|
|
Heaters
Fuels used in portable
heaters include kerosene/fuel oil, propane, natural gas, and
electricity. A brief description of each type follows:
Kerosene and Fuel Oil are by-products of petroleum
refining and are comprised of liquid hydrocarbons. Fuel oil is available
in several grades depending upon the range of distillation. The heat rating for these fuels is as follows:
Propane, or Liquefied Petroleum
(LP) Gas, consists of refined natural gases that are extracted
in a liquid state during refining, under pressure. It remains in liquid
state during storage and transportation. When the pressure is reduced,
propane vaporizes and becomes a gaseous fuel. When stored in a tank,
propane is in both liquid and gaseous state. One gallon of liquid
propane weighs 4.35 lbs. and expands to 36.35 cu. ft. of gas when
it is evaporated (at sea level). The vaporization rate of propane
varies according to the tank size, tank level, and ambient temperature.
Heat ratings for propane are as follows:
| |
1 gal. = 91,500 BTU's
1 lb. = 21,030 BTU's
1 cu. ft. = 1,000 BTU's |
Natural Gas is the lightest
of all petroleum products and is lighter than air. It remains in
a
gaseous state throughout the pressure and temperature changes that
occur during distribution. Natural gas is sold by the therm, with
one therm equal to 40 cu. ft. Heat ratings for natural gas are as
follows:
| |
1 therm = 100,000 BTU's
1 cu. ft. = 1,000 BTU's |
Electricity is sold
in kilowatt hours (kWH), with one kWH equivalent to 1000 watts usage
for one hour.
| |
1 three phase KWH = 3,412 BTU's
|
The chart below is useful for comparing
relative heating costs using different fuel types. These formulas
allow you to calculate the heating cost per therm (100,000 BTU's)
for each fuel type, using local market prices. The efficiency factors
shown reflect industry averages for each fuel type and will vary
slightly for specific heaters.
|
Fuel Type |
Unit Price |
|
Units per Therm |
|
Efficiency Factor
|
|
Heating Cost
|
Kerosene /
No. 1 Fuel Oil |
$___/gal. |
x |
0.79 gal. |
+ |
.86 |
= |
$____/Therm |
| Propane |
$___/lb. |
x |
4.79 lbs. |
+ |
.90 |
= |
$____/Therm |
| Natural Gas |
$___/Therm |
x |
1.00 |
+ |
.90 |
= |
$____/Therm |
| Electric |
$___/kWH |
x |
29.3 kWH |
+ |
.95 |
= |
$____/Therm |
|
[ top ]
|
