Heating old buildings efficiently with a heat pump and eXergiemaschine

With the residential complex in Bernsdorf, Velero Immobilien GmbH and Contractor Enloc Construct demonstrate how older buildings can be cost-effectively converted to climate-friendly heat supply using a hybrid heating system and booster heat pumps. For this project, two eXm max units (eXergiemaschine with 100 kW thermal output) were installed as booster heat pumps in residential construction for the first time.

Location: Bernsdorf in Upper Lusatia

Object: 4 old buildings in prefabricated concrete construction, 178 apartments, 8100 m² living space; heat supply via contracting by Enloc Construct

Challenge: The prefabricated housing estates should be converted from natural gas heating to a climate-neutral and future-proof heating technology without insulation measures on the buildings, which does not entail any additional costs for the tenants.

Solution: The contractor has implemented a hybrid system featuring air-water heat pumps, geothermal energy, and booster heat pumps. The air-water heat pumps operate as the primary heat pump at outdoor temperatures of approximately 5 to 18 °C, while the geothermal heat pumps run primarily during the cold season. All heat pumps deliver heat at a low temperature level of approx. 35 °C with a good COP. Four booster heat pumps, including 2 eXm max units, boost the temperature for high-temperature heating circuits and domestic hot water heaters.

How eXm. works: The eXergiemaschinen use energy from low-temperature storage units as a source, raise the temperature level to approx. 65 °C, and thus charge high-temperature storage units. These HT storage units can be used to supply HT heating circuits and domestic hot water systems.

Result: Instead of the fossil fuel natural gas, green electricity is now used, meaning the heating technology operates in a climate-neutral manner. Thanks to the high efficiency of the heat pumps and booster heat pumps, the heat contracting results in no additional costs for the tenants. Continuous monitoring by the contractor will ensure efficient operation—an important contribution to low heating costs.