Sam E wrote
That is what was being discussed tho.
That wasnt what was being discussed.
Most obviously with the low current use of a capacitor.
Nothing to stop you just rectifying the mains, then just doing a switch mode chopping that up and rectifying to a lower voltage without transformer either.
See above.
Guess again.
A true RMS one? If th meter is a true RMS one, it will boast about that.
I have trouble a Variac that size not drawing a watt or two, And aren't they rated in VA and not watts?
- Don Klipstein ( snipped-for-privacy@misty.com)
If it indicates less than .01 amp for that Variac, and the Variac is not disconnected somehow, I doubt the emeter is accurate at all.
- Don Klipstein ( snipped-for-privacy@misty.com)
Well, I tested it and it works - and the idle current IS less than .01 amps. I'll check it with my lab meter when I get a chance.
It is rated at 200 va - which at unity power factor would be 200 watts. As it was used for controlling a heating element it had a 200 watt limit. It is a 0 - 110% voltage transformer, and the idle current does not change from min to max . The meter I am using is a UPM EM100 energy meter set to the amp scale. The watt scale also reads 0, and when I plug one of the wall warts in it does read - HOWEVER, the minimum reading is 2 watts and 0.02 amps, so when it says 0, it means less than 0.02 amps, and less than 2 watts. (not less than 1, which I had previously reported)
Whatever light does not get out the windows (or escapes the house somehow) becomes heat.
Same story for the considerable amount of infrared wavelengths - some of which do go through glass.
Lightbulbs are pretty efficient at home heating also - it's just a matter of where the heat goes.
- Don Klipstein ( snipped-for-privacy@misty.com)
Indeed.
In my aforementioned electrically-heated home, I illuminated the playroom in the basement with six, 100-watt incandescent lamps, each with a bowl reflector.
During the heating season, I made little (if any) "bones" about it when my young daughters left them on after vacating the room. The living room floor, directly above, was always nice and toasty.
As the girls aged, I explained that they should try to turn them off to save energy which equated to money, particularly when we weren't running the heating plant. They "got it" and did quite well, remembering to turn off the lamps when they left the room.
Agreed.
As to your point that LIGHT becomes heat, I wonder how MUCH light would be required to heat a given space? Velly interesting...
In , Jim Redelfs wrote in part towards the end in response to a prior posting of mine:
Giving efficiency of lamps or for that matter almost every other electrical load in a house approaching 100% for converting the electrical energy consumed to heat, I would not be too concerned with how much of the heat materializes after spending a few or several nanoseconds being in the form of light along a path of electricity consumption becoming heat. I would just consider the watts consumed by the electrical load and multiply by 3.4 to get BTU/hour if that is what you want.
Should you want something more academic, as in watts or BTU/hour in a given quantity of light:
The most common "official definition" (my words) of "visible light" is "electromagnetic radiation" having wavelegths in the 400-700 nm range.
1 watt of such from most light sources used to illuminate homes has about 240-300 lumens. A lumen is amount of photometric output that illuminates 1 square foot to extent of 1 footcandle, or 1 square meter to extent of 1 lux. A "USA-usual" 100 watt 120V "big-3 brand" lightbulb with rated life expectancy of 750 hours and coiled-coil filament produces 1670-1750 lumens, and about 6.6 watts, maybe 6.7 watts of radiation of wavelengths 400-700 nm.Plenty of other "white light sources" produce radiation having roughly
240-320 lumens per watt of radiation of wavelength 240-320 nm, meaning 1 watt or 3.4 BTU/hour from 400-700-nm-"light" amounting to 240-320 lumens.Keep in mind that along with that 6.6-6.7 watts of radiation in the "official visible light range", the above 100W lightbulb produces plenty of infrared. Something like around roughly ballpark 50 watts of infrared radiated by the filament passes through the glass bulb. The glass bulb typically radiates a few watts more infrared, maybe as much as 10 or a dozen or so. Since a 100 watt 120V lightbulb can produce something like 75 watts combined of infrared and visible light with a trace of ultraviolet that is mostly in the "non-tanning portion of UVA as in 'Blacklight Range' ", when light output is 1710 lumens, each lumen of light escaping the fixture
*may* be associated with close to .044 watt of radiation that becomes heat in the home after exiting the lightbulb in form of radiation (in addition to heat from the fixture). .044 watt is about .15 BTU/hour.But also since energy going into a lamp within a home experiences well-approaching 100% efficiency of producing heat within the home, I suggest that room or building heating effects result mainly from power consumption of the light source rather than photometrics. At the usual rate of about 3.4 BTU/hour per watt.
