【 Weak current College 】 inspection of air conditioning thermostat---Power By 【 China power house network 】

When the air conditioner is not working properly, you will need to check compressor start relay, thermal and over-current protector and capacitors, you must check the electrical control system is very important to control the protection and enforcement components — the temperature control in the master selection switch. Here are some common thermostat for rapid detection method.

First, the bellows-type or diaphragm type temperature controller

1. symptoms: contact bad or burned, causing the circuit can't reach; contact frequently starting arc adhesion, causing the circuit can't fault; thermal cavity temperature sensor for leak, causing the contacts cannot control the actions and lose.

Maintenance: the thermostat knob is in the opposite direction of rotation, several times, using a multimeter R×l stalls measuring temperature controller powered by two terminals, resistance is small, that contact is normal; if resistance, that contact is bad; if not, may be the temperature sensor for leak. If leakage can be first Visual inspection, observation of thermal head seal welding head is cracked, the sensor is damaged and crack, heat pipe has no bending trace, and then put the sensor placed people 30 ~ 40 ~ C warm water, test contacts closed, if the contact is still not closed, indicates that the sensor within the Thermo agent has been leaking out; if contact can be closed, then the sensor shall be removed from the water, put in the low temperature for a period of time after the contact has broken, the range of thermostat thermostat described incorrectly, you can adjust the temperature range of the adjusting screw rectifying, counterclockwise l/2 circle and try again.

2. failure phenomenon: temperature controller appears as a result of arcing contacts after adhesion. contact does not automatically jump to open, you cannot shut down the compressor.

Maintenance methods: put the sensor in two-door refrigerator storage room (5-lO ℃), the measuring temperature controller two terminals is disconnected. If disconnecting the. indicate contact adhesive, available flat blade screwdriver disconnect stirring the mechanical force-contact; if contact can jump off, table H-thermostat for temperature control range low drift and clockwise adjust temperature range adjustment screw.

3. failure phenomenon: temperature sensor for leak.

Maintenance methods: hot towel to heat pipe heating and the knob to the lowest temperature, multimeter measuring temperature controller is connected to the switch. If the switch is blocked. the thermal agent has been compromised, you should replace new thermostat.

Second, hot and cold-temperature controller

Electric-type air conditioners in the thermostat, contact control box has two sets of contact agencies (cold-contact and heat-contact), using the same thermal bellows control on cooling and heating degree. Its symptoms and inspection methods and ordinary thermostat are basically the same, but note that you should also check cooling load, thermal load switching is sensitive, i.e. in the refrigeration compressor should be connected to the location, the location in the heating circuit should be connected to the electric heater circuit.

3. defrost temperature controller

Defrost temperature controller is set in a hot-air conditioner control circuit for switching solenoid valve components. Its heat pipe installed side heat exchanger coil. when winter heating, outdoor side heat exchanger Frost layer thickening the temperature is below a set value when defrosting controller-contact action. Disconnect the solenoid valve £ ® the original heating cycle into a refrigeration cycle. Common structure there are two forms: one is the thermal bimetal: one is the normal temperature controller. Detection method is part of the temperature sensor is placed in the corresponding temperature of water or air, multimeter measuring two terminals is disconnected or conduction can know good or bad!. Thermal bimetal thermostat is also used to control indoor side against the cold wind.

4. heat resistance

Electronic thermostat or microcomputer control of the air conditioner, have made a thermistor sensor components. Thermistor is their resistance with temperature changes and significant change in the component £ ® for air conditioner return air temperature 10-lap direction of thermistors. General characteristics with a negative temperature coefficient: resistance with temperature increase and decrease. Specific to a certain brand of empty Yuan for the use of the resistance of the thermistor, it varies with temperature-dependent properties are generally draw in random directions into the chart for detection, detection can under certain circumstances, using a thermometer and a multimeter for semiconductor measurement. controlled temperature sensing characteristic or characteristic value table to determine whether the normal performance when aging, Thermistor, namely temperature drift and the resistance of the correspondence between the change and should be replaced with new thermistor sensors.

The system is not functioning properly or long term will have failed after aging. In the repair process can sometimes take a replacement method, which uses a good same model, same specifications thermostat replacement saves maintenance time and can easily distinguish the thermostat is good or bad.

Weak current College】 【control valve selection and maintenance-of-Power By】 【China power house network.

First, the control valve selection

A, the importance of the control valve selection

Control valve is automatic control system of the actuator, its application quality direct response in the system of quality. As process control terminal symbol, its importance than in the past have been updated. Control valve applications or bad quality, except for the product itself, the user is correctly installed, use, maintain, correct calculation and selection are very important. Because the selection of the mistake, resulting in the system can stop, or even putting-, so for users and system designers should recognize the importance of the valve at the scene, you must control valve selection caused enough attention.

B, the principle of control valve selection

1, according to the technological conditions, select the appropriate structure and materials.

2, according to the technological characteristics of the object, select a control valve's flow characteristics.

3, according to the process operation parameters, select the appropriate control valve diameter size.

4, according to the requirements of the process, select the auxiliary device.

5. reasonable choice. Executive Body of the response should be able to meet the technological

To control the travel time of the request: the selection of control valve actuator should be covered with foot valve stroke and technology on the disclosure of rating requirements. In some occasions, such as selection pressure control valve (valve), consideration should be given to the actual possibility of pressure differential for appropriate amplification, which requires implementing agencies can provide larger forces. Otherwise, when the exception occurred on technology, the control valve before and after the actual pressure differential is large, occur off not or can not be opened.

Second, the control valve accessories

In the production process control system for valve raise various kinds of special demand, therefore, the control valve must be equipped with various ancillary installations (annex) to meet the needs of the production process. Control valves accessories including:

1, valve positioner for improved control valve performance characteristics, realization of the right positioning.

2, valve position switch to display the upper and lower limits of the valve stroke work location.
3, pneumatic control valve-valve when sources of failure, keep the valve is in the air source fails before the opening position.

4, solenoid valve for gas solenoid switch, guarantee the valve in a power failure while the valve is in the desired security opening location.

5. hand wheel mechanism when control system controller fails, you can switch to manual mode operation valve.

6, pneumatic relay enables executing agency action to speed up and reduce transfer times.

7. air filter regulator used to purify the air source, adjust the air pressure.

8, storage tank guarantee when the source of failure, so no spring of cylinder piston executive agencies to be able to work will control valve action to fail safe location. Its size depends on the size of the cylinder, valve action time requirements and the working conditions of the valve and so on.

In short, the role of the attachment is to make the control valve function better, smarter and more complete.

Third, the control valve maintenance

Control valve has a simple structure and action simple and reliable, but because it has a direct contact with the process media, its properties directly affect the system's quality and environmental pollution, control valve must be regular maintenance and periodic maintenance, especially for the use conditions and important occasions, should pay more attention to maintenance work. Focus inspection site

1, valve wall

For use in high-voltage differential and corrosive media in the control valve, the valve interior, diaphragm valve of diaphragm is often affected by the impact and corrosive media, must be focused on checking the pressure resistance, corrosion resistance.

2, valve seat

Control valve, due to media infiltration, fixed seating surface with thread within the vulnerable to corrosion, check for loose seat should be noted. The high differential pressure of the valve under work, you should also check whether the flush valve seat sealing surface.

3. the valve

The valve is regulating the work of moving parts, the media's most serious erosion, corrosion, maintenance time to seriously check valve parts are corrosion, wear, particularly in the high differential pressure of the valve wear more serious (due to cavitation phenomenon), it should be noted. When the valve damaged should be replaced, in addition you should also note the stem if there is a similar phenomenon, or loose with the valve connection.

4, diaphragm "O"-rings and gaskets. Should check control valve diaphragm, "O"-shaped gasket degradation, fissure damage.

5, sealing packing

It should be noted that PTFE packing and sealing grease degradation, combined with surface damage, should be replaced when necessary.

【 Weak current College 】 Central air conditioner selection method

Summary: China is now the market situation in the central air conditioning was good, the growth in number but as competition leads to lower prices. The average price of refrigerators have fallen significantly, but also reflects the progressive miniaturization trend of refrigeration. And details how the selection of central air conditioning.
Key words: central air conditioner market selection refrigerator

The first chapter of the China refrigeration units and large air conditioning equipment trends

China is now the market situation in the central air conditioning was good, the growth in number but as competition leads to lower prices. The average price of refrigerators have fallen significantly, but also reflects the progressive miniaturization trend of refrigeration. 

