Residential Heatingand Cooling

Prepared by:

Will George

Ryan Lester

Causality Parameters

• Temperature – variance in temperature creates different energy demands for heating and cooling. Degree day data was compiled on a state by state basis.

• Households - number of households was available for each state by decade and interpolation was performed to find the missing years.

Causality Parameter Trends• Weather is assumed to remain constant over the

years, but varies spatially.• Housing units have been steadily increasing:

Housing Units

0

2000000

4000000

6000000

8000000

10000000

12000000

14000000

1950 1960 1970 1980 1990 2000 2010

Year

Nu

mb

er

of

Ho

us

ing

Un

its

CA

GA

MO

NY

Heating Data• Natural gas consumption per state per

month is available for the past 17 years.• Heating fuel usage was extracted and

applied to the housing units and degree days to come up with a conversion factor in the form of Btu/Housing Unit/Degree day.

• Housing Units and Weather are the parameters affecting the heating and cooling requirements

National Natural Gas Usage

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

Jan-85

Feb-85

Mar-85

Apr-85

May-85

Jun-85

Jul-85

Aug-85

Sep-85

Oct-85

Nov-85

Dec-85

Month/Year

MM

cf (

Bil

lio

n B

tu)

Subtract the amount from the lowest month from each month to find the amount used for heating. (The quantity from the lowest month represents utility gas uses other than heating.)

Heating energy per degree day and housing unit

0.0E+00

5.0E-06

1.0E-05

1.5E-05

2.0E-05

2.5E-05

1988 1990 1992 1994 1996 1998 2000 2002 2004

Year

BB

tu/H

DD

/Ho

usi

ng

Un

it

TN

AL

ND

CA

Heating fuels used per household were available per decade per state (1940-2000). These were interpolated to estimate per year for each state.

Knowing the contribution in Btu by natural gas allowed the other fuel energies to be calculated.

Heating Fuels

Heating Trend

NY Heating Energy by Fuel

0.00E+00

5.00E+04

1.00E+05

1.50E+05

2.00E+05

2.50E+05

3.00E+05

3.50E+05

4.00E+05

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

BB

tu

Natural Gas Bottled Gas Electricity Fuel Oil/Kero Coal

Natural Gas usage is rising, Coal and Fuel Oil usage is dropping, and electricity is rising slowly. Wood usage has dropped significantly since the 1940s.

Emissions Factors (Mg carbon/BBtu)

• Natural gas 14.47

• Wood 100.67

• Kerosene 19.72

• Coal 25.9

Natural gas emits far fewer emissions than the other fuels

Cooling Data

• Have AC usage data by region for 1993, 1997, and 2001. Average proportion of energy used by region assumed to be constant over time.

• National energy use for a number of years given. Extrapolation and interpolation done on missing years.

Calibration CurvesAC Usage Per Household vs. Cooling Degree Days

0

2

4

6

8

10

12

14

16

0 500 1000 1500 2000 2500 3000

Cooling Degree Days

AC

Usa

ge

per

Ho

use

ho

ld (

MB

tu)

2001

1997

Linear (2001)

Linear (1997)

Cooling TrendState AC Usage

0.00

10000.00

20000.00

30000.00

40000.00

50000.00

60000.00

70000.00

80000.00

90000.00

1950 1960 1970 1980 1990 2000 2010

Year

AC

En

erg

y U

sed

(B

Btu

)

Louisiana

Massachusetts

California

Minnesota

Texas

Cooling Trend

• Energy used for each state has been increasing overall.

• This increase is a result in increased number of houses and an increase in the percentage of houses that have AC.

• Some of the inconsistency is due to spotty national AC usage data. Also, an increase in AC efficiency will cause a decrease in AC usage if the number of households remains steady.

Suggested Changes

• Migration to the warmer states– Heating degree days far outweigh cooling

degree days

• Increase people per household

• Change heating fuel

• Change thermostat setting

• Close off unused rooms