The electrical devices

Before designing the photovoltaic plant it is always necessary to accurately determine the electrical load and consider the eventual possibility of energy optimisation, as we must always remember that "the cheapest energy is the energy that is saved".

Fluorescent tubular lamps
These consume between 3 and 5 times less than incandescent lamps with the same brightness.
Long life- economical.
This type of lamp is suitable for workplaces, corridors, outside lighting.

Energy saving lamps (PL/PLC/PLS/4p)
Efficiency --> between 5 and 6 times higher than incandescent lamps
Length of life --> 8 times that of an incandescent lamp
Warmer light --> suitable for living spaces. Can stand considerable variations in temperature.

Halogen lamps
Between 2 and 3 times more efficient.
Less efficient than energy saving lamps or fluorescent tubes.
Bright, warm light.
Ideal for lights on timers.

Incandescent lamps
Also available for low voltages (12 or 24 ).
Low efficiency.
Low cost.
Using them at low voltage they do not last long.
Useful for short periods.

Sodium vapour lamps
High efficiency.
Orange, monochrome light.
Elevated price.
Require an electronic circuit.

Summarising, for example ...

Type of lamp Power [W] Flow [lm] Efficiency [lm/W] Relative no. compared to
60W incandescent lamps
Incandescent lamp 40 580 14,5 0,9
Incandescent lamp 60 980 16,3 1
Halogen 50 1000 20 1,23
Halogen 100 2300 23 1,41
Straight fluorescent 8 430 54 3,31
Straight fluorescent 13 950 73 4,48
Fluorescent U (PL) 9 600 67 4,11
Fluorescent U (PL) 11 900 85 5,03
Sodium 18 1800 100 6,14
Sodium 36 4800 137 8,41

It is important they have a compressor which doesn't consume much energy and a thick, heat-insulating lining. Energy saving refrigerators cost a great deal, but consume much less current. They have to be installed in cool places.