Air blower plate Tube or major end products. Air handling unit (combined air conditioner) and other terminal equipment increased, but their fan coil of mainstream status no significant threat.

First, the refrigerator specifications

According to BSRIA (UK) survey to calculate the product of cooling capacity, large equipment market size reduces (1000kw, 285Reftons); but be value calculation, cooling capacity in 401kw (114ton) and 401kw above refrigerator in 2000 accounted for 67%, or $ 4.24 billion. And only 1000kw total sales above $ 3.02 billion, accounting for total sales by 47%.

In recent years, a large number of small refrigerator, mainly scroll-type of application in the household, etc. Medium-sized refrigerator sales are on the rise, based on the following reasons:

• Screw by designers and users more and more popular. 

● Have a multiple small units instead of one large unit by tendency. So that only some of the load conditions, reducing the operating frequency to achieve energy savings and greater stability. 

Through State-owned enterprise reform and restructuring, very large industrial project investment is reduced, in the past, this is the main areas of large refrigerator. In other areas, there are large foreign-funded enterprises to invest in new commercial buildings, factories, etc. 

Adopts the foreign advanced technology drives higher performance of the emergence of new products, mainly in the screw and centrifugal compressors, heat exchangers and electronic control. At the same time, the absorption chiller technology is headed by domestic manufacturers develop and improve.

Second, the type of refrigeration

In the vast majority of Chinese sales of refrigerator is air cooled, accounted for 76% of the entire market, and in 1997, cold water unit accounted for 67% of the market. This marked an important change, this trend will continue.

Type 1, refrigerator

A clear trend is the application of the screw and scroll technology. Piston machines in 3 years ago, now the dominant market share but declining sharply to 15%. 

Absorption-type unit due to the improvement of electricity supply and rising oil prices, the market is shrinking. 

Because not too many such as airports, hospitals and high levels of office buildings and other large construction projects, centrifuge market in 2000 remained at around 850 sets.

1.1, absorption chillers

1.1.1, profile: absorption chiller development in large part to the decision by the energy structure of the State. In the past 2-3 years, the absorption chiller market due to the shrinking of the following reasons:

● Increase of supply of electricity;

● Oil price increases;

● Electric chiller replacement for HCFC (piston, screw and scroll, centrifuge);

● Electric chiller efficiency.

A brief history of 1.1.2,

Until the mid-1990s, the steam engine is mainly provided by domestic manufacturers, and direct-fired units are imported from Japan. Jiangsu shuangliang is the leader in China. Although shuangliang was United States te in the later half of the establishment of a joint venture, and the two sides to 99 years (actually is in March 2000, the translator's note) has lifted the joint venture relationships, shuangliang has been ranked first in China absorption chiller manufacturers. Shuangliang and has begun to expand overseas market. 

In the early 1990s, China manufacturers vision launched the fired absorption chiller (mainly oil). Fired machine initially adopts low calorific value of gas. As the gas pipeline network in large cities, burning natural gas-fired air conditioner is increasing.

1993-1995 market boom period. Under the Montreal Protocol, China announced the phasing out of the year 2006 and industrial refrigerators use CFC. due to the massive use of electric refrigerator no new refrigerants, as an alternative, the absorption chiller is rapidly expanding. In addition, the Government put the absorption chiller solutions at the time of application as the power shortage in a way, therefore also encourage the development of absorption technique. In this way, the market demand suddenly turned to absorption chillers, has also attracted dozens of competitors to enter the absorption chiller market. 

1995-1998 period of market stability. This period of market gradually moving towards maturity. Technology to improve rapidly, many market participants. Shuangliang, ambitious, Sanyo and Kalee dominated the market. Yantai EBARA and LG tonghe. Vision direct burning machine in the expansion. 

At the same time, after replacing electric refrigerator refrigerant, is gradually regain lost market. From 1998 to date, the absorption chiller is facing fierce competition in electric refrigerator: power supply increases, the price decline in some areas. Worse still is that oil prices are rising. Scroll and screw due to performance and efficiency reasons why more and more popular. HighFor initial investment and energy supply of convenience, cause some customers turned to other forms of refrigerator.
br>1.1.3, supply

Absorption chillers are the only proprietary central air conditioning products. China has become the subject of Japan's second largest absorption chiller production countries. 

The vast majority of domestic demand is met by domestic production. The number of export was minimal. But as shuangliang and far-sighted overseas expansion strategy execution, exports will increase. 

Of particular concern is the Kalee's strategy. It has decided to close the other factory and Shanghai a cold factories as global absorption chiller market supply center. Therefore, it will also promote exports. 

1.1.4, fuel analysis

Chiller in China became popular due to heating boilers is not required, thus saving costs. In major cities, absorption chillers are fired in the majority. In a region where heat or steam/hot water-mill.

Due to the high oil prices and the construction of gas networks, gas has become the fuel of chiller, and future trends. While the current single-effect absorption chiller in China is very rare. 

1.2, centrifuge

Centrifuge market capacity approximately 700-1200 wandering between computers. Because based on large-scale infrastructure projects, and in the last 2-3 years of large-scale infrastructure projects is not very much, so the market is a centrifuge dull. 

Centrifuges are characterized by the use of water cooling and is usually greater than the large unit 800kw. 

Market are United States brand such as York, Kalee, tring and monopolized by McQuay. Import unit about the entire domestic market share of 50% of this is the highest in all of the refrigerator. 

Since 1999 the surplus electric power supply, the sealing of the steady growth of the market of the centrifuge. Domestic manufacture of unit also introduced advanced technology. Hezhong Kalee had in Shanghai Assembly and manufacturing of hermetic compressor, and also with other parts of the joint venture to assemblethe refrigerator. While other companies or assembled by the compressor. 

1.3, screw

Screw machine market is growing. Because it is considered to have high performance and low noise, less than the models encroached 800kw piston machines share. Even greater than 800kw models, compared with centrifuge and flexibility features. Therefore, screw and more users and Design Institute. 

Screw another factor of growth in recent years for medium-sized refrigerator needs increase. In the industrial field investment principal is private enterprises and joint ventures, their factories mostly medium-sized buildings. Screw set of nature is the best choice. 

Screw machine group mostly water-cooling. But the forced-air cooling type, especially air source heat pump unit and gradually grow. Hitachi, Daikin, York, Tring, Kalee, dunhanbushi, McQuay and JI-young is a major participant in the market. However, approximately 1/4 of the import of the unit. All of these manufacturers are assembled in a factory in China. Hitachi will be held in Guangzhou Wanbao production unitary air conditioners air cooled screw, Guangzhou Wanbao has been producing water cold conditioning. 

There are also many local manufacturers from Bitzer, Hanbell, Fusheng, Refcomp, compressor or homemade of compressor to design and assemble the refrigerator. These manufacturers is Dalian bingshan, Zhejiang Trump, Shanghai Richfield, Chongqing jialing, Wuhan cold machine factory, etc. Italy brands such as RC, Climavereta, a well-known Clivet. Taiwan manufacturers Kuenling also in April last year established a factory in Shanghai. 

1.4, piston machines

Piston machines are scroll and screw segmentation of the market. And you've exited from the domestic market, the only commercial and industrial areas remain some market share. Most of the unit's cooling capacity lower than 350kw and the proportion of the heat pump. Kalee, York, McQuay and other domestic brands such as Dalian bingshan, Nanjing Wuzhou, JI-young and Yantai Moon in a leadership position in the market. In view of domestic technology has matured and the shrinking of the market, imported units are rare.

1.5, scroll

Copeland, Danfoss is China's largest suppliers of scroll compressor. The majority of scroll compressor for air conditioner unit.

In 2000, the China market total sales of approximately 2 million scroll chillers. The majority of the cooling capacity is 5-35kw, mainly for the Villa and more room apartment. As a residential central air conditioning, scroll the main types of machine market in 1999 and 2000 began to prosper. The next few years the situation remains good. 

Cooling capacity greater than 35kw of unit for small commercial areas such as Office, small hotels, theatres, etc. This type of most of the Vortex machine is modular Vortex machine. Only Te can provide a single large scroll units. 

2. recent trends

In the majority of Chinese sales unit is domestic manufacturers or joint ventures in China. Key components are now also localized. China refrigeration and air-conditioning industry with low cost and continuously improve the quality of products, are gradually shifted from import-export-oriented.

