Heating and cooling heat pumps, providing both space heating and cooling. Integrated heat pump systems, providing space heating, cooling, water heating and sometimes exhaust air heat recovery. Water heating can be by desuperheating only, or by desuperheating and condenser heating. The latter permits water heating when no space heating or cooling is required.
Heat pump water heaters, fully dedicated to water heating.
The peak load is met by an auxiliary heating system, often a gas or oil boiler. Efficient in large buildings is the water-loop heat pump system, which involves a closed water loop with multiple heat pumps linked to the loop to provide heating and cooling, with a cooling tower and auxiliary heat source as backup. The different heat sources that can be used for heat pumps in residential and commercial buildings are described in the section Heat sources. The next paragraph describes the types of heat and cold distribution systems that can be used in buildings. Table 1 summarises typical temperature requirements for various heat and cold distribution systems.