The Eternal Hybrid Water Heater is a unique water heater that blurs the lines between a tank water heater and a tankless while taking the best qualities of each. The Eternal Hybrid was developed and introduced in 2006 by the Taiwan based Grand Hall Enterprise Company Ltd. which has maintained its Grand Hall USA office in Dallas, Texas since 1985.
Conventional tank type gas water heaters operate in a manner similar to a pot on the stove with a burner in the 40,000 Btu range, the incoming cold water directed to the bottom of the tank by the dip tube and hot water is drawn off the top of the tank. About 70% of the capacity of the tank can be used before the outlet temperature starts falling and the water heater has to recover this means that you need to have enough storage capacity to meet your hot water needs. When water is not being used there is what is termed standby losses through the outer jacket of the tank and by air going up through the flue in the center of the tank. The common tank type water heater delivers an efficiency in about the 60% range.
Tankless water heaters do not store any water but have a large heat exchanger and a burner typically in the 199,000 Btu range. Whenever water is used the burner lights and it modulates depending on the flow to instantly heat the water passing through it to the temperature that you have set. When you are using small amounts of hot water intermittently waiting for hot water can be annoying. The tankless coil also has pressure losses that increase with higher flows and the coil requires servicing to delime it. The ability of the tankless to heat the water to the set temperature is largely dependant on the rate of rise and the temperature of the incoming water. A tankless unit may be able to deliver 7.5 GPM of 120 degree F water with 80 degree incoming water in the summer (40 degree rate of rise) may in the winter with 40 degrees F incoming water deliver only 3.8 GPM of 120 degree F water (80 degree rate of rise). In colder areas of the country tankless users often have very large tankless units or, sometimes multiple units working together to meet their needs. Tankless water heaters average about 80% efficiency.
The Eternal Hybrid Water Heater is a unique water heater that has a tank yet uses a large burner similar to a tankless water heater and a large surface area heat exchanger system that utilizes the maximum available heat out of the flue gases before exhausting them. The tank delivers stored hot water for use without having to wait for the water heater to turn on. Once the hot water in the tank has been depleted the Eternal Hybrid water heater then functions as a tankless delivering an endless supply of hot water at a lower flow. The Eternal Hybrid can deliver 9.4 GPM with a 45 degree F rate of rise and 5.2 GPM with a 80 degree F rate of rise. With a burner that modulates between 47,500 Btu and 236.000 Btu.
The Eternal Hybrid Water Heater uses a multi-pass heat exchanger system which drives heat downward then passes it through 44 baffled stainless steel pipes for maximum heat transfer. The water against the large surface area 44 heating pipe heat exchanger absorbs the heat quickly. The flue gases are so low in temperature they can be vented using PVC pipe. This reverse flow technology allows the Eternal Hybrid to deliver an efficiency of 86%. The Eternal Hybrid is 1/2 the size of a 50 gallon tank type water heater but has 300% higher output. It also is a clean burning water heater with nearly zero greenhouse gas emissions and meets the South Coast Air Quality Management Districts stringent Ultra Low NOx requirements. The stainless steel tank of the Eternal Hybrid is a self cleaning, maintenance free unit, and in residential use is backed with a 20 year no-leak warranty on stainless steel heat exchanger tank. The Eternal Hybrid has a 3 year warranty on all other parts, and a 1 year warranty on reasonable labor.
The Eternal Hybrid Water Heater Models GU-20 and GU-26 qualify for a Federal Income Tax Credit when installed between February 17, 2009 and December 31, 2010. Other Rebates and Grants may be available under the Appliance Stimulus Program, the Weatherization Assistance Program and state and utility rebate programs. Check with your state for details. There is probably no better time than right now to get rid of that old water heater that is costing you money and save money while going green.