Hot water from the air
IWB used the full renovation of the St Jakobshalle to further improve the carbon footprint of the heating network. At the beginning of 2018, the existing CHP in the heating centre of the St Jakobshalle was replaced with two air/water source heat pumps from CTA. The two identical units each deliver a heat capacity of up to 265 kW. Each heat pump is equipped with four compressors that enable demand-driven operation.
Two 11-metre-long air coolers stand on the roof of the hall. These extract energy from the air, with which the heat pumps can produce a hot water supply of temperatures up to 70°C, depending on the operating point. This energy is then transferred to the heat accumulator, from which the various consumers can then draw their heat. The accumulator is also the source of the heat for the hot water that the stars of FC Basel 1893 and international tennis players use to shower.
During summer, the heat pumps completely cover the hot water consumption of the consumers connected to it. At an ambient air temperature as low as 5°C—the average temperature in Basel is 10°C—the units produce 70°C hot water.
The heat pumps continue to produce usable heat even at an ambient air temperature of less than 5°C (and as low as -5°C)—even though, at 55°C, it can only be used for mild hot water return heating. During winter, two gas boilers, which are available for operation during the winter months and for peak loads in the heating centre, take over the residual heating to up to 80°C.