Rather than pads, the system uses nozzles to generate fine water droplets to lower ambient air temperature for transcritical systems.
The Opti-Mist Plus
While adiabatic condensers with pads have become a common condensing/gas cooling system for many transcritical systems, Canadian equipment maker RefPlus is marketing an alternative adiabatic system.
The system – the Opti-Mist Plus – uses atomizing nozzles to generate a fog of very fine water droplets, which evaporate to pre-cool ambient air entering a heat exchanger. This allows a CO2 system to operate in “subcritical” mode for more hours and thereby improve efficiency in warmer climates.
Introduced three years ago, the system is installed at a Sobeys IGA store in Montreal using a transcritical system, said André Paré, vice president of sales & marketing for RefPlus, headquartered in Saint-Hubert, Quebec.
The Opti-Mist Plus “can be as efficient or more efficient than a system with pads,” said Paré.
He noted that RefPlus didn’t want to use pads, an evaporative medium, because they have to be removed in the winter and cleaned. The Opti-Mist Plus operates as a dry cooler during winter and mild months.
The system uses a given amount of water only once, in a single pass, The water is cleaned in a pumping station that has filters, UV lighting and a demineralizer. The misting device can be installed on any outdoor condensing unit with “hydrophobic coated fins,” says RefPlus on its website.
The Opti-Mist Plus is lower cost and maintenance than a pad system, according to Tom Richgels, director of sales – USA for RefPlus. Its defining feature is that it’s “so simple,” he said.
At higher ambient temperatures, the unit maintains the condensing temperature at about 78°F, Richgels said.
RefPlus has installed more than 100 air-cooled condensers without a misting unit at Canadian stores, added RichGels.
“The Opti-Mist Plus “can be as efficient or more efficient than a system with pads.”
– André Paré, RefPlus