Use of a Two-Phase Thermosyphon as a Low-Cost, High-Performance Economizer for Refrigeration Systems

The electricity consumption of residential and commercial refrigerators is significant in the United States. A natural choice then is to use the low outside temperatures for cooling to reduce electricity usage for residential refrigerators. Our solution is to use two phase close thermosyphon as an economizer during the cold season to take advantage of colder outside temperatures. Benefits of the thermosyphon include a high heat carrying capability with a small temperature drop, low cost, and the ability to behave as a thermal diode. In this work, a model is adapted from the literature to investigate the effect of working fluids, filling ratio and heat input on the performance of thermosyphon for refrigeration applications. Among the working fluids explored ammonia provided the best performance, followed by methanol. Experimental results are also presented for a thermosyphon residing in a simulated refrigeration configuration. The measured temperatures agree well with model predictions. The result demonstrates it is able to maintain temperature drop with applicable range.