Performance investigation of a Scheffler solar cooking system combined with Stirling engine

Abstract

Energy demand has increased in developed and developing countries. This energy demand has put a lot of load on the current conventional sources of energy such as coal and petroleum products causing increased emissions of greenhouse gases, due to this governments and people are motivated to utilize sustainable energy resources. The current study of Scheffler's cooking system working on solar energy situated at Shoolini University, Solan, India has a cooking capacity of 600 meals per day and is utilized to cook food three times a day for 200 days each year. The heat loss of the system is having a crucial influence on the performance of the Scheffler cooking system. The present work is conducted to investigate experimentally the performance of the Scheffler solar cooking system in the month of May during which there is high solar intensity. The performance parameters for the system include solar radiation, the temperature of the receiver, the efficiency of the system, the amount of steam generated, and the heat losses in the system. Also, Scheffler’s cooking system is numerically integrated with the Stirling engine to produce electricity. The novelty of the work is to determine the heat losses in the system and to utilize those heat losses to generate electricity by the Stirling engine with Scheffler thermal cooking system. According to this study, the maximum heat loss from convection is found to be 900 W, while the maximum heat loss from radiation is 145 W. Additionally, the heat losses from the cooking pots reach 4 kW. The total maximum heat losses are calculated at 5057 W. The main contribution of this paper is the conversion of these heat losses into electricity using a Stirling engine. The maximum efficiency of the Scheffler cooking system was originally calculated at 26.5 %. However, after integrating the system numerically with the Stirling engine, the maximum efficiency increased to 54 %, a 27.5 % increase. The Stirling engine in the present study produces 0.9 kW of electricity.