EMMI Energy began developing new high-temperature heat pump technology in 2019. Following tests in a climatic test chamber, generation 1 of Pompeii was operational in 2020. Since 2021, 40 heat pumps have been in operation in four groups of homes.
The heat pumps are meticulously checked and adjusted, if necessary, based on data acquired by remote monitoring: « These tests revealed some initial problems, all now resolved, except for the noise level. We therefore designed the second generation of Pompeii, where the noise level has been reduced to 35 dB (below the Dutch directive threshold of 40-45 dB) » explains Denis Tien, technical engineer at EMMI Energy.
This second generation of Pompeii is currently being tested in one of the housing units.
Boiler replacement in no time at all
The Pompeii heat pump is designed entirely with the circular economy in mind. For example, all parts are reusable and recyclable. CO2 (R-744) is used as the refrigerant to achieve the high temperature. When CO2 is compressed, a large amount of energy is released and the temperature soars.
« CO2 is most cost-effective when operated at 85°C and a return temperature of around 40°C is obtained. Below 31°C, you get frost, which is not desirable » explains Denis.
By producing these high temperatures, the Pompeii heat pump can be connected to the home’s existing heating elements. Almost all heating elements, such as radiators, underfloor heating and convectors, are suitable for this heat pump. This means there’s no need to make any modifications other than replacing the central heating boiler.
Greenway® Neo Heat Pump N was chosen as the transfer fluid between the heat pump and the buffer tank.
« As the heat pump was designed using circular economy principles, it was important that the heat transfer fluid was also sustainable » explains Denis.
Perfect heat transfer
Denis was very satisfied, saying « I had heard of the Greenway® Neo N range and couldn’t find an equivalent alternative on the market. I had already tested another plant-based heat transfer fluid but it didn’t meet our expectations. After our first tests with the Greenway® Neo Heat Pump N, we found that the heat transfer worked perfectly ». « There are two connections from the heat pump to the buffer tank, to circulate the heat transfer fluid at 80-85°C, with a return temperature to the tank that must always be around 40°C. It’s very important for us that the heat transfer medium remains stable throughout the process » explains Denis.
For EMMI Energy, the safety and renewable origin of Greenway® Neo Heat Pump N played a crucial role in the choice, taking into account its other advantages. This heat transfer fluid also contains a bittering agent to prevent accidental ingestion in the event of a leak in the drinking water network. And the plant-based and natural raw materials also reduce the risk of soil contamination.
A bright future
The next step will be to continue marketing the Pompeii heat pump. The hybrid version is currently seen as a boiler replacement solution, but this is only an intermediate step. With this new high-temperature Pompeii heat pump, EMMI Energy can simply replace the gas boiler. More than 2.2 million homes in the Netherlands are now in a position to adopt this solution
