tekmar 667 Snow Detector & Melting Control Installation - Manual (Page 13)

13 of 32 © 2009 D 667 - 03/09
Section G: Δ T Hours (Relative Energy Usage)
Section G1
ΔT Hours
Section G1: Δ T Hours
The control records the temperature difference (Δ T) multiplied by the number of hours the control is in the Melt or Idle modes. This
allows the user to estimate the amount of energy used by the snow melt system. The energy consumption can be estimated by
multiplying the Δ T Hours by the system flow rate (in US GPM) and by the constant K shown below. Note: K values are calculated
averages for most ethylene glycol solutions at 50°F (10°C). K increases with higher temperatures.
% Glycol by Weight Freezing Point K (°F x hr) K (°C x hr)
0 32°F (0°C) 500 900
10 25°F (-4°C) 496 893
20 15°F (-9°C) 487 877
30 3°F (-16°C) 477 857
40 -13°F (-25°C) 462 832
50 -35° (-37°C) 439 720
Example: Δ T Hours = 5225°F x hr, System flow = 20 US GPM, Fluid = 40% glycol and 60% water, therefore K= 462.
Energy Usage = 5225 x 20 x 462 = 48,279,000 BTU.
To clear the current Δ T Hours recorded, press the ▲ and ▼ arrow buttons while viewing the Δ T Hours in the MONITOR menu.