Environment-friendly district heating network in Milan

| OCHSNER industrial heat pumps reduce the excessively high groundwater level as a side effect.

The Forlanini district in Milan, with about 2000 apartments, is supplied by a district heating network which is powered by natural gas boilers and a combined heat and power plant (CHP). While elsewhere groundwater levels continue to fall, Italy's fashion capital seems to be in the opposite position.

The plant is located in a basement 8 m below ground level and due to the rising of the underground water level it has been subject to flooding several times, which had caused serious damages. This was a critical situation, considering that a CHP with a capacity of 2,4 MW electrical and 2,5 MW heat capacity is installed in the building. In order to prevent these threats, between 50 and 250 m3 /h of groundwater were pumped away into a nearby river, all over the year, with large power consumption.

Groundwater represents an ideal heat source for heat pumps. Therefore, OCHSNER and its Italian partners developed an innovative approach to efficiently use this energy source. Wells were built for capturing water to be used in a geothermal plant, consisting of 2 heat pumps which are allocated in a new building. The available amount of groundwater and the heat demand are compared by a sophisticated control. According to the calculated value, one or both water-to-water heat pumps are activated. Each heat pump has a heating capacity of more than 800 kW at W10 / W35. A maximum flow temperature of 75°C provides reserves to guarantee a reliable heat supply, even at cold winter days.

The electric power for the screw compressors of the two heat pumps is produced by the CHP unit, which contributes to a short payback period. This project is an innovative approach to an environment-friendly heat supply in Milan.


EHPA invites everyone to submerge themselves in the possibilities that heat pumps are capable to offer in several industrial sectors. To read more stories the updated booklet is currently available on EHPA’s website.