A novel H2O/LiBr absorption heat pump with heat recovery for combined heating and cooling production using renewable energy

Absorption refrigeration technology was developed as a response to major challenges, including the energy crisis, rising fuel costs, and the environmental drawbacks of conventional vapor-compression refrigeration systems. Extensive research has focused on developing strategies to enhance the COP of absorption systems, with the aim of making absorption refrigeration technology more competitive compared to conventional compression systems This study investigates a hybrid absorption heat pump integrated with heat recovery combined heating and cooling production to improve the COP of absorption refrigeration systems. The system is based on low- and high-pressure absorber/evaporator pairs, operating with H₂O/LiBr as the working fluid, and driven by a low-temperature heat source. In order to drive the heat pump’s heat generator, natural gas (prepared in a boiler) or/and solar energy (prepared in solar panels) was used. The experimental reasearch were conducted on an experimental stand located in the Department of Heat Engineering and Thermal Equipment Laboratory from the Technical University of Civil Engineering, Bucharest. It can simultaneously supply both cooling and heating for preparation of domestic hot water. A performance analysis is carried out through experimental measuring data to calculate the total COP vs. COP for conventional single-effect absorption chiller under the same conditions. In recovery mode, the maximum total COP increases to 5.446 because of heat recovery from condenser and absorber. Nevertheless, the system achieves a temperature of hot water between 33.58–43.92 °C. Notably, the recovery heat mode performance is strongly influenced by the solar radiation during the month, which therefore represents a key design parameter for the proposed system.