2.1, steam compression type (volumetric) refrigerator

Since the Government's management and the mild climate, air source heat pump is the darling of the Yangtze River basin in the market. Winter for heating of coal-fired boilers in the area south of the Yangtze River has been banned. Therefore, including room air conditioner, mainly used for refrigeration,Also heating with heat pumps by the region's favorite. Heat pump for heating, so you can save the boiler. Direct-fired chiller applications. 

With piston or scroll compressors for refrigeration capacity is 5-10RT small air cooling or heat pump chiller's most used residential central air conditioning system. Cooling capacity is 20-400RT air-cooled, airsource heat pump and cooling piston, scroll or screw machine mainly used in commercial buildings. 400RT more vapor compression refrigerator mostly semi-enclosed centrifuge group. 

Because of its high efficiency and high reliability characteristics, closed screw is preempting piston machine market. At the same time as the primary surplus and electricity investment low factors also encroached on absorption chiller market. But screw compressor can reduce the cost of localization.

2.2, absorption chillers

Power shortage in the past, the Administration on the control of the total electricity consumption, but also no absorption of sales to any special preferential policies. Absorption of purchase by the user based on their personal economics on product quality, reliability and service assessment. 

According to industry statistics, 2000, the absorption capacity of approximately 2600 units (including steam double 50%, fuel oil chiller 25%, gas-fired air conditioner 25%). Single-effect and very little water-mill. 

In 2000, shuangliang, ambitious and Dalian SANYO is considered a market leader. Yantai EBARA and LG with and increased market share, but lost Kalee market share.

In 2001, the Government established a new absorption chiller national standard, which provides cooling water inlet temperature from 32 ° c to 30 ° c, while the new chiller in refrigeration at LHV State COP minimum 11 (on HHV State = 10). These indicators are considered even if the existing model is also very easy to reach.

2.3, refrigerant issues

Since 1995, China is the world's largest CFC use State. Under the Montreal Protocol, China plans to phase out the use of CFC within 10 years.

CFC phase-out plan in China:

Automotive air conditioning systems to the commercial and industrial refrigeration in 2002 to 2006 conditioner 2010

Now use the refrigerator HCFC-22 will be using the HFC-407C or-410A piston and screw and scroll machine replacement. Refrigeration units for refrigerant replacement ratio of unitary air conditioning unit to replace the much faster. Central air conditioning systems from the CFC (R12) replacement for HCFC (R22) has been completed. 

Piston, screw and scroll-the vast majority of still use R22. market has some use R134A and individual use R407C, usually the customer requirements. 70% of the centrifuge has shifted from R22 R134A. There are other alternatives such as R407C and R123. However, R134A will be the most common choice.

2.4, modular air conditioning unit

Commercial and residential use of modular room air conditioner market capacity of approximately 80 million-100 million units/year. More than 80% are air cooled split. 10% is water cooled Interior unit. Mostly local Assembly of the main manufacturers: Chunlan, Haier, gree, midea, kelon, JI-young and South China. This part of the market is growing rapidly. 

Beauty from two years ago, the introduction of Toshiba's technology has begun to manufacture Kalee and sell VRF air conditioning system. Haier technology from Toshiba Kalee. Initially, the main manufacturers of Japan Daikin to export from Japan, but because of reduced tariff price competitiveness, Daikin has decided this year to begin production in China (see August JAPN). 

Hitachi has announced that a Hitachi air conditioning and refrigeration equipment (Guangzhou) company plans to double the capital. Used to increase the air cooled chiller and the localization of the modular air conditioning unit.

Summary of chapter host selection

(—) Summarization of the chiller class

Chiller is the heart of the central air-conditioning system, the correct choice of chillers is not only a guarantee of success of engineering design, and operation of the system also produces long-term impact. Therefore, the chiller choice is an important task.

1. Select the chiller considerations:

★ Building uses.

★Various chiller performance and features.

¡Ï local water sources (including water temperature and water quality), power and heat (including the source type, nature and taste).

★ Building annual air-conditioning cooling load (thermal load) distribution.

★ First investment and running costs.

¡Ï on freon refrigerants restricted period and the possibility of using alternative refrigerants.

2. water chillers selection considerations:

Taking into account the above factors, the selected water chillers, you should also note the following points:

★ Large central air conditioning system with cooling source, use the structure is compact, small footprint and compressors, motors, condenser, evaporator and automatic control components are assembled in the same frame of chillers. On small full air conditioning system, the use of direct evaporative condensing unit.

¡Ï on suitable heat source especially heat or waste heat and other places or places of power shortage, the use of absorption chiller.

★ Refrigeration units generally use 2-4 bed suitable for small and medium scale to choose 2, larger optional3 bed, large choice of 4. Unit to consider their mutual between as spare and toggle the use of the possibilities. The same engine may use different types, different capacity unit mix of modular programmes to save energy. Parallel operation of the unit at least select a higher degree of automation, tuning performance better, can guarantee part of the load to the machine running efficiently. Piston chiller should preferred multi-head automatic control for chillers.

¡Ï selection driven chillers, cooling capacity when the stand-alone air conditioning φ ＞ 1163kW, use centrifugal; φ = 582 ~ 1163kW, use centrifugal or screw; φ "582kW, use piston.

¡Ï power driven chiller COP of refrigerating factor than the absorption chiller of high thermal conductivity, the former for the latter two times more. Energy from low tohigh in order to: centrifugal, screw, piston, absorption (foreign unit screw-centrifugal before). But various unit has its own characteristics, use it.

★ Choose refrigerator should consider their environmental pollution: noise and vibration, to meet the requirements of the surrounding environment; second, refrigerants CFCs on atmospheric ozone layer damage and the size of the greenhouse effect, with particular attention to the disabled timesheet CFCs. Direction in the prevention of CFCs pollution absorption chillers have a distinct advantage.

¡Ï without special room location or air conditioning retrofit retrofitted to consider modular chillers.

★ Made possible. China refrigeration equipment industry in the last decade has been developing rapidly, the vast majority of product properties are close to the international advanced level, in particular small and medium-sized chillers, and imported products, and prices have incomparable advantages. Therefore, other things equal, priority should be made by chillers.

(B) heat pump class

★ Heat pump units of cooling load calculation method and the conventional air conditioning systems, heat load calculation method in much the same heating system, regardless of the outdoor air heat consumption;

¡Ï selection when the local availability of water resources (including water, water temperature and water quality), power and heat (including the nature, quality or low heat source);

★ Air source heat pump water temperature is 45 ° c, fan coil units and combined air-conditioning units and other samples are available in quantity of heat, usually to 60 ° c for the water, so that must be the amount of heating equipment be amended;

★ Choose heat pump units, should generally be to winter heating load as select by, at the same time check the cooling load in summer;

★ For shopping malls, restaurants, and other internal load and fresh air load extremely large buildings, due to the heating load generally only cooling load of 60%-70%. Therefore, the use of heat pump unit and single cold units combined supply way, for example, "3 x 1" mode, i.e. 3 Typhoon heat pump units plus 1 single cooling unit;

★ Air source heat pump rated for quantity of heat, are usually standard conditions (environment temperature t0 = 7 ° c water temperature ts = 45 ºc, when the ambient temperature is below 7 ° c, the quantity of heat will be drastically reduced. General reductions as follows: t0 = 5 ℃, the percentage decline to 5%-8%; t0 = 3 ℃, the percentage dropped to 12 per cent to 14 per cent, t0 = 0 ℃, the percentage dropped to 25 per cent to 32 per cent; t0 =-3 ° c, the decline in the percentage of 45% and 50%; t0 =-5 ° c, 55% decline in the percentage ~ 65%. Note: in accordance with the standard condition of air-cooled heat pump units, in fact, in a 3 ° c, the following is not functioning properly;

★ Air-cooled heat pump units of a single smaller capacity, should be applied to small and medium-sized projects;

★ Winter outdoor air temperature during the day is always higher than the night. Therefore, outdoor heating calculation temperature long tw =-3 ° c in the daytime only, for use in buildings such as office buildings, shopping centres, etc, you can use an air-source heat pump unit. For a full day (24 hours) requirements for heating buildings, when using an air-source heat pump should be treated with caution;

★ Water source heat pump system is suitable for many residents of apartment buildings and an area of larger large villas. The design should ensure that the system flow calculation accuracy. For cooling towers, pumps and other equipment selection;

★ In relative humidity higher areas, selection of the heat pump, should pay special attention to the analysis of operating conditions, and to take effective measures of defrosting.

