Naked Science Forum
Non Life Sciences => Technology => Topic started by: cheri on 06/02/2008 22:09:46
-
Hi,
I have just heard that there is mercury in energy saving light bulbs and have heard this is very dangerous! Can anyone confirm thsi for me and explain the dangers and how I should dispose of these.
Cheri
-
There is mercury in florescent light bulbs, and the common energy saving light bulbs (there are different technologies) are basically miniature fluorescent light bulbs.
On the other hand, the amount of mercury in the light bulbs is far less than most people have in the fillings in their mouth.
-
Hi,
I have just heard that there is mercury in energy saving light bulbs and have heard this is very dangerous! Can anyone confirm thsi for me and explain the dangers and how I should dispose of these.
Cheri
Indeed there is mercury in most fluorescent-type bulbs - but less than you'd get in a traditional thermometer.
In the UK at least, commercial users of fluorescent tubes (businesses etc) has to get their used fluorescents "properly" disposed of, while households have tended not to use fluorescents so much and the issue has been largely ignored.
If you do break a fluorescent (or compact-fluorescent) bulb inside the house, the main thing is to sweep it up and get the dust and debris out of the house, and let the room air. Exposed mercury (lost under the floorboards or in a carpet) can evaporate over longer periods of time and if the vapours are inhaled over a long period of time cause brain damage, hence "mad as a hatter". Provided you sweep up promptly and air the room, one bulb is not going to cause you any trouble.
-
I'm starting to think that energy saving light bulbs aren't that great an idea. They must use a lot more resources to produce and there are situations where the extra heat from a normal bulb is not wasted, now they seem to be a threat to health.
Actually, I'm starting to have doubts about the whole recycling thing as well. Our council has a vehicle on the road, all week, going round collecting a few tin cans. How much CO2 does this thing chuck out? It also blocks the road so cars have to waste energy stopping behind it and then have to get past it. There seem to people employed specially to pick up the few tin cans my mum puts out.
My point is that we are doing as much damage doing the recycling as we are getting back from the recycling. Is it me?
-
I think the concerns over mercury can become exaggerated. Bear in mind the recent scares about mercury in tuna fish. I have yet to have broken a fluorescent bulb (compact or long tube), but still eat tinned tuna (one of the few forms of fish I will eat). Guess where my mercury is coming from.
Yes, CFL bulbs are more expensive to produce, and to buy; but that has to be offset against their far longer lifespan.
I do agree about many of the issue regarding recycling, but I use CFL's now because they do make economic sense (not simply because of tax distortions, but because their development has matured sufficiently), and because the range of products now exist to make them available for most of the applications I desire to use them for.
I am not trying to make a hard sell over CFL's, just looking at the risks within the contexts of risks in other areas of life. There are no risk free options, but these risks are minimal.
-
I'm starting to think that energy saving light bulbs aren't that great an idea. They must use a lot more resources to produce and there are situations where the extra heat from a normal bulb is not wasted, now they seem to be a threat to health.
Actually, I'm starting to have doubts about the whole recycling thing as well. Our council has a vehicle on the road, all week, going round collecting a few tin cans. How much CO2 does this thing chuck out? It also blocks the road so cars have to waste energy stopping behind it and then have to get past it. There seem to people employed specially to pick up the few tin cans my mum puts out.
My point is that we are doing as much damage doing the recycling as we are getting back from the recycling. Is it me?
I agree with you, Turnipsock and partly because my council will only collect
the recycling rubbish if the whim takes them and same goes for the other
domestic rubbish as well. But as to the hallogen (so-called) energy light saving bulbs are a waste of money as you said that they cost more to produce
and take up longer to light up a room. Not much of an incentive to us to purchase them. I think.
Recycling ditto
-
But as to the hallogen (so-called) energy light saving bulbs are a waste of money as you said that they cost more to produce
and take up longer to light up a room.
Halogen light bulbs are not the same as the energy saving light bulbs.
