Spotted: Today, significant energy is spent on keeping buildings warm or cool. In fact, nearly half of the greenhouse gas emissions associated with buildings are the result of heating, ventilation, and air conditioning (HVAC). Buildings, in turn, account for 39 per cent of energy-related global greenhouse gas emissions. In response, buildings are increasingly fitted with thermal energy storage systems that smooth and optimise heating and cooling throughout the day. Traditionally, these systems work by changing the temperature of water in huge tanks that are expensive and inefficient. This could be set to change, however.  

Instead of water, the HeatTank system developed by Hungarian startup HeatVentors, uses phase changing materials—substances that absorb and release heat energy when they solidify or melt—to store the heating or cooling energy from a building’s HVAC system. If the system is being used for heating, excess heat is stored, melting the phase changing materials (PCM). When the heat energy is needed later on, it is discharged and the PCM solidifies. The process is exactly reversed if the system is being used for cooling. Cold air solidifies the PCM, with the cooling energy later discharged when the PCM melts. The temperature range for solidifying and melting the PCM is much narrower than for water – 20 degrees Celsius for solidifying, and 40 degrees Celsius for melting.

By storing energy when it is most abundant and releasing it at more expensive times, the HeatTank system helps organisations reduce their carbon emissions while also saving money on energy costs. In essence, the system allows organisations to bypass the most expensive times of day or night for buying or producing energy. In addition, by more steadily regulating interior temperatures, the technology reduces the overall amount of energy an organisation consumes.

Rectangular in shape, the storage unit is 90 per cent smaller than current, water-based versions, making it suitable even for relatively small buildings. What is more, the system is 20-40 per cent more efficient than others on the market.

The company currently focuses on data centres, district heating and cooling networks, commercial buildings, and gas engines, all of which rely heavily on HVAC throughout much of the year. For data centres, a gap of cooling power for even five minutes can result in significant damage, something HeatTanks can help to prevent by providing immediate backup energy in case of emergency.

Energy storage remains one of the most significant challenges in transitioning entire economies to renewable energies. Innovators are seeking myriad solutions, from reusing old EV batteries for energy storage units to using captured CO2 for long-term energy storage. 

Written by: Keely Khoury