By combining heat pumps and hybrid panels, the Lisetta Hotel reduces its gas consumption by 75%.

A state-of-the-art heating loop

On the heating side, the first action was to replace the old oil burner with a state-of-the-art natural gas boiler.

In addition to this, the integration of air-water heat pumps and the recovery of heat from the refrigeration technology of the cold storage rooms make a further contribution to heating.

But that’s not all.

As Tobias Krechel, former Systent consultant and now hotel owner, explains.

“In order to achieve the highest possible energy efficiency and benefits for the hotel, however, an additional installation was needed, called the ‘eXergie machine’. This is a heat pump that, unlike conventional heating heat pumps, is designed for a higher temperature level and wide temperature range.”

This water-to-water heat pump will serve as a “heat booster” here while increasing the efficiency of the 64 Dualsun SPRING hybrid solar panels. In fact, the water-to-water heat pump uses the heat supplied by the Dualsun hybrid panels in the low-temperature storage tank.

In addition, both solar heat production and solar electricity production benefit from the cooling of the return circuit to the Dualsun SPRING PVT modules:

• For heat generation, the lower inlet temperature at the collectors allows for better absorption of solar energy.
• The photovoltaic cells, on the other hand, are rewarded with 0.5% higher efficiency for every degree of cooling.

Solar PV and PVT for self-consumption

On the electricity and hot water side, the installation of 102 m² of photovoltaic and hybrid modules in 2021 will make it possible to supply heat at around 45°C and up to 250 W of electricity per square meter of hybrid module on sunny days.

The solar electricity produced on the roofs is initially consumed by the hotel. Excess electricity is sold and fed into the public grid. If the photovoltaic yield is too low, the electricity is purchased from the grid, but the external purchase of electricity is low. In addition, as it is “green electricity”, the hotel’s power supply is already 100% neutral!

A project that pays for itself in 7 years

Thanks to the eXergie + Dualsun coupling, the Lisetta Hotel has been able to reduce its natural gas consumption enormously, which is excellent news from an economic and ecological point of view!

In summer, the production of hot water requires about 75% less natural gas. In the spring and fall, heating the outdoor pool costs about 40% less gas. So in addition to being renewable, it is also profitable!

Thanks to the public subsidies available in Italy and the feed-in tariff for photovoltaic electricity, the investment in the Dualsun PVT modules and the water/water heat pump pays for itself after 7 years.