Many large electrically driven heat pumps are running all over the world today and even more are ordered and planned for the future. Large heat pumps are defined as equipment with an output of about 500 kW or more. These are particularly used for district heating and cooling applications.
The point has often been made that the heat pump is competitive and is well established in markets where cooling is required, too. These markets are:
• simultaneous production of cold and heat (double utilization) such as in more recent HVAC applications or in the classical commercial cases of skating rink plus swimming pool, or refrigeration plus hot tap water production; and
• consecutive production of cold and heat in HVAC plants with the same equipment, known as the heating/cooling heat pump (air cooling and dehumidifying in the summer season and heating and possibly humidifying during the winter season).
The large heat pump for district heating and cooling use proves to be well-suited:
• for base load coverage in systems without combined heat and power generation (CHP),
• for low load, low temperature summer operation for domestic hot water production,
• where supply and/or return temperatures are low,
• where water is available as a heat source, for instance cleared sewage water, industrial waste water, lake or sea water. (There are also plants with a heat capacity up to 2.5 MW using ambient air as a heat source.)