Department of Energy Fact Sheet (282K PDF)

GFX Drainwater Heat Recovery System

The GFX Drainwater Heat Recovery System is a remarkable technology that reclaims a tremendous amount of heat energy that normally runs down your drain.  It increases the ability of your existing water heater to meet your hot water requirements without increasing its size.  The GFX is inexpensive, installs easily, and pays for itself in endless warm showers and saved energy.

What does it do?

GFX raises the temperature of incoming cold water by recycling free heat from waste water going down the drain.  Approximately 80% to 90% of all hot water energy goes down the drain, allowing GFX to recycle as much as 60% of the wasted heat.  The more hot water you use, the more energy you save.  This is especially beneficial in large process heating applications.

The GFX can eliminate the purchase of a larger water heater or an auxiliary water heating unit.  Because the GFX works best when demand is highest, you can as much as triple the capacity of your existing system.

How does it work?

As water falls down a vertical section of drain pipe, it clings to the inner surface in a very thin film.  The heat from this film is efficiently transferred to the cold water circulating in GFX (Gravity Film Xchange) around the outside of the drain pipe.  The incoming cold water is preheated before it goes into the water heater and plumbing fixtures thereby saving money and energy while increasing shower capacity.

The GFX unit can be fitted into a master residential drainwater system to effectively conduct waste water heat from a variety of sources.  Preheated water may be supplied to the entire house or fed to only the water heater and/or the cold water input of a shower.

What are the commercial applications?

In commercial applications, the GFX remarkably lowers water heating costs when demand for hot water is great and continuous.  Typical installations include gang showers, hair salons, laundromats and commercial laundries, hotels, motels, and dormitories.

The double-wall construction also makes it ideal for food processing applications where public safety is of major concern and the lack of internal welds eliminates leakage concerns and cross-contamination problems.

What about industrial applications?

GFX Cooling-Walls offer ultra-high recycling efficiency with inherent risk-management because GFX's lack of internal welds eliminates cross-contaminations problems caused by internal weld-failures and tube leaks common to shell and tube heat exchangers.  By eliminating cross-contamination issues, an ESCO can guarantee big energy savings with safe and reliable performance.