1. Variability of absorption heat pump efficiency for domestic water heating and space heating based on time-weighted bin analysis
- Author
-
Moonis R. Ally and Vishaldeep Sharma
- Subjects
Absorption (acoustics) ,business.industry ,020209 energy ,Environmental engineering ,Energy Engineering and Power Technology ,Thermodynamics ,02 engineering and technology ,Combustion ,Industrial and Manufacturing Engineering ,Bin ,Storage water heater ,020401 chemical engineering ,Natural gas ,Range (aeronautics) ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Environmental impact assessment ,Absorption heat pump ,0204 chemical engineering ,business - Abstract
Natural gas-driven absorption heat pumps (AHPs) are under renewed scrutiny as a viable technology for space conditioning and water heating for residential and commercial applications because of natural gas production trends, pricing, and the speculation that it might be a “bridge fuel” in the global transition toward energy sustainability. Since any level of natural gas combustion contributes to atmospheric carbon dioxide accumulation, the merits of natural gas–consuming absorption technology are reexamined in this paper from the point of view of expected efficiency as a driver for AHPs throughout the United States using a time-weighted bin temperature analysis. Such analyses are necessary because equipment standards for rated performance are restricted to one set ambient condition; whereas in actual practice, the AHP must perform over a considerably wider range of external conditions in which its efficiency may be vastly different from that at the rated condition. Quantification of variations in efficiency and system performance is imperative to address how to provide the desired application with the least environmental impact. In this paper, we examine limiting features in AHPs and relate them to systemic performances in 16 cities across all 8 climate zones in the United States, each containing 15 bin temperatures. The results indicate that the true expectation for AHP performance is significantly less than what might be optimized for the rated condition. Statistical measures of the variation in water heating COPs show that for most cities, the COP at the rated conditions is outside the 95% Confidence Interval. It is concluded that deployment of AHP water heaters may be restricted geographically by outdoor temperature constraints.
- Published
- 2018