The biggest problem I hear now is as to how much home heating by lamps is achieved at ceilings and how much of that is off-target by producing heat above where it is wanted/needed!
- Don Klipstein ( snipped-for-privacy@misty.com)
Don,
I'm happy to see that you've cranked out the above numbers, which I have wondered about but not taken the time to calculate.
Ceiling heating is easily utilized by running ceiling fans backwards at a fairly low speed. We've been doing that for years and find that it really improves comfort.
With respect to areas inadequately addressed by the EPA and DOE regarding LED lighting I submit that for those of us with less acute vision than we had when much younger I have found that LED lighting is often a problem. Incandescent lamps, and fluorescent lamps (due to their phosphor reemission) produce a fairly broad, continuous spectrum with the bulk of the energy in the longer wavelengths. LED lighting (that without phosphors) produces light in a very narrow spectral band, or bands, usually at the shorter wavelengths. By a judicious selection of materials the wavelengths and intensities of the components forming the resulting line spectrum the eye can be tricked into believing that the light is the same as that from an incandescent lamp. It looks like "white" light. About 50years +/- ago George Wald showed how this happens in his work on the molecular theory of color vision. A good overview of this is found in the lecture he gave when accepting the Nobel Prize for this discovery.
When I look at something under LED derived "white appearing" light doesn't mean that when my eyes were refracted the light source was the same. Consequently, my glasses and the eyes they are correcting are optimized, not for short wavelength lines, but rather for the predominantly longer wavelengths present in the incandescent illumination used by the ophthalmologist. As one ages and the ability to accommodate deteriorates this becomes non-trivial.
Boden
A *lot* of light! However, you must define light first (what spectrum) before you can answer it.
I now have an "always off" house!
The only three things which are "always on" are my phone answering machine, the refrigerator*, and the freezer*.
*New "Energy Star" appliances.Everything else has a handy "extension cord type switch" added next to the appliance so I can easily turn it "totally off" when not in use.
For my computer and TV/Stereo/Entertainment center areas, I have one or more power strips (no lights on these power strips) right next to each other so I can easily switch on just what I need to use (not everything all on with one power strip). Or I have little switches for one item plugged into the power strip.
So for my entertainment system, I can separately turn on the TV, stereo, Playstation, satellite TV, DVD, etc. I just turn on what I need. All the switches are right in one location and labeled, so easy.
Microwave is on switch, GFCI's are switched, outlet surge protectors are switched, garage door opener switched, HEPA air cleaners switched, window air conditioners switched, cell phone and other battery chargers, clock on range disconnected, space heaters switched so they are totally off, and of course the doorbell now only uses electricity when the button is pressed.
This was a one time expense. I used money I had saved from previous energy saving projects to pay for this. Anyway for the rest of my life I will have a lower electric bill.
In the past people have advised me to invest my money in the stock market (instead of in energy saving projects) because I would get a better return on my money. I'm glad I did not do that!
so, maybe it should use water?
Turning on and off electronic devices, does it shorten their life? Even if it does the electricity saved over the life of the unit will buy a newer more efficient unit when it finally dies.
So here is my own research, I have a TV that is about 25 years old and most of those years it has been turned off at the power strip. It gets used about and average of 1 hour per day and it still works.
I do know that the new cable boxes when shut off on a power strip loose their programming and can take some time to turn back on.
So we need to press the manufactures of these devices to have a very low consumption when we are not using them. I=92ve measured several cable and TV=92s off and they can consume more than 40 watts off.
About 25 years ago I read an article about the guy that built a supreinsulated freezer with thermal mass in it. He used a heat pipe to freeze it al winter and it wouel swing through the summer.
Wow this is a long ways from a door bell
Andy Energy wrote in news: snipped-for-privacy@k36g2000yqe.googlegroups.com:
I have two lighted buttons. I'm gonna burn in Hell for it. I just know it.
Feature creep :)
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