What you say about start-up time is true of the compact fluorescent light bulbs (which are the common energy saving light bulbs), although the matter is less severe than it used to be.
the newer technology for energy saving light bulbs is LED light bulbs. They are more efficient than compact fluorescents, and don't contain mercury, but are still a very immature technology. They are more expensive even than CFLs (at present, although inevitably prices will drop), and at present are still not available at very high power levels. They are becoming available in torches, where their low voltage, low power, characteristics are valuable, and their power output is still more than adequate for the purpose (since most other technologies used for torches have even lower output power due to their inefficiency and the limited available power to drive them).
-
LED light bulbs give off directional light, so the light goes where you aim it. LED bulbs are closer to the color of daylight — which new studies suggest is good for staying alert. Our LED light bulbs can be used to replace your standard fluorescent or halogen light bulbs. The bright, white LED light produced by our LED Light Bulbs works especially well for task lighting and reading light. LEDs not only produce light more efficiently, they also have a tiny mirror that reflects light in one direction. A more directed light means less wasted light.
LED light bulbs will be the trend.
-
LEDs give no better spectrum that daylight balanced florescent tubes (including compact florescent bulbs), but I agree that many florescent bulbs are not daylight balanced, but that is not to say you cannot obtain those that are (and I do). Most of the LED's I've seen so far seem in fact to have an inferior spectrum to properly daylight balanced florescent tubes, but it may be just that I have not seen properly daylight balanced LEDs yet (the fact that LEDs are still less available in general would mean that the specialist variants would be even more unavailable - this was a problem for a long time with specialist florescent tubes).
Directional light depends on the use you want to put it too.
The biggest problem with LEDs right now are relative costs, and low maximum light output. These will be addressed over time, but not there yet.
-
I very much doubt that the spectrum from a quantum device like an LED is really very 'good'. It will almost certainly consist of three (or possibly more) spectral lines or narrow bands. That is hopeless for illuminating a scene and getting the same visual response as the same scene in daylight.
If you are after a nice aesthetic effect you need a fairly continuous spectrum.
-
I very much doubt that the spectrum from a quantum device like an LED is really very 'good'. It will almost certainly consist of three (or possibly more) spectral lines or narrow bands. That is hopeless for illuminating a scene and getting the same visual response as the same scene in daylight.
If you are after a nice aesthetic effect you need a fairly continuous spectrum.
In principle, I believe that white LED's are like white florescent tubes, they are basically just florescent devices, where the monochrome radiation drives the different phosphors, so I expect the spectrum to be fairly similar (which depends totally on the design of the phosphors).
-
Of the two kinds of 'white' LED, neither is ideal.
One produces intense blue and uses phosphors to produce the longer wavelengths (Stokes shifted radiation). It is quite efficient but relies, for this efficiency, on an excess of very , very blue light. Fantastic if you are stumbling around a field at night with a tiny 'head' light, powered by a single AAA cell. Pretty vile if you want to relax and read a book. This contrasts with fluorescent tubes which produce UV, which needn't affect the colourimetry.
The other, organic type, produce three narrow bands of red green and blue, by direct 'LED' action. Not really nice to live with, either, for the reasons I have already given.
-
Just to confuse the issue, Philips now make an "EcoClassic" series of lightbulbs which are in fact a halogen bulb (possibly with an integral step-down power-supply?) inside a normal "general service" bulb. These are "energy-saving" inasmuch as halogens being almost twice as efficient as ordinary tungsten filament bulbs (but only half as efficient as CFLs). They will probably give a slightly whiter light than normal bulbs, but can be dimmed. Also they will have the continuous spectrum so render colours properly. In my local supermarket they cost about 4x as much as a standard bulb and only last 3x as long.
-
Fluorescent tubes and LEDs both produce a set of narrow wavelength bands. There is no such thing as a white LED; they can be made from three LEDs (Red, Green and Blue) with the power balanced to produce white, but more often now they are made from a blue LED combined with a phosphor that gives broader spectrum of yellow light. Both give the illusion of broad spectrum white light but are in fact a small number of narrow wavelength bands that "fool" the receptors in the eyes to appear white. The nature of fluorescence is the same - the light produce is broader band than that from LEDs but is still a multiplicity of fairly narrow wavelengths.
A filament lamp (or incandescent lamp) is "black body radiation" and is a continuous spectrum allbeit weighted according to the temperature of the filament. Most of the time the difference in these types of light may not be noticeable, but some could be if trying to discern particular colours, for example against a different coloured background.
