SIMULATION AND ANALYSIS OF AN OPEN-CYCLE DEHUMIDIFIER-EVAPORATOR-REGENERATOR (DER) ABSORPTION CHILLER FOR LOW-GRADE HEAT UTILIZATION

This paper is concerned with the investigation of a novel open-cycle absorption heat pump capable of utilizing low-grade heat sources such as solar heat, waste heat and the like as its source of power. Unlike most closed-cycle systems, which require a heat supply temperature significantly higher than that of the heat sink, the present cycle can operate at extremely small temperature differences between the heat source and sink. It employs ambient air in conjunction with an absorbent solution; the air is dehumidified, employed to produce chilled water in an evaporative cooler and then to regenerate the absorbent. The immediate application of this dehumidifier-evaporator-regenerator (DER) cycle is for cooling and air conditioning, but other applications in industrial heat pumping may be envisaged. A computer simulation of the cycle was conducted using a modular computer code developed for closed-cycle absorption systems in varying cycle configurations and with different working fluids. Some modifications in the code were necessary to adapt it for the simulation of the open cycle. Performance characteristics were determined for a wide range of operating conditions and the influence of various design parameters was investigated. The cycle appears to hold considerable promise, with some practical problems remaining to be solved.