The Research Of Cold Source And Water System In HVAC

Along with the rapid development of economy and the improvement of living standard, the energy consumption of the pubilc buildings is rising sharply because of the increase of the number of pubilc buildings. The energy used in air conditions accounts for more than half of the whole energy consumption in buildings, especially for the consumption of cold source and water systems. That is to say, it is necessary to find out the running situation of cold sources and water systems in public buildings, and then the energy saving potential can be analyzed in this paper.This paper analyses the primay pump, terminal variable flow control, the flow of invariable chilled-water refrigeration systems and cooling water systems on the side of units. The results show that when the number of the running units reduces, the phenomenon of large flow and little temperature difference still excits although the right selection of the chilled-water pumps and cooling water pumps and the proper design of the systems. Then, this paper discusses the problems result from oversize water flow, and some related suggestions and solutions are proposed.Furthmore, a large-scale public building (the main teaching building in Chongqing University) is taken as an example; the running situation of the cold source and water system is researched. Then, some problems exsiting in the operation are pointed out. In addition, detailed solutions aiming at above problems are put forward. Results show that it is more efficient for air conditioning systems after the renovation of cold source and water systems.The optimization control towards cold source and water system is taken from the following three parts: firstly, energy saving control in the outlet water temperature of chilled water; secondly, energy saving control in the number of the water chilling units; thirdly, time control of advanced available machine time and dead time. Moreover, the energy saving efficiency is 5.0%,7.8%,1.3%for each part, and the total energy saving rate is 9.8% which is very obvious. Therefore, this paper supplies foundation for the energy saving renovation of public buildings.Finally, the feasibility and energy saved when the chilled water systems adopt variable-frequency pumps directly are studied in this paper. The main teaching building in Chongqing University is taken as an example. The results show that the hydraulic characteristic curve of the chilled water system in this project is close to linear...