return water is better for 35, poor only 1.5 ~ 2 ° c, resulting in the actual flow of water over the design of large 1.5 times so that the water pump power consumption increased significantly. Therefore, the energy-saving air-conditioning system shall be started from the following aspects into consideration:

(1) designers should pay attention to the water system design, serious water system loop calculations, and to take appropriate measures to ensure loop hydraulic balance;

(2) carefully proofread and calculate the correlation coefficient of chilled water system, the practical implementation of energy-saving design standard value, the active promotion of frequency he speed pump, winter and summer dual-speed pumps and other energy-saving measures; (3) of the refrigeration system cooling water inlet temperature of the high power consumption to host the di {has an important impact in General, certain cases, water inlet water temperature high 1 ° c, high energy consumption lithium bromide absorption chillers.

3.5 air-conditioning unit and terminal equipment

Home-fan-coil and from looking at the overall level of similar foreign products compared to the same, but the comparison with foreign advanced level of the main difference is the power consumption, coil weight and noise. Therefore design must pay attention to selection of light weight, unit fan power for carrying (hot) the unit quantity too. Air conditioning units should be chosen unit fan and air pressure matches the rational, less air leakage, air crew transfer coefficients too. Chen points, depending on the project, actively promote water-loop heat pumps, heat recovery, VAV, vwv and other energy-saving technology.

4 run management

4.1 do equipment and pipe insulation to reduce energy consumption of excessive air conditioning equipment and piping heat insulation, for savings in energy consumption, lower operating costs is also very important. If the insulation effect is not good or repaired insulation repair is not good, not only excessive consumption of cooling capacity, also due to the cold water temperature caused by excessive temperature rise on the air conditioning system in the process was unable to guarantee its dew point and allows the machine an air conditioned room relative humidity is exceeded.

4.2 regularly on air conditioning system water treatment

Water side of dirt, corrosion and MOSS on the impact of the refrigeration system is also extremely large air conditioning energy consumption levels of important reasons too dust in the air, water, bacteria, oxygen and certain harmful acid gas continuously from cooling tower into ^ cooling water system, although Bay refrigeration system, the more confined water of dissolved oxygen on frozen pipes also produce corrosive effect, cumulatively, air-conditioning equipment will produce dirt, rust, rust residue and microbial fault propagation resulting biological sludge, pipe plug, cooling capacity loss, waste of energy. According to the theory of computation, cold suspected of dirt, each additional 0.1mm, heat efficiency to reduce the electricity consumption of 30 per cent, an increase of 5-8 per cent.

4.3 central air conditioning for metering and charging

Central air conditioning for metering and charging is building a basic energy-saving measures in Europe and the United States from Xiao-is-f} mature technology. According to foreign investigation data show: centralized air conditioning metering and charging, the energy saving rate of up to 8 per cent to 15 per cent.

4.4 operation training

Strengthening air-conditioning operator staff training, improve management quality, air operators operating permit system. The regulation and implementation of energy saving measures, and operations staff are directly related to the technical quality.

5. concluding remarks

Reasonable design, careful construction and science of management on air conditioning energy is vital. Owners are advised to make early in construction management personnel selection and training necessary to hire experts to enhance all aspects of the construction process or even the entire process (from the design of the system operation) of supervision, to ensure the completion of the central air-conditioning system should at least be able to run properly, and thus pursue a degree of energy-saving, on this basis to implement comprehensive Optimizer runs in order to achieve maximum energy saving effect.

