An Adaptive Direct Evaporative Cooler That Regulates the Sub-Ambient Temperature by Controlling the Evaporation Rate

Abstract

With the development of technology, people are demanding more comfort in their lives, leading to an increasing demand for space cooling. The traditional cooling process produces a great amount of energy consumption and carbon emission, which puts tremendous pressure on the environment. Direct evaporative cooling technology is a good choice for reducing energy consumption and carbon emissions. However, most of the current direct evaporative coolers offer excellent cooling performance at any temperature, whether the space needs to be cooled or heated. The unwanted evaporation cooling at low temperature will increase the heating energy consumption of air conditioners. Here, an adaptive evaporative cooling structure that can intelligently adjust the evaporative cooling ability according to the ambient temperature is proposed. The structure consists of temperature-sensitive hydrogel (prepared by chemical synthesis), perforated polyethylene terephthalate (PET), and silica coating (prepared by screen printing and hot pressing technology), and the evaporation rate of the cooler is regulated by both the hydrogel and the porous membrane. The cooler can maintain high-efficiency cooling performance during the hot time, while suppressing the cooler's overcooling behavior at low temperatures to achieve more efficient energy savings. When the ambient temperature is higher than 36 °C, its cooling capacity can reach 10 °C. And when the temperature is lower than 18 °C, it can inhibit the temperature difference to less than 1 °C. This cooler structure has important application prospects in these fields such as building, automobile, and personal wearable device. It can substantially reduce the energy consumption and environmental pollution.