Interesting Energy Conversions

Published 02/26/2023


Interesting Energy Conversions

List of really cool and interesting energy conversion tools.

Heat Pump Break-Even COP


Typically the COP of an air source heat pump will drop as outside temperatures go down. By knowing the break even COP you can then compare that to your heat pump's data sheet to determine at what temperature it would be cheaper to operate off of natural gas.

Calculates the Break-Even COP (coefficient of performance that an Air Source Heat Pump would need to achieve in order for operating energy costs to be cheaper than a natural gas furnace.


Does not account for ng or electric connection fees. New Paragraph

Break Even COP
Cost of Natural Gas ($/Dth) :Furance Efficiency % :Costs of Electricity (cents/kWh):Break Even COP :

Solar Panel String Voltage and Maximum Panels Per String Calculator

Panel Voltage goes up as panel temperature goes down.
Calculations are assuming a minimum PV panel operating temperature of 5°F (-15°C)

Calculate Max Number of PV Panels in a string
Panel Voc:Temperature Coefficient (%/°C):Max String Voltage:Result Max Voc:Result Max Possible String Voltage:Result Max Panels/String:

EV Range Calculator

Calculate the rolling force, air friction force and associated powers to drive at a given velocity.

This calculator assumes flat ground with no winds.


Example Vehicles:

Chevy Bolt: 3580 lbs, FA 2.397  m^2, Cd 0.308, Battery  350.4 VDC, Energy 66 kWh


Tesla Model 3: 3703 lbs, FA 2.22 m^2, Krr 0.011, Cd 0.23, Battery  350 VDC, Energy 75 kWh


Nissan Leaf: 3703 lbs, FA 2.27 m^2, Cd 0.28, Battery  364.8 VDC, Energy 21 kWh


Geo Metro EV: 1850 lbs, FA 1.71  m^2, Cd 0.25, Battery 72 VDC, Energy 11.2896 kWh

EV Range Calculator
Vehicle Speed (mph):Vehicle Weight (lbs):Road Friction:Frontal Area (m^2):Coefficient of Drag (Cd);Air Density (kg/m^3):Nominal Battery Voltage (VDC):Usable Battery Energy (kWh):Result Rolling Force (N):Air Friction Force (N):Power (to maintain this velocity) kW:Current Draw (to maintain this velocity) Amps:Horsepower (to maintain this velocity) hp:Watthour per mile (at this velocity) Wh/mile:Miles/Gallon Equivelant MPGe:Energy To Drive 20 miles (kWh):Max Range (at this velocity) miles:
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