Calculation power consumption metal halogen vs led

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Hi.
I need to make some basic power consumption calculation between 100W
halogen and 20W LED (equal to 100W ).

Test sample:
10 x 100W metal halogen lamps
or
10 x 20W LED
-----------------

Situation:
Working time per day : 16 hours

Calculation:
How to calculate power consumption based on this infos.
How much KWh will i spend in ONE year ( calculating with all other
losses like heat, power on/off etc. ) for halogen and how much in LED
version.

En2

Re: Calculation power consumption metal halogen vs led
On Friday, April 25, 2014 7:37:14 AM UTC-4, en2 wrote:

Huh?  Homework? The 10 halogens will use 16kW hrs per day... you can do the rest.

George H.

Re: Calculation power consumption metal halogen vs led

Assuming a nominally 100W equivalent 20W LED lamp has the same light output
as a 100W halogen lamp is *NOT* a good idea. If the marketeers have had any
influence, it *may* have as much light output as a badly blacken end of
life halogen bulb in a brownout - but is far more likely to have 10% less.
To find the tru equivalance, you need to get the original manufacturers
datasheets and compare the Lumens, though you may end up having to
calculate that from the Candela and the illumination pattern.  Its easier
to suck it and see - illuminate a translucent white screen at a suitable
fixed distance and use a Lux meter at a fixed distance the other side of
it, taking care to avoid light leakage round the edges.

I wouldn't be at all surprised to find you need 50% more LED bulbs than
expected to maintain the same illumination level.

Then there's aging.  Typically, at end-of-life the luminous output of a LED
has dropped by 50%.  Depending on brand, quality and how good the drive
electronics are, this can be expected in anything from 5000 to 15000
operating hours. Thats under a year for the cheap LEDs so you need to over-
specify the initial brigtness if you want acceptable results later on.

The next fly in the ointment is defect rate. 1% failure rate within the
year is entirely typical. I've seen in excess of 10% failure rate in a
large installation with cheap LEDs, including a significant proportion that
failed explosively destroying the fitting.  The supplier is currently being
sued, but that doesn't help with the current maintenance and replacement
costs, and if they fold, the client wont see a penny of their money back.
l
Consider fluorescent tube lighting - its a mature, well proven technology
with a TCO over most amortisation periods less than LED lighting.

One further factor you may not have considered is heating and air-
conditioning costs.  A significant part of the heat input into the space in
question may be from the lighting losses.  In a cold climate, reducing them
only results in you needing more of other forms of heating.  If you
predominently use electical heating this is a no-win situation. There are
some savings if you use some sort of combusible fuel heating and it costs
less than electric heat.   If you are in a warm climate, you will find the
cost of energy losses from the lighting is multiplied as the aircon must
remove the additional heat.  That means you benefit far more from energy
efficient lighting.

Good luck with calculating your annual costs, its a complex calculation and
if you attempt to figure in all known factors, rapidly gets rather ugly to
handle.

--
Ian Malcolm.   London, ENGLAND.  (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
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Re: Calculation power consumption metal halogen vs led
On 04/25/2014 09:30 PM, Ian Malcolm wrote:

-------------------------
Hi guys. Sorry, I think that there was some misunderstanding because
only Ian got the idea what i have to calculate. But, i should write more
details.. that's true.

@Ian
The calculation is quite big problem because i have to measure different
situations and different light systems and only then i can present the
cost/benefit solution. All comes down to one year cost.

****
Consider fluorescent tube lighting - its a mature, well proven
technology with a TCO over most amortisation periods less than LED lighting.
*****
That was presented as one of the options and it would be cca half of LED
prize. The problem is that full installation is quite big and if i
calculate basic power consumption between halogen vs LED, i will come to
cca \$5000 lost, in halogen version (annual). So, LED pay off would be in
cca 2-3 years. Now to calculate this with more accurate data i have to
take all possible situations.

Yes, it's not easy at all.

Re: Calculation power consumption metal halogen vs led

---
1W x 1000 is 1 kilowatt

1 year is 8766 hours

Watts is watts

John Fields

Re: Calculation power consumption metal halogen vs led
On Fri, 25 Apr 2014 13:37:14 +0200, en2 wrote:

Hey Mister!  How much do the five cent candy bars cost?

I'm not sure if you have a terrible teacher or if you slept through that
part of class, but:

Watts are watts, if no one is lying.  If the package says "power
consumption = 20W" (and no one is lying), it means that the thing uses 20
W.

KWh stands for kilo-watt-hour.  "Kilo" means 1000 of whatever.  Watt
means watt.  Hour means hour.  So one watt of power consumption for one
hour is one watt-hour.  One thousand watt-hours is 1 kWh.  Is this
starting to make sense?

--

Tim Wescott
Wescott Design Services
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Re: Calculation power consumption metal halogen vs led
underneath :

You say "test sample" in your post but have you actually baught samples
and tested them? - I can tell you that using the figures quoted on
packages/specs you are liable to make really big errors in your
calculations.  I have tested some cheap mains LED lamps for actual
consumption and other perameters like output and RF interference running
teperatures etc. and the quoted figures are mostly complete bollocks!!
Be very careful if you are doing a costing that really matters... for a
few domestic LED bulbs you can just swallow the errors!  C+