subject: The use of air conditioning tower cooling application principle - air conditioning, refrigeration - [print this page] The use of air conditioning tower cooling application principle - air conditioning, refrigeration -
A water-side free cooling principle and application form 1, the water-side free cooling principle Water transfer free cooling i.e. in the conventional air conditioning system based on the appropriate part of the additional piping and equipment, when the outdoor wet bulb temperature as low as below a certain value, close Refrigeration Unit, to flow through Cooling tower The circulating cooling water, directly or indirectly to the air conditioning system cooling, in achieving energy saving. With the transition of seasons and the arrival of winter, outdoor temperatures gradually drop, low relative humidity, outdoor wet bulb temperature also fell to the cooling tower exit water temperature decreases. At a time when indoor moisture load and cooling load is also in constant decline, reduced air conditioning dehumidification required end, appropriately increasing the freezing temperature, reduce the dehumidification capacity can meet the requirements of comfort air conditioning systems. 2, system application form Cooling by cooling water directly into the air terminal device is to be divided into two broad categories: indirect cooling system and cooling system makeup live. 2.1 indirect cooling system Indirect cooling system is a system of cooling water loop and chilled water loop are independent, not connected to the middle of the energy transfer mainly depend on heat transfer equipment to carry out. The biggest advantage is ensuring the integrity of loop chilled water system. Guarantee loop sanitation, but the existence of intermediate heat loss due to cooling effect of a decline. 2.1.1 of the original air-conditioning water system in a plate attached Heat exchanger . In the cooling tower cooling, close the refrigeration unit, cooling water and chilled water to access plate heat exchanger, respectively, achieved during energy transfer. 2.2 Direct Cooling System Direct cooling system is air-conditioning water system in the original set-pass pipeline, the chilled water loop and cooling water loop connected system. According to conventional air conditioning system in summer run, into the cooling tower cooling, the cooling unit will be shut down, by Valve Doors open bypass to the end of the cooling water directly to the user. Open cooling tower system can be closed. With open cooling tower, cooling water, direct contact with the outside world easily polluted air, dirt easily into the indoor air with the cooling water diversion pipeline, thus resulting coil tube obstruction by dirt, it is seldom used. Although the use of closed cooling tower to meet the health requirements, will be due to its principle of cooling by indirect evaporative cooling, heat transfer affected, with closed cooling tower is rarely applied in China, it is also rarely used. Second tower cooling system design issues needing attention 1. Cooling tower cooling mode choice of outdoor transition temperature point directly to the system cooling hours. Assumption is calculated to determine the end of the required air-conditioning supply at this time water wet as 12.7 , consider the range of cooling tower cooling, piping and heat exchanger temperature rise of heat loss to the water temperature 4.5 , can be in the outdoor wet bulb temperature equal to or lower at 8.2 when the cooling tower can be switched to cooling mode. 2. System Cooling Tower in the summer by summer cooling load and the selection of outdoor wet bulb temperature, the cooling tower should its cooling capacity cooling mode checked. 3. Indirect cooling system heat exchanger plate heat exchanger should be selected. Plate heat exchanger with the traditional shell and tube heat exchanger compared to highly efficient heat transfer. 4. In the direct cooling system, cooling water, chilled water loop Pump Bypass should be established. Tower cooling mode, the chilled water pump off, the cooling water side through the chilled water pump, this time by the cooling water circulation pump to provide power. Therefore, in system design to consider a change of cooling-specific pump. 5. In the direct cooling system design should pay attention to cooling water, filter sterilization, to prevent blocking of the end of the coil. 6. Take into account the specific outdoor wet bulb temperature and cooling the cooling tower under construction loading rate (cooling tower water temperature and outdoor wet bulb temperature difference) with the cooling filler size decreases, so the sets of cooling tower cooling tower system can be used in series to increase the cooling effect of the method to enhance the outdoor cooling tower cooling mode transition temperature, thereby increasing the cooling hours. 7. As the filter tower cooling season, mainly in the winter run, so in areas of low winter temperatures in the cooling water system should be set in freezing facilities, such as setting next to the tube, an additional heater. 3, project examples and economic analysis Tower cooling needs throughout the year especially for cooling or building there is a need within the area year-round cooling of buildings within the area, such as large buildings, large shopping centers or the need to strictly annual cooling and humidity control buildings such as computer rooms, PBX rooms, etc.. In a number of Fan Coil Unit Fresh Air Systems Applications can filter the season, winter free cooling is possible. So much has been applied in recent years in foreign countries, in China there are application examples. Such as Shanghai 1122 part of the standard engineering design center into the deep layer of surface area of about 1700m2, there are significant internal and external areas, winter is still cooling load occurs within the area, project Heating Cooling towers and water - water heat exchanger to form in winter for cold water system, natural, full to conserve energy.
