Chiller Tonnage (Delta-T and GPM)
Cooling capacity (tons, BTU/hr, kW) from chilled-water flow and the entering/leaving temperature split; required flow at a nameplate tonnage; water and 30/50% propylene-glycol factors. Q = GPM × 500 × delta-T (water); fluid factors per ASHRAE Fundamentals 2021 Ch. 31.
Formula and source
Q (BTU/hr) = GPM × factor × delta-T; tons = Q / 12000; kW = Q / 3412. Water factor 500 = 60 min/hr × 8.33 lb/gal × 1 BTU/lb-°F. Required flow at nameplate tons = tons × 12000 / (factor × delta-T).
First-principles fluid energy balance; ASHRAE Fundamentals 2021 Chapter 31 (secondary coolants) by name for glycol factors.
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