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Lamps / luminaires for walk-in freezers
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|
|
| At work we have a walk in freezer, approx 4m by 3m in area. It is
currently illuminated by light fitting with a 60W GLS lamp, which, of
course doesn't last long.
I have had a web-trawl to look for lamps which would operate for
extended periods in -30degC or whatever the temperature in there is (I'm
at home just now so can't recall). Nothing yet.
Which sort of lamps and associated ballasts would anyone recommend for
low temperatures ? T6 Fluorescent? 2-D? Compact fluorescent?
Incandescent? I wouldn't think rough service type lamp would have an
extended operating range, only more shock resistant than GLS.
If needed will replace fitting if it will improve time between
failures..
--
Z
Remove all Zeds in e-mail address to reply.
| |
| Andrew Gabriel 2006-05-17, 6:21 pm |
| In article <BNQdT2MEwnaEFwKe@imaris.demon.co.uk>,
Z <Z@imaZZZris.demon.co.uk> writes:
> At work we have a walk in freezer, approx 4m by 3m in area. It is
> currently illuminated by light fitting with a 60W GLS lamp, which, of
> course doesn't last long.
> I have had a web-trawl to look for lamps which would operate for
> extended periods in -30degC or whatever the temperature in there is (I'm
> at home just now so can't recall). Nothing yet.
> Which sort of lamps and associated ballasts would anyone recommend for
> low temperatures ? T6 Fluorescent? 2-D? Compact fluorescent?
> Incandescent? I wouldn't think rough service type lamp would have an
> extended operating range, only more shock resistant than GLS.
> If needed will replace fitting if it will improve time between
> failures..
Any fluorescent lamp will have an issue with this being way off
it's optimum operating temperature. This creates two problems:-
The lamp will be very dim. If you fit a thermal sleeve to the
tube, it will eventually warm up, but this can take half an hour,
so it's not suitable for occasional use. Secondly, the tube
starting voltage will be much higher than usual, which can make
the lamp much harder to start -- depends heavily on the control
gear. 6' and 8' tubes would be impossible to start using regular
switch-start control gear, and even 5' would be difficult.
5' tubes on SRS (Semi-resonant start) control gear used to be
the norm for very low temperature on 240V mains as it generates
500V across the tube for starting, but this has vanished from
the scene with the advent of electronic control gear. If you
go the electronic control gear route, you will probably have
most luck with instant start type, but you might have to do some
trial and error to find a ballast make that works reliably.
How come a GLS lamp in a walk-in freezer is being subject to
rough handling? On the assumption that the lamp doesn't need
to be left on, a filament lamp is probably the best choice.
What you could try for very low outlay would be an energy saving
lamp in the same socket. Pick one with an outer bulb over the
tube, as this will help the tube to heat up, but you'll still
have the same problem with long run-up, just supposing the
control gear generates enough voltage to start the lamp in the
first place.
--
Andrew Gabriel
| |
| Phillip Devoll 2006-05-17, 7:21 pm |
|
"Z" <Z@imaZZZris.demon.co.uk> wrote in message
news:BNQdT2MEwnaEFwKe@imaris.demon.co.uk...
> At work we have a walk in freezer, approx 4m by 3m in area. It is
> currently illuminated by light fitting with a 60W GLS lamp, which, of
> course doesn't last long.
> I have had a web-trawl to look for lamps which would operate for
> extended periods in -30degC or whatever the temperature in there is (I'm
> at home just now so can't recall). Nothing yet.
> Which sort of lamps and associated ballasts would anyone recommend for
> low temperatures ? T6 Fluorescent? 2-D? Compact fluorescent?
> Incandescent? I wouldn't think rough service type lamp would have an
> extended operating range, only more shock resistant than GLS.
> If needed will replace fitting if it will improve time between
> failures..
> --
> Z
> Remove all Zeds in e-mail address to reply.
I work in a walk in freezer and just use a standard screw in florecent and
it works fine as long as it does not get turned off...
if it does i leave the door open for a few minuter and it works fine
ps. my light has a glass shield around it if that matters...
| |
| Paul Hovnanian P.E. 2006-05-18, 12:21 am |
| Z wrote:
>
> At work we have a walk in freezer, approx 4m by 3m in area. It is
> currently illuminated by light fitting with a 60W GLS lamp, which, of
> course doesn't last long.
> I have had a web-trawl to look for lamps which would operate for
> extended periods in -30degC or whatever the temperature in there is (I'm
> at home just now so can't recall). Nothing yet.
> Which sort of lamps and associated ballasts would anyone recommend for
> low temperatures ? T6 Fluorescent? 2-D? Compact fluorescent?
> Incandescent? I wouldn't think rough service type lamp would have an
> extended operating range, only more shock resistant than GLS.
> If needed will replace fitting if it will improve time between
> failures..
Maybe the folks over on sci.engr.lighting can throw some light on this.
Here's my thinking:
A standard incandescent lamp shouldn't have trouble in this application.
If anything, the various fluorescents you are considering may have far
more problems at such low temperatures. The reduced life of an
incandescent might be due to the lower filament resistance at low
temperatures, when the bulb has been off and cools down. The resulting
inrush will be higher and might be over stressing the filament. One
thing to try would be to use a bulb with a higher voltage rating (130V
instead of 120V). If that doesn't help, some sort of 'soft start' series
device might help. I seem to recall a little button shaped device
intended for insertion into a standard lamp socket that was supposed to
extend lamp life by reducing the warm-up inrush.