(3) in the engine room of the ground source heat pump parts

1. heat pump in the engineroom the heat pump unit part can refer to the following steps for selection:

★ Water source heat pump unit capacity is not too large. Central air conditioner cold heat source equipment selection, equipment cooling (heat) about design cold (hot) load 1.05 ~ 1.10.

★ Water source heat pump unit type, should be as close as possible to the design of cold (hot) load. If set too large, the run time is short, start frequently. Unit capacity, long-running, conducive to dehumidify.

★ Closed water system water temperature, water temperature lower summer requirements, with the aim of improving energy efficiency, reduce power consumption. In winter the water temperature is not too high, because the temperature is high, although high cooling capacity, but also the high power consumption, the efficiency coefficient of variation.

¡Ï design-time objects that you want to consider building heating and air conditioning while using coefficient. At the same time using the coefficient value and building types, and the number of buildings, through theoretical and measured. The residential air-conditioning load calculation using coefficient of lists of data is: when the household page〈 100 households, the coefficient of 0.7; when the number of 100-150 households, 0.65 ~ 0.7; when the number of 150 ~ 200 households when 0.6.

2. outdoor ground heat exchanger parts can be selected with reference to the following steps:

Geothermal heat exchanger selection including the type and structure of selected, for a given building site conditions should try to run the design to meet the needs of the lowest cost. Geothermal heat exchanger selection primarily concern the following aspects:

★ Geothermal heat exchanger of the layout, including tube and bind methods, as shown in the figure. Tube can be divided into horizontal and vertical. Select the size depends on the site, the local soil types and mining costs, if the site is large enough and no hard rock, level than the economy; if space is limited by vertical layout, many occasions it is the only choice. If the site has a solid rock, the rock drill bits can successfully drilled. Connection way with serial and parallel two, in-line system is only one fluid channel, parallel system of fluid in the pipeline can have two or more runners. In-line or parallel connection depends on the size of the cost, in-line system a parallel system of pipe diameter, and the cost of large-diameter pipe. In addition, because the pipe diameter is larger, the system needs a lot of antifreeze, a corresponding increase in weight of the pipe, causing the installation labour costs are large.

★ Plastic pipe options, including materials, pipe diameter, length, circulating fluid head losses. Polyethylene is the geothermal heat exchanger tube materials most commonly used. This pipe of good elasticity, and can be formed by heating than tubes the fusion of its strength and better connection connector. Diameter of choice you have to follow the following two principles: first, the pipe diameter is large enough, circulation pumps for less energy consumption; Secondly: the pipe diameter is small enough so that the tubes of fluid in a turbulent region, make the fluid and the pipe inner wall of the heat exchange efficiency is good. At the same time when the design should also take into account the size of the installed cost.

★ Circulation pump selection. Selection of the circulation pump should be able to meet the continued driving fluid flowing through the heat pump and geothermal heat exchanger, and low power consumption. General in design cycle pump should be able to achieve each ton circulation fluid required power dissipation to 100W.

(4) water source heat pump unit

★ Water source heat pump unit capacity is not too large. Central air conditioner cold heat source equipment selection, equipment cooling (heat) about design cold (hot) load 1.05 ~ 1.10. water source heat pumpunit type, should be as close as possible to the design of cold (hot) load. If set too large, the run time is short, start frequently. Unit capacity, long-running, conducive to dehumidify.

★ Closed water system water temperature, water temperature lower summer requirements, with the aim of improving energy efficiency, reduce power consumption. In winter the water temperature is not too high, because the temperature is high, although high cooling capacity, but also the high power consumption, the efficiency coefficient of variation.

¡Ï design-time objects that you want to consider building heating and air conditioning while using coefficient. At the same time using the coefficient value and building types, and the number of buildings, through theoretical and measured. The residential air-conditioning load calculation using coefficient of lists of data is: when the household page〈 100 households, the coefficient of 0.7; when the number of 100-150 households, 0.65 ~ 0.7; when the number of 150 ~ 200 households when 0.6.

(5) where the chiller unit

Chiller design selection is sure to meet the needs of the cooling load and thermal load, but not too large margin to prevent the waste caused host investment. A system is a good idea to configure two or more host and configure independent cooling water circulation pump, cooling towers and water circulation pump, so you can make the system more reliable, low-load lower power consumption of pump. Since chiller operation no vibration, wear-free, reliable operation, such as the selection of a single host also has an obvious economic advantages without reducing its reliability.

Standard chiller for quantity of heat is the cooling capacity of 80 per cent, that is, if the heat load (such as refrigeration for sanitary hot water, or heating time for hot water or space heating load greater than cooling load), you can choose the high-voltage generator with large capacity, in order to improve the heating or select large cooling capacity unit to achieve (such a large initial investment). Each step of a number of high-voltage generator, heating capacity increased by 20 per cent increase, Q = 0.8 × 0.2. If summer cooling and hot water supply (by summer cooling capacity selection) are: or, and n is the increasing number of high-voltage generator. If the system needs summer refrigeration, winter heating and sanitary hot water supply (fulfill summer cooling capacity requirements checking after the selected models for quantity of heat in winter):

① meet summer and winter seasons usage requirements;

② as heat load in winter, take greater high-voltage generator meets;

③ If heat load in winter, take increasing unit model to meet the requirements (that means a unit increase the cooling capacity models). If you need to increase the unit model meets the requirements, the summer by regulating the burner to keep the economy running. In the transitional seasons system they rely on regulating the burner head to ensure economical operation. In addition, the cooling capacity and the proportion of the quantity of heat can also be used to adjust the implementation of some of the valve.

(6) heat pump unit

★ Unit load selection of air-source heat pump unit is normally based on building the capacity of the choice of the summer cooling load, thermal load in winter to check calculation. If the amount is greater than the unit heating heating load, then the units meet the requirements of winter heating; if the heating load is greater than the unit quantity of heat, you can press the following 2 situation considerations: when a unit quantity of heat heating load of less than or equal to 50% and 60%, you can increase the auxiliary electric heating appliances; whereas it should be considered at the beginning of the investment and operating costs to determine the unit of capacity, that is, the installed capacity of the appropriate increased unit.

¡Ï auxiliary electric heating installed capacity of air-cooled heat pump air conditioning system with auxiliary electric heating devices have the following forms are available: (1) in the fan coil system set small boiler to improve the water temperature in winter unit; (2) in other sources of heat (hot water or waste water), Use the pull-type heat exchanger increase winter water temperature; (3) direct burn (air supply for water, gas, diesel day) to improve the water supply temperature of the heater in winter; (4) with electric heater for improving the water supply temperature in winter.

★ Cool (hot) load in select air source heat pump unit, you should also consider building cool (hot) load. General public buildings, air conditioning equipment are often intermittent operation, that is run during the day, night off, so the day running, since the building's thermal (heat), room temperature needs to run after a certain amount of time to achieve the set value, if shorter this time, the choice of unit, we should consider the accumulation of cold (hot) load. It and cooling (heat) time-related, General cooling (heat) times 2 ~ 3h.

(VII) summarization of combined air conditioner class

At present, the comprehensive functionality of high-rise building of the central air-conditioning system, often to the desired temperature, humidity, ventilation rate, cold (heat) load of air distribution, uses a tiered or partition for centralized processing, its advantages are ease of building property management and use of energy.

Combined air conditioner is a combination of cell function, the user may act according to the air conditioning and air treatment needs, choose the desired sections for free permutations and combinations, have great freedom and flexibility.

Considering the operation and maintenance convenience, air evenly and other factors, should be appropriately set up middle segment.

Selection must note the following points:

1, the manufacturer provides a combined air-conditioning unit features a combination of a paragraph. Map to be given on the selected unit model, specification, section number, feature length, arranged in the order and left-position, and other basic requirements.

2. combined air-conditioning unit operation surface provides for:

(1), back to the fans have one side of the transmission belt;

(2) bag filters capable of handling filter bag side;

(3) automatic winding type filter is equipped with one side of the control box;

(4) cold (hot) media import and export side, the drain side;

(5) washers (above) of water sprinkler fittings.

When people in the face of the unit operations, air blow to the right, on the other hand to right-to-left-style, selection and ordering instructions required for left and right.

3. Select the table coolers, heaters and muffler, you must set the filter (below), to protect the heat exchanger and muffler surface cleanliness to prevent plugging holes, sewing, and should be set in the middle segment.