【 Weak current College 】 LIBR cold failure causes and prevention methods

A refrigerator cold lithium bromide produced cold failure reasons
Cooling failure refers to refrigerator cooling capacity diminishes with time, and the cooler itself manufacturing and operating conditions, usually about 1% per year. If the year cooling failure rate is 3% to 5%, that is seriously cool failure; if more than 10%, the nameplate values and after repair is still more than 10%, which indicates that the unit performance has been poor.
Chillers with cooling failure and tightness, water quality stability, solution, pumps, etc, they affect the vacuum unit, the amount of heat, inner circle, so that the cooling capacity.
1.1 tightness
LIBR require vacuum in 100Pa following, guarantee the refrigerant evaporating. Vacuum degree higher cooling capacity. Therefore, the unit running process if the tightness is affected, thus affecting the vacuum, the impact of refrigerating capacity.
Impact unit air tightness: ① ② seam sealing; heat exchanger tubes expansion; ③ valve, pump, sight glass sealing.
1.2 water stability
And lithium bromide refrigeration units run related media with cooling water, chilled water, water vapor. Steam from the boilers, water treatment, generally will not have the scale, algae, sediment, water quality can be guaranteed to have no effect on the generating units. Unit runs, operable on gas is going to take a portion of the water, the system expansion and contraction will also have some water loss. In order to ensure the unit correctly, add water, generally run 24 hours to add more than 10 kg of water, add content, and to the unit operation. Cooling water is obtained by cooling towers, evaporative capacity up to 1% to 2%/h. 24h unit operation, would add a lot of water for cooling water, water quality due to higher requirements to ensure that non-scaling, non-corrosive, not long, not health mud, otherwise it will affect the unit heat effect, thus affecting unit refrigeration capacity.
1.3 LIBR
In LIBR refrigeration units, average concentrations of aqueous solution of LIBR around 55% for heat and mass transfer and loop running. LIBR aqueous solution of quality directly affects the capacity of the refrigerating unit, its PH value and inhibitor is a key unit corrosion protection because they absorb the heat pipe surface after affect heat effects; and corrosion of impurities can clog the spray nozzle, leaching shock plate hole, thereby directly affecting the spray effects; at the same time, the impurities can clog the tubes and shielding pump strainer, directly affects the amount of solution cycle; if impurities into the shield pump, affect the shield pump rotation and mobility solution; if the shielding pump cooling fluid channel is blocked, you will burn out canned motor pump.
1.4 shield pump
Canned motor pump in LIBR refrigeration units in like a human heart, is the moving part, itself a performance decline. Without regular maintenance, or shield pump their own poor performance, all affect the solution cycle, resulting in the cold.
In addition, cooling towers, pumps, steam, fuel oil, gas, and also on the cooling capacity of the chillers.
Prevention of secondary cooling failure
① in product manufacturing process strictly "clean seal". Clean, prevent impurities and dust during the manufacturing process into the unit itself, and in the manufacturing process is completed with clean air and clean water cleaning unit. Seal, is the guarantee that the service has no welds, heave. Should increase gas tightness requirements, and nitrogen cover the total leakage detection method.
② the strict control of impurities and lithium bromide solution PH value. Use a better effect of lithium do inhibitors. To periodically check for solution of total impurity, pH, lithium content and octanol (energy enhancers), ensure that the requirement range.
③ choosing quality of pumps, valves, sight, and mount the unit prior to the effective detection, who do not meet the requirements.
④ regular detection of cooling water. If water quality is poor, and Nalco and algaecide and pipeline install electronic descaling Miriam. Each season run before joining of chilled water, the water must meet the requirements necessary to undergo treatment.
⑤ for cooling towers, pumps and other auxiliary equipment, in addition to selection by product specification, also carry out regular maintenance and inspection.
⑥ If found unit leaks, to detect leaks and repair welding, fill expansion, replacement parts, repair, at the same time air tightness test to achieve the required targets.
⑦ cooling water, chilled water pipeline scaling, through mechanical cleaning and chemical cleaning washing lines, so that the pipeline remains good heat effect.
⑧ by impurities filtering purge, Hydrogenation of Lithia adjustment of the pH value, plus maintain solution of lithium inhibition, Octyl enhanced cooling capacity, regeneration solution.
3 conclusion
LIBR cold failure is objective and existent, lightly. If taken seriously, take effective measures, it is entirely possible control.

【 Weak current College 】 family central air-conditioning design guideline (2)---Power By 【 China power house network 】