--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
Fast wine, loose cars, old women.
| |
| Phil Scott 2006-05-18, 1:21 am |
|
--
Phil Scott
Ideas are bullet proof.
"Z" <Z@imaZZZris.demon.co.uk> wrote in message
news:BNQdT2MEwnaEFwKe@imaris.demon.co.uk...
> At work we have a walk in freezer, approx 4m by 3m in area.
> It is currently illuminated by light fitting with a 60W GLS
> lamp, which, of course doesn't last long.
> I have had a web-trawl to look for lamps which would operate
> for extended periods in -30degC or whatever the temperature
> in there is (I'm at home just now so can't recall). Nothing
> yet.
> Which sort of lamps and associated ballasts would anyone
> recommend for low temperatures ? T6 Fluorescent? 2-D?
> Compact fluorescent? Incandescent? I wouldn't think rough
> service type lamp would have an extended operating range,
> only more shock resistant than GLS.
> If needed will replace fitting if it will improve time
> between failures..
Im in the business... use an incandescent bulb inside a vapor
tight fixture, gasketed glass rated vapor tight.
Phil Scott
> --
> Z
> Remove all Zeds in e-mail address to reply.
| |
| Victor Roberts 2006-05-18, 1:21 am |
| On Wed, 17 May 2006 20:12:38 -0700, "Paul Hovnanian P.E."
<Paul@Hovnanian.com> wrote:
>Z wrote:
>
>Maybe the folks over on sci.engr.lighting can throw some light on this.
>Here's my thinking:
>
>A standard incandescent lamp shouldn't have trouble in this application.
>If anything, the various fluorescents you are considering may have far
>more problems at such low temperatures. The reduced life of an
>incandescent might be due to the lower filament resistance at low
>temperatures, when the bulb has been off and cools down. The resulting
>inrush will be higher and might be over stressing the filament. One
>thing to try would be to use a bulb with a higher voltage rating (130V
>instead of 120V). If that doesn't help, some sort of 'soft start' series
>device might help. I seem to recall a little button shaped device
>intended for insertion into a standard lamp socket that was supposed to
>extend lamp life by reducing the warm-up inrush.
It's not clear if the OP means that the life of the GLS lamp
is shorter than expected, or that it meets its life spec but
life is shorter than desirable. I think he meant the
latter.
I also don't think that the temperature of the freezer will
increase the surge current enough to make a noticeable
difference in life. After all, the operating temperature of
the filament is about 2700 K, so decreasing the cold
temperature by about 50C doesn't change the resistance ratio
by very much.
It's possible to use fluorescent lamps in insulating sleeves
that are designed for cold ambient temperatures. These are
designed for outdoor applications in locations where winter
temperatures are cold. However, if this walk-in freezer is
used for food or any similar material, I would be concerned
about mercury contamination if (or more accurately when) one
of the lamps breaks.
Until recently the only non-mercury option would be
incandescent lamps, but if the short life of incandescent
lamps is a serious problem, it is becoming possible to use
LEDs for this type of application - though the initial cost
will be very high. The efficacy will be higher than GLS
lamps, especially on a 230-volt system and especially when
compared to long life GLS designs. But the efficacy will be
significantly lower than fluorescent sources, by at least
half.
The other option is a fiber optic light guide or light pipe
system that locates the lamps outside the freezer. This
removes both the waste heat and any potential mercury
contamination from the freezer. But, this option also has
high initial cost.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
| |
| meow2222@care2.com 2006-05-18, 8:21 am |
| Paul Hovnanian P.E. wrote:
> Z wrote:
>
> Maybe the folks over on sci.engr.lighting can throw some light on this.
> Here's my thinking:
>
> A standard incandescent lamp shouldn't have trouble in this application.
> If anything, the various fluorescents you are considering may have far
> more problems at such low temperatures. The reduced life of an
> incandescent might be due to the lower filament resistance at low
> temperatures, when the bulb has been off and cools down. The resulting
> inrush will be higher and might be over stressing the filament. One
> thing to try would be to use a bulb with a higher voltage rating (130V
> instead of 120V). If that doesn't help, some sort of 'soft start' series
> device might help. I seem to recall a little button shaped device
> intended for insertion into a standard lamp socket that was supposed to
> extend lamp life by reducing the warm-up inrush.
GLS are rated 750 or 1000 hrs. Converting to 12v filament would enable
you to use common 2000 hr and 4000 hr 50w halogen bulbs. It should also
be a low cost conversion.
12v would also enable the use of 2x or 3x 20w halogen lamps. When one
dies, you still have light output. With 2 lamps you need to replace one
twice as often compared to using one, but you dont lose your light at
the time, and if necessary you can go longer between relampings, since
the combined life will be more than the life rating of a single
identical lamp.
What issues there may or may not be from the food safety angle I
wouldnt know.
NT
| |
| Thomas Paterson 2006-05-18, 12:21 pm |
|
Victor Roberts wrote:
> On Wed, 17 May 2006 20:12:38 -0700, "Paul Hovnanian P.E."
