DESIGN OF A MINIATURE HVAC SYSTEM TO FUNCTION AS A MULTIPURPOSE COOLING SHIRT

The purpose of this project was to design and optimize a portable miniature cooling system. The device functions as a cooling shirt, which is particularly useful in high-temperature environments where maintaining a healthy body temperature is a concern. The design cooling capacity of the system is 0.586 kW, where it provides a circulating cooling fluid temperature of 21.1 ℃, with an ambient temperature of 35 ℃ using refrigerant R-134A for the prototype. The circulating cooling fluid consists of a loop that is pumped through a brazed plate heat exchanger on the evaporator side of the system. The prototype used water for initial testing. Examples of high-temperature environments include a tradesperson working in an attic during the summer (i.e., HVAC technician and electrician). The device is not limited to only high-temperature environments. It could be used in many other applications, such as health care or physical therapy settings. Certain spinal injuries can cause the human body to lose the ability to regulate its core temperature. This could result in a scenario of the body overheating during physical therapy sessions. This device could help regulate core body temperatures when overheating is a major risk. An additional application includes the possible treatment of sports-related concussions and other sports-related injuries. Targeting specific areas for cooling could potentially increase recovery time when compared to standard ice treatments. Another example application may include certain military aircraft. Pilots can experience periods of thermal discomfort during flight. A greenhouse effect happens in aircraft that contain large window areas such as the V-22 helicopter. The device could potentially be used to offset the higher heat loads experienced during flights. In conclusion, in this paper, a benchmark study, which included the design, fabrication, and testing of a working prototype by using the off-the-shelf components, was presented. The COP of the prototype was tested at different settings. The percent error between the theoretical and actual COP was calculated to be about 19%. The sources of error were discussed. The future studies will include simulations in commercially available software such as AxCYCLE to reduce the percent error between the design and actual working conditions as well as further downsizing of the device by using customized cycle components.