The reasons for the problems of the existing absorption heat exchangers

such as excessively large size

high manufacture costs

and high return temperature of the primary network hot water

were attributed to the “triangular heat transfer processes” inside the absorption heat pumps. The structures of new Multi-stage Vertical Large Temperature Lift/Drop Generation-condensation And Evaporation-absorption Elementary Units were introduced

as well as their principles on how to eliminate the “triangular heat transfer processes” with a relatively compact structure. A new type of the absorption heat exchanger

called the Multi-stage Vertical Large Temperature Lift/Drop Absorption Temperature Transformer (ATT)

was constituted by such elementary units. Simulation models for the ATT were built to compare its performance to the traditional single-stage absorption heat exchanger. Results showed that the ATT can reduce the minimum return temperature of the primary network hot water

from 26℃ to under 20℃. When return temperature of the primary network hot water is 26℃

the ATT can reduce the total KA (heat transfer areas multiplied by heat transfer coefficients) by 25%~32%

while the powers of solution pumps inside the ATT were only increased by 19%~48%

which were not remarkable. The ATT has obvious performance advantages over the traditional single-stage absorption heat exchanger.