> <Paul@Hovnanian.com> wrote:
> I also don't think that the temperature of the freezer will
> increase the surge current enough to make a noticeable
> difference in life. After all, the operating temperature of
> the filament is about 2700 K, so decreasing the cold
> temperature by about 50C doesn't change the resistance ratio
> by very much.
It may not be the inrush (I agree with your point about it being a
small shift in power) but it could be thermal shock. Typically
different materials expand and contract at different rates, for
situations with wildly varying temperatures, the lamp companies match
their materials so that the stresses remain managable in the operating
range, but possibly not outside of it. What might be happening here is
that the stresses in the pinch or adjacent are just too much,
particularly as the glass starts at -30=B0C and quickly the metal is at
2400=B0C (at least at the filament). A little crack here, a leak there
and suddenly you have fried filament.
> Until recently the only non-mercury option would be
> incandescent lamps, but if the short life of incandescent
> lamps is a serious problem, it is becoming possible to use
> LEDs for this type of application - though the initial cost
> will be very high.
And the LEDs might actually last their design life in this
environment!!! Subcooling 50=B0C would certainly drop the operating temp
all the way in to the silicon. Wow, I've found somewhere I believe LED
data for! Thanks Vic!
> The other option is a fiber optic light guide or light pipe
> system that locates the lamps outside the freezer. This
> removes both the waste heat and any potential mercury
> contamination from the freezer. But, this option also has
> high initial cost.
I don't know that this would prove beneficial unless you're able to
ensure that the interface through the insulation is sufficient to
prevent more heat flow out through the light pipe than the light source
originally produced. Normally I'd say fine, but we have a 50=B0C
differential driving quite a lot of thermal flux. The fiber optic
would probably work pretty well though. PMMA might get quite brittle -
I remember installing some .75" harnesses in Seoul in the snow in a
building without a facade. It took a day and a half to simply unroll
six harnesses very slowly. Glass fiber would be more expensive, but
might be better suited to the environment.
My big question is: Is this fridge continuously lit, or only when
there is someone in it? If it is intermittent, you have more shock on
the lamp, but the rate at which the lamp is being used is relatively
slow. The inefficiency and heat added by an incandescent isn't
important in this case, as opening the door will have much bigger
impact. On the other hand, fluorescents don't start well at low
temperatures, but can be kept warm (as you pointed out) with a sleeve
insulating it at roughly optimum operating temperature. If on
permanently, a well glass fitting with a small metal halide might
actually be a good solution. A preheat lamp could be used for startup.
Thomas Paterson
http://www.luxpopuli.com
| |
|
|
| Ian Stirling 2006-05-18, 2:21 pm |
| In sci.engr.lighting Paul Hovnanian P.E. <Paul@hovnanian.com> wrote:[color=darkred]
> Z wrote:
<snip>
IME, one test I did with philips CFs indicated that they start just fine
at -22C, but that was only once, and I haven't tried it for reliability
purposes, it was just to see if my garage lights will go on if it's
really really cold.
| |
| Victor Roberts 2006-05-18, 11:21 pm |
| On 18 May 2006 07:28:25 -0700, "Thomas Paterson"
<t_p_paterson@hotmail.com> wrote:
>
>Victor Roberts wrote:
>
>It may not be the inrush (I agree with your point about it being a
>small shift in power) but it could be thermal shock. Typically
>different materials expand and contract at different rates, for
>situations with wildly varying temperatures, the lamp companies match
>their materials so that the stresses remain managable in the operating
>range, but possibly not outside of it. What might be happening here is
>that the stresses in the pinch or adjacent are just too much,
>particularly as the glass starts at -30°C and quickly the metal is at
>2400°C (at least at the filament). A little crack here, a leak there
>and suddenly you have fried filament.
I still don't think that 50C added differential could name
enough difference to notice. But, I'm certainly open to
being proven wrong with some test data.
>
>And the LEDs might actually last their design life in this
>environment!!! Subcooling 50°C would certainly drop the operating temp
>all the way in to the silicon. Wow, I've found somewhere I believe LED
>data for! Thanks Vic!
Well - folks here who have read my comments about LED for
many years will be surprised that anyone thinks of me as an
LED supporter :-)
>
>I don't know that this would prove beneficial unless you're able to
>ensure that the interface through the insulation is sufficient to
>prevent more heat flow out through the light pipe than the light source
>originally produced. Normally I'd say fine, but we have a 50°C
>differential driving quite a lot of thermal flux.
The fiber is long and thin and constructed from low thermal
conductivity material. The light only makes it from one end
to the other because of the internal reflection. As long as
the fiber does not transmit IR there is little heat
transfer. Fibers have been used for this application for a
number of years.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
| |
| Ian Stirling 2006-05-19, 7:21 am |
| In sci.engr.lighting Victor Roberts <xxx@lighting-research.com> wrote:
> On 18 May 2006 07:28:25 -0700, "Thomas Paterson"
> <t_p_paterson@hotmail.com> wrote:
>
<snip>[color=darkred]
> I still don't think that 50C added differential could name
> enough difference to notice. But, I'm certainly open to
> being proven wrong with some test data.
It is 50C at 270K or so, which does make a fair difference to the inrush
current, which would exacerbate existing filiment problems.
| |
| David Lee 2006-05-19, 8:21 am |
| Ian Stirling wrote...
