Intellihot
Intellihot's iE6 tankless CO2 heat pump water heater, at the AHR Expo 2024.

Intellihot Begins Installing Tankless CO2 Heat Pumps for Water Heating in D.C. Schools

The U.S. company says this is the ‘world’s first’ tankless heat pump water heater.

Intellihot, a U.S. commercial water heater manufacturer, has begun installing what it says is the “world’s first” tankless heat pump water heater, which uses CO2 (R744) as the refrigerant, at public schools in Washington, D.C.

In development for three years, Intellihot’s Electron Series tankless heat pump water heaters were recently put on the market for commercial applications, including hotels, schools and high-rise multi-family buildings. Model iE6 was displayed at Intellihot’s booth at the AHR Expo 2024, held in Chicago January 22–24; Intellihot was named a finalist in the heating category in AHR Expo’s 2024 Innovation Awards competition for its new heat pumps.

Founded in 2009, Vernon Hills, Illinois-based Intellihot also manufacturers gas-fired tankless water heaters.

At the time of the AHR Expo 2024, Intellihot had installed two model iE1 Electron series heat pumps at each of two schools in the Washington, D.C., District 1 public school system, including the Kelly Miller Middle School; 20 more D.C. schools were scheduled to receive the units, according to Intellihot. The heat pumps replaced two gas units. “The D.C. district sought a reliable yet uncomplicated way to electrify water heating in its public schools,” says Intellihot on its website.

Thermal battery instead of water tank

Unlike other heat pump water heaters, the Intellihot unit does not link to a tank that holds potable water. Instead it employs a “thermal battery” where a glycol-water mix, heated by the heat pump, in turn heats a stream of cold potable water via a heat exchanger.

“Cold water grabs heat from the thermal battery, which uses the heat pump to recharge it,” explained Robert Svidron, Intellihot’s lead corporate trainer and applications engineer.

Intellihot says its units take up 80% less building space use 40% less energy than tank-type water heaters by heating water on demand rather than running all the time. The system makes it possible to use less storage because “you can store propylene glycol at a higher temperature – it is more energy dense,” said Svidron.

Another benefit of eliminating potable water storage is the prevention of Legionella bacteria, he noted.

Intellihot’s iE1 tankless CO2 heat pump water heater (at right) installed at Washington, D.C. school; image from Intellihot
Intellihot’s iE1 tankless CO2 heat pump water heater (at right) installed at Washington, D.C. school; image from Intellihot

The Electron Series tankless heat pump water heaters come in two factory-monitored configurations – a smaller iE1 unit, which incorporates the thermal battery, and a larger iE6 unit, which connects to a remote thermal battery. The iE1 unit features a COP of up to 4.9 and generates a heating capacity of up to 97,000BTUH (8.1TR/28.4kW), with an output water temperature range of 100 to 170°F (38 to 77°C). As many as four iE1 units can work together, inside or outside a facility.

The iE6 unit, which offers a COP of up to 4.2, is located outside of a building, while its thermal battery is situated inside. The iE6 consists of six individual heat pumps, each with its own rotary compressor and controller, and can pair with up to four thermal batteries. It generates a heating capacity of up to 300,000BTUH (25TR/87.9kW), with an output water temperature range of 100 to 190°F (38 to 88°C)

The iE1 and iE6 units are both solar-ready and come with grid connectivity that allows the use of off-peak electricity. Both operate in ambient air temperatures of -10 to 110°F (-23 to 43.3°C ) and include electric heating elements for redundancy.

“The D.C. district sought a reliable yet uncomplicated way to electrify water heating in its public schools.”

Intellihot

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