4.3 air handling and distribution
4.3.1 air-conditioning system air supply and return air clean filter processing.
4.3.2 indoor air distribution should be sent back on the way, when using the side sent back to the wind when it lay on the same side of the air below it. People should be in the air reflow, indoor air flow layout should be uniform, avoid dead ends.
4.3.3 air conditioning in the summer the temperature of air should not be greater than 10 ° c
4.3.4 room air conditioner air cycle should not be less than 5 times/h.
4.3.5 air velocity shall be based on a range of air, air, air outlet type, installation height, indoor noise and wind speed criteria allowed, etc. The noise requirements in place select wind speed in the following table:
Select a table in table 4.3.5 wind speed (m/s)
Indoor allow noise DB (A) main duct of the wind speed branch duct velocity outlet velocity (diffuser) 25 ~ 35 ≤ 2 ≤ 1.6 ≤ 0.8 ≤ 40 ≤ 3 ≤ 2.4 ≤ 1.2 ≤ 45 ≤ 4 ≤ 3.2 ≤ 1.6 ≤ 50 ≤ 5 ≤ 4 ≤ 2 ≤ 55 ≤ 6 ≤ 4.8 ≤ 2.4 ≤ 60 ≤ 7 ≤ 5.6 ≤ 2.84.3.6 back outlet should not be located in the Jet area or personnel long-term stay locations, use the focus back to the wind or walk back to the wind, the wind speed section, should not be greater than 0.5m/s. 4.3.6 to wind speed table choose the table back into the air outlet location suction speed m/s room upper 4 ~ 5 rooms close to the lower part is often where 3 ~ 4 near people often linger 1.5 ~ 2.0 for corridor air time 1.0 ~ 1.55 equipment, pipeline and arrangement
5.1 General provisions
5.1.1 equipment and piping material selection and arrangement should be consistent with national current norms, standards, regulations and requirements of local standards.
5.2 equipment materials selection
5.2.1 preferred environmental protection, energy saving air conditioning products
5.2.2 duct must be non-combustible material. When using the composite duct, the cladding material should be embarrassed burning B1 level. And harmless material.
5.2.3 rectangular duct of the aspect ratio is not greater than 4: 1.
5.2.4 condensate pipe U-PVC plastic pipe should be adopted.
5.3 equipment piping layout
5.3.1 family conditioning of machine must be placed in a well-ventilated place, safe and reliable, no use of steel bracket and expansion bolt mount on the wall.
5.3.2 on buildings near the road to install air conditioning outside the machine, its pallet bottom margin, height required 2.5m.
5.3.3 outdoor machine outlet is strictly towards adjacent side of doors and Windows, the installation location is adjacent to the bedroom door and window must not be less than the following horizontal distance.
1, machine installed capacity for 3m ≤ 2KW.
2, 5KW external machine installed capacity for 4m ≤.
3. external machine installed capacity for 5m ≤ 10KW.
4, machine installed capacity of 30KW is 6m ≤.
5.3.4 outside the walls of air-conditioning condensation water pipes should be organized.
5.3.5 condensate level tube should > 0.5% downslope.
5.3.6 air-conditioning condensation water drainage methods should be used indirectly. When the condensing pressure zone is set, the condensate outlet takes over Office must set the water bends.
6 preservation and insulation
6.1 anticorrosion
6.1.1 all non-galvanized iron fittings shall be rust after second brush antirust paint, non-thermal insulation outer surface second harmonic colour paint brush.
6.1.2 piping hangers and must be treated wood impregnation asphalt pads.
6.2 insulation
6.2.1 air conditioning pipes, ventilation pipes, cold or hot water for the return pipe, refrigerant pipes, water pipes, expansion tanks, heat storage (cold) water tank, heat exchanger, electric heater, etc. have cold, heat losses or condensation possible equipment, materials and parts required insulation.
6.2.2 non-closed-cell insulation of the external surface should be set trap layer and layer of protection.
6.2.3 insulation pipe brackets, wall or floor should prevent "cold bridge".
6.2.4 equipment and piping insulation should be based on the equipment and pipe cooling design guidelines (GB/T15586) dew calculation method to determine the thickness of the insulation layer.
6.2.5 insulation should be non-combustible and nonflammable materials.
6.2.6 through firewalls, both sides of the deformation joint 2m range of air ducts and air-type electric heater 0.8m range before and after air duct insulation must be non-combustible materials.
6.2.7 refrigerant piping insulation should be manufacturers of construction technology requirements.
6.2.8 about water temperature is 7 ~ 65 ° c with cold and hot water pipe insulation and its thickness should not be less than the table 6.2.8
Table 6.2.8 air-conditioning heat and cold water pipes minimum insulation thickness (mm)
Tube via DN ¡ü 2025 ~ 3240 ~ 507080100 ~ 125150 ≥ 200 rubber insulation glass wool Interior 27.530323535383841 outdoor 3535384141444747 insulation tube shell indoor 3030404045454550 outdoor 4040455055556060 Note: 1, only applies to Jiangsu and Shanghai area hot summer and cold winter, the canal water temperature is 7 ~ 65 degrees centigrade.
2, 20 ° c thermal conductivity of plastic, rubber into ≤ 0.04 (w/m.k), moisture resistance factor is less than 800
3, 20 ° c in centrifugal glass wool tube-shell heat conductivity in ≤ 0.042 (w/m.k), density is 64kg/m3.
The complex calculations, Jiangsu outdoor environment than Shanghai outdoor environments as well, the insulation thickness is less than Shanghai, Shanghai, Jiangsu can form.
7 monitoring and control