[color=darkred]
> It is 50C at 270K or so, which does make a fair difference to the inrush
> current, which would exacerbate existing filiment problems.
I don't know enough about incandescent filaments to know whether it is a
problem but it's possible that there could be a phase transition between
room temperature and the temperature of the freezer that could make the
filament more brittle at low temperatures.
Certainly there is an old story that claims that Napoleon's sodliers' tin
buttons disintegrated in the cold temperatures experienced during the
retreat from Moscow. Whilst possibly apocryphal, pure tin does have a
ductile/brittle phase transition at 13.2 degrees C (from beta/white to
alpha/grey tin).
David
| |
| Victor Roberts 2006-05-19, 9:21 am |
| On 19 May 2006 09:47:46 GMT, Ian Stirling
<root@mauve.demon.co.uk> wrote:
>In sci.engr.lighting Victor Roberts <xxx@lighting-research.com> wrote:
><snip>
>
>It is 50C at 270K or so, which does make a fair difference to the inrush
>current, which would exacerbate existing filiment problems.
It's a 50C adder to the difference between the starting or
cold temperature and the operating temperature. While the
glass-to-metal seals do not operate at 3000K, they still
operate well above 270K.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
| |
| Thomas Paterson 2006-05-19, 1:21 pm |
|
Victor Roberts wrote:
> On 18 May 2006 07:28:25 -0700, "Thomas Paterson"
> <t_p_paterson@hotmail.com> wrote:
> I still don't think that 50C added differential could name
> enough difference to notice. But, I'm certainly open to
> being proven wrong with some test data.
No test data, but you're changing the pinch from heating from 20=B0C to
300=B0C (280=B0C range) to -20=B0C to 300=B0C (320=B0C range). It's a
significant percentage, and importantly outside of the design criteria
the engineers worked to. I'm not saying this is the mechanism, solely
that I'd definitely believe it.
>
> Well - folks here who have read my comments about LED for
> many years will be surprised that anyone thinks of me as an
> LED supporter :-)
Never considered you one - nor am I, hence the surprise. Actually
designing a $500K LED install at the moment, so I do use them in the
right circumstances.
>
> The fiber is long and thin and constructed from low thermal
> conductivity material. The light only makes it from one end
> to the other because of the internal reflection. As long as
> the fiber does not transmit IR there is little heat
> transfer. Fibers have been used for this application for a
> number of years.
Quite right, fiber is fine. I was refering to light pipe. That's a
nice little air volume with its own convection currents due to the lamp
at one end, and now extra cold world behind it.
Thomas.
| |
|
|
"Paul Hovnanian P.E." <Paul@Hovnanian.com> wrote in message
news:446BE626.7E514B8B@Hovnanian.com...
>Z wrote:
>
> Maybe the folks over on sci.engr.lighting can throw some light on this.
> Here's my thinking:
>
> A standard incandescent lamp shouldn't have trouble in this application.
> If anything, the various fluorescents you are considering may have far
> more problems at such low temperatures. The reduced life of an
> incandescent might be due to the lower filament resistance at low
> temperatures, when the bulb has been off and cools down. The resulting
> inrush will be higher and might be over stressing the filament. One
> thing to try would be to use a bulb with a higher voltage rating (130V
> instead of 120V). If that doesn't help, some sort of 'soft start' series
> device might help. I seem to recall a little button shaped device
> intended for insertion into a standard lamp socket that was supposed to
> extend lamp life by reducing the warm-up inrush.
>
> --
> Paul Hovnanian mailto:Paul@Hovnanian.com
Too many years ago now, I was involved in a project involving low
temperature testing of incandescent, halogen incandescent, fluorescent and
mercury HID lamps. As I recall, the military wanted to know the
characteristics of various lamps used for lighting at bases in Greenland.
We took the systems down to -30F (-34.4C) which was the limit of our test
chamber and tested both bare lamps and lamps in sealed fixtures.
All of the lamps worked just fine and lasted their normal rated lives --
even the fluorescent with a bit of tinkering. Incandescent lamp materials
didn't seem affected by the temperature differential -- no seal or bulb
cracking as long as moisture was not dripped onto a hot lamp envelope.
Halogen lamps just didn't care about anything we did to them. They were the
500 and 1500 watt linear lamps with quartz envelopes. They would be my
overall choice for instant reliable light in very cold or wet conditions --
as long as there is minimial shock or vibration.
Fluorescent lamps were surprisingly good performers. Once started, however,
they have to be in an environment which will let the lamp "cold spot" warm
to its rated value, typically with a layer of air at 25C surrounding the
lamp. We used 1.5 ampere T10 lamps since they draw enough watts to heat
their surrounding air quickly.
Subsequently, a fixture was developed for the T10 lamps that made operation
at very low temperatures (below -20F) routine. It was a 2-lamp weatherproof
unit plus an incandescent lamp on a timer. When switched on, the
incandescent lamp came on immediately and heated the air inside the lamp
enclosure. The fluoresent lamps were powered on at the same time and
started. As the air heated, from both sources, the fluorescent lamp came to
full brightness. The incandescent lamp was then automatically switched off
and the fluorescent lamps easily maintained the optimum lamp compartment
temperature.
Later on, the major lamp companies simply enclosed the T10 lamp with a
glass outer jacket and thermal end caps and called it a "T10J". That lamp
is rated to at least -20F, is still listed and will operate at lower
temperatues with a slightly reduced light output.
