Performance analysis of a vapour absorption heat transformer with different working fluid combinations

The vapour absorption heat transformer (VAHT) is a promising system for achieving a heat pumping effect to high temperature levels for industrial applications. However, suitable working fluids and their relative performance are yet to be established. This paper presents a comparative performance study of a single stage VAHT with water-LiBr, R21-DMF, R22-DMF and R22-DMETEG as working fluids. It is identified that water-LiBr and R21-DMF systems perform favourably, yielding temperature boosts of about 30°C. For achieving higher boosts up to 60°C, a two-stage VAHT is suggested. A second law comparison with electrical heating is also presented. © 1984.