Cooling is produced in two steps. The first is called passive cooling and is fully sufficient for many applications. When passive cooling is not enough to keep the temperature down, step two, or active cooling, is activated. In step two, the heat pump compressor is used to produce cooling and this lowers the temperature in the house’s cooling/heating loop even more. The Optimum module is equipped with low-energy circulation pumps.
It is worth bearing in mind that passive or passive/active cooling is several times cheaper than traditional air conditioning. For example, passive cooling consumes around 0.2 kW (circulation pump).