T10J lamps are, I believe, still commonly used in commercial food freezer
facilities.
Mercury lamps took a few seconds longer than normal to start probably so the
starting glow could vaporize a bit more of the liquid metal into vapor. I
wish we could have tested the mercury lamps below the freezing point of
mercury (about -40 C or F).
One surprise was the number of ballast failures. In our tests, the ballasts
were also in the low temperature environment. We thought at the time the
failures were due to the electrolytic capacitors freezing and shorting, but
I don't remember if that was confirmed. Anyway, we recommended for food
freezer applications that the ballasts be mounted outside of the low
temperature area.
Terry McGowan
| |
| Peter Pan 2006-05-28, 8:21 pm |
| That must to had been an interesting project.
As for the mercury ballasts being unprotected, there might had been
more condesation on the windings. This in turn could lead to a higher
posibility of short circuit among turns. Did you try any potted
ballasts?
Would asume that aided start HID (HPS and MH) would work fine. At the
most the ballast might need to offer a higher starting current, to
insure a proper start.
In article <Aykeg.179349$eR6.73912@bgtnsc04-news.ops.worldnet.att.net>,
TKM <nomail@no.net> wrote:
> "Paul Hovnanian P.E." <Paul@Hovnanian.com> wrote in message
> news:446BE626.7E514B8B@Hovnanian.com...
>
> Too many years ago now, I was involved in a project involving low
> temperature testing of incandescent, halogen incandescent, fluorescent and
> mercury HID lamps. As I recall, the military wanted to know the
> characteristics of various lamps used for lighting at bases in Greenland.
>
> We took the systems down to -30F (-34.4C) which was the limit of our test
> chamber and tested both bare lamps and lamps in sealed fixtures.
>
> All of the lamps worked just fine and lasted their normal rated lives --
> even the fluorescent with a bit of tinkering. Incandescent lamp materials
> didn't seem affected by the temperature differential -- no seal or bulb
> cracking as long as moisture was not dripped onto a hot lamp envelope.
> Halogen lamps just didn't care about anything we did to them. They were the
> 500 and 1500 watt linear lamps with quartz envelopes. They would be my
> overall choice for instant reliable light in very cold or wet conditions --
> as long as there is minimial shock or vibration.
>
> Fluorescent lamps were surprisingly good performers. Once started, however,
> they have to be in an environment which will let the lamp "cold spot" warm
> to its rated value, typically with a layer of air at 25C surrounding the
> lamp. We used 1.5 ampere T10 lamps since they draw enough watts to heat
> their surrounding air quickly.
>
> Subsequently, a fixture was developed for the T10 lamps that made operation
> at very low temperatures (below -20F) routine. It was a 2-lamp weatherproof
> unit plus an incandescent lamp on a timer. When switched on, the
> incandescent lamp came on immediately and heated the air inside the lamp
> enclosure. The fluoresent lamps were powered on at the same time and
> started. As the air heated, from both sources, the fluorescent lamp came to
> full brightness. The incandescent lamp was then automatically switched off
> and the fluorescent lamps easily maintained the optimum lamp compartment
> temperature.
>
> Later on, the major lamp companies simply enclosed the T10 lamp with a
> glass outer jacket and thermal end caps and called it a "T10J". That lamp
> is rated to at least -20F, is still listed and will operate at lower
> temperatues with a slightly reduced light output.
> T10J lamps are, I believe, still commonly used in commercial food freezer
> facilities.
>
> Mercury lamps took a few seconds longer than normal to start probably so the
> starting glow could vaporize a bit more of the liquid metal into vapor. I
> wish we could have tested the mercury lamps below the freezing point of
> mercury (about -40 C or F).
>
> One surprise was the number of ballast failures. In our tests, the ballasts
> were also in the low temperature environment. We thought at the time the
> failures were due to the electrolytic capacitors freezing and shorting, but
> I don't remember if that was confirmed. Anyway, we recommended for food
> freezer applications that the ballasts be mounted outside of the low
> temperature area.
>
> Terry McGowan
>
>
>
>
| |
|
|
"Peter Pan" <pR_pMaVaEn4SPM@mac.com> wrote in message
news:280520061748397708%pR_pMaVaEn4SPM@mac.com...
> That must to had been an interesting project.
>
> As for the mercury ballasts being unprotected, there might had been
> more condesation on the windings. This in turn could lead to a higher
> posibility of short circuit among turns. Did you try any potted
> ballasts?
No. But that is a good idea.
> Would asume that aided start HID (HPS and MH) would work fine. At the
> most the ballast might need to offer a higher starting current, to
> insure a proper start.
I've heard that HPS lamps do very well in -20F and below temperatures. They
lighted the construction work on the Alaska pipeline during the 1970s, for
example. I don't believe that any special ballasts or other equipment was
required.
Terry McGowan
[color=darkred]
>
> In article <Aykeg.179349$eR6.73912@bgtnsc04-news.ops.worldnet.att.net>,
> TKM <nomail@no.net> wrote:
>
| |
| Paul Hovnanian P.E. 2006-05-29, 11:21 pm |
| TKM wrote:
>
> "Paul Hovnanian P.E." <Paul@Hovnanian.com> wrote in message
> news:446BE626.7E514B8B@Hovnanian.com...
