1. Energy & Its Impact on Global Society
Jerome K. Williams, Ph.D.
Saint Leo University
Dept. Mathematics & Sciences

2. Chapter 5: Home Energy Conservation and Heat Transfer Control
Home Design Activity
Building Materials
Site Selection of Home
Energy Conservation Measures
Heating & Cooling Home

3. Home Design Activity
If money were not a concern, what would be the most effective design to heat and cool a home?

4. Home Design Activity
Since we live in the “real world”, what can one do to control heating and cooling costs?
Choice of home design
Retrofitting an older house
Energy efficient appliances
Addition of solar energy features

5. Home Design Activity Ultimate Goal: Zero-Energy House (ZEH)
Idea is to make house livable on nearly no net commercial energy input
Run the meter “backwards” thereby having power company pay the homeowner money for unused energy

7. Building Materials Choice of materials is important
Metals are good conductors of heat and electricity
Fiberglass or Styrofoam are insulators; these will slow down the flow of heat between objects.
Color of material does have impact on heat transfer by radiation

8. Building Materials
Increased insulation is one of easiest, most cost-effective means of reducing energy consumption
Can save up to 50% on heating & cooling bills
Rate Heat Flow= (Q/t) = (1/R) x A x ΔT
Tables 5.1 & 5.2

10. Building Materials
A measure of material’s resistance to heat flow is thermal resistance R, also called R-value
The higher the R value, the better the insulating properties of the material
For composite materials, add up all R values for mixture

11. Example Problem
Calculate the total heat transfer for 12 hours through an insulated window (two glass panes with an air gap of ¼ in.) that measures 4 ft. by 7 ft. when the outside temperature is 5 oF and the inside temperature is 65oF.
Answer 13,100 Btu

12. Building Materials
R values include effects of conduction and convection
Convection can be reduced by planting trees and shrubs near a house to reduce wind
Inside convection loss around windows can be reduced by using floor drapes and valence

14. Building Materials
Windows: important source of heat loss (35% of energy requirements for insulated home)
Solutions to Problem
Double Pane Windows (Required New Homes)
Plastic Storm Windows (Cheaper; Replace often)
Weather Stripping & Caulking (Easy; Cheap)

15. Site Selection of Home Location, Location, Location
Use Wind to cool in summer but not freeze in winter
Path of Sun: Solar energy panels face south to capture energy in winter

16. Heating & Cooling Home Air Conditioning vs. Passive Cooling Systems
Heating Options
Gas Furnace
Heat Pump System
Electrical Resistance Heating System

17. Energy Conservation Measures
Home Energy Audit

18. Problems
3, 5, 7, 8