Experimental Study On The Performance Of The Heat Exchange Muffler For Subway Heat Recovery

In this paper,a new type heat exchange muffler which can effectively overcome the shortcomings such as larger equipment,longer air duct,lower heat recovery,poorer economy and closer to the exit of the pavilion of the traditional subway exhausting heat recovery system were firstly proposed.Firstly,the heat exchange muffler experimental platform which can achieve independent control of the temperature,humidity,wind speed and noise of entrance air was established according to the similarity principle,and it can also simulate the heating transfer between the circulating water and the air through the heat exchange muffler.Secondly,the characteristics of the silencing performance and the flow resistance were compared between the heat exchange muffler and the conventional muffler through the experiment.In addition,the heat exchange performance of the heat exchange muffler was tested and analyzed.The influence of the wind speed on the noise attenuation performance and the flow resistance characteristics of the wind side,the effect of the inlet noise level on the noise reduction performance of the heat exchange muffler and the conventional muffler,the influence of the water velocity on the water side resistance loss of the heat exchange muffler were studied through the experiment.The effects of the wind speed,water velocity,air temperature and water temperature on the heat transfer performance of the heat exchange muffler were also studied.Finally,a typical subway station was taken as an example to study the heat recovery capability and the potential for space saving after replacing“general muffler+heat exchanger”of the new type heat exchange muffler in the exhausting heat recovery system.The above research results show that:(1)The noise attenuation effect of the heat exchange muffler is slightly higher than that of the conventional muffler under various experimental conditions,and the noise attenuation per unit length of the heat muffler is about 0.3dB(A)higher than that of the conventional muffler.The noise reduction is about 2%higher than that of the conventional muffler.(2)The quality of heat recovery per unit volume of the heat exchange muffler can reach to 30.6 kW/m~3 when used for heat recovery under a given working condition in a typical subway station.(3)The space volume can be significantly saved to 37.2%when the“conventional muffler+heat exchanger”was replaced by the heat exchange muffler.(4)The wind speed and air temperature have a significant influence on the heat exchange capacity of the heat exchange muffler,while the water velocity and water temperature have little effect on the heat transfer amount.The lower water speed should be adopted to reduce the energy consumption of the water pump when the heat exchange muffler is used in the heat recovery system of subway exhausting.