Page 177 - Applied Photovoltaics

Light emitting diodes (LED) are now also an option following the development of
blue and white LED products (Steigerwald et al., 2002; Holcomb et al., 2003). LED
lighting is approximately the same lighting efficiency as fluorescents (Bohler, 2002)
and is well suited to small, low power lighting tasks.

Refrigerators and freezers
Refrigerators and freezers can be major energy users and should be chosen carefully.
If appliances in your country have an energy rating, make sure you purchase the most
efficient model. Otherwise choose the smallest possible for your needs. To reduce the
load on your RAPS system, gas appliances can be used, although they are often more
expensive. Never connect the electric element on a gas refrigerator to a RAPS system,
as it consumes large amounts of power. A DC chest-style refrigerator is said to use
only one third the power of an AC unit when inverter losses are taken into account
(Pedals, 2003).

Dishwashers

Preferably use the type that allows connections to both hot water and cold water, as
this uses only 30% of the electricity of one connected solely to cold water with an
internal heater. The best approach is determined by the type of hot water system
installed. For instance, if the hot water is heated by electricity generated by the RAPS
system, connect to cold water. On the other hand, if your water is heated by solar
collectors or a slow combustion stove, connect to hot water. This will use
considerable hot water but is still more economical than using the RAPS system to
generate electricity to heat the dishwashing water.

Microwave ovens

Microwave ovens are the only oven type suited to a RAPS system. They offer highly
efficient cooking, with relatively small heat losses. Other specific purpose cooking
appliances can use large amounts of electricity, so should be used sparingly, if at all.

Stoves using induction heating are often less efficient that claimed, depending on how
they are used. However, if used appropriately, they may be suitable for connection to
a RAPS system. Wood or gas stoves should be considered.

Home entertainment and computing equipment
Hi-fi systems, videos, televisions and computers generally use low levels of power
but, since they may be used for long periods, it is wise to check manufacturers’
energy ratings and buy the lowest rated units. Headphones and liquid crystal displays
use considerably less power than sound speakers and conventional cathode ray
picture tubes respectively. An international standard for energy-efficient electronic
equipment, Energy Star, was produced by the US Environmental Protection Agency
and has been adopted by several countries, including Australia (Australian
Greenhouse Office, 2003a).

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