# Energy Loss, Emission Reduction, Surface Temperature, and Annual Return Calculators

These calculators estimate the performance of an insulated system given the operating temperature, the ambient temperature, and other details about the system. As an aid to understanding the relationships between energy, economics, and emissions for insulated systems, simple spreadsheet calculators have been developed for equipment (vertical flat surfaces), and horizontal pipe applications.

The Equipment Spreadsheet estimates the heat flows through a vertical flat steel surface (typical of the sides of a large steel tank containing a heated or cooled fluid). Information concerning a hypothetical insulation system (e.g., the area, operating temperature, ambient temperature and wind speed, insulation material and surface emittance of a proposed insulation system) may be input by the user. Calculated results are given over a range of insulation types and thicknesses and include: 1) surface temperature, 2) heat flow, 3) annual cost of fuel, 4) payback period, 5) annualized rate of return, and 6) annual CO2 emissions.

Energy Calculator for Equipment (Vertical Flat Surfaces)

The Pipe Spreadsheet estimates the heat flows through horizontal piping. Information concerning a hypothetical insulation system (e.g., the length of run, pipe size, operating temperature, ambient temperature and wind speed, insulation material and surface emittance of a proposed insulation system) may be input by the user. Calculated results are given over a range of insulation types and thicknesses and include: 1) surface temperature, 2) heat flow, 3) annual cost of fuel, 4) payback period, 5) annualized rate of return, and 6) annual CO2 emissions.

Energy Calculator for Horizontal Piping
3E Plus® Insulation Thickness Computer Program, North American Insulation Manufacturers (NIAMA)

## Inputs

Users will need to input the following:

• Surface area in square feet for equipment or length of piping and pipe size
• Operating temperature in °F
• Ambient temperature in °F
• Wind speed in mph (guidance provided with calculator)
• Insulation type (calculators provide for a selection of five major types) (1)
• Insulation installed cost (calculators provide typical values) (1)
• Emittance of surface (guidance provided with calculator)
• Expected useful life of the insulation system in years
• Operating hours per year
• Efficiency of fuel conversion as a percentage (guidance provided with calculator)
• Fuel type and cost (calculators provide for a selection of five major types and typical cost for each)

(1) Please refer to the calculator introduction notes for additional information

## Outputs

Based on input, calculators will provide the following by thickness, in inches, of insulation:

• Surface temperature in °F
• Heat loss in British thermal unit per hour (Btu/hr)
• Cost of fuel in dollars per year
• Installed insulation cost (estimated)
• Payback in months
• Annual return as a percentage (Simple Internal Rate Of Return (IRR))
• CO2 emissions in Metric Tonne/year

## Release Notes

The calculators are housed at the National Institute of Building Sciences' Whole Building Design Guide (WBDG) website under the Mechanical Insulation Design Guide (MIDG). Calculators can be used online without any specific software requirement, and you can print the results page for each calculation.