Modular simulation of cogeneration system based on absorption heat exchange (Co-ah)

Abstract

Restricted by the return water temperature of district heating network, conventional cogeneration plants cannot efficiently recover the low-grade waste heat of exhaust steam. A novel cogeneration technology based on absorption heat exchange (Co-ah) has been successfully applied to waste heat recovery of thermal power plants, enlarging the heating capacity of district heating network. In this paper, a modular simulation code is developed to simulate and analyze the complicated Co-ah system. The establishment and solution of system equations are accomplished automatically, so any changes in operating conditions or system configuration can be easily dealt with. The theoretical models are validated by the practical operating data. A comparison between the conventional cogeneration system and Co-ah system is made. With the help of the absorption heat pump, the Co-ah system recovers more waste heat from the exhaust steam and exhibits better exergetic and economic performances than the conventional system. The effects of three key parameters including back pressure, extract flow rate and extract pressure on cogeneration performances are analyzed in details, providing a guide for regulation strategies when operating conditions vary.