Experimental and theoretical investigations of a γ-type Stirling engine powered by a parabolic solar concentrator in the city of Karaj: a case study

Department of Energy, Materials and Energy Research Center, Karaj, Iran

^a Corresponding author: m.kianpour984@yahoo.com

Received: 18 June 2014
Accepted: 19 June 2015

Abstract

This paper provides theoretical and experimental investigations on the performance of a Stirling generator in the city of Karaj which is located about 40 km west of Tehran. A designed and fabricated γ-type Stirling engine was mounted in the focal point of a parabolic solar concentrator to generate electricity at the site of the Materials and Energy Research Center (MERC) which is located in the south east of the city of Karaj. This engine was able to operate with any heat source when the source provides a minimum temperature of 220 °C and therefore, a parabolic concentrator with 1.9 m diameter was used for this purpose throughout the experiments. The maximum of net electrical power obtained in the system was 11.16 W with calculated total efficiency of 0.54% when the solar radiation at the experimental area was measured to be 860 W.m^-2. In order to program the generator to operate as a small stationary power plant at the site of MERC, the annual performance of the Stirling generator was evaluated by using the solar data collected at the site for consecutive 12 years. Typical days were extracted from the data for each month of the years to estimate the average hour numbers of the days when the solar radiation was sufficient enough to produce electrical power by the Stirling electrical generator.