Combining sorption storage and electric heat pumps to foster integration of solar in buildings

Abstract

This article presents a numerical study on the building integration of a liquid sorption storage combined with an air-source electric heat pump. The double staging of the sorption storage (i.e. a chemical heat pump) and an electric heat pump leads to significant electricity demand and CO2 emission reductions. Further, it provides an effective coupling between the heat demand of the building and the electricity supply, allowing for optimal integration of solar energy using photovoltaics. For the buildings analyzed, an autarky level of up to 83% is achieved. Winter electricity demand and emission reductions respectively reached values of up to 41%. The storage integration was studied performing dynamic building simulations. The simulation model for the liquid sorption storage was based on a grey box approach. This features a simple analytical model being tuned to match with performance data available from experiments conducted on a lab scale test rig. The presented integration of a compact seasonal thermal energy storage at the building scale represents a promising approach for a grid compliant integration of renewable energy, significantly reducing electricity demand peaks and related CO2 emissions in winter.