Dynamic duo: How to combine an air-to-water heat pump with a boiler

摘要

Air-to-water heat pumps represent a growing alternative to geothermal heat pumps in many parts of North America. The latest refrigeration technology allows these units to maintain heating capacity down to 0℉ (outdoor temperatures) while also delivering 140° water to the load. An air-to-water heat pump, such as in Figure 1, gathers low-temperature heat by refrigerating outdoor air during the heating season. The low-grade heat is "upgraded" to higher-temperature heat using a refrigeration cycle. This heat is transferred to a stream of water, or water/antifreeze mixture, where it's ready for distribution using a low-temperature hydronic distribution system.