Absorption heat exchangers for long-distance heat transportation

A novel system for long-distance heat transportation that uses two types of absorption heat exchanger (AHE) is introduced in this paper. Using this system, industrial waste heat at 65-70 degrees C can be recovered and transported through long-distance pipelines. The Transportation Temperature Difference (TTD) can be doubled compared with ordinary system that is based on conventional heat exchangers. Considering the reduction of the pipe network cost balance with the added AHEs cost, the Minimal Economic Distance (MED) is presented. When the transportation distance is longer than the MED, the AHEs system can save both initial cost and operation cost. The ratio between the MED and the pipe diameter is in direct proportion to inside water velocity of the long-distance pipeline. Moreover, the MED would be shorter with lower relative cost of AHEs, or better performance of AHE, or the poor performance of the normal heat exchanger. In this paper, the development of the AHEs is briefly introduced. Applications in some projects show a great potential in district heating that uses low-grade heat from industries as the heat source. (C) 2017 Elsevier Ltd. All rights reserved.