| Abstract: | The feasibility of using a heat pump is considered as an alternative to other forms of drying where low temperature drying of a substance is necessary, either through quality control or because of inherent vulnerability to higher temperatures. This paper describes the construction and instrumentation of a purpose-built dryer, using uniformly saturated cotton as a constant drying load. The machine incorporates both a heat pump cycle using R12 refrigerant and also controllable electrical resistance heaters. A liquid-line subcooler is included to remove heat from the system. Instrumentation includes measurements of wet and dry bulb temperature, refrigerant temperature and pressure, air and refrigerant flow rates, and thermal and electrical energy. Drying rate is monitored by weighing samples. |
