Figure 2. Prototype design 1.
Testing and Methodology
the new stockpot designs were tested at the PG&E Food Service
Technology Center located in San Ramon, CA, U.S. All findings were then
translated into FSTC Report 5011.08.12, Eneron Inc. Prototype Commercial Stock Pot Testing, May 2008.
engineers at the Food Service Technology Center documented
cooking-energy efficiency and production capacity of three different
range tops when using two prototype 24-qt stockpot designs. These
results were compared with baseline numbers obtained using a standard
24-qt aluminum stockpot. The testing followed the controlled conditions
outlined in the American Society for Testing and Materials (ASTM) F1521
Standard Test Method for Performance Range Tops.
pot used for baseline testing was a 12-in.-diameter, aluminum stockpot
with a capacity of 24 quarts. It was purchased off-the-shelf from a
restaurant supply house and represented a typical cooking vessel
designed for use on a commercial range top.
first prototype stockpot was the same model as the standard pot, with
the bottom modified to include 1⁄16-in.-wide aluminum fins. The fins
were 5⁄8-in. high and spaced 1⁄8-in. apart. These parallel fins form
heat exchange channels. The second prototype pot was designed with
1⁄8-in.-wide perpendicular grooves in the fins, producing a bottom of
small rectangular fins.
Three ranges were
used during testing. Range A and Range B employed an open ring-shaped
burner, rated at 30,000 Btu/hr per unit. Range C employed a star-shaped
burner, rated at 20,000 Btu/hr per unit. A ring burner emits flame in a
concentric circular pattern, and a star burner emits flame in a
traditional star pattern. While both ring burners were rated at 30,000
Btu/hr, they were slightly differing in design and produced unique
Three test runs were performed
for each stockpot on each of the three range tops. The cooking-energy
efficiency and production capacity were determined by heating 20 lb of
water from 70° to 200°F. The results depicted in Table I are the
average of three individual test runs for each pot-range combination.
each range, the testing results showed a substantial improvement for
the prototype stockpots over the standard stockpot design.
Figure 3. Prototype design 2.
Range C was rated at 20,000 Btu/hr per burner and,
therefore, was expected to have longer heat-up times than the two
30,000 Btu/hr burner ranges (Range A and Range B). However, the results
from Range C were the most impressive out of the three appliances,
easily showing the largest improvements over the baseline levels with
the prototype stockpots. In fact, Range C exhibited quicker heat-up
times with the prototype stockpots than Range A, even though Range C
had 30% less horsepower than Range A.
next test conducted was a simmer energy-rate test to determine whether
there are potential energy savings when using the prototype stockpots
to simmer liquid at approximately 205°F (96°C) on Range C. To conduct
the test, each stockpot was filled with 20 lb of water and placed on a
burner. After raising the water temperature to 205°F, the lid was
removed from the pot and the burner was adjusted to hold the water
temperature at 205° ± 1°F. Time and energy was monitored for 1 hour to
allow calculation of the simmer energy rate.
of the prototype stockpots allowed the burner to operate about 3100
Btu/hr lower than the standard pot while holding a steady simmer.
Unlike the energy-efficiency tests, the results from the two prototype
pot designs were nearly identical, presumably because of the much lower
flame level on the burner. Table II represents the results of the
Testing found that the pots’
cooking efficiency varies based on the appliance used. This is because
the flame profile plays a role in coupling the flame into the heat
exchange channels; it needs to allow the flame to get in the channels
(i.e., in between the fins to be able to fully utilize the increased
surface area). Certain flame patterns will fit better with certain fin
Comparing the two prototype designs,
the continuous fin structure pot will have better mechanical strength
than the model with short fins. The continuous fin structure also
provides better lateral heat transfer and improves the heating
uniformity across the bottom of the cookware.
Pot under test.
proposed stockpot designs proved to be a remarkably effective method of
increasing range-top performance. Heat-up times were substantially
reduced and production capacities increased. Energy performance was
also significantly improved. By simply using an advanced pot design,
the 25–30% energy efficiency of a standard, gas-fired range top was
raised to more than 40%. When used on a range top with energy
efficiency in the low 30s, the number approached 60%.
benefits were not limited to full-input operation, as shown by the
simmer tests. Less energy was required to maintain temperature,
enabling a further increase in savings. While this test was done on
stockpots, the same concept can be implemented on other types of
cooking vessels, such as a griddle plate, for more-efficient gas-fired
This is an edited version of FSTC Report 5011.08.12, Food Service Technology Center, May 2008.