Feasibility of a compact heat recovery ventilator module with an integrated air-cooled solar absorption air-conditioner

A solar absorption air-conditioner is simulated with an air-to-air heat exchanger to evaluate the feasibility of a compact solar air-conditioning ventilator module. The air-to-air heat exchanger considered in this study is a membrane type total exchanger and the absorption air-conditioner is a single-effect LiBr-water machine with air-coil heat exchangers. All components are modeled in effectiveness-NTU methods including a dehumidifying DX evaporator coil and a cross-flow absorber allowing the whole system to be described by a set of simultaneous algebraic equations, which are then solved easily by a matrix solver. It is predicted that the baseline air-conditioner would produce cooling power in 1.4–5 kW from hot water in 50–100 °C with a COPthrm over 0.7 without the risk of crystallization and that the heat transfer coefficients of the air-coils and the pressure losses would greatly influence the performance. Total cooling power of the baseline system at 80 °C hot water temperature condition is found 19.2 kW, of which 15.7 kW is attributable to AHX and 3.5 kW to the absorption air-conditioner. Corresponding total COPelec is 76, to which the contributions of AHX and the absorption air-conditioner are 62 and 14, respectively. Air flow rates are found to greatly influence the overall performance and should be carefully chosen. It is concluded that the proposed idea is technically feasible and worth further development as an alternative solution.