The Application Of Free Cooling In Off-Seasons

With the increasing concern on energy-saving in China, energy cost of building air-conditioning system, as a large part of the whole countries' energy consumption, must be reduced through certain ways. Water-side free cooling systems (also known as tower cooling systems), as one of the energy-saving method to normal air-conditioning system in off-seasons, are steadily gaining attentions in the minds of system designers, building owners and plant operators.This paper gives an introduction on the cooling theory of the water-side free cooling system and several application stories of this system in different buildings home and abroad. Based on the weather characteristic of off-seasons, it discusses the applicable conditions of tower cooling system, including the meteorological terms, building types, the load characteristics and the terminal model of HVAC systems. It also analyzes the operation of the equipment, cooling tower, plate-frame heat exchanger, pumps etc. while using in the free cooling system and evaluate in depth some important parameters of the system, such as the annual operation hours, the load to be dealed by the system, and the supply water temperature to show the energy-saving potential and efficiency of tower cooling. In addition, the author did an on-site test of a real tower cooling systems in a building in Shanghai, the test data and report has given a good example to indicate the operation situation and energy-saving effect of using this system.