能源地铁车站板式热交换构件瞬态传热问题的理论解

Analytical Solution to Realistic Transit Heat Conduction Problem for Slab-type Heat-exchangers in Energy Subway Station

能源地铁车站技术是一种利用地球地温能的新型建筑节能技术,对其传热计算方法进行的研究是推动该项技术前进的重点与难点。根据能源地铁车站板式热交换构件实际瞬态传热的特点,对该传热问题的理论解进行了研究与探讨。首先根据有足够埋深、有足够的换热面积两个作为热交换构件的前提条件,探讨了地铁车站中可用作热交换构件的地下结构构件,并根据其外形特点将其分为板式热交换构件和桩柱式热交换构件两大类;其次通过分析板式热交换构件实际瞬态传热特点,利用傅立叶变换对其热流边界条件进行变换,推导出能源地铁车站板式热交换构件实际瞬态传热问题的理论解;最后,分别用理论解和数值解对某具体工况进行了计算,理论解和数值解得到的两条曲线基本重合,可见,该理论解推导正确。

As a new rising kind of building energy saving technology which makes use of geothermal energy, energy subway station is of great potential in China if obstacles of the calculation and design method are overcome. In this paper, analytical solution to realistic transit heat conduction problem for slab-type heat-exchanger in energy subways station is studied. Firstly, it is discussed weather an underground structure in energy subway station could be used as heat-exchanger for a qualified heat exchanger should have enough surface area to contact the heat source which meets the temperature requirement. Qualified heat-exchangers in energy subway station are classified as slab-type heat-exchangers and column-type heat-exchangers according to their shape. Secondly, theoretical solution to realistic transit heat conduction problem for slab-type heat-exchanger in energy subways station is presented after an analysis of the realistic heat conduction problem and transforming the rectangle-wave heat flux boundary condition to trigonometric function polynomial using Fourier Transformation. Finally, the theoretical solution is validated using numerical solution by build numerical modals. Compared to the two temperature curves at the heat exchange surface of the validation modal, the two curves are highly consistent with each other which prove that the analytical solution introduced in this paper is absolutely correct.