Go with the Flow – river water cooling
A mountain river brings wonderful cooling on hot summer days. We, too, want to make use of this. We have developed an intelligent system to use the water from the Isarco river flowing through Bolzano to cool the WaltherPark. The river serves us in two ways – we use its coldness and its power. And this is how it works: We branch off river water via a channel on the left bank of the Isarco river. The channel leads to heat exchangers near the shore. The cold river water flows around the heat exchangers and is then fed back into the Isarco river.
Only gravity, the natural gradient of the Isarco river, channels the river water to the heat exchangers. There is no need for technical aids such as pumps, suction and filter systems. Fish that get into the channel can swim out again without getting caught in the heat exchangers. The cold of the river water in the heat exchangers is transferred to a cooling pipe in which water circulates. This pipe leads across the river to the WaltherPark energy centre – and from there to the individual consumers in the building. The water in the pipe gives off cold on its way through WaltherPark. It therefore heats up and is conducted back to the heat exchangers on the Isarco river shores. The cycle then starts all over again. Even the heat exchanger system itself is cooled naturally by the cold river water. Since no waste heat is generated, the surrounding neighbourhood is not heated up either. The Isarco river is warmed by the cooling system to a maximum of one tenth of a degree. This limit was set forth by the local government. If the river Isarco is not cold enough in summer or the cooling demand is particularly high in extreme heat, we also use district heating for cooling. District heating is converted with the help of heat exchangers.
Alongside the shopping gallery, our cooling network also cools the flats, offices and the hotel located inside WaltherPark. In the future, other nearby buildings will also be connected. Our cooling concept makes a difference in terms of carbon footprint: 92 percent of the energy used to operate the cooling system comes from renewable or equivalent sources. This saves us around 104 tonnes of crude oil or 176 tonnes of CO₂ per year compared to a conventional cooling system.