Designing Research Of Radiant Air-conditioning Based On Combined Evaporative Cooling And Mechanical Refrigeration

At present, promoting green building, energy conservation has become a trend. The so-called green building means in the entire life cycle of building, reduce energy consumption, protect the environment, and provide healthy, suitable and efficient space for people, harmonious coexistence with nature. However, the key to realize green building is adopting an air-conditioning system, which must be energy saving, safe and comfortable. Evaporative cooling and radiant air-conditioning system just meets this requirement. However, there are a series of problems in the designing of this air-conditioning system. This article takes this as a starting point, from a theoretical point to analysis the radiant air-conditioning system, and then from a new perspective to introduce a different design method of radiant floor air-conditioning respectively.First, introduce the theory of work and condensation of radiant air-conditioning in a theoretical point, anatomize cognitive errors of people, and propose several measures to avoid condensation. Then, introducing three new radiant air-conditioning systems, and describe radiant air-conditioning system based on evaporative cooling and mechanical refrigeration in detail.Then introduce the cold source, fresh air handling units, the end of the system.In addition, after the radiant air-conditioning system coming into our country, has got a great progress. There are also some design manuals giving designing methods, different manuals give different calculated methods, the results vary widely, thus, affecting the laid area, thereby affecting the initial investment. And the lacking of design parameters of radiation can’t meet the needs of designers.This paper avoids the complex calculation of radiant cooling capacity, propose a new design method. In order to get the design parameters required, first of all, analysis the factors impact the performance of radiant air-conditioning system. Analyze the simulation results of the previous scholars and summarized the correlation of factors impact the capacity of the end, get the relationship between the surface temperature of floor with cooling capacity, as well as the temperature of conditions at room is26℃, relation schema between the water temperature and the cooling capacity, relation schema between the average temperature of supply and return water with effective area (laying rate). As the design temperature of radiant air-conditioning is25～28℃, in order to improve designing parameters of the radiant cooling system, take the test bed of radiant air-conditioning based on evaporative cooling and mechanical refrigeration, after experimental tests, respectively, summing up the relationship between the cooling ability with supply water temperature at indoor temperature of25℃,26℃,27℃,28℃respectively.According to test results, the maximum cooling capacity is close to100W/m2,when the indoor temperature is28℃. Then, introduce a new designing step of radiant floor air-conditioning system details, which is based on the parameters obtained.Finally calculated on the basis of an office building in Xinjiang, analyze the potential of energy saving in radiant air-conditioning system, which take the technology of evaporative cooling as a cold source and fresh air unit. Three kinds of half-centralized air-conditioning systems are designed, which are systems of fan-coil unit and fresh air, evaporative cooling and fan-coil unit in dry coil, evaporative cooling and radiant air-conditioning, and compared the investment costs, operating costs. The calculation shows that in summer air-conditioning operate period, the operating power of evaporative cooling and radiant air-conditioning system is37percents of that in conventional mechanical cooling and fan-coil unit system, can save19percents electricity than system of evaporative cooling and fan-coil unit.