A prototype liquid desiccant dehumidification system

Many agricultural food products undergo some form of drying before they are available for purchase. This paper describes the progress of a liquid desiccant solar crop drying system (LDSCD), which is currently being tested in Queensland, Australia. The prototype consists of batch grain drying bin, air-drying sub-system and a regeneration sub-system. In the liquid desiccant system technology the use of electricity is limited to circulating air and liquids. The weak desiccant is regenerated using thermal energy provided by a solar collector and a heat exchanger. Initial results show that the LDSCD is an achievable alternative to conventional drying techniques. The drying system can deliver air at very low relative humidity (RH)regardless of ambient conditions and with small increase in drying temperature. On completion, the proposed project would make drying grain and other agricultural products more viable in the tropics (Atherton Tableland), where high ambient relative humidity makes heated-air dryers expensive to operate. The system would also have appeal in the colder parts of the country (such as in Victoria and Tasmania) where high humidity and low temperatures also make drying more expensive.