10-20-14, 02:28 PM | #1 |
Master EcoRenovator
Join Date: Mar 2014
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HP COP vs NG boiler $ Balance point
I want my Heating System controller (Arduino) to be able to automatically switch between HP and NG boiler, based on $ calculations.
Code must calculate the HP COP vs. Natural Gas $ Balance Point. Code will use near real-time $ inputs for NG & Electricity (pots adjusted monthly), to calculate the $ balance point, calculate HP COP real-time, then select HP or NG boiler. Coefficient of performance - Wikipedia, the free encyclopedia COP = Q / W where Q is the heat supplied to the reservoir. W is the work consumed by the heat pump. note: W is in Kwh & must include pumps. In USA units: Q = BTU/h = F x DT x 500 x SH where F is Gallons/min DT is Delta Temperature *F between Load Out & Load In SH is Specific Heat, water = 1, propylene glycol 30% water mix = .935 NG Mcf = 1,000 ft3 Therm = 100,000 BTU = 29.3Kwh $Therms = $Mcf / 10.25 My energy prices vary greatly. Over the past several winters my average delivered NG $8.00/Mcf = $.78/Therm & delivered Electricity rate about $.16 / Kwh Easy to use online Heat Cost calculator: Electric Heat vs. Gas/Oil Heat Cost Calculator/Comparator My Cost of heat (per 100,000 BTU) $.16 / Kwh Electricity = $4.69 $.78 / Therm with 85% Efficiency NG boiler = $0.92 Convert to Balance point: 4.69 / .92 = 5.0978 COP Balance Point Formula: BP = ( $ per Kwh / (( $ per Mcf / 10.25) x (1 / Boiler Efficiency %))) x 29.3 COP of about 5.1 seems too high???? Please feel free to give corrections............. Last edited by buffalobillpatrick; 10-20-14 at 03:31 PM.. |
The Following User Says Thank You to buffalobillpatrick For This Useful Post: | roflwaffle (10-20-14) |
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