7.1 General provisions
7.1.1 family household central air conditioning system should be a separate monitoring and control system, automatic content should technology comparisonOK, to simplify, accurate and reliable.
7.1.2 automatically control the use of electric, supplemented by manual function.
7.2 detection and signal display
7.2.1 in the facilitate the observation, set test display device.
7.2.2 display parameters are as follows:
1, indoor air temperature, outdoor air temperature.
2. send and return air temperature.
3. air conditioning system energy independent measurement of the instantaneous measurement, dispensing and peak-time measurement.
4, the return water temperature.
5, fans, pumps, heaters, and other devices running state display.
7.2.3 air-conditioning system sensitive components and testing component installation locations, should meet the following requirements:
1, indoor and outdoor air temperature: should stay away from a heat source locations, to be representative.
2. send the backwater temperature should press factory installed.
7.3 regulation and control
7.3.1 air-conditioning systems of regulation, should be the user's control precision requirements.
7.3.2 air-conditioning centralized control system should have the following control elements:
1, equipment Kai Ding control system and interlock control.
2. equipment running status monitoring and fault protection.
3, parameter setting and display.
4. implementation of components of the control.
7.3.3 the design-time, system monitoring content selection should be based on usage requirements, user management level for technical and economical comparison.
7.3.4 when using vwv, use 2-way valve and frequency conversion water pump.
7.3.5 freeze in the winter there may be areas of new fans and air conditioning units, water coil, frost protection measures taken.
7.3.6 air conditioning and ventilation equipment should be independent of the power circuit.
7.3.7 duct heater with fan interlock, forced draft fan should delay off feature, and should be set no wind power failure protection, electric heater of wind pipes should be ground.
Choice of automatic control valve 7.3.8 should meet the following requirements:
1. water 2-way valve, with equal percentage characteristic.
2-way valve, water, use of parabola properties or linear characteristics.
3. differential pressure regulating valve of imports and exports should be consistent with the relevant provisions of the manufacturing plant and should be selected by calculation.
8 noise and vibration isolation
8.1.1 muffler design should be consistent with the civil code for design of building sound insulation (GBJ118-88) and the urban regional environmental noise standards (GB10070-88), etc.
8.1.2 anti-vibration design should comply with the urban regional environmental vibration standards (GB10070-88).
8.1.3 selecting equipment and system design, noise reduction measures should be taken of the following:
1. Select the device with high efficiency and low noise.
2. air pressure option must first evaluates the rich content should not be too large.
3. fan the use of direct transmission mode.
4. blower outlet and return to the duct outlet should not be sharp bends and adjustable.
5, elbow, three links Department Yishe Distributor, as few installed or not installed control valve.
6. when the requirements of the muffler, muffler devices installed.
8.1.4 wind tube of wind to chosen in the following table. (See table 4.3.5)
8.1.5 air-conditioner room settings should stay away from high vibration noise requirements in the room when the room has an impact on the room, you must use sound, vibration, noise, sound absorption, and other measures.
8.1.6 muffler yishe in air conditioning room, noise elimination of air pipe should not be affected by high noise or sound insulation measures should be taken.
8.2 noise and sound insulation
8.2.1 air-conditioning equipment of the sound power level, the use of the measured value.
8.2.2 Select muffler, according to the system the amount of the required noise, noise frequency characteristics and muffler acoustic performance and aerodynamic characteristics and other factors, the use of impedance compound muffler.
8.2.3 muffler to layout in airflow stable straight pipe, when necessary, also in the main and branch on settings to prevent crosstalk between the rooms.
8.2.4 room sound insulation of doors and Windows and doors should be used.
8.2.5 pipeline through wall Department must use elastic material compacting fill its gap.
8.2.6 duct connection should avoid sudden expansion or contraction connections, three links should not be used T-Word, pipes and competent connections used 45 ° clockwise flow direction of connection, the connection with the duct outlet should set the diffusion tube.
8.3 isolation
8.3.1 fan, water pump, and heat source equipment, air conditioning terminal devices and wind pipe pipe hangers should consider isolating vibration reduction measures.
8.3.2 speed when the device is less than 1500r/mm, to choose spring damper, device speed greater than 1500r/mm up to date with rubber shock absorber or vibration isolation pads.
8.3.3 using isolator should be isolator manufacturers, determined by calculation, isolator and Foundation should add a layer between elastic vibration isolation pads.
8.3.4 have vibration of equipment and systems connected duct, pipe, hose connections should be adopted. And the fire.
8.3.5 piping hangers hangers should be flexible.

