Environmental Engineering Reference
In-Depth Information
pronounced when low-quality heat is adequate for the industrial process or space heating, such as
the heat rejected by the steam to a condenser after driving a turbine.
2.6.2
Residential Sector
Of the total energy used by the residential sector, about 40% is used for appliances and lighting
(mainly electricity), 34% for space heating (mainly fossil fuel as petroleum and natural gas),
16% for water heating (mainly electricity and natural gas), and 10% for air conditioning (mainly
electricity). This is depicted in Figure 2.10. Significant savings in space heating could be realized
by conservation (e.g., lowering the thermostat in winter and raising it in summer) and by better
insulation. Solar heating could be more widely utilized both for space and water heating. Appliances
can be made more energy efficient and smaller. Lighting could be converted from incandescent to
fluorescent bulbs.
2.6.3
Commercial Sector
Of the total energy used in the commercial sector, about 26% is used for lighting, 19% for
space heating, 9% for office equipment, 8.5% for water heat, 7.5% for air conditioning, 7% for
ventilation, 5% for refrigeration, 3.5% for cooking, and 14.5% for other uses (see Figure 2.11). As
Air conditioning 10
Water
heating
16
40
Appliances
and lighting
34
Space heating
Figure 2.10
Proportions (%) of primary energy use in the U.S. residential sector. (Data from U.S.
Department of Energy, Energy Information Agency, 1990.
Residential End Use Energy Consumption, 1990
.)
Other 14.5
Cooking 3.5
26
Lighting
Refrigeration 5
Ventilation 7
19
Space
heating
Air conditioning 7.5
Water heating 8.5
9 Office equipment
Figure 2.11
Proportions (%) of primary energy use in the U.S. commercial sector. (Data from U.S.
Department of Energy, Energy Information Agency, 1990.
Energy Markets and End Use, 1990.
)
