Discover Copper Online

Spring 1997

Copper Ensures More Hot Water

Diagram showing how the GFX is installed. One unit captures about 60% of the heat from draining water, but when three units are installed in line, the recovery rate can rise to more than 80%.

Ever turned on the shower only to be chilled by tepid or even cool water because others had bathed just ahead of you? Now, there's a new all-copper device that can reduce such aggravation by helping water heaters deliver plenty of hot water more quickly.

The GFX Heat Exchanger, manufactured by the Vaughn Manufacturing Corp. of Salisbury, Massachusetts, captures heat from hot drain water and transfers it to the incoming water (see illustration). The now-warmed water goes to the water heater, reducing the heater's energy requirements to bring it to the 100'F to 140'F temperatures used in most households.

Prof. Gary Crossman of the College of Engineering and Technology, Old Dominion University, Norfolk, Virginia, has tested the energy-saving device. He confirms that as much as 60% of formerly wasted heat energy can be captured by a single GFX. This in effect enables a water heater to deliver up to three times as much hot water as a heater without GFX. Depending on the volume of hot water needed and the cost of energy, the GFX can pay for itself in less than a year. The most commonly used model costs about $180.

The device was invented and patented by Dr. Carmine Vasile of Oakdale, New York. It is designed to be vertically mounted in place of a cutaway section of drain pipe of the same diameter. The assembly takes advantage of the phenomenon whereby draining water clings to the inside surface of vertical pipes. This makes for high heat transfer from the Type DVW copper tubing used for the central drain to the cold water coming in through the spiral of 1/2- or %- inch-diameter Type L copper tube wrapped tightly around the replacement drain. Vasile claims that if his heat exchangers were installed in all American homes, need for imported oil could drop by some eight billion gallons.

According to Dan Cautley, a research engineer with the National Association of Home Builders (NAHB) in Upper Marlboro, Maryland, a simple installation shouldn't require more than two hours of an experienced plumber's time.

A GFX has been installed in one of the NAHB's energy-efficient demonstration homes in Bowie, Maryland. (See Copper Topics 76.) In addition, Cautley is having a GFX installed in a new home he is building for sale. When these energy savers are put in at the time of construction, much less time is required for installation.

James F. Vaughn, III, president of Vaughn Manufacturing, notes that the notion of capturing the heat in drain water is not new. There are at least two competing devices. However, when demonstration "Healthy Home" was built recently in Toronto, Canada, the GFX was specified. Doug Hart, a director of Watershed Energy Systems Corporation, Toronto, said, "We selected the GFX because it is not only more efficient, but does not entail any storage of drain water containing fats, which, in other devices, can cause clogging." The GFX is most effective in winter when incoming water is coldest; it is less efficient in summer when incoming water is warmer. For maximum energy savings, the GFX should be located so that all drained water, including that from sinks and washing machines, is piped through the GFX.

Vaughn Manufacturing offers the GFX in a variety of versions, including parallel units for situations with limited ceiling height. For larger homes, apartment houses or industrial applications, two or three GFX units can be linked one on top of another for increased heat savings. A three-unit system, for instance, can recover up to 82% of heat from draining water, according to Vaughn.

The long-lived, no-maintenance GFX has gained UL approval and meets the building codes of a number of states. In addition, Vaughn has applied for acceptance by the international Association of Plumbing and Mechanical Officials (IAMPMO), Walnut California. All the tubing in the GFX unit is supplied by Reading Tube Company, Reading, Pennsylvania.

Reading Tube Company: 888/253-7253
Vaughn Manufacturing: 800/282-8446

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