Controllable Cycle Investigation of Direct Fired Absorption Head Pump for Residential Heating Systems.

Abstract

A prototype of a monovalent air-to-water absorption heat pump is developed with a heating capacity rating of 25 kW for residential heating systems. The ambient air supplies the external enrgy, and the driving energy comes from a two-stage adjustable oil burner. As the temperature of the outside air rises, residential heating requirements drop, but the output heat of the heat pump remains constant. Therefore heat pumps have to turn on and off in fixed- cycles. The intermittent losses caused by the fixed-cycle operation of conventional absorption heat pumps have been avoided by a new, patented operating method. This makes this absorption heat pump particularly suitable for use in residential heating systems. Based on this system we developed a procedure that makes a controllable cycle possible for a sorption heat pump, which is suited to actual heating requirements without fixed-cycles. The significant improvement is the possibility of year-round operation in heat pump modem whereby ambient heat can be fed to the evaporator even when the outside air temperatures are below - 3 C and the sorption heat pump can operate at his optimal COP. This will be achieved by the control of the concentration of the ammonia-water solution and by theadjustment of an infinetely variable burner.