College】 【weak energy saving central air conditioning system for the analysis and summary --- Power By China's weak home 【Network】.

<br> <BR> Abstract: In 2005 the State to promote speed up construction of a conservation-oriented society, energy saving and become the focus of attention, so the application of energy-saving central air conditioning system control technology and the creation of conservation-minded society is significant. .In this paper, the key to the design of air conditioning control, air conditioning use in the process of energy conservation measures and management of three central air-conditioning, energy-efficient central air conditioning system was analyzed and summarized for the central air conditioning system to provide a meaningful view of energy saving .. .<BR> <BR> Keywords: central air conditioning; energy; measures <BR> <BR> Introduction With the economic and social development, central air conditioning in commercial and residential buildings of more and more widely, central air conditioning is a modern building .indispensable power running system. .Central air conditioning system to provide comfort to people living and working environment, but also consumed a lot of energy. .With the power and the number of devices increases, the energy consumption is also increasing. .According to statistics, China's building energy consumption accounts for about 30% of total energy consumption. In buildings with central air conditioning, central air-conditioning energy consumption accounts for 70% of the total energy consumption, and the trend of increasing year by year [1] .. Therefore, the central air conditioning system of energy-saving technologies is of great significance, in addition to emphasizing the use of functional, it should also attach importance to energy saving factor, lower investment and operating costs. .<BR> <BR> 1. The key to the design of air conditioning control <BR> <BR> 1.1 <BR> <BR> design control cooling and heating loads in the central air conditioning system construction design stage, the heat load and must be itemized by .when the cooling load calculation. .Dynamic load calculation method should be used according to actual load to choose the appropriate hot and cold sources. .Because the system cold and heat source and equipment performance in part load energy efficiency have a major impact on the system, therefore, selection of equipment on the one hand, taking into account the specific design conditions, the system should also be stressed operating conditions and part load .system performance. .<BR> <BR> Design load of hot and cold air-conditioning system design is too large, selection of equipment did not fully take into account the load characteristics of air-conditioning system and equipment performance, air conditioning unit capacity, pipe diameter, pump configuration, terminal equipment design is too large, resulting in .investment, operating cost increases. .Air-conditioning system and many buildings are lower than full capacity, even in the hottest month of the air conditioning units are still idle. .Pump selection is too large or too large pump motor power matching, low-efficiency operation, a waste of energy. .Parallel operation of multiple chilled water pump, no adjustments based on changes in cooling load the number of open sets, but no matter the size of the cooling load, cooling load is switched on by the largest chilled water pumps, wasted energy. .<BR> <BR> 1.2 Control of air conditioning water system design <BR> <BR> mostly constant flow water system, the design water flow rate at the maximum cooling load and the supply and return water temperature difference 5 ℃ determined. .The actual prevalence of a large flow of small temperature difference and the maximum load appears little time, most of the time in part load operation, the actual temperature is less than the design temperature difference, the actual flow ratio of 1.5 times the design flow rate, greatly exceed the design flow, .pump power consumption significantly. .<BR> <BR> Designers should pay attention to water system design, for each water loop for hydraulic balance calculation, significant differences between the circuits on the pressure to take effective measures to ensure the loop water balance, avoid water, heat imbalances ., proofread carefully and calculated parameters of air-conditioning water system, the practical implementation of the value of energy efficiency design standards, the use of electric two-way valve on the end of the flow through the air to control the flow rate changes with the load, and actively promote the variable frequency pumps, winter ., summer dual two-speed pumps and other energy-saving measures. .The results show that in recent years, increasing supply and return water temperature errands to reduce the energy consumption of delivery system is greater than the efficiency of the resulting decline in heat transfer equipment, the increase in energy consumption, so terms of the entire air conditioning system has a certain energy efficiency, not only to .eliminate the large flow of small temperature difference phenomenon, but also the gradual introduction of low flow, large temperature difference of the design. .Because of greater supply and return water temperature, equipment operating parameters change, the design should be determined through the technical and economic comparison. .Should also be concerned about the cooling water temperature on energy consumption of air conditioning systems. .<BR> <BR> (1) reduce the cooling water temperature <BR> <BR> the cooling water temperature is lower, cooler cooling coefficient is higher. .Supply cooling water temperature rise of 1 degree Celsius Austin, cooler COP has dropped by nearly 4%. .Reduce the cooling water temperature to the cooling tower need to strengthen the operation and management. .First, stop the cooling tower, its access to water valves should be closed. .Otherwise, as from the closure of the cooling tower water temperature is high, a mixture of cooling water temperature will improve the cooling coefficient cooler reduced. .Second, the cooling towers used for a period of time, should be timely maintenance, or the efficiency of cooling towers to fall, may not be sufficiently cool the cooling water. .<BR> <BR> (2) improve the chilled water temperature <BR> <BR> chilled water temperature is higher, cooler the higher cooling efficiency. .Chilled water supply temperature is increased by 1 degree Celsius cooler cooling coefficient can be increased by 3%, so do not blindly reduce the daily operation of chilled water temperature. .First of all, do not set too low cooler chilled water set temperature. .Second, be sure to close the stop valve to run cooler, take the bypass to prevent the part of the chilled water pipe, or, after running the water cooler will be reduced, leading to chilled water temperature is cooler down low .level. .