Analysis On The Heating Performanceof The Large-space Air Handling Unit

Compared to the usual buildings, the large-space buildings have the geometry characteristics of high height and large span, resulting that the design of winter heating is pretty complicated. It is very common that there is severe temperature stratification in the vertical direction and the horizontal distribution of heating comfort is very uneven. The temperature of the upper region is high, which results massive heat loss of this region. The operating energy consumption will rise markedly. Although many domestic and international scholars have done lots of study and development about heating methods of large-space building, the problems of heating methods about the large-space building have not been settled perfectly. The basic reason of this is that these heating methods can not solve the problem of rise of hot air driving by the thermal buoyancy. Considering this, this paper put forward a new type of heating method of large-space building, which can solve the common problem of vertical sir temperature stratification well. The method is called the large-space air handling unit.A series of relevant experiments about the large-space air handling unit have done firstly to examine the ability of solving the problem of vertical air temperature stratification. Then the results of experiments were compared to the computing results of theories, to find the computing methods of the design of the large-space air handling unit. And the numerical simulations were carried out under the experimental condition. The results of numerical simulations were compared to the experiments to examine the accuracy of numerical simulation when was used to analyze the air temperature distribution and the air distribution of the large-space air handling unit. Then a new type of the large-space air handling unit was presented in this paper when the outdoor fresh air was supplied. To examine the heating and energy-saving effect of the new heating method, a series of relevant numerical simulation were carried out. Then the method of CFD was used to compare the heating and energy-saving effect of five different heating methods. Finally considering the different vertical air temperature distribution, the existing computing methods of heating load were not suitable for the computation of the heating load about the large-space air handling unit. A new computing method of the heating load method about the large-space air handling unit, called zonal model, was put forward. And the computing results of the zonal model were compared to the results of CFD to examine the feasibility of this method.The research indicts that the large-space air handling unit can solve the problem of the adverse vertical air temperature stratification, which can reduce the energy loss significantly. Besides the heating comfort produced by the large-space air handling unit can reach the requirement of relevant standard. When the outdoor fresh air was needed, the heating and energy-saving effect produced by the new large-space air handling unit was more observably. Compared to other computing method about the heating load of the large-space air handling unit, the method of zonal model is more accurate and quickly.The research of this paper can solve the key problem of heating about the large-space building well. And the results about this paper can supply important reference value to the designer about the large-space air handling unit.