ActiveWall heat pump technology

ActiveWall is an “air to air” heat pump. It consists of two large surface air heat exchangers, with a solid state heat pump between them. The function of the heat pump is to transport heat from the “cold” heat exchanger to the “hot” one. This is in contrast with the natural flow of heat, which is from hot to cold.

Heat exchanger design

3D Thermal model of ActiveWall heat exchanger
ActiveWall heat exchanger, 3D thermal steady state modelling with LISA 8.0 FEM.

For any heat pump it is important to keep the temperature difference between the “hot” side and the “cold” side as small as possible. Because when it becomes larger, the performance of the heat pump gets worse. In order to reach a small temperature difference, the heat exchangers need to be designed with great care. We use 3D thermal modelling to optimize our heat exchanger design.

Energy efficiency – performance

For the end user, the bottom lone is the cost of energy for creating a comfortable indoor climate around the year. In data on heat pump performance you will often see “the COP” (Coefficient of Performance) of a heat pump. But that really is only a part of the story…..

ActiveWall COP as function of outdoor temperature
ActiveWall Coefficient of Performance as a function of outdoor temperature (RWTH Aachen University)

First of all, “the COP” relates to one specific outdoor temperature, but of course the outdoor temperature is not at all constant over a whole year.

But even more important, the COP just tells you how much electricity you need for one unit of heating. But of course, for your total energy costs it is equally important to know how many units of heating you need over a year.

With a common heat pump you will mostly have floor heating. It means you have a slow system, and you will have to heat all through the night in order to have a good comfort by the time you wake up. On the contrary, ActiveWall is a fast system. Therefore, you do not need all those nightly hours of heating. Which means that the amount of “units of heat” you will need during a year are at least 33 % less than with a common heat pump.

And finally, ActiveWall provides not only convective heating but als has a radiative component. Because of that, the air temperature can be lower than that of a common heat pump. Which gives you another 10 % advantage over common heat pumps.

To conclude, ActiveWall has an overall energy performance equal to the performance of a common heat pump with a COP of 5,0.

Cost performance

A common 9 kW heat pump will cost you 6.500 – 14.500 Euro including installation. An equivalent ActiveWall system will cost you 6.900 – 9.800 Euro.

(Besides that, you can save on building costs with ActiveWall)