When ethylene/propylene glycol is added to a hydronic loop, the most important design adjustment vs pure water, besides freeze protection, is (conceptual)?
Choices
- (A) Ignore NPSH
- (B) Lower pipe roughness in all systems
- (C) Delete expansion tank
- (D) Reduced specific heat, higher flow for same Btu, higher pump/heat exchanger per unit ΔT, plus inhibitor chemistry
Correct answer: (D)
Reduced specific heat, higher flow for same Btu, higher pump/heat exchanger per unit ΔT, plus inhibitor chemistry
Explanation
Glycol: density,cp,viscosity, chemistry — larger pumps, coils.