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
Smaller
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

Refrigerators
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.