<BR> <BR> 1.3 Design of new wind energy system <BR> <BR> the rational use of the new air system, you can effectively control energy usage. .To meet the sanitary conditions and reduce the need for fresh air or on the actual system with variable air volume adjustment. .A ventilation system, the use of indoor wind energy to preheat the new and pre-cooling treatment (ie heat recovery technology) and so can reduce the energy consumption of air conditioning systems. .<BR> <BR> 2. Air conditioning energy saving measures in the process of building air conditioning <BR> <BR> 2.1 Energy <BR> <BR> (1) the construction of rational design envelope. .Heat within the building can be cold room walls, doors and windows to pass the source, so the building envelope performance in the construction of energy-saving insulation plays an important role. .Especially the window structure, the control should be able to play the role of sunlight and to limit the size of the window wall; relatively large area for the windows of buildings should be considered heat-absorbing glass, heat-reflective glass or shading measures such as sun visor, roof, .EAVES, curtains to prevent heat absorption. .When the outdoor temperature can lower the air as the use of natural energy, so the construction of the window should be able to open or set to open in its natural ventilation openings. .<BR> <BR> (2) doors and windows to improve air tightness. .Especially in the summer, reducing the room air changes. .For example, the design can be used with good windows and doors closed. .Article is to raise additional doors and windows closed an important means airtight. .<BR> <BR> (3) for the cooling load of the larger buildings. .Its surface color of the light as well. .Periphery structure of the building design heat capacity of the material put on the outer sheath of the indoor side. .And the heat capacity of thermal insulation material on the outside of the small envelope to reduce heat storage load. .<BR> <BR> (4) choose a more reasonable indoor air parameters. .If the calculated parameters for the outdoor air setting, the summer air conditioning indoor air temperature and humidity, the lower calculation, room cooling load calculation of the greater, the greater the energy system. .Comfort requirements are met under the conditions of the summer to try to improve the indoor design temperature and relative humidity, to minimize the indoor winter design temperature and relative humidity, do not blindly seek to force the indoor air temperature is too low in summer, too dry, the winter indoor design temperature over .high. .<BR> <BR> 2.2 <BR> <BR> rational use of environmental factors when the outdoor temperature is lower (especially at night), pay attention to the room ventilation, use of shade during the day and pay attention to measures to try to close the doors and windows when the air conditioning energy conservation are all .consumption of effective measures. .<BR> <BR> 2.3 build intelligent systems control <BR> <BR> integrated system of intelligent control technology from time to time the central air-conditioning energy saving control system, is more effective electronic means of control. .Intelligent integration control system, especially the emergence of the module, reducing the threshold of technology in general should be based on the actual situation of building energy consumption, the use of intelligent integrated system of different control solutions to save energy. .It can be based on the actual operation of air conditioning, and automatic air conditioning operating parameters of the adaptive optimal regulator, to reduce energy consumption. .<BR> <BR> Same time, with the development of intelligent buildings, the establishment of a complete set of air-conditioning intelligent automatic control system is also indispensable, its air conditioning system plays a key role in the operation. .Air conditioning automatic control system despite an increase in investment, but can maintain a good indoor environment based on operating costs savings. .A well-designed and well-controlled operation management system can significantly save operational costs, to allow property owners to recover the investment within a short period of time can also improve the automated service quality, reduce the external environment. .<BR> <BR> 3. To strengthen the management of central air conditioning <BR> <BR> daily management is practical and effective central air-conditioning energy saving is the key. .No matter how good a design air-conditioning system, if managed properly, reach the same energy-saving purposes. .Energy for air conditioning purposes, the daily management of energy-saving measures include: <BR> <BR> (1) strengthen the training of air operators, to improve management quality. .Know how to change the parameters according to the outdoor reasonable and effective regulation. .Actively promote the water loop heat pumps, the use of heat recovery, variable air volume, variable volume systems, energy-saving technologies. .<BR> <BR> (2) strengthen the routine and periodic maintenance of equipment and systems to and washing. .Such as air conditioning components such as maintenance, condenser heat transfer surface of heat transfer equipment such as regular cleaning, or ash, filters, decontamination equipment cleaned regularly. .<BR> <BR> (3) Always check to automatic control equipment and instrumentation to ensure their normal work. .Operating parameters of the system to monitor, and never found in the normal operating parameters of system problems, a reasonable transformation. .Recurring equipment selection problem is too large, higher energy consumption. .Pre-cooling time as short as possible. .<BR> <BR> (4) When the transition to a cooling load of the indoor season when the outdoor air should be as far as possible the natural cooling capacity, savings in the amount of artificial cold cold source. .<BR> <BR> Central air-conditioning energy involved in a wide range of very wide, from the design of air conditioning, air conditioning installation and operation management and other aspects worthy of improvement. .In any case to improve energy efficiency, should come from improving energy efficiency measures taken to solve the problem, this is the way of scientific air conditioning energy. .<BR>.

