The perimeter covers the area between the main station and Bürkliplatz as well as between Lindenhof and Schanzengraben. The aim is to cover the high heating and cooling requirements of the numerous office and retail spaces with a connected grid fed with renewable energy from Lake Zurich. Since 2003, ewz has been implementing and operating additional lake heat networks around the Lake Zurich basin.
Buildings that are connected to a lake heat network are supplied with heating and cooling via lines from the energy centre or have their own heating system. The lake water is collected with a sieve and transported to the central lake water system using pumps. In winter, we use a heat exchanger to extract heat from the water circulating in a primary circuit. This heat serves as an energy source for the heat pump. This raises the carrier medium to the required temperature level (approximately 40 to 65°C). Distribution in the buildings takes place via a secondary circuit. In summer, the system works in reverse: ‘free cooling’ allows the lake water to be used directly for room cooling instead of electricity-powered air-conditioning systems, ensuring comfortable temperatures. At the end, the lake water removed is returned to the lake or the Limmat river without any chemical changes, and the cycle starts over again.
The supply temperatures on the customer side are approx. 67 °C (district heating) and approx. 12 °C (district cooling). In the City Anergy supply area, we supply the properties with energy directly from the lake water intermediate circuit (operating temperatures -1 °C to 17 °C). Heat pumps or cooling machines are necessary to bring temperatures to the required level.
The heart of an energy network is the energy centre. Due to the size and energy volumes, CoolCity requires spaces offering 4,000 m2 and a room height of 5 metres. After an intensive analysis, existing ewz substation in Selnau was determined as the location. The substation offers outstanding architectural conditions and an ideal location for the future distribution of heating and cooling.
You can find out about important milestones in the expansion of district heating here. The most important construction phases of CoolCity are listed below.
Status: planned
Status: planned
Status: planned
Status: planned
Status: planned
Status: active
