Electrocaloric Heat Pump Achieves High Efficiency, Cooling

In a world constantly seeking ecological and efficient solutions, a remarkable advancement in the field of cooling could signify a turning point. Researchers have developed a solid-state electrocaloric cooling device capable of generating a temperature difference of 20 kelvins with high efficiency. This innovative system could compete with current solid-state cooling strategies and provide a promising alternative to vapor compression cooling systems, which are both inefficient and harmful to the environment.

The principle of this new cooling system relies on a phenomenon called electrocaloric cooling, where an electric field applied to a material alters the direction of electric charges, causing a temporary increase in temperature, followed by a decrease when the electric field is removed.

Developed by Junning Li, Emmanuel Defay, and their colleagues at the Luxembourg Institute of Science and Technology, this technology utilizes strips of a material known as scandium lead tantalate. These strips, stacked and immersed in a thermal fluid (silicone oil), create permanent hot and cold zones of approximately 20 °C difference when an electric field is applied or removed.

Specifically, Li and colleagues have designed a dual-loop electrocaloric heat pump capable of generating a maximum cooling power of 4.2 watts. This device achieves 64% Carnot efficiency, surpassing many vapor compression and caloric cooling devices. The details of their peer-reviewed design have been published in Science.

Future Prospects and Optimizations

These temperature-difference zones can be utilized as hot and cold reservoirs to circulate oil through pipes for heating or cooling buildings or objects. Although the theoretical efficiency of the device is 67%, its current design achieves an efficiency of approximately 12%. According to Defay, this efficiency could be improved by finding a better heat conductor than scandium-lead tantalate.

Neil Mathur from the University of Cambridge commented, “Superlative performance has been achieved by combining known elements.” He emphasizes the advantage of using thin strips of electrocaloric material for enhanced cooling performance. However, he notes that the research has focused on the cooling power of the metal strips themselves rather than the overall performance of the entire device.

Energy and Environmental Impact

This innovation, signifying a significant advancement compared to traditional cooling systems, could substantially reduce energy consumption, considering that current cooling systems account for approximately 20% of global electricity consumption. Future research could focus on enhancing the device’s efficiency and exploring its potential for large-scale applications.

Featured Image: Design-to-test roadmap. (A) EC regenerator with a configuration of 10 columns and 14 rows in REG-TI design. The inset shows the side view of this regenerator with copper wire, Kapton film and silver epoxy. (B) The picture of the experimental set-up for the temperature span measurement of EC regenerator. (C) The temperature span measurement with IR camera. (D) The heating box with temperature controller.