Energy harvesting from air conditioners by using a thermoelectric application

Abstract

Air conditioners operate according to a simple refrigeration cycle, where evaporators are used to provide cooled air to air-conditioned rooms. This process normally involves making condensed water at the evaporator. Otherwise, the heat absorbed from the evaporator is directed to the outside environment by the cooled air at the condenser. This working cycle led to an idea to use low-temperature condensed water and high-temperature air for energy generation by using a thermoelectric module. The purpose of this study was to harvest energy from air conditioners by using thermoelectric power generation. This study used eight thermoelectric power generators (TEGs) attached to an aluminum heat sink, where the TEGs were heated on one side. The cooled side of the TEGs was attached to three aluminum water-cooled blocks. The necessary data, such as the condensed water temperature, heated air temperature, the condensed water rate, and the power generation, were collected. The thermostat of the air conditioner was set at 20, 21, 22, 23, 24, and 25 °C. The results show that the thermostat setting significantly affected the power generation of thermoelectric power generation module because the condensed water rate increased when the thermostat setting decreased. The condensed water rate, the hot-side and cool-side of TEG, and the condensed water temperature were reported. The power generation values were 4.28, 4.05, 3.74, 3.56, 3.36, and 3.15 mW for the thermostat settings of 20, 21, 22, 23, 24, and 25 °C, respectively. The correlation of the power generation of the TEGs and the condensation rate were related to the thermostat temperature and are reported. Moreover, the multiple linear models for the power generation of the TEGs were related to the influence independent variables and are reported. Based on the results, the energy harvesting from air conditioners by using a TEG can be used for applications such as monitoring systems.