Conference Year



Heat pump, absorption, ammonia-water, prototype, space heating


This paper presents the experimental evaluation of two packaged prototype single-effect ammonia-water absorption heat pump systems designed to provide 23.45 kW of space heating with a cycle COP of 1.65 at ambient air and hydronic return temperatures of 8.3°C and 38.3°C, respectively. These prototypes were fabricated with materials and methods that would allow for mass production and significantly reduce total system cost when compared to commercially available absorption heat pump systems. Both prototypes were investigated at their design ambient and hydronic return temperatures, and performed within 95% of their target. Their performance was investigated for a range of ambient and hydronic return temperatures to allow for characterization of system performance. The impact of parasitic power on overall heat pump COP and reduction strategies were investigated. The ability to modulate system output was investigated and both units were able to achieve 4:1 modulation. Performance of the single-effect prototypes was compared to that of a commercially available GAX absorption heat pump system and was found to be comparable.  Additional testing on one of the prototypes was performed to estimate the Annualized Fuel Utilization Efficiency (AFUE) for the climate region IV.  An economic payback of 3-5 years compared to a condensing boiler was predicted based on the projected cost and measured performance of the prototypes.Â