Heat pumps have the potential to save energy in a number of heating, cooling or industrial applications. This potential was recently highlighted by their acceptance as renewable energy sources by the EU Energy Performance of Buildings EU Directive (EPB) recast. This acceptance will increase the interest for heat pumps, not only for new buildings but also for the renovation of old buildings.
They are principally considered for upgrading low temperature heat from renewable sources such as air, water, ground or even waste water, to a useful temperature level. In domestic and commercial applications, they can also work reversibly and produce cooling from higher temperature sources. Except in some specific and small applications, HFCs are the mostly used working fluids in heat pumps, due do their adequacy to variable system conditions and to the required high temperature level or high capacity. In addition, they don’t incur the restrictions and safety measures required for flammable fluids.
CO2 is used for hot water systems (not space heating) but does not have the most appropriate properties for space heating. This is why HFCs are preferred.
Heat pumps, have a COP (kWh delivered/kWh used) higher than 1, mostly between 2.5 and 5 (the smaller the temperature lift the higher the COP), and therefore use less resources than conventional heating systems, fueled by gas or electricity, for the same heating power.
Their application range is very broad, going from residential and commercial space and water heating or cooling, to heat recovery from refrigeration, and industrial processes.
Heat pumps are contributing significantly to reduce primary energy and CO2 emissions; and represent an important tool to reach the 2020 targets for renewable energies in the EU.