There are numerous potential applications for suitably tailored absorption heat pumps, especially in the range of medium and large heating capacities of 500 kW (1.7 × 10⁶ Btu/h) and above. In many cases, this is the most suitable technology to utilize the available heat sources. This is demonstrated in this paper with three examples of current installations in southern Germany.

At a municipal composting plant, waste heat is generated at a temperature around 45°C (113°F). Previously, this waste heat had to be rejected to the ambient by means of a cooling tower. Now, a direct-fired single-stage absorption heat pump lifts the waste heat to a temperature of 82°C (180°F), enabling its utilization in the local heating network of a commercial area.

At a spa with various swimming pools located next to a thermal spring, a combined heating and power (CHP) engine plant was installed. The reject heat of the gas engine drives a novel two-stage absorption heat pump that utilizes the spring water as a renewable heat source to provide heating of the pools and the building.

In Munich, a solar-assisted local district heating system was installed in a new housing development with about 300 units. At this site, a seasonal hot water storage for the solar system of about 5700 m³ (2.0 × 10⁵ ft³) was erected. At the beginning of the heating season, it serves the local heating network directly, and afterwards—at a lower temperature level—it is utilized as a heat source for an absorption heat pump that is driven by the municipal district heating network. By that concept, two effects are accomplished: the available temperature change of the hot water storage is increased and the mean temperature of the solar system is decreased. Thus, an increase of the annual efficiency of the solar collectors and finally an increase of the annual solar gain is accomplished.

Units: Dual