【 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.