Use of Absorption Heat Pumps to Raise District Cooling Waste Heat Temperature for District Heating Supply in Tallinn: Technical and Economic Analysis

Decarbonisation of District Heating (DH) networks is essential to achieving the European Union’s climate goals. In this context, there is growing interest among DH stakeholders in the recovery and reuse of underutilised heat sources. Waste heat recovery from district cooling (DC) networks offers a compelling option that can be used as input for various heat pump integrated DH solutions. In this regard, absorption heat pumps (AHP) showcase a promising solution to elevate a lower-temperature waste heat source with reduced electricity consumption. However, AHPs are not widely applied in DH context, primarily due to the lack of suitable waste heat sources or the necessary conditions for their effective operation. This article aims to explore various configurations of AHP and their potential integration with DC plant waste heat for DH application. The potential for adopting AHPs to boost efficiency and lower carbon emissions is evaluated through a techno-economic examination of three distinct technological configurations. For Tallinn case study, it was observed that AHPs can be more efficient, reduce energy consumption, and achieve a lower LCOH while being combined with HP condenser cooling. This study is expected to provide a theoretical support for the positive impact of using AHPs to reduce the usage of fossil fuels in the Tallinn DH network.