4, paragraphs, tables, cold water, and so on, apart from the existing sewer received to the air conditioning unit, you should consider the drainage of water plant.

5. choose washer (above), you should note a few level rows.

6. Select the table coolers, heaters (above), should indicate the type and number of rows, use the cold (hot) media properties, such as temperature and pressure. Unit with steam heating, air temperature not less than 20 ° c; to hot water heating, air temperature not less than 15 degrees centigrade.

7. choose dry steam humidifier requires instructions humidification, for steam pressure and controls methods (manual, electric or pneumatic).

8. choose the fan section to illustrate fan models, specifications, installation forms, outlet locations, the fan should be set before the middle segment, ensuring uniform airflow. Air supply unit air enthalpy drop shouldbe not less than 34kJ/kg.

9, indicate the location of the air interface, orientation and size, delivery, return air valve type, specifications, the use of control mode (manual, electric or pneumatic). Blower outlet should have flexible short-tube, fan base should be damper.

10, needs to stay out of the hole and instrument mounting hole locations and the locations of fan power supply lead.

11, unit basis shall take precedence over the Interior of the plane, there should be based around the floor drain, drainage ditch or to exclude the condensation water and the water at the bottom of the venting device.

12, unit around or unit and unit (multiple) layout should be sufficient for the operation and maintenance of space.

13, taking into account the anticorrosion performance unit, Cabinet material best selection of galvanized steel, glass steel or special alloys. For ferrous metals production component surface should be made for anti-corrosion treatment; should be used in fiberglass body oxygen index of not less than 30 of flame retardant resin production.

14, unit standard air leakage rate:

(1) unit within the static pressure to maintain 700Pa, unit air leakage rate is not more than 3%

(2) clean air conditioning system of units within the static pressure to maintain cleanliness 1000Pa, less than 1000 level, unit air leakage rate is not more than 2%; cleanliness level is greater than or equal to 1000, the unit is not greater than the air leakage rate of 1%.

On unit performance appraisal requirements: unit of the air flow, pressure, cooling and heating of the measured value should be greater than or equal to the nominal value of 93% water resistance unit-and the input power of the measured values must not be greater than the nominal value of 110%.

Basic parameter should satisfy the following requirements:

A unit volume measured value not less than 95% of the rated value, full pressure measured value not less than the rated value of 88%.

B unit rated cooling capacity of air enthalpy drop should be not less than 17kJ/kg; air supply unit air enthalpy drop should be not less than 34kJ/kg.

C the amount of air turbine heating temperature at least should not be less than steam heating temperature 20 ° c hot water when heated temperature 15 ° c

Unit in 85% of rated voltage start properly and working.

Unit of the coil and the pipeline in any or all of the following conditions should be long-term normalRun, and no leakage:

A cooling coil in 980kPa pressure, or pass hot water used in 980kPa pressure, 60 ℃ hot conditions;

B hot water coil in 980kPa pressure, 130 ° c under the conditions of hot water;

C steam coil in 70kPa pressure, 112 ° c for steam conditions.

Unit inside the insulation, acoustic materials with non-toxic, no smell, self-extinguishing and non-absorbent performance. You should not use bare asbestos or fiberglass material. Insulation, acoustic materials and panels should be strong, smooth, seamless, out-of-the box at run time without condensation on the surface.

Condensate water treatment unit should be set, outside of the box in the run should not be leaking water, there should not be stagnant water in the tank, drainage should be smooth.

Box and check the door should have good air tightness, air leakage rate of less than 5% be-check locking performance is much better to prevent internal and external pressure differential switch itself. Coil face the wind, the wind speed exceeds 2.5m/s should be retrofitted retaining plate. Water jet segment into, out of the wind side should have excellent water board.

Unit box should have adequate stiffness, running should not be deformation. Units using ferrous material, the surface should be treated with preservatives.

Summary of chapter III of the auxiliary equipment selection

First, the water pump class product selection guide:

1. Select clear water pump mainly see parameter flow and head;

2 centrifugal pump is suitable for large-volume, large-head of the establishment;

3, pipeline pump flow range is not large, applies to lift low places.

4. regular select horizontal pump, when the installation has limitations when selected vertical pump;

5. when the single-stage pump does not meet the requirements for select double-stage pumps;

6. when the temperature of 65 ° c, t > hot water pump is selected; when t ≤ 65 ° c, cold water pump.

Second, the new fan equipment selection steps are as follows:

1, according to the installation settings to select new fan;

2. the device air flow, pressure when you choose to not less than the design value is in principle;

For special industries, such as hospital (operating room, intensive care Wo Ward), laboratory, workshop, according to the instruments industry related regulations identify needed new air flow.

3. determine the amount of refrigeration and heating design operating conditions;

4. in principle, a fresh air handling units only a floor of new air volume required;

Third, fan-coil equipment selection steps are as follows:

1. clear the selection of unit type, specifications, diffusers, and so on.

In the selection of fan coil unit refrigeration units, is to design warm-up load and thermal load unit display. In most cases, coil have sufficient latent heat capacity, can meet the design requirements. If using outdoor air is appropriate dressing their load and calculation formula: water temperature rise (° c) = air temperature rise (° c, db)

First to determine the work requirements:

Refrigeration: indoor warming refrigeration load (), the total heat indoor cooling load (), the air temperature (° c, db/℃ wb), the water temperature (° c), the amount of wind ();

Heating: usually chosen by the refrigeration unit, heating capacity is adequate, receipt of same by water flow to selected. That is, with water temperature for indoor heating load required. Indoor heating load (), the air temperature (° c).

Then determine the unit specifications, the required water quantity, water temperature and pressure drop, and other parameters.

2, clear the selection of the unit of water left out or closing out a direction (and related piping layout etc).

3. clear fan motor bearings is used for oily or not oily axis pump. If you choose not to use the oil axis pump, consistently within regular refueling.

4, notice the water of the thermal insulation measures so as to avoid the summer use of condensation, defaced indoor building.

5, hot water, water temperature in winter pass normally does not exceed 60 ° c, could reduce scaling of alternating hot and cold while mitigating role expanding lhe forces weakened, affecting heat transfer.

6, unit coil set the highest operable.

IV. Summary of cold water tower

1, according to the cooling water temperature: temperature in high-temperature Tower, Tower, Tower.

2. follow the installation location of the current situation and the requirements for noise: crossflow Tower and countercurrent Tower.

3. follow the chiller cooling water cooling water selection, in principle, slightly larger than the cooling tower water chiller for cooling water.

4. selection of multiple water tower to select the same model.

Secondly, the cooling tower selection need attention:

1, Tower body structure material to stability, durability, corrosion resistance, assembled with precision.

2, water allocation uniformity and Wall flow less splattering device selection is reasonable, is not easy to stop up.

3. spray fillers of the type conforms to the requirements for water quality, water temperature.

Match 4, fan, to guarantee long-term uptime, no abnormal noise and vibration, and leaves with good resistance to water erosion and is of sufficient strength. Fan blade installation angle adjustable angle to ensure consistent and motor current not exceeding the rated current of the motor.

5. low power consumption, low cost, small and medium-sized steel framed glass Tower also calls for the quality of light.

6, Tower should try to avoid the heat source, exhaust and flue gas occurs at the point, chemicals and coal pile piled nearby.

7, cooling tower or tower and the distance between other buildings, apart from considering the requirements of ventilation Tower, Tower and building mutual influence, you should consider building fire, explosion-proof safety distance and the construction and maintenance of cooling towers.

8, cooling tower of fles direction by 90 °, 180 °, 270 ° rotation.

9, cooling tower of the material is resistant to low temperatures-50 ° c, but the average temperature for the coldest month is less than-10 ° c in the region should indicate when ordering in order to take measures to prevent icing. Increase in the cost of cooling tower is about 3%.

10, the cycle of water turbidity is not greater than 50mg/l, short-term 100mg/l is not greater than not contain oil and mechanical impurities, if necessary, take out the algae and water stabilization measures.

11. water distribution system is designed for nominal amount, such as the actual difference between the water and the nominal quantity of ± 15%, when ordering should indicate to modify the design.

12, cooling tower parts in storage during transport, it shall not be pressing weights, and attention to fire exposure. Cooling tower and installation, transportation, repair process must not use electricity, gas welding, flame, no use of firecrackers in the vicinity of the fireworks.

