Blowdown Heat Loss

Estimates the sensible heat carried away by water discharged in blowdown, which must be replaced and reheated.

$$\text{Heat loss (BTU/hr)}=BD\times C_p\times \Delta T$$

Variables

Symbol	Meaning	Unit
BD	Blowdown rate	lb/hr
$C_p$	Specific heat of water (approximately 1.0)	BTU/lb·°F
$\Delta T$	Blowdown water temperature minus makeup water temperature	°F

Worked example

Blowing down 1,000 lb/hr at 212°F against 60°F makeup: 1,000 × 1.0 × (212 − 60) = 152,000 BTU/hr.

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Part of The Blueprint of Water