Weak current College】 【plate heat exchanger plate structure, combining form and seal.

<br> Summary: plate heat exchanger in the normal condition of the main failure mode is a seal failure. By stiffness on the slab, plate sealing structure including plate seals, gaskets, found the plate stiffness can improve heat exchanger capacity overall pressure; reasonably .design seal groove, can effectively improve the sealing gasket in the seal grooves in the stability and reliability seal. It also describes some prevent seal failure of practical experience. <br> <br> Keywords: plate heat exchanger; seal; fail; stiffness; .structural form <br> <br> Chinese book classification number: TH6 document identification code: A article number: 1671-3133 (2007) 01-0115-04 <br> <br> Introduction <br> <br> Plate heat exchanger is .a high efficient, energy saving heat transfer equipment, with high heat transfer coefficient, compact, supplies, forms, easy maintenance and many other advantages, the gradual expansion of the field of application, has been widely used in machinery, electric power, metallurgy, .chemical industry, textile, beverage, urban heating industries and areas that demonstrate strong competitiveness. <br> <br> 1 plate heat exchanger of the overall structure of the <br> <br> Plate heat exchanger to metal plate (thickness 05 ~ 10mm .) for heat exchanger components are made of stainless steel, industrial pure titanium or other materials for thin plate pressing. Will usually die plate pressed into a variety of Groove or wave shape, you can increase the stiffness of the plate to prevent plate deformation under pressure ., but also enhances the level of turbulent fluid, increasing heat transfer area. Each plate corners all open a hole, the slab is surrounded around the hole with sealing gasket tank pressure, and in the hole of the week is placed in the slot, to .allow the washer fluid or fluid into the plate surface blocked between the channel. If the number plate in accordance with the heat requirements then arrange on the stand, with fixed clamping plate and active clamping plate by clamping screw press, in the adjacent plate-form .fluid channel, with the help of the four corners of the orifice plate and gaskets. <br> <br> Plate heat exchanger plate structures vary, their design is the ultimate goal is to strengthen the plate heat exchanger increase plate surface effects, stiffness, .improve the heat exchanger capacity of pressure. Ideal form factor design, not only has a large heat transfer area, lower pressure drop, higher heat transfer coefficient, but also has good rigidity, so very thin plate in the fixed clamping plate, and activities of .the clamping plate clamping force of mutual support, to resist pressure to imbalances within the channel on the impact of its production. To this end, in the form factor design but also the supporting point of distribution as well as the layout of the rebar. < .br> <br> A piece of plate according to their functionality can be divided into diversion section, heat exchanger parts, sealing parts, edge support and a hanging position, five parts, which heat is the core of the slab structure, and its structure .depends on the nature of the heat transfer medium, according to the design of heat transfer and fluid dynamics. <br> <br> 2 plates of structural form <br> <br> Plate heat exchanger as a key element, its structure and design .sensible or not will have a direct impact on the plate of heat transfer performance, as well as the total resistance drop of carrying capacity. Currently there are over 100 species of core structure, its main corrugated form: Chevron wavy (including horizontal Chevron wavy and .Vertical Chevron wavy), horizontal wavy, vertical, diagonal ripple ripples. China's production of plate heat exchanger plate structure, mostly to Chevron wavy, belong to the typical mesh mobile plate-type structure, its characteristics are in the Board room of fluid channels, .the wrong column in full-contact, the contact points in the fluid surrounding the flow formation between spirals along tracks, resulting in strong disturbance. If you increase the degree of fluid flow, you can reduce the thickness of the laminar, effectively improve no transformation .of convective heat transfer coefficient, so as to achieve the aim of increasing the heat transfer coefficient. Experimental proof: for water, when the Reynolds number Re = 20 ~ 200, velocity-02 ~ 05m / s, the fluid that is entering turbulent state ., has a very high heat transfer coefficient. To this end, in the plate and decorate with uniform, and the appropriate contacts decrease spacing, in addition to greatly enhance the overall rigidity of the plate, can withstand a large differential pressure. <br> .<br> 3 plate combination forms <br> <br> Depending on the plate heat exchanger market research, our heat exchangers manufacturers design factor mainly Vertical Chevron wavy. <br> <br> Fluid in the above two forms of plate consisting of channel .flow can form a reticular flows, but the flow resistance and heat transfer coefficient. <br> <br> When horizontal Chevron corrugated slices, fluid after plate between the channel more smooth, fluid resistance is very small, very low pressure drop, but the .heat transfer coefficient than vertical Chevron corrugated plate slightly lower, thus more suitable for low-velocity, high viscosity and flow quite big occasions. <br> <br> When using vertical Chevron corrugated plate (ripple angle of 120 °), fluid in the .plate between the channel flow through time is extremely easy to generate turbulence, high heat transfer coefficient and thus can produce ideal heat effect, its main disadvantage is the pressure loss is relatively large, and therefore only apply to the pressure is not too big, not .applicable to high viscosity, low flow resistance requirements. <br> <br> Following to Tianjin a heat transfer equipment factory production of the BR100-plate and BRh070-plate for example (both plate duration aspect ratio closer) for instance, to compare the .same working conditions, two plate-type heat exchangers for the pressure loss value. The former is a landscape Chevron corrugated plate, the latter as vertical Chevron corrugated plate structure. <br> <br> Working conditions: 80 ¡ .æ quenching oil cooling to 60 ° c, quenching oil processing capacity 8t / h. Quenching oil proportion of physical data: γ = 800kg/m3; dynamic viscosity μ = 13 × 10-3Pa · s. 31 of the BR100-type heat exchanger .<br> <br> Channel cross-section: 000289m2; equivalent diameter: 00082mm; its resistance-associated to: En = 19500Re-047. .Then: <br> <br> ΔP = Enμ2/γ/g <br> <br> Type: Re-Reynolds number, Re = d / V; V = υ pipeline average velocity (m / s); d is pipe diameter .(m); viscosity υ as movement (m2 / s); En; for resistance coefficient μ for dynamic viscosity (Pa · s); γ for weight (kg/m3); g = acceleration due to gravity (98m/s2); .Δ p is the pressure drop (MPa). <br> <br> Calculate: Δ P = 005MPa. <br> <br> 32 BRh070-type heat exchanger <br> <br> Channel cross-section: 000195m2; equivalent diameter .: 00074mm; its resistance correlations to En = 53641Re-0537. <br> <br> Calculate: Δ P = 015MPa. <br> <br> The calculation results can be seen, in the same condition, two form factors by pressure drop .considerably. <br> <br> Two form factors have advantages, there are also some limitations. For example, when asked to heat transfer coefficient of high and low resistance drop, use either form will not be reached relatively satisfied with the results. < .br> <br> If the horizontal Chevron wavy and Vertical Chevron corrugated plate mixed Assembly, can produce very different results. Its premise is that two form factors of the plate size, position, size, through-hole diameter dimension, gasket structure dimensions should .be identical. The mixed Assembly of the plate in the overlay, happens to be able to form the corresponding contacts, can form a network stream, its resistance drop and heat transfer characteristics between two corrugated plate between separate Assembly. <br> <br> .4 plate stiffness analysis <br> <br> Plate stiffness is the plate in accordance with the requirements of the Assembly, the fixed clamping plate and active clamping plate clamping on both sides of the resistance under different pressures media role and deformation ability. <br .