Research on a new type waste heat recovery gravity heat pipe exchanger

The industrial waste heat carrier, such as exhaust gas, mostly contains oil, particles, fibers and other impurities. If the conventional heat transfer enhancement techniques are applied in the gas side to recovery waste heat, the gas side flow channels are easily to be blocked, which not only greatly reduces the waste heat recovery efficiency but some time also makes the heat exchanger out of work In this paper, a new type waste heat recovery heat pipe exchanger has been designed and applied to recover thermal energy in high temperature exhaust gas emitted from setting machine in the dyeing and printing industry. Its major feature is that clean air passes though fin-enhanced vertical tubes whose inner side is a condenser while dirty gas passes though inner smooth surface of horizontal tubes whose outside is an evaporator. The new type heat pipe exchanger has a big boiling chamber. The condensed water falls down to the chamber by gravity. Three-month continuous operation of recovering dirty exhaust gas waste heat shows that the new type heat pipe exchanger can save 15% natural gas without any blockage of the gas side channel. (C) 2016 Elsevier Ltd. All rights reserved.