ES290262A1 - Method of absorbing thermal energy at low temperatures and apparatus for carrying out such methods - Google Patents

Abstract

In a refrigerating cycle of the type in which a working medium is compressed, cooled in a heatexchanger, expanded, warmed in said heat exchanger and re-compressed, the pressure of the working medium is maintained above its critical pressure at all points in the cycle and the expansion takes place at temperatures below the critical temperature of the working medium. The cycle may be performed in a conventional reversed hot-gas engine (Fig. 1, not shown) or one having a stepped displacer piston (Fig. 4, not shown). Alternatively, and as shown, working medium from a reservoir 27 is supplied through a regenerator 26 to an expansion space 32 above a compound piston 21, 23 when a valve 30 is opened. When the pistons move downwardly valve 30 is closed and the medium in space 32 is expanded, the expanded medium being displaced from space 32 to a compression space 34 via regenerator 26, valve 31 and duct 33 as the pistons move upwardly. The medium is compressed on the next downward stroke and returned to reservoir 27. In a further embodiment a space 40 above a piston 41 (Fig. 3, not shown) is selectively connectible via a regenerator 46 to high and low pressure reservoirs 52, 49, while in Fig. 5 (not shown) the apparatus comprises a compressor 91, expansion piston 94, a counterflow heat exchanger 92 and a further heat exchanger 95 in which the expanded medium cools a load 96.