Two-stage high temperature hybrid heat pump with parallel heat sinks.

Hybrid heat pumps have operated well at temperatures above 100ºC for a decade and several improvements have been made during this period. Heat delivery at two temperature levels with a single, integrated heat pump with two absorbers in parallel is yet not exploited. Thus, current solutions deliver to one heat demand, even though industries often have several heat demands at various temperature levels; a more efficient and advanced solution should be able to deliver heat at several temperature levels. An ammonia/water hybrid heat pump was simulated at various loads, achieving ratios of delivered heat to work input in the range 2.1-2.8. Both static and dynamic simulations were performed, and values for storage capacities to even the loads were predicted. The system manages to operate and deliver the requested capacities from both 20°C and 27°C bottom cycle refrigeration, and achieves required setpoint at all loads, steady and dynamic ones. The COP at 20°C bottom cycle might be not acceptable for commercialization, whereas at 27°C the COP values are improved by 15% (total COP), 18 % (HT COP) and -18% (LT COP).