Not a game changer, but a way to kick the can a bit down the road, for low-grade industrial heat processes.
Highlights
A heat-driven heat pump achieves supply temperature of 270 °C. Thermoacoustic cycle ensures the high reliability and environmental friendliness. When the temperature lift is 125 °C, COPh is 0.41, and the heat supply is 1903 W at 5 MPa. A higher pressure generally increases the heat supply. Thermosyphons can efficiently and stably release the heat from the engine unit.Abstract
Heat-driven thermoacoustic heat pumps (HDTAHPs) are promising for high-temperature heat pumping for their extremely simple structures, but their supply temperatures are relatively limited. In our work, we develop a high-temperature HDTAHP, consisting of a thermoacoustic engine unit and a thermoacoustic heat pump unit. The former converts thermal energy into acoustic power, while the latter consumes acoustic power to pump heat. The two units are connected via acoustic resonators to form a closed-loop configuration. Experimental results demonstrate that, with a hot end temperature of the engine unit at 300 °C and a cold end temperature of the heat pump unit at 145 °C, both the coefficient of performance for heating (COPh) and the heat supply decrease as the heat supply temperature rises from 220 °C to 270 °C. Specifically, COPh declines from 0.43 to 0.36 while heat supply decreases from 2877 W to 2671 W. Similarly, with a cold end temperature of the heat pump unit at 100 °C, increasing the heat supply temperature from 140 °C to 200 °C results in a drop in COPh from 0.42 to 0.31 and a decrease in heat supply from 3321 W to 2870 W. Furthermore, when maintaining a maximum heat supply temperature of 270 °C and a maximum temperature lift of 125 °C, the system achieves peak values for both COPh and COPR at 5 MPa, with values of 0.41 and 33%, respectively, corresponding to a heat supply of 1903 W. At 8 MPa and a hot end temperature of the engine unit of 350 °C, the heat supply reaches its peak of 2873 W, with corresponding COPh and COPR of 0.36 and 29%, respectively. This work provides a promising solution for high-temperature industrial heat supply.
“The former converts thermal energy into acoustic power, while the latter consumes acoustic power to pump heat.”
Can anyone explain this in layperson’s terms?
In this setup, temperature difference of two reservoirs generates very loud noise driven by spontaneous heat flow, which is coupled to the heat pump stage via a resonant cavity, where it drives active heat transfer between two others, different reservoirs.
In other setups, electric power is used to generate the acoustic power for the pump stage.
Awesome. Thanks.