Common in the future: air conditioning without electricity

The temperature, as a result of climate change, is rising linearly with the demand for the currently available traditional and energy-consuming air conditioners. At this moment, there are 1.6 billion conventional air conditioners, and this number will rise to 5.6 billion by 2050. These systems consume a lot of energy. Therefore, SoundEnergy from Twente has developed a sustainable system in which thermo-acoustic technology is used to cool industrial buildings and processes.

The THEAC-25 system cools CO2 neutrally without using electricity and harmful chemicals. It operates silently without any mechanical moving parts, in contrast to traditional cooling systems. “In many industrial processes in which natural gas or diesel is burned, there is a need for cooling. Think of a bakery or a diesel generator. Instead of using an industrial air conditioner (a chiller), our THEAC-25 can directly turn residual heat into usable cooling. Our innovation saves up to 75% on average in electricity, maintenance costs and the high costs of using toxic refrigerants.”

The Thermo-Acoustic Energy Converter (THEAC) is comprised of four interconnected, cylindrical vessels. Each vessel contains two back to back heat exchangers with a regenerator. In these regenerators, a temperature difference causes a pressure wave. This (sound) wave causes displacement of the gas between the two exchangers in the first two vessels. By displacing the gas through the circular feedback tubes, the sound wave starts to oscillate and amplify itself. The opposite happens in the last two vessels, which results in cooling taking place. In the THEAC-25, instead of a two-phase refrigerant (Freon), the inert gas Argon is used as working gas. Our atmosphere consists of 0.94% Argon, making it easy to use. More importantly: Argon does not contribute to the greenhouse effect. In addition to extracting heat from solar vacuum tubes that can be placed on roofs, the THEAC-25 system can directly use the residual heat from factories, diesel generators and other industrial production companies. By using few components and fixed parts, the THEAC-25 system is maintenance-free and has an estimated service life of up to thirty years.

SoundEnergy is a technology-powered company based in Enschede and focuses on converting process heat. Their THEAC product is especially interesting for sectors that work with high temperatures. Examples are bakeries, glassblowers and foundries. The THEAC system can be heated to around 160 degrees for free using the residual heat from, for example, ovens. The sustainable and innovative system is then able to provide sufficient energy to make an industrial building completely self-sufficient and thus independent of the electricity grid. This reduces the local contribution to the greenhouse effect. The current THEAC weighs 800 kilos and is too heavy, expensive and large for a regular household. SoundEnergy is, therefore, working on a version with other materials and a different placement of heat exchangers, which would result in a more efficient, small and light system. It will take several years before this new and improved system is ready, but it promises a bright future. 

SoundEnergy is very successful. In 2015, the company won the Young Technology Award, a yearly award for fast-growing innovative companies. This summer, the American magazine Forbes wrote that SoundEnergy “could just save the planet”. In a 2017 article, it is mentioned on Twente.com that the company received investments from, among others, Cottonwood Technology Fund and the Twente Innovation Fund to produce the first prototypes and to receive the first orders. Now, it is going like a bomb. The smart air conditioners have already been shipped to Mali and Dubai. The Integraal Kind Centrum in Delden is the first customer in the Netherlands. “Thanks to the mix of regional, provincial and European aid and subsidies, we achieved a great deal of technical progress within a relatively short time and introduced the THEAC-25 commercially. Now, as a sales organisation, it's important to scale quickly and fully focus on the identified focus markets.”