Performance Study of a Double Absorption Heat Transformer

Abstract

To upgrade the temperature of low or moderately heat source to a more useful temperature level, a novel H2O /LiBr double absorption heat transformer (DAHT) is proposed, which utilizes the strong solution from the generator to absorb the refrigerant vapor in the absorber/evaporator. A thermodynamic model of the system is developed to simulate the performance. Based on the first law of thermodynamics, the thermodynamic circuit process performance of the DAHT is analyzed. The calculation of the thermodynamic process of the DAHT is conducted by using an engineering equation solver (EES) program. The coefficient of performance (COP) and COP•ΔT(ΔT is gross temperature lift), serving as important design parameters to illustrate the system thermodynamic performance, are presented. The effects of absorber/evaporator temperature, evaporator temperature, absorber temperature, and condensation temperature on the COP and COP•ΔT are investigated. When the absorber temperature is 130°C, the evaporator and generator temperature is 80°C, the absorber/evaporator temperature is 105°C, and the condensation temperature is 30°C, the maximum COP of the DAHT can reach as high as 0.332.