n Heat Pump Water Heaters

Heat

By Francesco Lo Presti

As countries look to lessen their carbon footprint and meet tough climate goals, all eyes are on the building sector. There has been a push by almost all levels of government for innovation in the industry for “greener” technology.

Technology like hybrid electric water heaters combine two different and traditional forms of heating — electric and gas.

“A heat pump water heater (HPWH) is a standard electric water heater with a heat pump. However, instead of generating heat directly, hybrid electric water heaters use electricity to move heat from one place to another,” explained Karl Fernandes, senior product manager at Rheem.

Further, Fernandes explains, “Essentially, the hybrid electric heat pump works as a refrigerator but in reverse. While a refrigerator pulls heat from inside a box and sends it into the surrounding room, a stand-alone airsource heat pump water heater pulls heat from thesurroundingairandtransfersit,atahigher temperature, to heat water in a storage tank.”

The system is comprised of three main components, the heat pump (on top), external condensercoils(aroundthetank),andthetank and electric elements. “By using a fan, the heat pumpevaporatorcandrawinambientheat,any air above 35 degrees,” explains Gregg Holladay, the business development manager of specialty markets with Bradford White. “The refrigerant then absorbs the heat, and the compressor increases the temperature and pressure of the 134A refrigerant, amplifying the heat. Next, the heated refrigerant runs through the coils, heating the water through thetank”

Holladay also adds that, “The heat pump is the first response for recovery as hot water is drawn from the tank, using only about 500 watts of power to replace the heat. If the tank is depleted, the heat pump may also activate and standard heating elements to recover faster, following each manufacturer’s proprietary sequence ”

An HPWH has four operating modes, “heat pump-only mode, hybrid mode, electric-only mode, and vacation,” said

Patricia Kirchner, product implementation manager at AO Smith

Tankless options

Storage units have dominated the water heating market; they are a standard and reliable option for homeowners. This also remains true for the heat pump water heater market and the majority of products available on the market are storage-type heat pump water heaters.

But tankless-type heat pump water heaters have started to make their way into the market. “Our technology doesn’t store any water. Our heat pump absorbs heat from the air and stores the heat in our specially designed thermal battery. This battery has a heat exchanger inside. When the water flows through the heat exchanger, it gets heated to the desired temperature,” explains Sri Deivasigamani, CEO of Intellihot. A concern with tank-type

Hybrid

water heaters is that the water is stagnant within the unit. This can be concerning if there is an abundant amount of bacteria growth within the storage tank. Although some manufacturers of tank-type units have developed innovations which feature protection to help prevent the growth of bacteria on the tank lining.

Benefits

One of the main benefits of adopting a hybrid electric water heater is that they are considered more efficient than other water heaters, gas, oil, or standard heaters. According to NR Can, a hybrid electric water heater is up to four times more efficient and uses up to 70 per cent less energy, on average, than a standard electric water heater. Additionally, electric water heaters led the overall water heater market and accounted for 51.3 per cent of the revenue share in 2022, according to a report done by Research and Markets.

Additionally, because the technology uses electricity, “There are no direct emissions from the home, unlike gas or oil. HPWHs use roughly 3,000 less kWh than a standard

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