Requires constant temperature, and humidity in the production process of working conditions and environmental quality assurance, require a centralized or decentralized air conditioning refrigerating system. Public building large shopping malls, restaurants, and hotels of high-rise building air conditioning refrigeration system design, air conditioning water system is extremely important to rationally divided and security guarantees, it is also related to the equipment investment cost and operation cost and management of safety and reliability. Therefore in air conditioning refrigeration system when the choice, must seek refrigeration system correctly divided, reduce the bearing capacity of air conditioning equipment.
Refrigeration system heat exchange equipment, high thermal efficiency, compact structure, small volume, light weight, good seal performance,cleaning maintenance is convenient, simple operation and leak proof, good resistance to scale. Due to the plate heat exchanger can Comparatively fully meet the above requirements, which has been widely applied.
Second, air conditioning and refrigeration system in the application of engineering case.
Somewhere a comprehensive service building, with a total construction area of 177000 ㎡， main building 63 layers (elevation 200 m), two deputy building respectively 33 (117.6 m) elevation and 30 layer(layer elevation 109.8). The skirt building 6 layer (elevation of 26.5 m), 2 (10.28 m) in the basement. Main building 7 to 22 floor for office, 24-59 and 61 layers for guest rooms, 62 layer for sightseeing, 23, 42, 60 are the equipment layer. Deputy building for office buildings, the skirt building for the market, the Chinese restaurant and western restaurant, coffee shop, bar, gym, massage room, sauna, bowling room, billiards room, disco, beauty a barber shop, a kitchen, warehouse and other public facilities. The basement for freezing station, laundry room, for the transformer room, water supply and drainage pump room, sewage treatment room and garage and five civil air defense.
1, Scheme selection
(1) Scheme is a set total refrigeration station. The refrigeration equipment (water side) from 1 mpa under pressure increases to 2 mpa, refrigeration unit price increased by 4%, the corresponding equipment, accessory equipment and air conditioning equipment initial investment cost and the bottom end device costs also mentioned a lot. Clearly not economy, is not reasonable.
(2) the second scheme of high-level and low-level separate refrigeration station (set up on the podium and senior). Although this solved the refrigeration equipment of under pressure and initial investment problems, but two frozen stood the equipment operation management, maintenance inconvenience, and the system operation reliability is low, also increased the management personnel. In addition, placed at the top equipment, hoisting difficulty big, against noise and vibration equipment needs to have enough assurance. Therefore, plan nor desirable.
(3 )plan one or two advantages, using the plate heat exchanger heat exchanger, divided into primary and secondary cooling water pump system. The skirt building set to primary pump system, high-level design become secondary pump system, the two systems of refrigeration station set on the second floor in the basement. Already so solved the problems of plan a, 2, and can select high efficiency large centrifugal chiller, water chiller in a long-term design load of 40% to 80% efficient work in the area. For senior secondary pump system, the plate heat exchanger for water - water heat exchanger, solve the problem of the system is practical, reliable and safe.
2, concrete implement
Pump used in the design of primary and secondary loop.
(1) Primary pump loop refrigeration station is located in the basement floor. Central chilled water for primary chilled water directly to the user, and for secondary pump loop plate provides the cold source, water - water heat exchanger used for high-rise and super high pressure area. Level of chilled water supply and return water temperature 7 ℃ and 12 ℃ respectively, and the pump head 40 m. H2O, expansion tank in the deputy building B day.
(2) Senior secondary pump loop area and super-tall area air conditioning freezing water, by the 23rd layer (layer equipment) placed in the main building on the plate heat exchanger by the water - water heat exchanger. Secondary pump is located in the elevation of 131.2 m (42), the pump head 40 m. H2O. The secondary supply and return water temperature of 8.5 ℃ and 13.5 ℃, respectively, at the top of expansion tank on the elevation of 196.6 m (63) According to Bernoulli's equation to find the middle of the main building, high-rise, super-tall air-conditioning refrigeration system in the work and resting in the pipe network pressure and static pressure value, to determine its maximum as pressure requirements for all kinds of equipment and pipe fittings.
In a tall building air conditioning refrigeration system, after technical economy comparison, determined using water - water heat exchanger, plate heat exchanger the top area, the area air conditioning water system were set up. And then, the top along the vertical direction is divided into two or more air conditioning water area, thereby lowering the air terminal device of refrigeration equipment and pressure requirements, reduce the investment cost, and ensure the safe operation, convenient maintenance management, received good social and economic benefits.