-
Figure 1b in the middle of page 8 of this datasheet
http://www.lumileds.com/pdfs/DS25.pdf
shows a typical emission spectrum from a "white" LED.
The LED comprises a blue semiconductor emitter and a broad-band yellow phosphor.
As you can see, there is something of a gap in the spectrum in the region of 450-525nm (blue-cyan-green region). The overall colour is also somewhat too blue-ish (too high a colour-temperature) to be very welcoming in the home.
Figure 1c at the bottom of the same page shows a "warm white" emitter. This spectrum is much more continuous and much more friendly... (in reality it really does fell like the light from a conventional torch-bulb) although the efficiency is rather poorer than for the more common ordinary-white products. To my knowledge Lumileds do not yet make a "warm white" product in their higher-power ranges (3W/5W).
For interest, figure 1a at the top shows typical emission spectra for monochrome LEDs too.
-
It will be good when they do get it right.
I have a boat and my present cabin lights either eat up current or look sick, depending on which I use!
I am less bothered by saving energy at home.
I think that movement/people sensors are a better way forward for energy economy. How many rooms in our houses are lit whilst no one is in them?
Or we could all have headlamps all day every day.
-
I think that movement/people sensors are a better way forward for energy economy. How many rooms in our houses are lit whilst no one is in them?
I can think of lots of problems with this at present.
Firstly, most of the lights we use at present have a fairly noticeable startup time (maybe not that great if you are expecting it, but if you are moving constantly from one room to another, the the constant momentary switching of lights as you move between rooms can be annoying).
Then it will not in any case mitigate the need for switches on lights, since people sometimes still want to switch off the light while they are in the room (e.g. when they want to sleep), and may possibly have cause to have lights on in the room even in their absence (e.g. security lights). This does not mean it is a useless feature, only that it should not be considered to be the sole means by which lights could be switched on and off.
In any case, lighting is still a small consumer of energy when compared to heating.
-
it should not be considered to be the sole means by which lights could be switched on and off.
True. My Son has this in his bathrooms and I stagger in for a pee in the middle of the night POW!!!! Deadly.
There are lots of possibilities for more intelligent control; a system could detect the door opening (and doors should be closed) to speed the reaction time. It wouldn't he hard to have a manual override when you actually need it (or voice control; "I'm going to sleep. Wake me at 7a.m. with Radio 4 and the lights on half power. Don't turn on for anyone else's voice.")
LEDs would start up quickly.
-
In any case, lighting is still a small consumer of energy when compared to heating.
Exactly. The politicians have jumped onto the low-energy lighting bandwagon in a big way (maybe prodded by the lighting industry???), but heating and transport use vastly more energy.
I can't find the source, but it is often quoted that in the UK lighting accounts for 15% of domestic electricity consumption. Nationally, houses get about 4x as much energy from gas as electricity (but similar total CO2 emissions). 10000 miles in a car again results in comparable CO2 emissions to either annual gas or annual electricity use. So in terms of CO2, for the UK direct domestic emissions, due to lighting we're looking at about 5%.
-
I like the idea of a really intelligent system for controlling lights (and many other things too) but I don't think any commercial systems are likely to be available (at least at a reasonable cost) in the near future. I hate getting up to use the loo in the night and getting blinded, albeit temporarily, by an unnecessarily bright light.
Is it only just me that thinks that the long-life claims of the fluorescent "long-life" bulbs are hugely exaggerated? I have not bothered to do any controlled experiments, but my impression is that they do not last anything like as long as number of hours claimed, to the extent that they are possibly more expensive per hour than a filament lamp, at least in terms of depreciation cost. Of course the majority of the cost of using light bulbs is in the electricity consumed over the life of the product. For a 100W bulb with a life of 1000 hours this amounts to about £10 at current rates where the bulb only costs about £1. My impression is that the compact fluorescent bulbs only last about 3x as long (not the vast number claimed - is it >10x??), but cost at least 3x as much for an "equivalent". And there's another thing; the equivalent wattage values also seem wrong and the lights always seem dimmer than the incandescent equivalent. This view seems born out by the table of relative efficiencies here:
http://en.wikipedia.org/wiki/Luminous_efficacy#Overall_luminous_efficacy
which shows only a 3x to 4x efficiency compared with incandescent 100W bulb. This is still a significant saving but why the gross exaggeration? I note the white LEDs vary from being less efficient to 6x as efficient so care in selection here!
