Dutch thermoacoustic heat pump developer BlueHeart Energy has announced that its thermoacoustic heat pump engine technology is currently being tested in residential environments and is expected to hit the European market in spring 2027.
“This first launch will be deliberately modest,” says CEO Michiel Hartman pv magazine. “Early units will be delivered in limited volumes, allowing partners to validate performance in real-world conditions as production capacity increases. A broader rollout will follow gradually, with scale-up expected to take at least another year. In other words, while some customers may purchase systems within the next twelve months, widespread availability will come later.”
The timeline coincides with a broader shift in the European residential energy landscape. Households are increasingly faced with a surplus of solar energy, especially as net metering systems are phased out in markets such as the Netherlands.
At launch, systems with the new engine are expected to be priced similarly to existing heat pumps. The initial value proposition will therefore focus on other benefits: reduced noise, greater flexibility, compatibility with existing buildings and improved integration with renewable energy systems.
Over time, the economic benefits are expected to become more apparent not necessarily through lower equipment costs, but through lower installation costs and lower utility bills. The ability to avoid major building modifications and take advantage of flexible energy prices could make a significant difference to the total cost of ownership.
System design
A thermoacoustic heat pump works without the conventional processes of compression, condensation and evaporation. Instead of a refrigerant cycle, it uses high-intensity sound waves to transfer heat. These waves generate pressure fluctuations in a gas, creating temperature differences that can be exploited to move heat. The approach reduces mechanical complexity and can improve durability due to fewer moving parts.
“One of the defining characteristics of thermoacoustic heat pumps is flexibility,” says Hartman. “Conventional systems perform best over a narrow temperature range. When combined with sources such as photovoltaic thermal (PVT) panels, they may require additional components to control temperature, which increases cost and complexity. Thermoacoustic systems can operate efficiently over a much wider range of input temperatures, without prior conditioning. This makes them well suited for integration with variable renewable sources.”
Image: Copeland
Heat pumps with built-in motors can be used for space heating, domestic hot water (DHW) and cooling in both residential and industrial applications.
The engine was first presented in 2022 and uses helium gas and sound waves instead of a conventional compression cycle. Two pistons generate an acoustic wave at 60 Hz, causing the gas to alternately compress and expand, while heat exchangers absorb the resulting temperature differences.
The system is compact and modular, with individual units delivering heating power from 1 kW to 6 kW. The power can be scaled up to 600 kW by combining multiple units. It operates over a wide temperature range, with source temperatures from approximately -25 C to 40 C and outlet temperatures up to 80 C, making it suitable for both new buildings and renovations with existing radiators.
“It is compact and very quiet, because the constant frequency allows for effective noise cancellation,” says Hartman. “Compared to conventional systems, it responds more quickly to demand and experiences minimal wear and tear thanks to its smooth operation and limited number of moving parts.”
The motor measures approximately 55 cm x 55 cm and weighs approximately 60 kg. The noise level is said to be below 40 dB(A), made possible by vibration-dampening pistons and constant frequency operation. “The simple architecture ensures little maintenance and a design life of approximately 20 years,” says Hartman.
Inside the motor, two linear drivers, similar to speakers, generate pressure oscillations that propagate as sound waves through a closed helium circuit. These oscillations cause the gas to compress and expand at specific locations, allowing heat transfer. A regenerator converts this oscillating movement together with heat exchangers into a continuous heat flow.
Electrical energy drives the pressure waves, the helium undergoes cyclic compression and expansion, and heat is absorbed on one side and released on the other. The result is a temperature increase, effectively concentrating heat via sound waves in a sealed, pressurized system.
The regenerator is a key component, consisting of a porous structure designed for efficient heat exchange with the oscillating helium. It acts as a thermal storage medium and allows heat transfer between the gas and the solid material. As the gas moves back and forth, temperature gradients and phase shifts between pressure and velocity create a net directional heat flow.
BlueHeart Energy does not produce complete heat pump systems. Instead, it provides the core engine, which is integrated into final products by partner companies. As a result, market access depends not only on the company, but also on its partners.
The company is currently working with an unnamed Spanish heat pump manufacturer to launch a system using the thermoacoustic engine by the end of the first quarter of next year. Demonstrations at recent trade shows include both the stand-alone engine and integrated systems.
Performance
Performance comparisons with conventional heat pumps are nuanced. “Vapor compression systems can achieve very high efficiency at specific operating points,” says Hartman. “Thermo-acoustic systems offer more consistent performance under a wider range of conditions.”
Rather than peaking at a single optimal point, the system maintains a relatively stable efficiency profile, especially at higher temperature increases, such as raising water from 10 C to 55 C or more. This makes it very suitable for existing buildings, where higher operating temperatures are often required.
“In practical terms, this makes the technology particularly suitable for retrofits,” says Hartman. “Older buildings, which represent the majority of Europe’s housing stock, often cannot accommodate low-temperature heating without expensive upgrades. Thermoacoustic systems can work with existing radiators and pipes, reducing the need for extensive renovations.”
As production increases and partnerships expand, the coming year will be critical in determining how quickly thermoacoustic technology gains traction in the market. Success will depend not only on technical performance, but also on the ability to address practical challenges for homeowners, installers and industry stakeholders.
“What is clear,” said Hartman, “is that the technology is arriving at a moment of significant change. As energy systems become more decentralized, dynamic and renewable-based, flexible solutions such as thermoacoustic heat pumps can play an increasingly important role.”
Blueheart Energy is a spin-off from Netherlands Organization for Applied Scientific Research (TNO) and is based in Heemskerk, in the province of North Holland, where it operates a small factory and a testing facility.
In April 2025, American heating specialist Copeland invested an undisclosed amount in Blueheart Energy.
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