DIY enclosure for home storage

[Gomev]

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Yes, exactly. For a given brightness, LED's are about 1/6th of the wattage (so 6W LED is equivalent to 40W old school incandescent - roughly - varies quite a bit between manufacturers I noticed.

They may be equivalent of 40W incandescent brightness wise but they don't produce the equivalent heat.
As a generalism, LEDs convert over 95% of electrical energy into light, while incandescent bulbs may only convert 10%, so conversely LEDs convert only 5% of electrical energy into heat, while incandescent bulbs convert 90%.
So a 40 watt incandescent uses 38 watts to heat, a 6W LED uses approx 0.3 watts for heat.

A bit general and figures will vary between bulbs and opinions but an indication of performance.

 

[Everest]

They may be equivalent of 40W incandescent brightness wise but they don't produce the equivalent heat.

Obviously! But, I only wanted about 18W of heat, so three 6W bulbs was an ideal match.

As a generalism, LEDs convert over 95% of electrical energy into light, while incandescent bulbs may only convert 10%, so conversely LEDs convert only 5% of electrical energy into heat, while incandescent bulbs convert 90%. So a 40 watt incandescent uses 38 watts to heat, a 6w LED uses approx 0.3 watts for heat.

Not sure where you got those figures from, but they are incorrect. LED bulbs (of that size) are only about 15 to 30% efficient in converting electric energy to light energy. Depending on wavelength, 1W of light energy is around 680 lumens, hence an LED lightbulb that produces 700lm and consumes around 5W is only 20% efficient. Obviously much better than an old-fashioned tungsten incandescent bulb but the have an efficiency of 1.5% to 2%, not 10%

Having said all that, the light vs. heat efficiency of any type of bulb is irrelevant to this application where the LED is within an enclosed (and insulated) compartment.

100% of the supplied electrical energy will end up as heat, whether that is generated directly as the waste heat convected and conducted from the LED package itself or the IR, visible and UV light radiated energy falling on a surfaces within the battery compartment.

 

[Gomev]

Obviously! But, I only wanted about 18W of heat, so three 6W bulbs was an ideal match.
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100% of the supplied electrical energy will end up as heat, whether that is generated directly as the waste heat convected and conducted from the LED package itself or the IR, visible and UV light radiated energy falling on a surfaces within the battery compartment.

Really! If you believe that 3 6W led bulbs create 18W of heat and that 100% of the supplied electrical energy will end up as heat then fair enough.
(so which part of the energy is used to produce light ?)

 

[Archev]

Really! If you believe that 3 6W led bulbs create 18W of heat and that 100% of the supplied electrical energy will end up as heat then fair enough.
(so which part of the energy is used to produce light ?)

I see.

 

[Everest]

Really! If you believe that 3 6W led bulbs create 18W of heat and that 100% of the supplied electrical energy will end up as heat then fair enough.
(so which part of the energy is used to produce light ?)

Absolutely As I said, each LED bulb will produce around 700 lumens of light energy - that is just over 1W of the supplied energy. The remaining 5W will be released as heat from the LED itself and, to a lesser degree some as Infra-red electromagnetic radiation (which is 'light', just not within the human visible spectrum).

The 1W of visible light energy will be fully absorbed by the inside of the battery compartment, as there are no gaps or windows. There are no plants within the compartment to convert light into chemical energy either. Hence, the light (visible and IR) will be converted to heat on the inside surface - that is known as radiated energy (i.e. just as the light from the sun warms up surfaces on the earth).