ClueLuma

Net heat-recovery source benefit calculator

Recovered useful heat avoids source input but added electrical auxiliaries reduce the net cost saving.

Units
B=Erecovered×100ηsource×pheat−Eaux×pelectricB = \frac{E_{\text{recovered}} \times 100}{\eta_{\text{source}}} \times p_{\text{heat}} - E_{\text{aux}} \times p_{\text{electric}}

Calculator

Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.

MMBtu/yr
%
$/MMBtu
kWh/yr
$/kWh
$/yr

Worked example

Given

  • ErecoveredE_{\text{recovered}} = 600 MMBtu/yr
  • ηsource\eta_{\text{source}} = 80 %
  • pheatp_{\text{heat}} = 9 $/MMBtu
  • EauxE_{\text{aux}} = 12,000 kWh/yr
  • pelectricp_{\text{electric}} = 0.12 $/kWh
B=600×10080×9−12,000×0.12=5,310B = \frac{600 \times 100}{80} \times 9 - 12{,}000 \times 0.12 = 5{,}310

Symbols and units

SymbolMeaningUnit
BBannual net energy-cost benefit$/yr
ErecoveredE_{\text{recovered}}annual useful recovered heatMMBtu/yr
ηsource\eta_{\text{source}}displaced source efficiency%
pheatp_{\text{heat}}purchased fuel-energy price$/MMBtu
EauxE_{\text{aux}}extra annual electrical energykWh/yr
pelectricp_{\text{electric}}electrical energy price$/kWh

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Results are estimates for study and screening. Check the inputs, units and assumptions before you use them for design, billing or contract decisions.