Lamps and Electric Appliances

Lamps

For information on lighting technologies see the report prepared for HERA.

It contains information on:

• Incandescent Lamps,
• Gas Discharge Lamps,
• Light Emitting Diodes (LEDs) and
• Efficiency and Costs.

amongst others.

Audio and video devices

Most appliances such as TVs, receivers or video recorders operate on AC. There are a few exceptions including some DC TVs. Color TVs consume more than black & white ones. There are considerable differences between individual brands. TVs should not be operated in stand-by. Controllers and inverters may disturb operation of TVs and radios.

Power demand of color TVs
Size	Power
17 cm	20 W
25 cm	40 W
37 cm	60 W

Transistor radios and cassette players are operated by batteries at a voltage below 12 V. Since batteries are expensive, such appliances should also be connected to the solar system through a voltage converter.

Water pumps

Some tens of thousands of pumps powered by solar generators are currently in use worldwide. A variety of pumps for low water demand are available on the market. These include single-stage centrifugal pumps for lifting heads < 10m and diaphragm pumps for larger heads, both DC- and AC-operated. They are surfacemounted, floating or submerged pumps. DC pumps with brushes need regular replacements.

The energy requirement (E) for a daily water demand (Q), a pumping head (h, water level to tank inlet or pipe outlet) and a pump efficiency (η = 0.2-0.4, depending on type and pumping head) is

E [kWh] = h [m] x Q [m³/d] / 367 / η

Refrigerators

Refrigerators are available for AC and DC. DC refrigerators are more expensive. They cost more than 600 €. The size has only a small effect on the price. Only low-consumption refrigerators of the compressor type are suitable for solar systems. A 100 l high-quality refrigerator without an icebox may consume approximately 300 Wh at 24°C and 450 Wh at 32°C. Ice production, a high demand for cold drinks and a low-efficiency type can easily double or triple this figure. Box types are more efficient. Special types are available for vaccine storage. Starting at low voltage levels (<11.5 V) is a problem for many refrigerators.

Source: Klaus Haars, GATE-ID technical brief: Electricity from Sunlight, Solar Energy Supply for Homes and Buildings, Eschborn, 2002.

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