> <br> In normal working condition, the plate must have sufficient strength, it also requires a certain stiffness in order to control the plate of the deformation process, making the heat transfer medium plate channel layer thickness uniform to ensure heat transfer efficiency. According .to the principle of thermal expansion or contraction, raise or lower the temperature will cause a plate of expansion or contraction, but the plate of expansion or contraction to vulnerability from the fixed clamping plate and active clamping plate restrictions. When the contract is not completely free .to do, will result in stress, this requires a heat transfer plates should have adequate stiffness and pressure resistance. In the slab structure design often requires reasonable layout support points and increasing rebar. Plate stiffness depends not only on the supporting point location of density and .precision, also depends on plates of length, width and thickness, and other factors. <br> <br> Currently, foreign and domestic heat plate plates vary, there are hundreds of forms. The aspect ratio is 1: 1, 2, 3 ., etc. In the special working conditions also have 1: 1.1: 4, 1: 5, 1: 6. Different conditions with different aspect ratios, its carrying capacity. The author after years of developing and manufacturing sheet-found that the plate of .the aspect ratio is impact plate stiffness of one of the important factors. <br> <br> Conditions for liquid-liquid, heat exchanger plates of design have to narrow the development trend of the long type. Narrow long plate can effectively reduce the fluid .flow phenomenon of edges, making it in the channel as possible uniform flow, heat transfer enhancement. In addition, also for improving the slab of lateral rigidity offers extremely favorable conditions. Plate of longitudinal stiffness can rely on 4-6 on clamping bolts and fixed .clamping plate, active clamping plate to calculation in guarantee; plate of lateral rigidity, not only to consider two plate clamping force and deformation after, but also the liquid pressure and tension, gasket and plate bearing point of deformation, dislocation, and many other factors .. When a plate of lateral rigidity is not sufficient to overcome the above deformation, likely in sealing gasket and leak happens between the plates. Practice shows that the plate of aspect ratio at 1: 25, 1: 3 or so, the plate heat exchanger .unit carrying capacity up to 2.5MPa and below this value of the form, the whole machine bearing capacity in 1.0-1.6MPa. <br> <br> 5 plate sealing structure analysis <br> <br> In the plate heat exchanger design, .plate's overall structure and seal strength has very close relations, reasonable structure design of the seal not only increases the stiffness of slab, improving heat exchanger for pressure resistance, and guarantees good tightness. Sealed structure is made of plates of seals and gaskets, sealing gasket .consisting of performance (performance of physical properties, chemical and technical properties), seal Groove forms, gasket compression ratios are the three elements of sealing design. <br> <br> 51 seal groove <br> <br> Seal groove shape directly related .to the gasket in the seal groove positioning, affect the sealing gasket on a running stability, also directly linked to the sealing effect. Reasonable seal groove design should make the sealing gasket on stress, heat conditions, where the design does not occur on the basic .of displacement, and to maintain the original compression ratio. In order to achieve the above requirements, the design of the seal groove, should as much as possible to adopt the enclosed form. In addition, to take full account of plate material tensile properties, .you should make the seal groove angle possible. At present, China has developed a form, the seal grooves in the inclination of 25 ° ~ 35 °; and some well-known brand abroad, the majority of plate seal groove angle is 20 ° left .and right, most small-to-7 °. <br> <br> At present, domestic and international variety of plate-type seal groove design uses the plane form, as shown in Figure 3a. Its advantages are simple sheet molding processing, .gasket structure is simple, easy-to-bonding, sealing gasket in the seal grooves and good stability. But there are disadvantages, for example in adhesive sealing gasket and seal groove, bit must be quite accurate, is not allowed to have offset, or .clamping, gasket be divorced from the lost seal seal groove. In response to this situation, this article on the seal Groove Forms has done a lot of research and testing, developed a new type of structure, as shown in Figure 3b, The sealing gasket .assembling time good stability, positioning, improved sealing Groove parts of stiffness, reduced Assembly process of the clamping force, reducing the degree of deformation plate. For many years with the result shows that the seal Groove Forms drastically, greater promotion value. <br> .52 gasket <br> <br> Gasket is the plate heat exchanger is an important part in the Assembly by using the adhesive will put in jail in plate gasket tablets in the seal groove, hole week trough under fluid flow needed to place the gasket and .thus to allow or block a fluid into the plate between the channel, the purpose of achieving heat. Gasket material, structure, format and compression ratio is directly related to the plate heat exchanger sealing effect. <br> <br> 521 gasket material < .br> <br> Currently used for sealing gasket material is synthetic rubber and asbestos rubber. Synthetic rubber commonly used with NBR, EPDM and Viton. Synthetic rubber sealing gasket of physical performance indicators mainly in working condition of permanent deformation and elongation, rubber sealing rubber .hardness indicators should be under the seal grooves in the form and the amount of compression. <br> <br> 522 gasket of structural form <br> <br> Gasket of structure, there are a variety of forms, the forms are generally have .rectangular cross sections, trapezoid, Hexagon, Pentagon, etc. Commonly used in the form of two types: a form as shown in Figure 4a, its sealing gasket cross section in the upper part of the pointed; another form as shown in Figure 4b, .the upper plane. The former is through sophisticated to the size difference in the middle to increase the degree of deformation gasket, its structure design actually remains flat seal, seal, because the plate nonlinear tablets seal groove bottom is flat, when the plate seal groove .bottom plane defects, this structure can be offset by some. The latter is designed to reduce the amount of compression sealing gasket, its compact form flat clamping. Its main disadvantage is the Assembly of the plate, the plate is easy to misplace, clamping force .is too large, easily plate deformation. Through the analysis of research and testing, this design and the PCT as shown in Figure 3B sealing Groove corresponding gaskets section shown in Figure 4c, makes Assembly easier, also improves the ability of the pressure plate. < .br> <br> 523 gasket compression ratio <br> <br> General to gasket compression ratio of its original thickness that compression ratio as gasket design basis. According to many years of design experience, as well as domestic and foreign large amounts of heat .exchanger analysis of sealing structure, the author believes the compression ratio is in 20% to 25% is ideal. <br> <br> 6 conclusion <br> <br> Plate with mixed combinations, you can make today's plate heat exchanger applications more .widely. Not only that the plate heat exchanger greatly enhance adaptive capacity, and also has higher heat transfer coefficient, low flow resistance, and high efficiency, energy saving, good value for money. <br> <br> At the same time, depending .on the plate of stiffness, reasonable design seals and gaskets, can effectively improve the sealing gasket in the seal grooves in the stability and reliability seal, is to ensure that the seal effect of the important conditions. Through the use of the user tracking survey and .feedback information, as shown in Figure 3b sealing Groove forms and shown in Figure 4c gasket is best design, its bearing capacity and service life of a previous design of product has greatly improved. <br> <br> In order to adapt to the heat .exchanger for multi-purpose development trends, but also continually explore research, development of better, newer products, further improve our plate heat exchanger products level. <br> <br> Reference documents: <br> <br> [1] Zhang source .of chemical principles [M] Chengdu: Chengdu University of science and technology press, 2003 <br> <br> [2] Xu guozhi, anyuan benign fluid in the plate heat exchanger within the shape channel Dynamics [M] Beijing: petrochemical equipment press ., 2004 <br> <br> [3] Jin Ming Cong, Cheng still die, Zhao Yong xiang heat exchanger [M] Chongqing: Chongqing University Press, 2001. <br> <br> [4] Hu guozhen chemical sealing technology [ .M] Beijing: chemical industry press, 2002 <br>.