-
I have just had a compact fluorescent go in the bathroom, fair enough its not on for long stretches but it has lasted over 8 years. (maybe longer)
I decided to replace it with the same type and went shopping for some yesterday. The prices seem to have reduced dramatically as I can now get them at the local supermarket for .69p each (1 euro or just over a $1 ) and made by Phillips. A pack of 4 ordinary filament lamps was .99p.
Some information from the packaging:
8 years lifetime based on an average of 3 hours burning per day
18watt, equivalent to a 100watt filament bulb
1100 lumen 130mA
Uses 5 time less electricity
Energy class A
Not suitable for dimming and electronic switches.
These also seem to start and reach max luminance very quickly, I'd say within around 5 seconds.
-
O dear, maybe I was too cynical or basing my observations on non-reputable manufacturers. The prices do seem to have come down a lot as the last 18W compact Fluorescent I bought cost me over £3.00. I note that adverts on the web still have them at £2.89 or so (a few random samples) though some are around £2 with claimed 8000 hour life (8x a typical filament lamp), but not as low as the price at your supermarket, TMM. Also I note that the lamps in my 5 lamp array in my living room, which has a mix of filament lamps and compacts as I am replacing the filament ones when they die, have markedly different colour temperatures on switch on which take about 10 minutes to settle. There is then still some difference, but acceptable, and the brightness is closer to being matched.
There does seem to be a lot of different types with differing behaviours. I will try Philips, if I can get them locally.
-
BTW I bought the Philips ones from a "Netto" store, .69p each for either 11w or 18w.
Argos stores also have them for £1.29
But, doing a search it seems that the average price is around £2.50, so it seems its worth shopping around.
It does not state what the colour output is only that it was measure against a 1000 hr soft colour bulb of similar output.
-
it is often quoted that in the UK lighting accounts for 15% of domestic electricity consumption.
This is a bald statistic and could be correct. But that 15% ends up as heat, which does not need to be provided by the heating (when heating is required) Lights are used more in winter, when the heating is also needed more so I think that quite a chunk of the 15% figure is irrelevant.
If you REALLY wanted to cut down on energy use you would not have central heating, which heats all rooms all the time, even though no one may enter them for a whole week- there's a lot more than 15% to be saved there. High powered fan heaters and radiant heaters could 'follow you' around your home; you would be almost unaware of the way your heat was getting to you and you would save a packet.
-
If you REALLY wanted to cut down on energy use you would not have central heating, which heats all rooms all the time, even though no one may enter them for a whole week- there's a lot more than 15% to be saved there.
Its well worth it to use thermostatic radiator valves in that situation as they help a lot, especially as the main central heating thermostat in most homes is usually located in the hall-way or entrance, the coldest place!
It would also be great if you could use a programmable interface for controlling each radiator as well..
Maybe soon or done already!
-
The easy answer to saving on heating power is to wear more clothes. Long Johns are a portable heater.
Some politician said something about making the whole country use energy saving bulbs by such and such a year. They clearly don't understand the central heating system. Anyway energy saving bulbs are a lot more damaging in their production.
Or old bathroom light has run for about 8 years as well. It went four days ago and has not been replaced and nobody has missed it. I do seem to have some infra red properties in one eye.
One good thing about energy saving bulbs is that they take a bit of time to get up to full brightness, which means they don't hurt your eyes when you first switch them on in the midle of the night.
I wonder if the idea of using long johns instead of a heater could be expanded to using a head torch instead of normal lighting?
-
If you REALLY wanted to cut down on energy use you would not have central heating, which heats all rooms all the time, even though no one may enter them for a whole week- there's a lot more than 15% to be saved there. High powered fan heaters and radiant heaters could 'follow you' around your home; you would be almost unaware of the way your heat was getting to you and you would save a packet.
It is no more difficult to switch off a central heating radiator than to switch on an electric heater.
