Experimental Design and Construction of a Prototype Solar Powered Intermittent Absorption Vapor Refrigerator

Chapter One of Experimental Design and Construction of a Prototype Solar Powered Intermittent Absorption Vapor Refrigerator

At present, non-renewable energy sources are depleted constantly, Harmful emissions from fossil fuels and chlorine-based refrigerants have led to economic and more severely, environmental hazards. The world has been working to reduce hazardous emissions while developing renewable energy sources and technology. Leading the industry of renewable energy is solar power. By collecting and storing solar heat, and transferring this energy to power an absorption refrigerator, energy efficiency can improve, eradicating usually necessary (poor and sometime unavailable) electricity.

The development of an inexpensive, modular, small scale cold room based upon the absorption refrigeration process. This project was developed to proffer means of providing refrigeration to agricultural products in communities lacking or unable to afford conventional energy sources (electrical energy).

A solar driven ammonia absorption refrigeration system was designed, a modular prototype constructed and tested. It was an intermittent system where ammonia and water were used as refrigerant and absorbent respectively. The main components like evaporator, condenser and generator were designed based on certain assumptions such as generator temperature 70^oc, refrigerating effect of 5 tonnes (for full scale construction). The necessary heat and mass transfer equations describing the working properties were specified. The theoretical obtained COP was 0.25. Information on designing the condenser, evaporator, and generator of the unit has been presented.

It was assumed that the vapor generating from the generator was 100% pure ammonia vapor. The thermal energy input was calculated to be with I_s (solar intensity) = 600 W/m² where collector efficiency was assumed 30% and collector mirror surface area was 2.3m², but for purpose of increasing the efficiency, it was the collector area was increased by 20%.