Hungary-based HeatVentors, a company specializing in efficient and cost-effective thermal energy storage, transfer and use, was featured in the latest episode of the Blue Planet podcast released on Monday. The programme, hosted by former President János Áder of Hungary, chairman of the board of trustees of the Blue Planet Climate Protection Foundation, included insights from HeatVentors chief executive József Kakas.
Áder recalled that research into a new method of thermal energy storage began around 15 years ago at the Budapest University of Technology and Economics, led by Rita Farkas and Zoltán Andrássy. Their goal was to replace water with alternative materials for energy storage, leading them to experiment with phase-change materials.
Kakas explained that the researchers drew inspiration from space technology, where optimized thermal storage systems are used in the walls of space stations. The key lies in phase change, when a material absorbs a significantly larger amount of energy during a change of state. After examining several thousand materials, researchers selected around 100 capable of storing thermal energy across a temperature range from minus 130 to plus 120 degrees Celsius. A decade of research eventually made it possible to ‘box’ this physical process and apply it to building heating and cooling systems.
According to Áder, the technology offers a safer solution with a longer lifespan, shorter return on investment and significantly lower carbon dioxide emissions compared with conventional systems. Kakas added that the system works similarly to an ice battery: it is typically stationary but can be transported if needed. Waste heat from a factory, for example, can be transferred to a kindergarten, replacing gas-based heating.
HeatVentors’ systems are currently in use in seven countries, including Spain, Portugal, Germany, Italy, Oman and Singapore, although most installations are in Hungary. Áder highlighted the growing energy demands of data centres, which have proliferated alongside the digital revolution.
Kakas noted that a 10-megawatt data centre consumes as much energy as a town of around 25,000 people, with most of that energy used to operate and cool servers. HeatVentors’ solutions reduce cooling-related energy use and enable waste heat to be stored and reused elsewhere. This can cut electricity consumption by around 20–25 per cent and indirectly reduce carbon dioxide emissions, with daily energy losses in the storage system limited to about 2 per cent.
Áder also pointed out that roughly 80 per cent of global energy consumption still comes from oil, coal or gas, underlining the need for greater efficiency. Kakas said HeatVentors completed a €4 million capital increase last year with Hungarian and international investors, paving the way for the company’s expansion into a major international player, particularly in the data centre sector. Under EU rules, data centres must measure and reduce their energy use, an area where HeatVentors’ technology can provide support.
The company is actively developing the market for phase-change-based thermal energy storage across different climate zones, including in Oman, where its system operates in a luxury hotel under daytime temperatures often reaching 50 degrees Celsius. Áder cited estimates suggesting that widespread use of such systems in Europe could save €20 billion and prevent 250 million tonnes of carbon dioxide emissions.
Kakas added that HeatVentors will present its technology at the Planet Budapest 2026 sustainability expo from 25 February.
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