Performance Investigation and Enhancement of Solar Ejector Cooling System (Case study area: Addis Ababa, Ethiopia)

Abstract

In this research performance investigation of solar ejector cooling system has been carried out in on-design and off-design operating conditions and enhancement of the ejector is studied. Addis Ababa is taken as a case study area and important data were gathered from the Ethiopian National Meteorology Agency (ENMA) of six consecutive years (2013-18). Hourly and monthly performance analysis of the system is carried out at on-design and it showed a good result. The hourly maximum overall coefficient of the performance and the cooling capacity were obtained as 0.2049 and 186.9 W/m2 , respectively, at 12:00 in March when the design points are (𝑇𝑔 = 90OC, 𝑇𝐶 = 30OC and 𝑇𝑒= 12OC). The collector area per ton cooling capacity is found to be 22.3 m2 at noon for all cooling seasons in Addis Ababa. Off design operating condition map is derived for the system. The results are compared to related researches which is done previously in other countries and it showed good agreement. It was determined that the Solar ejector cooling system could be used for office-cooling purposes during the hours (8:00–15:00) in Addis Ababa/ Ethiopia. The optimum dimension of Ejector is obtained using one-dimensional hung et al. theory with the help of flowchart with cooperation to EES code. Constant-pressure type ejector with steady state three-dimensional model has been carried out for the ejector (with and without mixer) numerical study in ANSYS 16.0 FLUENT. R-134a is the working fluid which is selected for the study and considered as an ideal gas. The results are compared between with and without mixer ejector. The performance of ejector is improved by 10.4 % and the mixing quality also enhanced