Thin-layer modeling in heat pump drying of green peas

Abstract

Consulta en la Biblioteca ETSI Industriales (Riunet)

[EN] Drying is one of the most essential and common processes nowadays applied to industry and, among other things, in food treatment and preservation. The main purpose is to process the food for consumption by increasing its shelf life. Hence, the drying process allow to achieve this by removing the moisture content from the raw material, reducing and eliminating biological activity and spoilage of the fresh products. Common drying is known for its elevated energy consumption and therefore it is costly. The conventional drying has also a negative effect on the environment and climate. That explains the importance on developing sustainable technologies like heat pump drying to look after our most valuable asset that is nature and its resources. Heat pump drying is a relatively new technology developed at NTNU. It merges the drying and heat pump cycles in which the heat pump is used to recycle energy, for reheat the air during drying the raw material. Due to this recycling of heat from the drying exhaust air, energy is saved and the total energy input to the system is significantly reduced. Other important challenge for the drying process is to maintain as much as possible the fresh qualities in the final product after processing or drying. Lots of research work and experiments done in HPD technology have indicated a high potential in achieving high qualities and energy saving with this technology. Experiments in a laboratory scale heat pump dryer were conducted using green peas. Three set of tests with twelve trays were performed with varying the temperature and relative humidity of the drying air. All results and conclusions are discussed and description clearly made by the author to facilitate the understanding of the reader.