More than 13, round tower, Tower and Tower design between net distance should remain less than 0.5 times Tower body diameter. Countercurrent flow cooling tower and the square Tower can be side-by-side layout.

14, selection of the pump should be equipped to ensure the flow of cooling tower, lift and process requirements.

15, when you select multiple cooling towers, use the same model as possible.

In addition, measure the effectiveness of the cooling tower is usually also adopts three indicators:

(1) cooling tower water inlet temperature and outlet temperature t1 t2 difference Δ Δ t t, is known as the cooling water temperature, in General, the higher the temperature, the cooling effect is better. In terms of production, the greater the Δ t production equipment cooling water flow rate can be reduced. But if the water temperature t1 is high, even if the temperature difference between Δ t, cooling water temperature may not be reduced to meet the requirements, so this indicator is needed, but the description of the problem is not comprehensive enough.

(2) cooling water temperature t2 and air wet-bulb temperature ξ proximity Δ Δ t ', t ' = t2-ξ (° c), Δ t ' called cooling high. Δ t ' value is smaller, the better the cooling effect. In fact Δ t ' could not be equal to zero.

(3) into account in the calculation of the cooling towers of tricking water density. Tricking water density refers to the effective area of 1m2 every hour on the cooling water. Q with symbols. Q = Q/F, m3/m2.h (Q-cooling flow, m3/h; effective F-cooling tower water spray area, m2)

Other notes:

1. in accordance with the conditions and amount of water to determine its main parameters.

2. optimization for efficient (the same water body machine small).

3. optimization of low noise (the same water fan input power low noise low).

4. packing material good long life, flame-resistant packing optimization for first.

5. selection location consideration should be given effect by the monsoon.

Requirements:

1, the resistance of pipe cannot be lower than fill pipe inlet diameter.

2, cooling tower water pipe valve closer from the Tower, the better.

3. recommends that the return pipe insulation outdoor part.

4, multiple parallel cooling recommendations made two road, waterway, easy to adjust in units of energy-saving operation.

5, cooling tower startup must first open water pump, after the fan. Not allowed in the absence of rain water is fan operation.

Therefore, in the water pipe is equipped with a tilt of the water board, if you start the fan without water, the water distributor flip, water boards will scrape to packing, packing away by the wind blowing out or cloth water card bad, cooling tower starts, we must first open water pump, blower, open back stopped working, first stop after stop water pump, blower.

5. air inlet product selection guide

1. first, according to technological requirements and field conditions, etc., determine the form and sent back to the wind, air distribution and air outlet type;

2. Secondly, according to the air flow to determine the dimension of the diffusers;

3. once again, the selection is also note the following requirements:

(1) General use louver or slit air outlets, and other side sent, conditional, should be affixed to the side to send air flow. Process air conditioning room, when the room temperature permitted fluctuation range is less than or equal to ± 0.5 ℃, the air should stick to the side to send.

(2) when there is a ceiling available, according to the room height as well as the use of the site on the air, using circular, square and gap type diffuser and orifice plate air. When the unit area air is big, and workspace called wind smaller or regional temperature requirements strictly, should adopt the orifice plate air.

(3) space for a large public building and room temperature permitted fluctuation range is greater than or equal to ± 1.0 ¡æ tall plant, use vents or swirl diffuser air.

Used to attach the side sent, should meetthe following requirements:

(1) air distance from the ceiling on the edge of the large, air services should be set up 10-20 degrees centigrade of diversion.

(2) air should be set so that the Jet is not about skewed to the Distributor.

(3) there shall be no Jet process stops. In addition, air export wind speed, air distribution, air type, installation height, Interior allows wind speed and noise standards, and other factors. Muffler requirement is high, suitable for mining2-5m/s, vent air can take 4-10m/s.

Back to the arrangement of diffusers, should meet the following requirements:

(1) back on the air outlet should not be located in the Jet area and who stay for a long time, the use of the site, the side to send in the air of yishe with side.

(2) where applicable, may be set back to the wind or corridor air return, but Corridor section wind speed should not be too large.

Weak current College】 【HVAC professional English table (4).

Refrigeration
The first section of general terms
Section 6.1.1 of refrigeration refrigeration
Artificial methods from a substance or a space out of the heat for the air-conditioning, refrigeration and scientific research and so provide cold source technology.

Section 6.1.2, refrigeration engineering refrigeratingengineering
Refrigerator and its main equipment and system design, manufacture, application and action technology.

Section 6.1.3, cooling capacity refrigeratingeffect
Unit of time, from the refrigerator evaporator of refrigerant out of the heat.

Section 6.1.4 bar standard refrigeration capacity standardrating [ofrefrig-ratingmachine]
p>
Section 6.1.5 of air conditioning load cooling capacity ratingunderairconditioningcondition
The working conditions of air conditioning, refrigerator cooling capacity.

The first section 6.1.6 condensingpressure condensing pressure

Refrigerants condensing pressure.

Section 6.1.7 articles condensing temperature condenoingtemperature

The refrigerant vapor condensation in the condenser, correspond to the condensing pressure saturation temperature.

The first article 6.1.8 evaporatingpressure evaporation pressure

Refrigerant liquid in the evaporator evaporation pressure.

Section 6.1.9 evaporatingtemperature article evaporation temperature

Refrigerant liquid in the evaporator in gasification, corresponds to the evaporation pressure of the saturated temperature.

The first article 6.1.10 suctionpressure inspiratory pressure

Compressor inlet suction tube refrigerant gas pressure.

The first article suction temperature suctiontemperature 6.1.11

Compressor inlet suction tube refrigerant gas temperature.

Article 6.1.12 bars gas pressure dischargepressure

Compressor outlet exhaust tube refrigerant gas pressure.

The first section exhaust temperature dischargetemperature 6.1.13

Compressor exit of the exhaust pipe to the temperature of the refrigerant gases.

The standard conditions article 6.1.14 standardcondition

Comply with the standards stipulated in the refrigerator running conditions.

The first article 6.1.15 airconditioningcondition air-conditioning operation

In order to meet the air conditioning requirements stipulated in the refrigerator running conditions.

Article 6.1.16 [chiller] [refrigerating] coefficient of performance (COP) coefficientofperformance

In the specify conditions, refrigerator cooling capacity and its ratio of net input of energy.

The first article cold-water chilledwater 6.1.17

A refrigeration system out of the cold-temperature water or natural water.

The first section of the cooling water coolingwater 6.1.18

Refrigeration equipment for cooling water.

The first article enthalpy enthalpy 6.1.19

Substances with a thermodynamic properties. Defined as the material product of the volume, pressure, and can be combined.

The entropy of entropy 6.1.20

A thermodynamic State functions. For a State by State 1 to 2 of reversible processes in a closed system, with its changing value to the given points. Dq represents the temperature of which is t, system and environment to exchange heat between reversible base units.

The exergy exergy 6.1.21 bar

Energy may be converted to the long hard parts.

The first section fire no anergy 6.1.22

Energy cannot be converted into useful work.

The article-enthalpy diagram 6.1.23 pressureenthalpychart

To pressure and enthalpy value coordinates representing material status changes of thermal state diagram.

The first article enthalpy entropy diagram 6.1.24 enthalpyentropychart

The enthalpy, the entropy for coordinates and represents the physical status of thermodynamic state diagram.

The first section press junto 6.1.25 pressurevolumechart

To pressure and conformity coordinates representing the ratio of material status changes of thermal state diagram.

The first article refrigeration room refrigeratingstation 6.1.26; refrigeratingplantroom

Install the refrigerator and, its by-laws, in the case of devices in the room, also called the freezing point.



HVAC professional English table (5)
The second section of refrigerants and refrigeration cycle

Section 6.2.1 of refrigerants workingsubstance

In working in a thermodynamic cycle.

Section 6.2.2Article refrigerant refrigerant

Refrigeration system, the completion of the work of the refrigeration cycle.

Section 6.2.3 of azeotropic refrigerant azeotropicmixturerefrigerant solution

Two or more of the refrigerant, according to certain component mutually dissolved generated mixed refrigerant. In the constant pressure of the refrigerant has a constant temperature of evaporation and condensation temperature, gas and liquid phase with the same component.

Section 6.2.4 non-azeotropic refrigerant nonazeotropicmixturerefrigerant solution

Two or more of the refrigerant, according to certain component mutually dissolved generated mixed refrigerant. In the constant pressure of the refrigerant evaporating temperature and condensing temperature does not remain constant, and gas and the liquid has the same composition.

