两管制空调水系统供热供回水温差范围探讨
Discussion on temperature difference range between heating supply and return water of two-pipe air conditioning water systems
摘要：
对于夏热冬冷地区的两管制空调水系统，输配管网和末端根据夏季工况确定。在确定的电价政策下，冬季的供回水温差越大，节能性和经济性越好，但受末端换热设备构造对水流状态要求的影响，供回水温差不能无限增大。结合节能要求、层流雷诺数、末端换热设备换热系数及两管制系统阀门的调节精度，以上海某实际项目为例，采用试算法得到该工程的冬季空调供回水温差范围为10～25 ℃，可供类似工程设计参考。
Abstract：
For the two-pipe air conditioning water system in hot summer and cold winter zone, the transmission and distribution pipe network and the terminal are determined according to the summer working conditions. Under the determined electricity price policy, the greater the temperature difference between the supply and return water in winter is, the better the energy saving and economy is, but due to the influence of the structure of the terminal heat exchange equipment on the water flow state requirements, the temperature difference between the supply and return water cannot be increased indefinitely. Combined with the energy saving requirements, the laminar flow Reynolds number, the heat exchange coefficient of the terminal heat exchange equipment and the adjustment accuracy of the valve of the two-pipe system, taking a practical project in Shanghai as an example, the temperature difference of 10 to 25 ℃ between the winter air conditioning supply and return water of the project is obtained by using the test algorithm, which can be used as a reference for similar engineering designs.
Keywords:two-pipe; heat supply in winter; temperature difference between supply and return water; laminar flow; heat exchange coefficient; adjustable ratio; valve authority