Solar thermal technology for post harvest food preservation processing

摘要

Solar thermal systems have been widely used and recommended for applications in the areas of food preservation and food processing throughout the world. For such systems it is normal to specify solar thermal collection systems which operate in the temperature range 40C to 150C for which a wide range of collector types have been developed over recent decades. These include passive and active flat plate solar water and air heating systems, solar and hybrid heat pump systems and thermal systems basedon solar concentrators. Typical applications include grain and spice drying, pasteurisation and sterilisation in the dairy industry, and the provision of agro-industrial process heat in many and varied food processing industries such as fish and fruit canning. In virtually all of these instances the industrial process heat requirement is large but the temperature is relatively low and often falls within the solar low-grade heat range of 40C/100C With the increasing dependence forecast for the industrialcountries on renewable energy utilisation over the coming decades of the next century, and the major emphasis in developing nations on reducing their reliance on imported energy resources, it is appropriate now to review the role of solar thermal in meeting this agro-industrial energy demand.