Insights: Heat-Pump Domestic Water Heaters

Heat-pump water heaters offer commercial and high-rise residential buildings in New York City an energy-efficient, cost-effective and environmentally friendly means of heating domestic water.

Conventional Water-Heating Systems are Inefficient

Heating water in New York City’s buildings can be expensive and harmful to the environment, especially if fossil-fuel-burning heaters or furnaces are used. In fact, older heaters can waste up to 20% of their fuel, and even newer models can waste up to 10%. This results in more money spent and more carbon emissions released into the environment.

Heat Pumps Offer a Better Way for Water Heating

Heat pumps use the same operating principle as an air-conditioner or refrigerator by using electricity and compressors to absorb energy from air or water and transfer it into domestic water at a useable temperature. Heat-pump water heaters offer commercial and industrial buildings an energy-efficient means of heating water to temperatures as high as 185°F in a single pass.

The principle of moving heat with a heat pump, rather than generating it by burning fossil fuels (e.g., natural gas) or electric resistance, makes water heating with heat pumps the best alternative for conserving energy. Depending on the temperature of the air or water source, domestic water can be heated using one third to one fourth of the energy required by gas or electric resistance.

Colmac Heat-Pump Water Heater Advantages

• Energy-efficient water heating: Heat-pump water heaters maximize energy efficiency and have a significantly higher Coefficient of Performance (COP) than gas or electric-resistance systems. Colmac systems are the most efficient method available today for heating domestic water and typically achieve COPs of 4-6, compared to the most-efficient boiler that only reaches .95. This means that Colmac heat-pump water heaters are up to 600% more efficient than conventional options.
• Supporting sustainability and building electrification: Heat-pump water heaters’ extremely high COPs make them a green, sustainable water-heating option since they drastically cut energy consumption and don’t require fossil fuels. This means that installing Colmac systems is in line with building-electrification efforts that are part of New York City’s Roadmap to 80 by 50, which seeks to cut greenhouse gas emissions 80% by 2050. In addition, the Colmac high-efficiency vapor compression cycle method has zero direct carbon emissions and can be part of a LEED points design and/or qualify for environmental utility incentives or credits.
• Recovering otherwise-wasted heat:One of the main sources for Colmac heat-pump water heaters is heat coming from other HVAC operations that would otherwise be expelled into the atmosphere and wasted. Such heat sources include building exhaust systems, chillers or cooling towers, and utilizing this waste heat further boosts efficiencies and environmental protection.
• Significant cost savings:When using heat-pump technology, three to five units of energy are moved from the source to the process water for every input of electrical power, and with ample thermal storage, much of the cost can be shifted to off-peak hours. What’s more, while heating potable water, Colmac systems create cool air or cold water, which reduces cooling costs simultaneously. This means that by using Colmac heat-pump water heaters, a building’s hot-water production can be cash-flow positive.
• Reliable performance: Designed for low maintenance and easy service, Colmac heat-pump water heaters have a life expectancy of 15+ years, with many units lasting 25+ years. The Colmac WaterHeat single pass system delivers a constant leaving-water temperature for continuous water heating whenever the unit is running.
• Safe and sanitary water: Safe for potable (sanitary) domestic water systems, the double wall-vented condensers used by Colmac fully isolate the refrigerant from the water system. Additionally, by heating water to 140°F-185°F in a single pass, Colmac WaterHeat has created a true hazard analysis and critical control point (HACCP) for the eradication of Legionella in hot-water storage systems without the use of UV or chemicals.
• Fulfilling NYC energy code:Section C403.4.6 of the 2014 NYC Energy Conservation Code indicates that condenser-water heat recovery must be installed for heating service water if the total installed heat capacity of the water cooled system exceeds 6,000 MBH of heat rejection. This equates to approximately 400 tons of installed cooling capacity. Engineers find this portion of the code to be difficult to comply with because it’s contrary to the economizer code. The issue becomes: how do you preheat domestic water in the cooler months when the condenser water is cold? Colmac solves this problem because, even with 45°F water, its systems can create 140°F+ domestic hot water. Not only does this comply with the code, but it exceeds it drastically.

Applications for Colmac Heat-Pump Water Heaters

 Air-source heat-pump water heaters: Hotels, apartments, offices, dormitories, laundry facilities, hospitals, schools, industrial processes, pools and hydronic heating.

• Water-source heat-pump water heaters: Hotels, apartments, offices, dormitories, potable water cooling, hospitals, schools, industrial processes, geothermal and hydronic heating.

Further, for mechanical and plumbing engineers, any time a building is air-cooled or using variable refrigerant flow (VRF), Colmac heat-pump water heaters make for a smart selection.