Page 162 - Applied Photovoltaics

installed virtually anywhere and subsequently increased in capacity as necessary.
Since the capital cost of photovoltaic systems is high, however, most villages in
developing countries need financial assistance for the supply of such a power system.
Many countries, including Brazil, China, Thailand, Laos, Spain, Sri Lanka, India,
South Vietnam and Indonesia, have active photovoltaic programs, largely aimed at
providing power to rural communities. The largest markets for small solar home
systems are India (450,000 systems planned), China (150,000), Thailand (150,000),
Kenya (120,000), Morocco (80,000), Mexico (80,000) and South Africa (50,000).

As an example of the typical systems used, about 10,000 systems with an average
output of 150 Wh/day, using the following configuration, have been installed in
Indonesia (Schlangen & Bergmeijer, 1992):
x one 45 W p photovoltaic module, mounted on a small pole fed through the roof
of the house
x one 12 V, 70 Ah vented lead-acid battery, mounted in a frame attached to an
inside wall
x one small regulator, to protect the battery against over-charge or excessively
deep discharge
x two 6 W lights
x one plug and socket for connection of TV, radio or other appliances.

Similarly, in Spain, 1500 Andalucian homes are supplied with power via two 52 W p
modules, a battery and regulator (BP Solar, 1993) and in Malaysia, 11,600 PV
systems are used to power homes, long-houses, health clinics, community halls,
schools and churches. Applications range from basic lighting to vaccine refrigerator-
freezers (BP Solar, 2002).

8.10 REFRIGERATION
Photovoltaic panels are widely used to power refrigerators for (Ball & Risser, 1988):
x medical purposes, which account for about 20% of all photovoltaic powered
refrigerators
x recreational vehicles, such as campervans
x commercial use
x residential use.

Critical medical supplies, costing many thousands of dollars can be lost if there is a
power failure to a vaccine or medical supply refrigerator. Therefore, its availability
must approach 100%. The World Health Organisation sets specifications for
refrigerators used in international aid projects (WHO, 2000). Because of their rapid
deployment, modularity and low maintenance needs, photovoltaics are often used,
even when cheaper energy sources are available. New applications are continually
being developed. In Greece, for example, use of photovoltaic-powered ice storage
units for pre-cooling goats milk on remote farms is being examined (Kallivrousis et
al., 1992).

DC refrigerators of high efficiency are becoming cheaper and should be used in all
applications to avoid conversion losses and the extra cost of a larger inverter, as well
as to improve reliability. Most units are 12 or 24 V dc . They are typically five times

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