Control Strategies for Active Regeneration in a Dual-Source Heat Pump

This paper presents a proof-of-concept for active regeneration (AR) in a dual-source heat pump (DSHP). DSHPs include multiple heat sources in a single unit to combine the benefits. Combining an air-source heat exchanger with a ground-based heat exchanger is a common strategy. Reducing the dimensions for ground heat sources is a major challenge to enable installation where space is a limiting factor. Additionally, noise emissions can be reduced by not activating air sources during noise-vulnerable times. In this study, an ice storage (IS) is used. This IS is to be used cyclically for heating during relatively cold periods and using AR with the air source during relatively warm time periods. A proper heat management system (HMS) is developed. A simulation-based analysis of parameter settings for the HMS and IS volumes is conducted. The concept of the HMS is successfully demonstrated and AR can keep small IS volumes charged for usage during cold periods. However, due to an improper HMS setup especially during spring, AR does not have a positive impact on the efficiency of the DSHP. Further technological investigation on AR as well as improvements to the HMS are therefore required to allow a holistic evaluation of AR on both overall efficiency as well as further parameters like space requirement reduction and noise emission control.