Sipping CO2-cooled wine

Natural refrigerant CO2 provides the cooling at the Abbazia di Novacella winery, northern Italy. Accelerate Italy reports.

High up in the picturesque mountains of South Tyrol, northern Italy, at the nine-centuries old Abbazia di Novacella/Kloster Neustift, two Yukon CO2-based water-brine chillers serve a high-efficiency CO2 transcritical system with gas coolers and heat recovery. The chillers were provided by Enex, headquartered in the nearby province of Treviso.

At the heart of the medieval abbey site, a state-of-the-art HVAC&R system – fitted by local installer Studio Fleischmann – adds a cutting-edge modern twist to the process of winemaking that has taken place here for centuries.

Each of Enex's Yukon chillers, installed in August 2017, has a cooling capacity of 60 kW. The two units are used to cool must when it increases in temperature during the fermentation phase; at the same time, heat recovery produces sanitary water at 90°C for cleaning the wine barrels.

Yukon is Enex’s new family of CO2-based ‘plug and play’, medium-sized water/brine chillers. The Yukon is particularly suited to space cooling in medium and large commercial buildings that have a significant hot water demand, such as hotels, hospitals, gyms – and wineries in the heart of South Tyrol!

The Yukon allows for overfeeding of the evaporators, which increases efficiency. It is available in two design concepts – the LPR (low pressure receiver) model for small systems and ‘gravity overfeeding’ for larger systems.

The optional addition of ENJECTOR technology improves the efficiency of the CO2 transcritical cycle by recovering the energy contained in the high-pressure fluid entering the condenser/gas cooler.

In the Yukon system, the water chiller, depending on the cooling load request from the air-conditioning system, generates cold water.

It can operate in several ways. In the first operating mode, it rejects the heat into the ambient air. A second operating mode is used when hot water is required. A three-way valve transfers the available heat to a water cylinder, and the mass flow of refrigerant bypasses the condenser/gas cooler. A third option is to reheat the water in the cylinder. Here the CO2 passes through both the heat recovery heat exchanger and the condenser/gas cooler. In this manner, it is possible to produce sanitary hot water almost for free.

Founded in 1142 (one of the oldest active wineries in the world), Novacella Abbey is a member of the association of top Italian wine producers (Grandi Cru d’Italia). Today it owns 25 hectares but controls and vinifies must from another 50 hectares owned by cooperative members, its exclusive suppliers. The cool climate and mineral richness of its vineyards is in fact ideal for cultivating delicious white wines. In addition to vineyards, the monastery owns forests, meadows, and orchards. The products made on site are sold in the monastery shop.

Novacella has proven to be self-sufficient and quick to adapt to changing circumstances over its entire history. A former hospice and refuge for pilgrims, it now runs a number of economically self-supporting entrprises, from herb garden to winery and from power plant to education centre.

Click here to read the full version of this article in Accelerate Italy magazine.

By Andrew Williams

Mar 12, 2018, 10:55




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