≫ section 6.2.5 of freon freon

Used as refrigerant in saturated hydrocarbons halogen derivatives of hydrocarbons.

≫ section 6.2.6 of ammonia and ammonia

A molecular formula for NH3 of inorganic compounds refrigerant.

≫ section 6.2.7 of LIBR lithiumbromide

Absorption refrigeration of the absorbent. A formula for the solid salt crystal LiBr.

≫ section 6.2.8 article refrigerant water waterasrefrigerant

In absorption refrigeration, water as refrigerant.

≫ section 6.2.9 of refrigerant secondaryrefrigerant; refrigeratingmedium
Indirect refrigeration system to absorb the refrigeration space or medium heat and transfer it to a fluid refrigerant, also known as refrigerant.

≫ section 6.2.10 strongsolution article concentrated solutions; strongliquor

Solute composition higher solution.

Section 6.2.11 of dilute solution weaksolution

Solute composition lower solution.

Section 6.2.12 Strip anticorrosive corrosionsnhibitor inhibitor;

Join the liquid to lower the freezing point of an additive.

The first article antifreeze antifreezeagent 6.2.13; antifreezer

Join the liquid to lower the freezing point of an additive.

The first section 6.2.14 flashgas Flash gas

Liquid refrigerant because of sudden depressurization of partial evaporation gas.

Section 6.2.15 bar Non-Condensable gases noncondensablegas; foulgas

In condensing temperature and pressure, no condensation and exist in the gas in the refrigeration system.

The thermodynamic cycle thermodynamiccycle 6.2.16 bar

Refrigerant thermal change over again to the initial state of a series of thermal process.

Section 6.2.17 bar cyclic reversiblecycle

Consists of a series of reversible processes consisting of ideal thermodynamic cycle.

The Carnot cycle Carnotcycle section 6.2.18

Includes two isothermal process and two adiabatic process will maximize thermal energy into mechanical energy in an ideal reversible loop.

The first section 6.2.19 reverseCarnotcycle reverse Carnot cycle

And the Carnot cycle is the same as the opposite of the loop.

The refrigeration cycle refrigeratingcycle 6.2.20 bar

The refrigerant in the refrigeration system experienced a series of thermal process consisting of the thermodynamic cycle.

Section no. 6.2.21 compression refrigeration cycle compression-typerefrigerationcycle

By refrigerant liquid gas, vapour compression, vapour of machinery of liquefaction and liquid expansion, four segments of refrigeration cycle.

The first article compression compression 6.2.22

Compression refrigeration system, upgrade the refrigerant pressure process.

The expansion of expansive 6.2.23

The fluid pressure reduction, enlargement process.

The first rule 6.2.24 throttlingexpansion throttle expansion

Refrigerant through any expansion hypotensive components. With the outside world without mechanical power delivery.

The first article condensation condensation 6.2.25

Gaseous refrigerant through the process of cooling becomes a liquid.

The first article supercooled subcooling 6.2.26

Liquid refrigerant temperature down to the appropriate pressure condensation temperature following phenomenon.

Section no. 6.2.27 undercooling degreeofsubcooling

Condensing temperature and cold temperatures.

The first article overheating supeheat 6.2.28

Gaseous refrigerant pressure temperature rise to a correspondingOf the phenomenon of saturated temperature above.

The first article superheat degreeofsuperheat 6.2.29

Overheating temperature and the difference between saturated temperature.

The 6.2.30 article absorption refrigeration cycle absorptionrefrigerationcycle

Powered by the heat from the refrigerant gas, vapour absorbed liquid absorption, heat absorption liquid refrigerant vapour out and refrigerants condensing, expansion, and other processes of refrigeration cycle.

The vapour blasting 6.2.31 of refrigeration cycle steamjetrefrig-erationcycle

Use of Jet will refrigerants ejection from the evaporator, condenser to make the process of completing the cycle of refrigerants.

Weak current College】 【what compensator (compensator).

Compensator
Compensator also called expansion joints, expansion joints, the Compensator. Compensator in a certain range can be axial expansion, but also to a certain point of connection between different in overcoming the pipeline axial offset arise, can greatly facilitate the valve pipe installation and removal, pipe allows expansion of free expansion, once crossed its maximum expansion of the role of the limit to ensure the safe operation of the pipeline. Compensator in a certain range can be axial expansion, but also to a certain point of connection between different in overcoming the pipeline axial offset arise, can greatly facilitate the valve pipe installation and removal, pipe allows expansion of free expansion, once crossed its maximum expansion to limit the amount of, ensure the safe operation of the pipeline. Main to protect piping security operation, has the following effect: compensation absorption pipeline axial, lateral and angular thermal deformation; vibration absorbing devices, reduce equipment vibration effect of the pipeline; absorb earthquake, land subsidence on the deformation of the pipe.
1. the products to various drainage pipes, water tanks, pumps, water meters, valves installation Mtbr provides great convenience, to long distance pipeline expansion due to temperature differences has played a very good effect.
2. the product is divided into cast iron pipes (HT), galvanized (DX) and steel (SF). Working pressure-PN6, PN10, PN16 three.
3. the installation must release the pressure plate bolts, the La-installation length, and then tighten using a diagonal method, do not press too, such as overhead, both ends must install the appropriate retention bracket.
4. flange connection using GB4216.3-4126.5 standards.
5. If the use of other sizes can be manufactured.
Compensator connections:
Flange connections, welded two, buried compensator (non-trench, located well installation) generally use welding.
Compensator installation notes:
1, the Compensator should be checked before installing their models, specifications and pipeline configuration, you must meet the design requirements.
2, with internal sleeve compensator should note that internal sleeve of direction consistent with the medium flow direction, hinge-type compensator hinge rotation planes should be consistent with the displacement of rotation plane.
3, need for "cold tight" compensator, the pre-distortion of auxiliary components should be installed in the pipeline before demolition.
4. strictly forbidden to use compensator deformation method to adjust the pipeline installation variance, so as not to affect the proper functioning of the Compensator, reduce the service life and increase piping, equipment, support widget loads.
5, the installation process, do not allow welding slag splash to wave the surface of the shell does not allow wave shell and other mechanical damage.
6. piping to be installed as soon as possible after the removal of wave compensator for installation of auxiliary position of yellow component and fasteners, and as designed is supported to provide location so that the tube Department in environmental conditions have adequate compensation.
7, compensator all active components shall not be an external component card dead or limit the scope of their activities, should ensure that the activities part of the normal operation.
8, hydrostatic test, coping with compensator pipe end in time fixed pipe support for strengthening the pipeline without moving or turning. On the gas medium and its connecting pipe compensator, attention should be paid to whether water filling need temporary support. Hydraulic test water washing of 96 chloride ion content not exceeding 25PPM.
Compensator:
Due to the Compensator has a good overall performance, so it is widely used in chemical industry, construction, water supply, drainage, oil, and heavy industry, refrigeration, sanitary, plumbing, fire, electric power and other infrastructure projects.

Weak current College】 【electric actuator selection considerations.

