Refrigeration Systems

Your kitchen refrigerator (or any other) cools food by removing heat from its interior and dumping it into the kitchen. This means it moves heat from a cold place to a warm place. However, the second law of thermodynamics states that it is impossible for heat to flow from a cold body to a warm body, while the reverse will always happen, and heat (q) will spontaneously flow from a hot reservoir to a cold reservoir, as shown in Fig. 12.1. For heat (qc) to flow from a cold area to a warmer area, work (w) must be performed such that, according to the first law of thermodynamics, the total heat (qh) transferred is: