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GFX Tested Performance
DOE’s Uniform Test Method
for Water Heaters: 10CFR Pt. 430, Subpt. B, App. E
Measured Performance of 5
Electric PFWH’s
(Power Feedback Water
Heaters) using a Model G3-60 GFX
|
WATER HEATER (#1,2,3 all 50 gal) |
ENERGY FACTOR (EF) |
STANDING LOSS (Btu/hr) |
FIRST HOUR RATING (gallons) |
|
1. Standard |
1.3 +/-0.125 |
220 |
108* |
|
2. Plastic (Hi-Eff.) |
1.51 +/- 0.31 |
193 |
180* |
|
3. Stone Lined (Hi-Eff.) |
1.6 +/- 0.11 |
178 |
180* |
|
4. Tankless (13.5 kW) |
1.8 +/- 0.1 |
NIL |
Continuous @ 2.2 gpm |
|
5. Point-of-Use (2.5 gal.) |
N/A |
N/A |
2 to 3 gal. @ 2.2gpm |
* Estimated because GFX prevented upper element energization during standard draw test.
HPWH
Performance with E-Tech’s Add-on Heat Pump (“HP”)
|
WATER HEATER |
EF** |
STANDING LOSS |
FIRST HOUR RATING |
|
1. Standard |
1.28 +/- 0.16 |
260 |
46 |
|
2. Plastic |
1.365 +/- 0.155 |
165 |
58 |
|
3. Stone-Lined |
1.45 +/- 0.12 |
127 |
60 |
** Outperforms heat pump water heater
The Old Dominion GFX study was part of a larger project to evaluate several
electric water heating technologies, including heat pump water heaters. When
the results for the GFX are compared to those for heat pump water heaters, the
GFX looks better. For the three electric heaters tested, the measured energy
factor was higher with the GFX than with an add-on heat pump water heater (see
Figure 4). These results do not conclusively show that the GFX will outperform
a heat pump water heater in the field, however, because of complexities like
batch usage and water temperature. Nonetheless, given the much lower cost of
the GFX, it appears to be a practical alternative to heat pump water heaters.@
(Quote from Extraordinary Water Heat Recovery Device, Energy
Design Update, December 1996)
Performance of all 5 Electric Water Heaters without GFX or HP
|
WATER HEATER |
EF |
STANDING LOSS |
FIRST HOUR RATING |
|
1. Standard |
0.845 +/- 0.015 |
339 |
46 |
|
2. Plastic |
0.915 +/- 0.015 |
359 |
58 |
|
3. Stone Lined |
0.92 +/- 0.01 |
134 |
60 |
|
4. Tankless |
0.99 +/- 0.01 |
NIL |
1.5 gpm |
|
5. Point-of-Use |
N/A |
N/A |
1.25 to 1.6 |
KEY CONCLUSIONS
"The GFX drain water
recycling unit is an extremely effective heat exchanger. Its measured effectiveness
(recycling efficiency) was very close to that specified by the manufacturer at
60 percent."
"When properly installed, the
GFX reduces energy consumption at varying load patterns from 47 to 64 percent
with the average being 55 percent."
"GFX can increase the energy
factor from 57 to 73 percent over resistance water heaters alone."
"Resistance water heaters
utilizing GFX as a pre-heater can produce Approximate First Hour Ratings of 108
to 180 gallons; about two to three times that of resistance water heaters
alone."
"With a drain water
temperature near 100 degrees F the GFX can increase the temperature of the
water entering the water heater from 20 degrees F to 30 degrees F depending on
inlet water temperatures."
"GFX provides enough energy to
the inlet water to prevent the upper element energization (fast recovery
cycle). This occurred in all tests with the three resistance water
heaters."
"In typical 24-hour hot water
draw profiles the" tankless water heater" combined with the GFX as a
preheater consumed approximately 36 percent less energy than Water Heaters #1
and #2 combined with the GFX and 18 percent less than Water Heater #3 with the
least standby losses."
- Reference:
"Virginia Power Water Heater Testing and Optimization Project",
Final Report (May 31, 1996) by Douglas Taylor and Prof. Gary Crossman,
College of Engineering and Technology, Old Dominion University, Norfolk,
VA 23529.
- Was
estimated since so much energy was recycled the "First Hour Ratings
could not be calculated for GFX because the upper element did not
energize."
- Estimated
from an average measured energy savings of 36% , 18% compared to #1 &
#3, respectively.
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© 2002 Waterfilm Energy, Inc.