Methodology for the energy analysis of an air cooled GAX absorption heat pump operated by natural gas and solar energy

In this work a methodological analysis and energy evaluation of an air cooled absorption system, with generator–absorber heat exchange (GAX), and operated by a hybrid natural gas–solar energy source is presented. Given the characteristic non-linearity of the resulting system of equations, the methodology proposed envisages a calculation sequence for the external currents and an iterative procedure for the internal currents. The system studied intents to be an alternative for space conditioning in the residential sector, the unit was designed with a capacity of 10.6 kW (3 Ton) of cooling and uses as working fluid ammonia–water. Giving priority to internal energy integration, an arrangement is proposed for the GAX cycle that allows 19% of solar contribution at full load, being greater at partial loads. In spite of using ambient air up to 40 °C with a relative humidity of 24% as cooling source, a COP value of 0.86 for cooling and 1.86 for heating was calculated, with an internal energy integration of 16.9 kW, 37% more than the energy that is supplied to the generator.