Assessment on the developed solar thermal processing (STP) system for roasting cashew kernels

Abstract

Existing roasting techniques are not adaptable to farmers in developing countries because of high initial investments and rapidly increasing prices for non-renewable energy resources. Many technological efforts have been made to facilitate rural communities by mechanizing the roasting process, however, many of these technologies depend on fuels or electricity. The study aims to assess the viability of a developed Solar Thermal Processor (STP) system for roasting cashew kernels through thermal performance and productivity. The performance evaluation was conducted based on ASAE S580.1 suggested time for testing and reporting solar cooker performance. The process parameters involved in the data gathering are temperature and load manipulation with a drum speed of 10 rpm. Climate-Temperature data profiling shows that the STP’s solar concentrator was able to produce a solar flux up to four times the available solar irradiance equal to 396.6°C of temperature. At no-load condition the maximum drum temperature reaches 296°C. For roasting 10 kg of cashew kernels, the recommended temperature is 110°C-120°C for 60 minutes. Furthermore, the collected data shows that the design of the machine was able to reduce roasting time by 30 minutes for a full load of 10 kg with an average moisture reduction of 3.9% per hour. The developed system can be a great help in increasing the monthly income of cashew kernel processors by minimizing operational costs, as well as increasing the market value of their products.