Another form of refrigeration that becomes economically attractive when there is a source of inexpensive thermal energy at a temperature of 100 to 200°C is absorption refrigeration. The Absorption Refrigeration Unit enables the student to understand the principles of absorption refrigeration systems in use today. A dual energy source is provided that includes LP gas & electrical. The heat generated by these sources makes ammonia evaporate from a water/ammonia solution. The ammonia vapor rises and condenses into a liquid by flowing, through a finned heat exchanger.
The water is separated off and returns to the absorber. The ammonia then falls to the condenser whereby it boils (due to the lower pressure in the evaporator) and vaporizes thereby absorbing heat which cools the refrigerator. The vapor then falls back the absorber vessel and is reabsorbed by the water solution and the cycle repeats. The unit is mounted onto a mobile stand that incorporates a work surface. The main components of unit are evaporator, condenser, separator, absorber, boiler & a heater. Instruments are provided for the measurement of temperature & power.