Heat pump, Adsorption, Ammonia, Carbon, Recuperation, High efficiency
An innovative adsorption cycle heat pump technology is presented that is compact and capable of achieving high energy efficiency for integrated space heating, air conditioning, and water heating. High energy efficiency is accomplished by effectively recuperating heat within the system to minimize energy consumption. This substantially reduces the thermodynamic losses that occur when the sorbent beds are thermally cycled without effective heat recuperation. Furthermore, equipment cost is reduced by thermally cycling the sorbent beds very rapidly using embedded microchannel heat exchangers, which reduces size and cost of the beds. Performance of the cycle is assessed for ammonia refrigerant and carbon sorbent using two models to simulate a sorption compressor, a simplified lumped-parameter model and detailed finite element analysis. Results from the two models are compared for validation and also used to explore the effects of system configuration, bed geometry, and operating conditions. Primary energy coefficients of performance (COP) as high as 1.03 are predicted for cooling and 1.68 for heating at AHRI standard test conditions, assuming 90% fuel utilization and 3% parasitic power. Furthermore, a heating COP of 1.24 is feasible at -25C outdoor temperature with no more than 50% reduction in heating capacity.