>
> Too many years ago now, I was involved in a project involving low
> temperature testing of incandescent, halogen incandescent, fluorescent and
> mercury HID lamps. As I recall, the military wanted to know the
> characteristics of various lamps used for lighting at bases in Greenland.
>
> We took the systems down to -30F (-34.4C) which was the limit of our test
> chamber and tested both bare lamps and lamps in sealed fixtures.
>
> All of the lamps worked just fine and lasted their normal rated lives --
> even the fluorescent with a bit of tinkering. Incandescent lamp materials
> didn't seem affected by the temperature differential -- no seal or bulb
> cracking as long as moisture was not dripped onto a hot lamp envelope.
> Halogen lamps just didn't care about anything we did to them. They were the
> 500 and 1500 watt linear lamps with quartz envelopes. They would be my
> overall choice for instant reliable light in very cold or wet conditions --
> as long as there is minimial shock or vibration.
>
> Fluorescent lamps were surprisingly good performers. Once started, however,
> they have to be in an environment which will let the lamp "cold spot" warm
> to its rated value, typically with a layer of air at 25C surrounding the
> lamp. We used 1.5 ampere T10 lamps since they draw enough watts to heat
> their surrounding air quickly.
>
> Subsequently, a fixture was developed for the T10 lamps that made operation
> at very low temperatures (below -20F) routine. It was a 2-lamp weatherproof
> unit plus an incandescent lamp on a timer. When switched on, the
> incandescent lamp came on immediately and heated the air inside the lamp
> enclosure. The fluoresent lamps were powered on at the same time and
> started. As the air heated, from both sources, the fluorescent lamp came to
> full brightness. The incandescent lamp was then automatically switched off
> and the fluorescent lamps easily maintained the optimum lamp compartment
> temperature.
Interesting. What was the thinking behind the dual lamp setup given
evidence that fixtures seem to operate well at these temperatures by
themselves?
--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
This isn't right. This isn't even wrong. -- Wolfgang Pauli
| |
| Peter Pan 2006-05-30, 3:21 am |
| In article <SeEeg.110879$Fs1.1947@bgtnsc05-news.ops.worldnet.att.net>,
TKM <nomail@no.net> wrote:
> "Peter Pan" <pR_pMaVaEn4SPM@mac.com> wrote in message
> news:280520061748397708%pR_pMaVaEn4SPM@mac.com...
>
> No. But that is a good idea.
If you don't find any let me know. I only know of one company in Mexico
that pot their ballasts.
>
>
> I've heard that HPS lamps do very well in -20F and below temperatures. They
> lighted the construction work on the Alaska pipeline during the 1970s, for
> example. I don't believe that any special ballasts or other equipment was
> required.
>
> Terry McGowan
>
>
>
>
| |
| Phil Scott 2006-05-30, 3:21 am |
|
--
Phil Scott
Ideas are bullet proof.
"Paul Hovnanian P.E." <Paul@Hovnanian.com> wrote in message
news:446BE626.7E514B8B@Hovnanian.com...
>Z wrote:
>
> Maybe the folks over on sci.engr.lighting can throw some
> light on this.
> Here's my thinking:
>
> A standard incandescent lamp shouldn't have trouble in this
> application.
> If anything, the various fluorescents you are considering
> may have far
> more problems at such low temperatures. The reduced life of
> an
> incandescent might be due to the lower filament resistance
> at low
> temperatures, when the bulb has been off and cools down. The
> resulting
> inrush will be higher and might be over stressing the
> filament. One
> thing to try would be to use a bulb with a higher voltage
> rating (130V
> instead of 120V). If that doesn't help, some sort of 'soft
> start' series
> device might help. I seem to recall a little button shaped
> device
> intended for insertion into a standard lamp socket that was
> supposed to
> extend lamp life by reducing the warm-up inrush.
US made bulbs have additives that proved corrosion to the
element after a fixed number of hours...that keeps the company
in business. Chinese made bulbs as a rule dont have that
feature.
proof? maybe this...at our high school in the 50's there was
a bulb that burned 24/7 for decades...outside no less on one
of the exterior walls..odd looking clear bulb. hard to
reach...that was probably made before these additives came
into use.
on the temperature/inrush situation... all that is a function
of the percentage decrease in resistance with
temperature...over a range of absolute zero kelvin to room
temperature. 50 degrees or so F isnt much...its not the key
issue.
you can put a 150 watt bulb in though, with a resistor made
for the purpose behind it to dim it to 120 watts...and get
exponentially longer life.
Phil Scott
Phil Scott
>
> --
> Paul Hovnanian mailto:Paul@Hovnanian.com
> ------------------------------------------------------------------
> Fast wine, loose cars, old women.
| |
| Phil Scott 2006-05-30, 3:21 am |
|
--
Phil Scott
Ideas are bullet proof.
"Thomas Paterson" <t_p_paterson@hotmail.com> wrote in message
news:1147962505.590620.32710@y43g2000cwc.googlegroups.com...
Victor Roberts wrote:
> On Wed, 17 May 2006 20:12:38 -0700, "Paul Hovnanian P.E."
> <Paul@Hovnanian.com> wrote:
> I also don't think that the temperature of the freezer will
> increase the surge current enough to make a noticeable
> difference in life. After all, the operating temperature of
> the filament is about 2700 K, so decreasing the cold
> temperature by about 50C doesn't change the resistance ratio
> by very much.
