A thermoacoustic heat pump is a heat pump that does not use compression, condensation and evaporation to generate heat, but a sound wave. The thermoacoustic technique has been known for years, but never until now, with the BlueHeart, has it also been used to heat and cool your home.

A heat pump

If it doesn’t work with compression, condensation and evaporation of refrigerant, is it a heat pump? “Yes,” says developer Michiel Hartman firmly, “it is a misunderstanding that technology determines what a heat pump is. A heat pump is simply a device that has low temperature water in it on one side, and high temperature water comes out on the other. You create a temperature difference, and you take heat from a source. Which technology is hidden underneath is not important. We really take a different approach, but it is still a heat pump.”

60 times per second hot-cold

The BlueHeart does not work with refrigerants. The main principle of the device is that gas heats up when the pressure is increased, while the temperature drops when the pressure is lowered. The device is filled with helium. This is a non-flammable gas and causes fewer thermal losses than ordinary air. With two pistons, a sound wave is created in it with a frequency of 60 Hz. Such a wave is in fact nothing more than a compaction and dilution that runs through the gas. In the compaction of the wave, the gas comes under high pressure and therefore becomes warmer. During dilution, the pressure is lowered and the gas becomes colder. If you place heat exchangers exactly at the points where there is the greatest compaction and dilution, you can capture heat and cold.

That sounds very simple, but the development took years. That time was needed, among other things, to find the right shape, to find the right material, and to prepare the device for mass production. “The biggest challenge in the development of the device was to perfectly coordinate the three components,” says Hartman, “the pistons, the acoustic barrel through which the wave passes and the heat exchangers. In this we are years ahead of others who now want to do the same.”

Whisper quiet

“In theory, you can bring water to very high and very low temperatures with this acoustic technique, but we have made the BlueHeart in such a way that it can heat water up to 80 degrees and cool it down to -15 degrees.” This temperature also makes it suitable for renovation projects, for example, where high-temperature delivery systems are the standard. It is also relatively small, so it can easily be placed in the systems of existing heat pumps. You just remove the compressor and the evaporator and then connect the BlueHeart.

A major challenge with traditional heat pumps is that they quickly produce a lot of noise. The BlueHeart is very quiet. “Because it always works at 60 Hz, we can easily make it whisper-quiet with noise canceling. That is not possible with other heat pumps, because they keep changing frequency.”

Faster response time

There are even more advantages to the technology over traditional heat pumps. This allows the BlueHeart to respond much more easily to heat or cold demand, because it is not tied to the cycle of compression, condensation and evaporation. It also does not wear out, if at all,” says the developer. “There is a moving part in it, the piston, but because it runs so smoothly, there is no wear on it. And even if it would wear out a bit, you can lower the frequency slightly. Which you then also adjust in the noise canceling to.”