Temporally-displaced heat pump systems.
By Neil Stacey
Conventional heat pumps use mechanical work to exchange heat, against a temperature gradient, between two reservoirs that are spatially displaced; ie heat is removed at one location and discharged at another. An alternative approach which has not previously been explored is a heat pump configuration with temporal rather than spatial displacement; ie heat is removed from a reservoir at one time, and heat is discharged to the same reservoir at another time. This approach may be superior for instances where the heat requirements change in regular intervals, such as a greenhouse requiring cooling during the day and heating at night. The simplest mechanical cycle for achieving this would be to compress a gas when heat is required and discharge the heat produced by compression. Subsequently that same gas could be decompressed at a later time when cooling is required. This is the same as a standard refrigeration cycle, except that instead of the compression and decompression taking place simultaneously at different points in a circuit, they instead take place at different times according to demands.