It may not be the inrush (I agree with your point about it
being a
small shift in power) but it could be thermal shock.
Typically
different materials expand and contract at different rates,
for
situations with wildly varying temperatures, the lamp
companies match
their materials so that the stresses remain managable in the
operating
range, but possibly not outside of it. What might be
happening here is
that the stresses in the pinch or adjacent are just too much,
particularly as the glass starts at -30°C and quickly the
metal is at
2400°C (at least at the filament). A little crack here, a
leak there
and suddenly you have fried filament.
thats not been a problem in the industry...
> Until recently the only non-mercury option would be
> incandescent lamps, but if the short life of incandescent
> lamps is a serious problem, it is becoming possible to use
> LEDs for this type of application - though the initial cost
> will be very high.
And the LEDs might actually last their design life in this
environment!!! Subcooling 50°C would certainly drop the
operating temp
all the way in to the silicon. Wow, I've found somewhere I
believe LED
data for! Thanks Vic!
> The other option is a fiber optic light guide or light pipe
> system that locates the lamps outside the freezer. This
> removes both the waste heat and any potential mercury
> contamination from the freezer. But, this option also has
> high initial cost.
I don't know that this would prove beneficial unless you're
able to
ensure that the interface through the insulation is sufficient
to
prevent more heat flow out through the light pipe than the
light source
originally produced. Normally I'd say fine, but we have a
50°C
differential driving quite a lot of thermal flux. The fiber
optic
would probably work pretty well though. PMMA might get quite
brittle -
I remember installing some .75" harnesses in Seoul in the snow
in a
building without a facade. It took a day and a half to simply
unroll
six harnesses very slowly. Glass fiber would be more
expensive, but
might be better suited to the environment.
My big question is: Is this fridge continuously lit, or only
when
there is someone in it? If it is intermittent, you have more
shock on
the lamp, but the rate at which the lamp is being used is
relatively
slow. The inefficiency and heat added by an incandescent
isn't
important in this case, as opening the door will have much
bigger
impact. On the other hand, fluorescents don't start well at
low
temperatures, but can be kept warm (as you pointed out) with a
sleeve
insulating it at roughly optimum operating temperature. If on
permanently, a well glass fitting with a small metal halide
might
actually be a good solution. A preheat lamp could be used for
startup.
Thomas Paterson
http://www.luxpopuli.com
| |
| Phil Scott 2006-05-30, 3:21 am |
|
--
Phil Scott
Ideas are bullet proof.
"Victor Roberts" <xxx@lighting-research.com> wrote in message
news:ri9q62duj7tsl650gj5ha94p473ke7i46b@4ax.com...
> On 18 May 2006 07:28:25 -0700, "Thomas Paterson"
> <t_p_paterson@hotmail.com> wrote:
>
>
> I still don't think that 50C added differential could name
> enough difference to notice. But, I'm certainly open to
> being proven wrong with some test data.
you are not wrong... its not a problem in the refrigeration
business.
Phil Scott
>
>
> Well - folks here who have read my comments about LED for
> many years will be surprised that anyone thinks of me as an
> LED supporter :-)
>
>
> The fiber is long and thin and constructed from low thermal
> conductivity material. The light only makes it from one end
> to the other because of the internal reflection. As long as
> the fiber does not transmit IR there is little heat
> transfer. Fibers have been used for this application for a
> number of years.
>
> --
> Vic Roberts
> http://www.RobertsResearchInc.com
> To reply via e-mail:
> replace xxx with vdr in the Reply to: address
> or use e-mail address listed at the Web site.
>
> This information is provided for educational purposes only.
> It may not be used in any publication or posted on any Web
> site without written permission.
>
| |
| Phil Scott 2006-05-30, 3:21 am |
|
--
Phil Scott
Ideas are bullet proof.
"David Lee" <davidlee_malvern@dont.use.this.bit.hotmail.com>
wrote in message news:kvOdnd2uP6GVAfDZRVnyug@eclipse.net.uk...
> Ian Stirling wrote...
>
>
> I don't know enough about incandescent filaments to know
> whether it is a problem but it's possible that there could
> be a phase transition between room temperature and the
> temperature of the freezer that could make the filament more
> brittle at low temperatures.
bzzzzzzzttt...not a problem.
>
> Certainly there is an old story that claims that Napoleon's
> sodliers' tin buttons disintegrated in the cold temperatures
> experienced during the retreat from Moscow. Whilst possibly
> apocryphal, pure tin does have a ductile/brittle phase
> transition at 13.2 degrees C (from beta/white to alpha/grey
> tin).
>
> David
>
| |
| Phil Scott 2006-05-30, 3:21 am |
|
--
Phil Scott
Ideas are bullet proof.
<meow2222@care2.com> wrote in message
news:1147950448.211850.42700@j73g2000cwa.googlegroups.com...
> Paul Hovnanian P.E. wrote:
>
> GLS are rated 750 or 1000 hrs. Converting to 12v filament
> would enable
> you to use common 2000 hr and 4000 hr 50w halogen bulbs. It
> should also
> be a low cost conversion.
>
> 12v would also enable the use of 2x or 3x 20w halogen lamps.
