Cooling-System Coolant Flow for a Heat Load

gpm = Q / (c x deltaT), c = 500 water / 427 glycol. 150,000 Btu/hr at a 10 F rise needs 30 GPM (water) or 35 GPM (50/50 glycol, ~17% more); a tighter 5 F rise doubles the flow to 60 GPM. A sizing aid; the equipment ratings and fluid properties govern.

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Formula and source

gpm = Q / (c x deltaT); c = 500 water, 427 (50/50 glycol).

The sensible-heat coolant-flow relation gpm = Q / (c x deltaT), by name.

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