Dynamic simulation of an absorption heat pump for recovering low grade waste heat

Abstract

Numerical simulation was carried out to predict the transient operating characteristics and performance of an absorption heat pump recovering waste heat of 30°C–40°C. The effects of the temperature and the mass flow rate of the heat transfer medium, the heat transfer area of the system components, and the solution circulation rate on the system performance are investigated in detail. The results obtained indicate that a higher heating capacity is obtained with an increase in driving steam temperature, waste heat temperature, and mass flow rate of hot water and waste water. It is also found that the heating capacity becomes higher with an increase in heat transfer area of the system components except solution heat exchanger. An increase in solution flow rate leads to higher heating capacity but to lower COP. A practical absorption heat pump, installed at a chemical plant, was also simulated numerically. The simulation results were compared with the operation data of the practical system.