> When one
> dies, you still have light output. With 2 lamps you need to
> replace one
> twice as often compared to using one, but you dont lose your
> light at
> the time, and if necessary you can go longer between
> relampings, since
> the combined life will be more than the life rating of a
> single
> identical lamp.
>
> What issues there may or may not be from the food safety
> angle I
> wouldnt know.
walk in freezer lights are only on when someone is inside,
maybe half an hour a day in most cases... so a 2000 hour bulb
will last 4,000 days in that case, about 10 years...that also
alligns with my experience.
Maybe the OP's freezer lights are not going off when the door
is closed and no one is inside...
Phil Scott
>
>
> NT
>
| |
| Don Klipstein 2006-05-30, 4:21 am |
| In article <e5gm2k$38e$3@news.tdl.com>, Phil Scott wrote:
>--
>Phil Scott
>Ideas are bullet proof.
>"Paul Hovnanian P.E." <Paul@Hovnanian.com> wrote in message
>news:446BE626.7E514B8B@Hovnanian.com...
>
>
>US made bulbs have additives that proved corrosion to the
>element after a fixed number of hours...that keeps the company
>in business. Chinese made bulbs as a rule dont have that
>feature.
I have seen China-made 100W 120V lightbulbs sold in the USA to mostly
have rated light output of 1100-1200 lumens among the ones that dare to
state a claim of lumen output that can be believed by those who know what
to expect...
Along with life expectancy usually in the 1,000-1,500 hour range.
Compare to a "Big 3" 120V A19 incandescent achieving 1170-1210 lumens
while having rated life expectancy of 750 hours, and longer life versions
with 50% more life or double that life still achieving 1050-1100 lumens.
I would take the 25 watt decrease in power consumption available from a
75W "Big 3" lamp over a 100W Chinese one of similar light output!
>proof? maybe this...at our high school in the 50's there was
>a bulb that burned 24/7 for decades...outside no less on one
>of the exterior walls..odd looking clear bulb. hard to
>reach...that was probably made before these additives came
>into use.
Did you research power consumption and light output of that one or any
other of the famous lightbulbs lasting a century?
If you can check out the light output and the power consumption, I would
bet my favorite bicycle that whatever "century bulb" has light output
less than 60% of that of a "big 3 brand" "prime" 750 hour or 1,000 hour or
1,500 hour one of same design wattage and same design voltage.
Keep in mind that having an incandescent lamp operate at a filament
temperature on the conservative side for impressively long life expectancy
usually increases electricity cost of achieving a given illumination
level more than lightbulb replacement cost is decreased if the life
expectancy is designed to be increased beyond both 750 hours and roughly
250-300 megajoules of energy handling by the filament at rated voltage.
>on the temperature/inrush situation... all that is a function
>of the percentage decrease in resistance with
>temperature...over a range of absolute zero kelvin to room
>temperature. 50 degrees or so F isnt much...its not the key
>issue.
>
>you can put a 150 watt bulb in though, with a resistor made
>for the purpose behind it to dim it to 120 watts...and get
>exponentially longer life.
The resistor that reults in a 150W 120V lightbulb receiving 120 watts...
That is roughly 103 volts delivered to the lightbulb, with roughly 17
volts across the resistor.
With 1.15-1.16 amps through the resistor...
This is roughly 19-20 watts of power dissipated into the resistor, and
beware that a 20 watt "sandstone style" resistor can fry a small piece of
bacon at roughy 12 watts!
And what does this gain?
Power consumption reduced by about 8% or about 12 watts (from 150 to
about 138 watts)
Life expectancy of a 750 hour lamp increased to maybe 5,000 hours
Light output reduced from about 2900-2980 lumens to about 1730-1800
lumens - awfully close to high endf of 120V 100W A19!
Do please consider the cost of 38 watts of extra power consumption
against savings of making 750 hour lamps last maybe 4700-5,000 hours!
- Don Klipstein (don@misty.com)
| |
| Victor Roberts 2006-05-30, 1:21 pm |
| On Mon, 29 May 2006 22:25:19 -0700, "Phil Scott"
<philscott@philscott.net> wrote:
>
>US made bulbs have additives that proved corrosion to the
>element after a fixed number of hours...that keeps the company
>in business. Chinese made bulbs as a rule dont have that
>feature.
This is so ridiculous that it is hardly deserving of a
response. But, since it has been cross-posted to a
non-lighting group, it should be answered. I can't prove a
negative, but I know how hard lamp design engineers work to
optimize both life and efficacy in the face of both energy
regulations and market forces that demand the lowest cost
product. No responsible company would throw away product
life, though they do trade life for better efficacy as is
well known to those who understand incandescent lamps. Also,
remember that when a lamp burns out a company has no
guarantee that the consumer will buy their brand as a
replacement.
>proof? maybe this...at our high school in the 50's there was
>a bulb that burned 24/7 for decades...outside no less on one
>of the exterior walls..odd looking clear bulb. hard to
>reach...that was probably made before these additives came
>into use.
This is not proof of anything other than an outlier or a
misapplication. There have always been lamps that ran at
lower operating temperatures than normal due to
manufacturing mistakes and also lamps that were operated at
lower than rated voltage due to wiring problems - which will
also reduce filament temperature and greatly extend lamp
life.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
|
|
|
|
|