This Old House
7
This Old House By: Steve White Ryan Anderson
description
This Old House. By: Steve White Ryan Anderson. Thermal Resistance of the House. Denoted by “R Value” It is the ability of an object or material to resist heat transfer through it. Heat into the house (in the form of natural gas). Heat out of the house. Governing Equation. - PowerPoint PPT Presentation
Transcript of This Old House
This Old House
By: Steve White Ryan Anderson
Thermal Resistance of the House
• Denoted by “R Value”• It is the ability of an object or material to
resist heat transfer through it.
Heat into the house (in the form of natural gas)
Heat out of the house
Governing Equation
• q=∆T*As/Reqv.
• To find the equivalent thermal resistance of the house, solve for Reqv.
• Reqv. depends on the materials used to construct the house, the dimensions of the walls and roof, the temperature difference from inside to outside the house, as well as many other factors including the size, shape and quantity of windows.
Data & CalculationsDecatherms
Used Watts *Adjusted Watts
Temperature Difference R Value $ Spent
October 3.5 1424.651 1111.228 8.373 1.890041 26.25November 12.7 5169.448 4032.17 14.873 0.925237 95.25December 14.8 6024.239 4698.906 19.873 1.060865 111
January 13.9 5657.9 4413.162 20.873 1.186392 104.25February 11.7 4762.405 3714.676 17.373 1.173133 87.75
March 8.5 3459.867 2698.696 12.373 1.150044 63.75April 6.3 2564.372 2000.21 8.873 1.112726 47.25May 2.2 895.495 698.4861 3.873 1.390859 16.5
Total : $552
*Adjusted Watts Watts Decatherms
Used $ Spent % Savings
October 0.41865 0.536731 0.330757232 2.48 90.55November 0.74365 0.953397 0.587525655 4.41 95.37December 0.99365 1.27391 0.785039827 5.89 94.70
January 1.04365 1.338013 0.824542662 6.18 94.07February 0.86865 1.113654 0.686282741 5.15 94.13
March 0.61865 0.793141 0.48876857 3.67 94.25April 0.44365 0.568782 0.350508649 2.63 94.44May 0.19365 0.248269 0.152994477 1.15 93.05
Total : $31.54 94.25
Collected Data from monthly bills and Temperatures from Almanac
Calculations based on an R Value of 20
* Adjustment based on 78% efficient furnace
Actual House
• Walls constructed of bricks and plaster in the 1950’s
• Low quality single pane windows
• Cost $552 to heat from October to May
Standard R Value Home
• Constructed of newer materials with an overall R value of 20 (which is typical for newly built homes)
• Would cost $31.54 to heat the home from October to May
Application
• By raising the thermal resistance of a home, the cost of heating can be reduced significantly
• In this instance, the heating cost could be lowered by 94.25% by simply raising the thermal resistance to standard levels
