Combi Boilers - Efficient Hot Water and Space Heating | A
VARIOUS FORMULAS FOR WATER HEATING CALCULATIONS
Nov 03, 2006 · Steam Boilers & Appurtenances, Combustion & Instrumentation Controls, Deaerators, Exhaust Systems, Heat Exchangers, Heat Pipes, Industrial Pumps, Water Heaters, Water Softeners, Boiler Seminars, Services & Parts. 8 Common Boiler Formulas BR = (1 / CC) * BC BR = (1 / 8.6) * 10,000 BR = 1,163#/hr Where, BR Blowdown rate BC Boiler capacity in #/hr
Mar 13, 2016 · I'm looking at a 50,000 btu boiler with a heat exchanger to heat a 33,000 gallon pool to 90 degrees f. I've run then calculation through the formula above, and it's coming up with a 600,000 btu boiler to raise the water temp (68f) in 5 hours to 90f, which seems to be a really high number?
The formula indicates a water temperature of 60°F. However, since 60°F water is too cool for a hot water heating system and too warm for a chilled water system, to calculate the correct flow rate, the formula should be based upon more appropriate water temperatures for each type of system, such as the specific heat of the water or the density
Johnston Boiler Company Boiler Glossary
VARIOUS FORMULAS FOR WATER HEATING CALCULATIONS % Efficiency = GPH X 8.25 X Temp. Rise X 1.0 Btu/Hr. Input Specific Heat Btu/Output = GPH X 8.25 Lbs./Gal. X Temp. Rise X 1.0 Btu/Input = GPH X 8.25 X Temp. Rise X 1.0 % Efficiency Gal/Per/Hr. = Btu/Hr. Input X % Efficiency Temp. Rise X 8.25 Rise (°F) = Btu/Hr. Input X % Efficiency GPH X 8.25
q = h (7.48 gal/ft3) / ( (1 Btu/lbmoF) (62.34 lb/ft3) (60 min/h) dt) = h / (500 dt) (2) where. q = water flow rate (gal/min) h = heat flow rate (Btu/h) ρ = density (lb/ft3) dt = temperature difference (oF) For more exact volumetric flow rates the properties of hot water should be used.
During a design review, the commissioning agent re-selected the heat exchanger assuming EWT=160˚F and LWT=80˚F (27˚C). The resulting LWT back to the boiler was 80˚F (27˚C), increasing boiler efficiency, the heating water flow rate dropped about 40%, allowing for a smaller pump, and the heat exchanger weight and cost dropped to 20% of that