If you are constantly allowing a room to cool down and get warm again, you will have a lot of condensation in the room, which will more than offset any savings in your heating bill with increases in repair bills. By all means, if you are not using a room for weeks on end, then switch off the heating in the room and allow it to cool down, but don't expect to switch the heating on and off like toy do a light bulb.
Also, allowing one room to cool down while heating a neighbouring room is only valid if you have good internal thermal insulation within the house. Most houses maximise the thermal insulation (even then not always very effectively) between the interior and the exterior, but make no significant effort to thermally partition the interior.
On the whole, most people who use central heating are paying less for their heating than those heating each room separately. In part this is because heating by gas is more energy efficient than converting the gas to electricity, distributing the electricity across the grid, and then converting the electricity to heat; and few people have a gas heater in each room. Gas heaters are also a safety liability (so is is gas central heating, but the risks are managed in a single sealed unit rather than the risks associated with an open gas fire, let alone a gas fire in each room).
-
A water-filled radiator takes a lot of energy to get it hot enough to warm the room; there is a huge time lag, compared with a radiant / fan electric heater. You could enter the room, spend half an hour in there and leave before the average radiator had any appreciable effect. The radiator would need to have several times the normal power output and would have a larger water capacity - another waste of energy.
To compare local electrical heating with GCH you need to do much more than compare the cost of delivering electrical power to the device with the cost of providing the hot water in the system. There is a further distribution system involved and there are pipes all over the place which lose heat under floorboards etc; just observe how fast they cool down when the boiler stops.
The total cost of comfort is what is relevant here and it may be necessary to think laterally rather than to hang on the what we know and love. To make a fair comparison you would need to factor in the cost and convenience of adding extra insulation, replace all existing equipment and also the control system. I think the water-based system has several shortcomings in the modern context.
Conventional central heating is nice but expensive. It wasn't introduced as a result of today's factors but as a luxury which we could all (?) afford. We just accept the cost and are reluctant to do without it.
You just don't need a room to be warm if you're not in there but you can demand that it warms up fairly quickly when you go in. Condensation is not a problem if there are no cold surfaces. There has to be less heat flow from a warm room to the window of an unheated adjacent room than keeping that adjacent room warm. Yes, there is little attention paid to internal insulation, nowdays, but it would be cheap to install (and injecting foam into internal walls would not even involve building regs).
In many houses there are heated rooms where no one goes for days on end. This must use more energy than necessary; can there be any question about this?
Of course it's true that a well insulated house would need very little energy to keep it warm - about the amount that is used for lighting, perhaps.
Apart from being sexy technology, do the new lamps really have that much going for them, bearing in mind that we could all wear thicker clothes and save much more money / energy by operating our heating a couple of degrees lower?
-
But if you are constantly heating and cooling rooms as one moves in and out, how can you avoid there being cold surfaces as the surfaces warm up less quickly than the air? The problem is that the materials that make up the walls of our rooms is they have a high heat capacity which is good at insulating the rooms, but very slow to warm up or cool down. If we have an inner metal surface in the rooms, then this would help, but it means major changes to the design of our rooms.
Central heating may have been a technology that replaced earlier means of heating (such as open fires) in the 1960s, but it is actually more efficient than many of the technologies it replaced (and much healthier than things like paraffin heaters, or even poorly maintained gas heaters, both of which can be dangerous in the house).
-
Who is 'cooling' the room? There will be no 'cold surfaces' compared with the ambient air at the time the local heater is turned on. There need be no air below dew point. When the heater turns on, the existing air will just get less humid - no more water will become available.
The thermal inertia of the fabric is not really relevant when a powerful radiant heater is concerned. If you spend much time in the room then it will all have warmed up; if you leave after a short time, only the air and surfaces (and you) will have warmed up.
What is so special about having every room warm when no one is in it? Sounds a total waste to me.
-
If the room does not cool, then there is no need to heat it - so you have a contradiction there.
The assumption in what you are saying is that you rapidly need to heat a room because it has been allowed to cool down in your absence, so ofcourse the surfaces would have cooled down also.
If you spend much time in a room then it really does not matter what means you are using to heat it. This debate is about rooms where you do not spend much time, but will occasionally enter the room, and will seek to rapidly heat up the air while not having time to heat up the surfaces, thus the warm air, carrying moisture, will then condense that moisture on the cold surfaces.
