The Alto Cumulus, called the first industrial CO2 condensing unit, can also be a heat pump or a chiller.
Carnot's Alto Cumulus module
Quebec-based OEM Carnot Refrigeration has unveiled a CO2 condensing unit that can also serve as a heat pump or chiller for industrial applications like cold storage and food processing.
The new packaged unit, called the Alto Cumulus, is based on the Inrow with Cumulus platform that Carnot, a pioneer of CO2 refrigeration technology in North America, has successfully deployed at data centers throughout Canada.
Carnot introduced the system at the Global Cold Chain Expo, held June 10-12 in Chicago.
“Alto means it’s adaptive – it can be a condensing unit, heat pump or chiller; it’s a modular approach,” said John Miranda, chief marketer for Emergent Cold Technologies, which represents Carnot in the U.S. He called it the “first industrial CO2 condensing unit.”
The Alto Cumulus is generally configured as a split system with the evaporator in the cooling area.The initial application for the unit is expected to be for a hardening room and freezer at a California ice cream plant, which is awaiting a permit, said Miranda.
Another project for which he has offered a quote to a customer is for process cooling at 60F° year-round. In this case, the system would work as a heat pump in the winter and an air conditioner in the summer, he noted.
The system can also work as a chiller with CO2 or glycol as the secondary fluid.
The unit can make use of hot-gas defrost in the evaporator. “We’re harnessing all of the heat-recovery benefits of CO2,” said Miranda.
The Alto Cumulus employs an air-cooled condenser or adiabatic condenser, depending on the ambient temperature. “Eighty percent of the applications in the U.S. will be with adiabatic,” said Miranda.
For a contractor, the Alto Cumulus reduces the amount of piping needed because the unit is placed directly above the cooling target. However, the unit is more costly than a condensing unit with a synthetic refrigerant, noted Miranda.
The heat of rejection of a single module (one condenser/fan) is 10 TR (35.2 kW), which can deliver temperatures between -40°F (-40°C) and 40°F (4.4°C). The system can expand to up to six condensers/fans, which would accommodate 60 TR (211 kW). “The condensing coil is the limiting factor,” said Miranda.
The system can use up to four compressors, in single stage for medium temperatures or two-stage for low-temperatures
Miranda acknowledged that as a packaged industrial system the Alto Cumulus is similar to a low-charge ammonia packaged unit, though the Alto Cumulus has smaller piping and different refrigerant.
“Eighty percent of the applications in the U.S. will be with adiabatic.”
– John Miranda, Emergent Cold Technologies