First, according to valve type electric actuator
Valve type quite a bit, it works too, generally to turn the valve plate angle, lifting the valve plate, and other ways to achieve open and close control, and electric actuator mating time should first select according to the type of the valve actuator.
1. point-travel electric actuator (corner < 360 degrees)
Electric Actuator output axis of rotation is less than a week, i.e. less than 360 degrees, usually 90 degrees on the realization of process control valves open and close. Such electric actuator installation interface method is divided into direct-attached type, the base two crank.
A) direct-attached: refers to the output shaft of the electric actuator and valve stem in the form of a direct-connect installation.
B) base crank: refers to the output shaft connection by crank and the valve stem.
This type of electric actuators for butterfly valve, ball valve, plug valve, etc.
2. multi-turn electric actuator (corner > 360 degrees)
Electric Actuator output axis of rotation is more than a week, that is greater than 360 degrees, it will normally take many laps to achieve process control valves open and close.
This type of electric actuators for gate valves, globe valves, etc.
3. direct-travel electric actuator (direct line)
Electric Actuator output axis of movement to the straight line motion mode, not a rotation.
This type of electric actuators for single seat control valve, double seat control valve and so on.
Second, according to the production process control requirements determine Electric Actuator control mode
Electric Actuator control mode General split into switching (open-loop control) and Regulation (closed-loop control).
1. switch (open-loop control)
Switch actuator on the valve normally open or closed control, valve or in the fully open position, either in full off position, this type of valve is not required to carry out precise control of the media flow.
Of particular note is the switching actuator due to structural forms of different also can be divided into separate structure and integrated structure. Selection of required to address, or often occur in the on-site installation time and control system does not match conflict, etc.
A) split structure (usually called the common type): control unit with electric actuator, actuator cannot separate the valve control, required plus control unit can control, General external use controller or control cabinet form.
The disadvantage of this structure is not easy to install the system as a whole, increasing the wiring and installation costs, and prone to failure, when a fault occurs, not easy to diagnose and repair, price is not ideal.
B) integrated structure (often referred to as a whole): control unit with electric actuator packaged as a whole, without the need for external distribution control unit can be reality in-place operation, remote control simply output-related information to it.
The advantage of this structure is to facilitate the installation of the system as a whole, reducing wiring and installation costs, easier to diagnose and troubleshoot. But the traditional integration structures also have many imperfections, the smart electric actuator, the smart electric actuator followed will be explained.
2. adjust the type (closed-loop control)
Regulation-type electric actuator not only with switch integrated structure and precise regulation of the media flow. Because of the function, it also precise control of the valve, from the scope of their works in this not for detailed instructions. The following regulation-type electric actuator selection needed if there is a brief description of the arguments made.
A) control signal type (current, voltage)
Regulation-type Electric Actuator control signal generally has a current signal (4-20mA, 0-10mA) or voltage signal (0 to 5V, 1 ~ 5V), when you need to clear the selection of control signal type and parameters.
B) work (electric drive type, power off)
Regulation-type electric actuator works normally electric opening (in 4 ~ 20mA control, for example, electric drive type refers to the corresponding signal is 4mA valve clearance, 20mA corresponding is valve open), and the other for power off-(4-20mA control, for example, electric drive type refers to the corresponding signal is 4mA valve open, 20mA corresponding is valve clearance). the General selection required a clear work forms, many of the products after the factory and cannot be modified, Ogilvy valve control production of intelligent electric actuator can be modified at any time by setting the scene.
C) breaking, protection
Breaking, protection refers to the line, such as fault control signal is lost, Electric Actuator control valves open and close to the set of values, common protection value is full, full off, hold position three situations and difficult to modify after the factory. Ogilvy valve control production of intelligent electric actuator can be set through the site, and for flexible changes can be set anywhere (0 ~ 100%) for the protection of values.
Third, according to valve required torque determine electric actuator output torque
Valves open and close the torque required to determine electric actuator selection much output torque, generally by users or valve manufacturers themselves matching, as the actuator manufacturers only the output torque of the actuator, the valve is normally responsible for opening and closing the desired torque from the valve diameter size, work pressure, and other factors, but because the valve manufacturers processing precision, Assembly process distinct from the different manufacturers with the specifications of the desired torque valve also differ, even with a valve manufacturers of the same specification valve torque also vary, elected type actuator torque selection is too small it will cause does not close the valve, actuator required to choose a reasonable range of torque.
4. According to the selected actuator determine electrical parameter
Because different actuator manufacturers of electrical parameters vary, so the selection is generally required to determine the electrical parameters, mainly motor power, rated current, secondary control circuit voltage, are often the result of negligence, control system and electric actuator parameter does not match the result in time off trip, fuses, thermal overload relay protection fault-off, etc.
5. According to the used select enclosures, explosion-proof rank
1. shell IP protection, etc.-Level 2. explosion-proof rank

Weak current College】 【display luminance calculation method.

<br> To full color screen, for example, usually red, green, blue and white balance ratio is 3: 4: 1 <br> <br> To P16 (2R1GB) 5000CD/square as an example: <br> Red LED .lamp brightness: brightness 5000 (CD) / M2 & # 247; point/M2 & # 215; 0.3 (white balance proportion accounted for 30 per cent) & # 247; 2 & # 247; 0.8 (System loss) .= 240CD <br> Green LED lamp brightness: brightness 5000 (CD) / M2 & # 247; point/M2 & # 215; 0.6 (white balanced ratio of 60 per cent) & # 247; 0.8 = 960 <br .> Blue led brightness: brightness 5000 (CD) / M2 & # 247; point/M2 & # 215; 0.1 (white balance proportion accounted for 10 per cent) & # 247; 0.8 = 160 <br> <br> .(240 & # 215; 2 + 960 + 160) & # 215; 0.8 & # 3906/215; = 5000CD/square meters points <br> <br> (1) known exactly rejecting and brightness for single-tube .brightness. <br> For example: 2500 point density per square meter, 2R1G1B requests per m² brightness for 5000cd/m2, then: <br> Red LED lamp brightness: 5000 & # 247; & # 215 2500; 0.3 & .# 247; 2 = 0.3cd = 300mcd <br> Green LED lamp brightness: 5000 & # 247; & # 215 2500; 0.6 = 1.2cd = 1200mcd <br> Blue led brightness: 5000 & # 247; & .# 215 2500; 0.1 = 0.2cd = 200mcd <br> The brightness of each pixel is: 0.3 & # 215; 2 + 1.2 + 0.2 = 2.0cd = 2000mcd <br> <br> (2) a known single tube brightness .for full screen brightness. <br> For example: P31.25, Nichia tube, for example. <br> The main aspects of a specification HSM display the red and green <br> HSM-PH-A + (Nichia) 180 - .440mcd1020-2400mcd <br> Because white balance with luminance ratio of red green blue = 3: 1; 6: white balance in proportion to the Green tube brightness to match other tubes. So are as follows: <br> Red: Green = 3 .: 6, green tube brightness is 2 x red tube, ie Red tube brightness: 2400 (blue) & # 247; 2 = 1200mcd again because the red, green, blue, four tube, red tube 2, therefore, a single red .tube brightness: 1200 & # 247; 2 = 600mcd. <br> Green: Blue = 6: 1, brightness of the Green tube is the blue tube of 6 times, that is, the blue tube brightness: 2400 (blue) & .; # 247; 6 = 400mcd <br> Because, 1 light pixels = 2 red tube + 1 green tube + 1 blue tube; <br> That is one pixel brightness = 600 (red) & # 215; 2 + 2400 ( .green) + 4 (blue) = 3400mcd = 3.4cd <br> Per m2 brightness = 1 glow brightness of pixels; & # 215 per square meter of the pixel density (number) = 3.4cd & # 215; 1024 (pixel .count) = 3482cd. To calculate the optical loss of 20 percent, the actual brightness should be: 2785.28cd. <br> Additional knowledge: <br> Control LED brightness: <br> There are two ways to control the LED brightness. One .is to change the current flows through the LED, LED tube allows continuous operating current in 20 MA or so, in addition to the Red LED a saturation, other flows through the LED brightness is basically the current proportion; another option is to use the Visual .of the human eye with inert, pulse-width modulation method to implement gamma control, which is a cyclical change optical pulse width (the duty), as long as the repeating cycle of lightened short enough (that is, the refresh rate is high enough .), the human eye is not luminescent pixel in dithering. Since the pulse width modulation is more suitable for digital control, so in general using computer to provide LED display content today, almost all of the LED screen are using pulse width modulation to control the .levels of gray. <br> LED control system is scanning bed centralized control of all pixel point grayscale, scan panels from the control box of the pixel brightness value decomposition (ie pulse width modulation), and then to the row the opening signal LED to .pulse form (lit 1, off to 0) the row for serial transmission to the appropriate control of the LED, lit. This method uses the device less, but the serial transmission data volume is large, because a duplicate lit cycle, each pixel in .16-level gray require 16 pulse, 256-level gradation of need 256 pulses, because devices operating frequency limit, usually only LED screen do 16-level gray scale. <br> Another way is to scan the contents of the plate serial transmission not .every LED switch signal is an 8-bit binary value of brightness. Each LED has an own pulse width modulator to a control point on time. Thus, in a repeat lit cycle, each pixel in 16-level gray only need four pulse, 256 .-level grayscale with just eight pulse, greatly reduce the serial transmission frequency. This decentralized control LED grayscale method can easily achieve 256-level gradation control. Often the master box, scan panels and display and control unit consists of three parts. Master box from .the computer's display card gets one screen pixel color brightness data, and then reassign the number block scanning panels, each scan Board is responsible for controlling the LED screen on the number of rows (columns), and each row (column) on led display and .control signals are transmitted using serial manner.BR> <br> <br>.