Next level efficiency: Enex&rsquo;s renewed range of CO2 heat pumps

CO₂ heat pumps are now performing more efficiently than ever with Enex’s latest technology. Chief Executive Sergio Girotto explains what makes these heat pumps stand out from the competition.

Known for pushing boundaries when it comes to CO₂ refrigerant-based HVAC&R technology, leading Italian system supplier Enex is at it again – this time improving efficiency and applicability of CO₂-based heat pumps.

“Enex has sold heat pumps since 2007, but our improved range is even more efficient,” Girotto said.

Enex has revamped its range of CO₂ heat pumps, which have been available since the beginning of 2015. The range now includes a 120 kW unit as well as an increased heating capacity of one model - from 24kW to 30kW.

“The 120kW unit is the largest built in a complete package available on the market.”

The heat pumps are customisable to users’ needs, including:

Version for space heating
Possibility for contemporaneous use of heat and cold (chilled water for air conditioning)
Option to include an effective ‘double circuit’ for heating sanitary water
Connection of up to ten units in parallel
Available as air-to-water and water-to-water

In addition to these options, the renewed range of heat pumps feature high efficiencies and improved defrosting in air-to-water versions. The new design has been refined through exhaustive laboratory tests, from which official test reports are available.

Case in point: hotel in Milan achieving savings, short payback period

“The main application of Enex’s heat pumps – for which they were designed – is sanitary hot water heating. Hotels, hospitals, and any place that requires large amounts of hot water are ideal applications.

“We’ve recently seen increasing interest in space heating; it’s also possible to use our heat pumps for this purpose, provided a proper circuit design is used.”

Enex has installed several complete heat pump systems in the Milan area. For example, three heat pumps were installed at one of the most visited pavilions at EXPO Milano 2015.

Another system, comprised of two heat pumps, was installed at a prestigious hotel. The hotel required the capacity to heat up to 10,000 litres of water per day to 70°C.

“We proposed to combine the use of cold energy, where available refrigeration capacity is used to chill water for the air conditioning system in summer.”

One Airheat24 and one Airheat48 were installed in parallel, with a combined production capacity, on average, of about 1,000 litres/hour of hot water, heated from 10°C to 70°C. The yearly average COP is higher than 4.0.

According to Girotto, the total savings compared to the use of natural gas is about €7000 per year, considering only hot water production, while ‘free’ energy obtained from the chilled water circuit amounts to more than €4000 per year, even if the period during which the AC is used is limited.

Considering the simplicity of the heat pump installation in comparison with a traditional system using natural gas, the payback is extremely short; less than two years. "

“The solution is even more attractive when the reference system is an oil boiler, for example, where natural gas is not available, i.e. in tourism hotels in some Mediterranean islands.”