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:
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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
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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:
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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

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---
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:

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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 :

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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+

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