By studying a VAV air conditioning system and using a large number of experimental data and theoretical analysis, a optimal control strategy of cooling tower water temperature was found and proposed, based on change rate of chillers and power equipment energy consumption.Keywords-Cooling Water system in central air conditioning system ; wet bulb temperature; control of cooling water temperature ; COP of Water chiller; System EER (energy efficiency ratio)
I INTRODUCTIONIn recent years, due to the growing demand for the construction of comfortable, air-conditioning energy consumption has become the main part of the building energy consumption, optimization and energy saving research of water system the priority among priorities for energy consumption of air conditioning system is 60%-80% that become top-drawer into energy saving air conditioning systems. Optimization of variable water volume control on the central air-conditioning chilled water system has become increasingly mature, and on the cooling water of variable flow due to the impact for performance of water chiller is ignored, so there are some disputes.Studied a large number of experimental data of VAV air conditioning system of a intelligent research and combined with theoretical analysis, this paper proposes an variable air flow rate of cooling water cooling tower optimization and control strategy of cooling tower outlet temperature based on energy change rate of air-conditioning chillers and power equipment .
II ANALYSIS OF ENERGY SAVING STRATEGIES IN COOLING
WATER SYSTEM
A. Research platformStudying on the energy saving control scheme of air conditioning cooling water system is based on the research platform of a certain University VAV laboratory. Laboratory air system has six simulation rooms. Cooling water system is comprised of a the cooling tower with variable frequency control fan, a cooling water pump with transducer, two parallel cooling water pumps with the same certain lift, two sets of parallel capacity chillers. In addition, the system is also equipped with a large number of sensors about temperature, flow rate, velocity, electric quantity. The system covers an area of about 100 square meters, is a complete simulation of one real air conditioning system.
B. Performance analysis of cooling water systemIn the cooling water system, energy using equipments include chillers, cooling water pumps, cooling tower fans. When the system load is constant, factors effecting chiller energy consumption of the chilled water system have been fixed, factors affecting the energy consumption of the cooling water system are condensation temperature and cooling water flow speed through chiller. Because in the margin of safety, the lower condensation temperature and larger cooling water flow speed, the better heat transfer efficiency that reduce compressor power consumption, to reduce the energy consumption of chiller per unit about refrigerating capacity. Therefore, reducing the cooling water temperature into the chiller (cooling tower outlet temperature) and in...