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Types of generators, advantages and disadvantages.
05/20/12
here are many advantages and disadvantages to different types of generators.
Portable generators are great for camping, disaster preparedness emergencies
or other backup power needs. Nearly all generators use either gasoline, diesel,
natural gas or propane. The following information will hopefully answer any
questions or concerns you may have concerning different fuel sources.
Gasoline
Advantages:
Common fuel source - easily obtained
Increases portability of smaller generators
Disadvantages:
Highly flammable
Short shelf life (approximately 12 months)
Storing large quantities is hazardous
May not be available during power outages
Somewhat Expensive ($1.50 to $2.00 per Gallon)
Inefficient
Diesel
Advantages:
Least flammable fuel source
Easily obtained
On site fuel delivery available
Disadvantages:
18-24 month shelf life, without additives
Installing large storage tanks raises cost of system
May not be available during power outages
Propane
Advantages:
Long shelf life
Clean burning
Easily stored in both large tanks or in smaller 5 - 10 gallon cylinders
Obtainable during power outages - gas stations may be unable to pump fuel during
an area wide outage
Home delivery available for larger tanks
Disadvantages:
Pressurized cylinder of flammable gas
Fuel system is more complicated (increased possibility of failure)
Larger tanks are not aesthetically pleasing (unsightly)
Fuel system plumbing results in higher installation cost
Somewhat Expensive ($1.60 to $1.80 a gallon)
Natural Gas
Advantages:
Unlimited fuel source - refueling not necessary
Clean burning
Available during power outages
Disadvantages:
May be unavailable during natural disasters (earthquakes, etc)
Lower power output (30% less BTU's per unit than gasoline)
Fuel system plumbing results in higher installation cost
Not available in many areas
Gaseous fuels such as natural gas, vapor propane and liquid propane are the
most common choice for small automatic standby generators. Propane engines are
economical to build and these fuels provide good starting reliability and are
in common use. These fuels are available everywhere. When purchasing a gaseous
fueled Generator you must remember the following:
Specify which kind of fuel you will be using when placing the order. If there
is a mistake it may not be possible to convert a Generator in the field between
natural gas/vapor propane and liquid propane. It usually is possible to convert
between natural gas and vapor propane however.
If you order a Generator for vapor propane it is sometimes set up at the factory
for natural gas and must be converted in the field to vapor propane. The installation
manual will describe the steps for this simple conversion which usually involves
connecting a fuel line to another port or changing an orifice and a mixture
setting. If you fail to make this conversion the Generator will not run properly
and may not start at all.
A vapor propane system draws the fuel from the top of the tank usually through
a pressure regulator at the tank. The liquid in the lower part of the tank must
be able to absorb sufficient heat from the tank surroundings for vaporization
to take place. Therefore, it is important that the tank has enough exposed surface
area for this heat transfer. There can be a problem of insufficient fuel flow
in very cold weather or if the tank is less than half full or is too small.
In practice this only is an issue in the far northern areas of the USA.
A liquid propane system draws the liquid from the bottom of the tank and small
high pressure tubing is used to carry it to the Generator. The Generator is
then equipped with a special device to vaporize the fuel before combustion.
This eliminates the low temperature vaporization concerns at the tank in cold
climates. However it may complicate using propane for other appliances since
it is being supplied in liquid form to the point of use.
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