AbstractThe paper describes the integration of a chemical and a vapour‐compression heat pump for energy storage applications. The vapour‐compression system is designed to operate using the UK cheap rate ‘Economy 7’ electricity tariff. The system is characterized thermodynamically using various refrigerant/absorbent pairs in the chemical storage circuit and an ozone‐friendly refrigerant, R134a, in the vapour‐compression circuit. Results indicate that the H2O/Na2S pair provides a high energy storage density and is the most suitable for use in this system. The paper also describes the design features of a domestic‐sized version of this heat pump system. Air in the sunspace (conservatory) of a house was used as a heat source for