Development of a Sustainable Nano-refrigerant using agro-waste (rice husk ash) as a base material for a domestic refrigeration system

¹ Department of Mechanical and Mechatronics Engineering, Afe Babalola University, Ado Ekiti, 360101, Nigeria
² Department of Mechanical and Industrial Engineering Technology, University of Johannesburg, Doornfontein Campus, Johannesburg, South Africa
³ Department of Mechanical Engineering, Nile University of Nigeria, Abuja, Nigeria.
⁴ Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park Kingsway Campus, JOHANNESBURG, 2006, South Africa
⁵ Department of Mechanical and construction Engineering, Faculty of Engineering and Environment, Northumbria University, Newcastle, NE7 7XA, United Kingdom

^* Corresponding Author: stephenakinlabi@gmail.com

Abstract

Silica nanoparticles were synthesized from Rice husk ash (RHA) through the top-down approach production greyish coloured particles. The spectroscopical investigation showed a compositional analysis of 74.6% silicon, 20% oxygen and 5.4% carbon. Microstructural studies indicated an average particle area of 7.8nm² and average particle size of 4nm. The nanoparticles were dispersed into the lubricant oil of the compressor such that when the refrigerant is dispersed over the compressor, the particles mix with the refrigerant giving the nano-refrigerant mixture. The nanoparticles were dispersed into the mineral oil at concentrations of 0.2wt%, 0.3 wt%, 0.5 wt% and 0.6 wt% and fed into the compressor to combine with the refrigerant in the vapour compression system. The refrigerator was run for 240 minutes for each sample as well as the control sample which was the refrigerant R600a. Performance evaluation was carried out to assess the viability of the developed nano-refrigerant. Generally, an increase in the refrigerating effect compared to the control sample by all concentrations apart from the 0.6wt% by 13, 7.5, and 12.5% and a corresponding increase in the COP by 31, 23 and 35% compared to the control sample for the 0.2 wt%, 0.3 wt% and 0.5 wt% concentrations respectively was recorded.