Water-to-Water Heat Pumps for a 30-Apartment Building
Retrofit Solution for a Multi Family Building in Milan
Originally constructed in 1980, this building, located in Milan, Italy, was recently renovated. It includes 30 apartments with a heated area of 1800 m2, and a good level of insulation. The heat distribution system consists of radiators and radiant floor system.
The old heating system was replaced with two multifunction water-to-water heat pumps and supported by a backup gas boiler. The heating system has an installed power of 214 kW and operates with a supply temperature of 55°C. The management and monitoring of the energy plant are performed using INTELLIPLANT system.
Domestic hot water is produced at a maximum temperature of 48°C, through a dedicated 750-liter thermal storage tank. The system’s coefficient of performance (COP), with an output water temperature of 55°C, is 3.36.
In this system, the use of geothermal energy from groundwater is maximized, significantly reducing the need for heat integration from the gas boilers, which is used only as an emergency backup. This solution enhanced the energy efficiency of the existing buildings, reducing fossil fuel consumption, and improving the indoor thermal comfort.
Lessons learned
- Maximized use of groundwater energy
- No gas boilers needed, only back-up
Key facts
| Building | Heat Pump and Source | ||
| Location | Milan, Italy | Number of HP | 2 |
| Construction | 1978 | Installed power | 214 kW |
| Refurbishment | yes | Operation mode | hybrid (back-up gas boiler) |
| Heat distribution | radiators, underfloor | Heat source | groundwater |
| Heated area | 1800 m² | Type of system | central |
| No. of apartments | 30 | Model | WSHN-XEE MF 35.2 Intelliplant |
| level of insulation | good | ||
| Heating sytem | Domestic Hot Water | ||
| Heating temperature | 55°C | Max. temperature | 48°C |
| Additional heating | gas boilers | Storage | 750l connected to HP |
| Other information | |||
| Climate Zone | Cfa | COP | 3.36 (55°C) |
| Refrigerant | R410A |
Description of the technical concept
The temperature set for the heat pumps is 55°C.
Through a 3-way valve, water can be supplied at a lower temperature to the floor heating system (around 26°C in heating mode).
The 55°C water temperature is also ideal for the apartments equipped with radiators. Both radiators and radiant system are managed by a climatic curve controlled by Intelliplant, which adjusts based on the external air temperature
Intelliplant provides the capability to optimize the use of the source pump to conserve groundwater as efficiently as possible. The final branch of the system is dedicated to charging a DHW thermal storage.
The gas boiler and an electric resistance are used to perform the anti-legionella cycles.
Intelliplant allows to optimize the use of the source pump to save groundwater as efficiently as possible.
IT011 Viale Lombardia