By Jason Fleming
Hot water is the lifeblood for many commercial applications. A restaurant lacking hot water will be forced to shut down for lack of hygiene. Hotel room showers that cannot reach the set-point temperature leave clients dirty and disappointed. A laundromat without the ability to wash clothes loses its purpose.
Selecting a water-heating system that efficiently and reliably meets demand is crucial. For many, the gut reaction might be to follow convention and choose a storage-tank water-heater. However, the North American market is gradually learning what the rest of the world has known for 50 years—tankless water-heaters, whether operating individually or banked together, will always meet hot-water demand at a fraction of the gas input of the storage-tank variety.
Advantages of tankless
Tankless water-heating technology relies on heating incoming water to reach the set-point temperature in seconds. The heaters carry with them the advantages of efficiency, redundancy, versatility, and serviceability.
Tankless water-heater performance relies on modulating boiler technology, which tracks and meets hot-water demand with pinpoint accuracy, matching energy consumption to the present requirements. Unlike with storage tank heaters, there are no standby losses resulting from the burner firing during periods of inactivity. When combined for larger commercial applications, the entire system adjusts usage to match demand.
In terms of thermal efficiency, tankless water-heaters can be up to 20 per cent more efficient than a minimally compliant storage-tank water-heater, based on thermal efficiency standards reported by the U.S. Department of Energy (DOE). This can translate to significant energy savings over time that offset—and eventually pay back—any upfront capital investment, which will typically be higher for tankless. In certain large commercial applications, though, the upfront capital investment may actually be less for tankless, especially when savings from pre-engineered (i.e. pre-racked) tankless systems are factored in. These savings, combined with reduced annual maintenance and further supplemented by provincial energy rebates, can drive lower cost of ownership for the water-heating system.
When banked (i.e. combined together into one interconnected system), tankless water-heaters offer much-needed redundancy of operation. If one unit happens to go offline and needs to be serviced, the remaining units will split the heat demand to maintain the set-point temperature. This capability keeps hot-water-reliant operations running, even if one or more units need servicing.
Aside from being smaller and able to be wall-hung or rack-mounted, tankless water-heaters can work in concert with other heating units in an application. A large hotel may wish to combine a storage tank with a tankless heater to cut down on the required number of units, while continuing to reap the benefits of efficiency and redundancy. Tankless units can even supplement solar-heated applications, serving as a fallback on cloudy days. Further, units can be installed indoors or outdoors and be individually or common-vented.
Tankless heaters are built with modular construction, meaning they are fully ‘parts-replaceable.’ Thus, in the case of a malfunction, only the faulty component needs to be replaced, instead of the entire system. This not only reduces cost, but also eliminates the downtime that would otherwise be needed to install an entirely new unit.