Even the moisture in your breath will be more likely to condense on the cold surfaces.
-
1.
thus the warm air, carrying moisture,
Where does this moisture come from? If it comes from your breath, it implies you are in the room for a long time - so it would be warm and, low humidity.
2. I'm not expecting the room to cool down a lot; though, if it does, you are wasting even MORE energy keeping it warm with radiators working all the time. Would you include your garden shed in the central heating loop? I don't think so, so I am right in principle!
3. We have to assume the same conditions for both systems. A well insulated house would need very little heat input. Why not just use the lights then?
4. Many tens of pounds a year just to keep rooms warm is an expensive way of preventing condensation.
5. Do you have shares in a central heating company A-S?
6. Good insulation goes without saying.
-
1. thus the warm air, carrying moisture,
Where does this moisture come from? If it comes from your breath, it implies you are in the room for a long time - so it would be warm and, low humidity.
Your breath will contain moisture, but the air itself will contain humidity even if just drawn in from outside. Ofcourse, in some rooms, like the kitchen and bathroom, you have other causes of moisture as well (and I not only have the heating on in the bathroom, but actually have a dehumidifier, which is rated at 60W consumption, permanently switched on).
2. I'm not expecting the room to cool down a lot; though, if it does, you are wasting even MORE energy keeping it warm with radiators working all the time. Would you include your garden shed in the central heating loop? I don't think so, so I am right in principle!
I have no problem with switching off heating in rooms one very rarely ventures into, but the debate is whether, in those rooms one regularly enters, central heating is any disadvantage, or even an advantage, over distributed heating systems.
The spare bedroom has the radiator permanently switched off, except when I am expecting guests - but I can do this with central heating, and I don't need rapid response heaters.
4. Many tens of pounds a year just to keep rooms warm is an expensive way of preventing condensation.
Not when you consider the cost of repairs due to rot caused by condensation.
-
I can't help but thinking (as I suspect sophiecentaur does) that this amount of problems of condensation indicates a problem with excess humidity, and that keeping everywhere heated to avoid it is a poor workaround.
Where is the humidity coming from? Is steam from the bathroom or kitchen being poorly managed? Use lids on saucepans, switch off kettle promptly, use some kind of air-extract when cooking. Ditto for bathroom - better to air the bathroom (with the door to the rest of the house closed) for 20mins after a bath/shower than to heat the whole house forever!
Are you regularly drying washing inside the house? FAR better to dry it outside or in an airy outhouse/conservatory. Do you have heavily-used non-flued gas heaters (combustion by-product being water vapour)?
A small amount of air circulating in the house (a couple of windows ajar) while letting a little heat escape ought to help considerably with the humidity issues.
-
but the air itself will contain humidity even if just drawn in from outside
Not at all; if the outside air is actually 100% saturated, as soon as it comes inside and its temperature rises, the humidity goes down. You will only get condensation if that air gets COLDER than it was when outside. Whether you use your system or mine, the idea is that inside is warmer than outside.
Bathrooms and kitchens are the source of extra water and could cause condensation elsewhere. But a small temperature differential between inside and outside is enough to act as a 'pump' as long as some air leaves the house.
Air flow can be a problem if the prevailing wind is working against you but I still feel that CH is not the most economical way of dealing with what is, in fact, a different problem from heat loss.
-
There is mercury in florescent light bulbs, and the common energy saving light bulbs (there are different technologies) are basically miniature fluorescent light bulbs.
On the other hand, the amount of mercury in the light bulbs is far less than most people have in the fillings in their mouth.
But, how much mercury is there in enough bulbs to fill every socket in every American(or World)household and business? That's the amount that will be going into public landfills(and into our groundwater), if the current agenda succeeds in total elimination of incandescent bulbs.
There is currently a DEQ program for some commercial bulbs that requires businesses to ship spent bulbs to a recycling center, because of the groundwater pollution potential. But it is only partially effective, with the help of "watchdogs" to report noncompliance. They will have a harder time enforcing this on the public, especially with bulbs that can slip into a garbage bag unnoticed. People will more likely ignore the warnings, like they do with their batteries. The eventual result is the blaming of the Water Company for HEAVY METAL POLLUTION.