Hybrid Heat Pumps with Solar Thermal Collectors for DHW production
Refurbishment of a 150-apartments building in Milan
The energy retrofit project in Milan, Italy, concerns a 1970 residential complex with 150 apartments and 10,000 m² of heated space. Using radiators and benefiting from good insulation, the building’s energy system efficiency has been improved.
The upgraded heating system combines 4 air-to-water SHEEN EVO 2.0 heat pumps, 4 gas boilers, 4 solar thermal collectors, and an INTELLIPLANT management system for optimized performance of the system. With 360 kW from heat pumps and 800 kW from gas boilers, space heating is provided at 55°C.
DHW production is supported by three storage tanks, reaching up to 70°C, using the heat pumps, the solar thermal collectors and the gas boiler.
Achieving a Coefficient of Performance (COP) of 3.36, the system uses R32 refrigerant for lower environmental impact. The integration of these technologies has enhanced energy efficiency and reduced costs, particularly for domestic hot water production.
Lessons learned
- The heat pump system combined with storage tanks and thermal solar collectors have proven to be an excellent solution for improving the building’s energy efficiency and cut down the costs for domestic hot water (DHW) production
Key facts
| Building | Heat Pump and Source | ||
| Location | Milan, Italy | Number of HP | 4 |
| Construction | 1970 | Installed power | 360 kW with HPs 800 kW with gas boilers |
| Refurbishment | yes | Operation mode | hybrid |
| Heat distribution | radiators | Heat source | air |
| Heated area | 10,000 m² | Type of system | central |
| No. of apartments | 150 | Model | SHEEN EVO 2.0 HP Intelliplant |
| level of insulation | good | ||
| Heating sytem | Domestic Hot Water | ||
| Heating temperature | 55°C | Max. temperature | 70°C |
| Additional heating | gas boilers | Storage | 750l connected to Solar Plant 750l con’d to one HP 1500l con’d to one gas boiler |
| Other information | |||
| PV installed | 6kWth | COP | 3.36 |
| Climate Zone | Cfa | Refrigerant | R32 |
Description of the technical concept
The heating demand for the apartments is met by a combination of two different hybrid systems.
The radiators are supplied through a thermal storage tank filled with technical water, whose required temperature level is maintained by three-high efficiency heat pumps. Additionally, three gas boilers serve as backup heaters.
The domestic hot water (DHW) production is managed at three different temperature levels. First, water is preheated using the solar thermal collector field. It then flows into a second tank fed by a heat pump dedicated to DHW production. If needed, the final temperature adjustment is provided by the gas boiler.
The entire system is monitored and controlled by Intelliplant, which optimizes the plant operation by selecting the best heat source input based on solar radiation availability and the required temperature level to be supplied to the user.
IT010 Hybrid Heat Pumps with Solar Thermal Collectors for DHW production