Energy saving spotlights

grahamc2003

Ben84 wrote: »

We don't always want light and heat at the same time. It makes more sense that lightbulbs emit light and heaters emit heat, so that we have more control over our environment.

Anyway, I accept that a lightbulb emitting heat in a thermostatically controlled heated room will result in the thermostat turning the heating on slightly less often, but I don't believe removing this heat source is causing people to use more energy. In the worst case situation they would use the same amount of energy to attain the same temperature inside the house as it is now being emitted by another appliance in the room. Basically, to heat your room to any temperature requires a set amount of energy, it may come from one or more sources, but in this example you're simply reducing the energy input to the heater by increasing the energy input to the lightbulb. No net gain is the result, your electric meter will count just as many kWh used.

Yes. Or put another way, if you replace a 100W lightbulb with a 7W lightbulb, then intead of getting a 100W contribution to your heating requirements, you only get a 7W contribution, and for the same room temperature profile during times heating is being used, you'll have to put in an extra 93W from somewhere else.

It boils down to the benefit of energy efficient bulbs being about 50% of what most people (including the decc) think, assuming heating for 50% of the time.

Interestingly, the 93W loss of electrical heat will mostly be replaced by 93W of extra gas heating. If we wind the clock forwad 20 years when most electricity will come from low carbon sources (the bulk from Nuclear), then it's likely there'll be more co2 emissions from the extra gas burnt than from the electricity saved.

whasup

The notion that energy efficient lighting will just result in extra gas heating is a but simplistic. That will be partly true in the depths of Winter but for most of the Summer months heat from light fittings is unwanted. It might even be the difference between switching on a fan or a cooling unit to take heat away. And of course gas is a lot cheaper than electricity so it makes sense from a cost point of view - which is most peoples motivation.

don0301

grahamc2003 wrote: »

Yes. Or put another way, if you replace a 100W lightbulb with a 7W lightbulb, then intead of getting a 100W contribution to your heating requirements, you only get a 7W contribution, and for the same room temperature profile during times heating is being used, you'll have to put in an extra 93W from somewhere else.

I understood the W rating is the power consumed, which is not the same as heat dissipated.

As 100W bulbs are no longer available, and can you get a 7W incandescent bulb for domestic use? I take it you are comparing a 100W incandescent bulb being replaced by a 7W CFL bulb.

If that's the case, then aren't you comparing apples and oranges?

incandescent bulbs are much more ineficient than CFL bulbs regarding heat.

as to:

grahamc2003 wrote: »

Interestingly, the 93W loss of electrical heat will mostly be replaced by 93W of extra gas heating. If we wind the clock forwad 20 years when most electricity will come from low carbon sources (the bulk from Nuclear), then it's likely there'll be more co2 emissions from the extra gas burnt than from the electricity saved.

whasup answers that i think

whasup wrote: »

The notion that energy efficient lighting will just result in extra gas heating is a but simplistic. That will be partly true in the depths of Winter but for most of the Summer months heat from light fittings is unwanted. It might even be the difference between switching on a fan or a cooling unit to take heat away. And of course gas is a lot cheaper than electricity so it makes sense from a cost point of view - which is most peoples motivation.

Ben84

grahamc2003 wrote: »

Yes. Or put another way, if you replace a 100W lightbulb with a 7W lightbulb, then intead of getting a 100W contribution to your heating requirements, you only get a 7W contribution, and for the same room temperature profile during times heating is being used, you'll have to put in an extra 93W from somewhere else.

It boils down to the benefit of energy efficient bulbs being about 50% of what most people (including the decc) think, assuming heating for 50% of the time.

Interestingly, the 93W loss of electrical heat will mostly be replaced by 93W of extra gas heating. If we wind the clock forwad 20 years when most electricity will come from low carbon sources (the bulk from Nuclear), then it's likely there'll be more co2 emissions from the extra gas burnt than from the electricity saved.

Gas too can be made from non-fossil fuel sources. There's a new pilot plant at Didcot which turns sewage in to methane, cleans it up and pumps it in to the gas supply where it's burnt in cookers and boilers just the same as fossil fuel gas. Farm waste and food factory waste can also be used.

In the future we may start using more district heating systems to deliver heating, perhaps as a way to use the thermal output of nuclear power plants. It would be good to have houses that are completely nuclear powered, both for electricity and attached by pipe to supply hot water for washing and space heating.

zeupater

:money:

don0301 wrote: »

I understood the W rating is the power consumed, which is not the same as heat dissipated.

As 100W bulbs are no longer available, and can you get a 7W incandescent bulb for domestic use? I take it you are comparing a 100W incandescent bulb being replaced by a 7W CFL bulb.

If that's the case, then aren't you comparing apples and oranges?

incandescent bulbs are much more ineficient than CFL bulbs regarding heat.
...

:wall:
:question: ... :think: ... :idea: ... :silenced:

:DZ

zeupater

Ben84 wrote: »

.... It would be good to have houses that are completely nuclear powered, both for electricity and attached by pipe to supply hot water for washing and space heating.

Hi

Decent post until the above was written, I was going to post on biogas, but no need now .... Anyway, regarding the above - how does a nuclear plant work ? .... what does it do with the heat ? .... would the heat provided by nuclear be more or less efficiently utilised if converted to electricity at source and delivered via wires or piped to the customer as steam ? ... what are the relative losses (resistance vs thermal) over distance ? ... how many reactors are close enough to a population density to make this economical ? .....

HTH
Z

Martyn1981

Z. If we all lived close enough to nuclear power plants, we wouldn't need to worry about lighting. We'd all just glow in the dark!

M.

grahamc2003

Ben84 wrote: »

Gas too can be made from non-fossil fuel sources. There's a new pilot plant at Didcot which turns sewage in to methane, cleans it up and pumps it in to the gas supply where it's burnt in cookers and boilers just the same as fossil fuel gas. Farm waste and food factory waste can also be used.

In the future we may start using more district heating systems to deliver heating, perhaps as a way to use the thermal output of nuclear power plants. It would be good to have houses that are completely nuclear powered, both for electricity and attached by pipe to supply hot water for washing and space heating.

District heating was around a long time ago - Battersea for example heated much of the local area with the waste heat (which then wasn't waste of course).

On the original nationalisation to form the cegb, licences issued by the government only allowed electricty to be sold, so from that momentous day, all the heat had to be wasted. What a colossal mega waste over the years. I've never understood why environmentalists haven't been up in arms about this waste, which probably is greater than the total amount saved by all 'green' initiatives put together. I cringe at the waste every time I see a cooling tower.

For district heating, the stations would have to be reasonably close to urban environments. I personally don't see that as a problem if starting from a clean sheet with an integrated design, but I expect others wouldn't like the thought of a Nuke close by. You could tap off high grade heat for heating and industrial purposes in an integrated design, but the current situation is only low grade heat (<100C) is cooled in cooling towers or run out into rivers (as for most Nukes).

I expect those who lived onboard a Nuclear sub for months on end underwater just a matter of metres from the reactor would feel very safe in such an integrated Nuke/home environment, but I expect most wouldn't.

rogerblack

District heating only really works when you can do whole districts.
This means that it works really well if, for example, you could build a whole new town, or suburb, putting in the very large required pipes at the same time as the sewers and other utilities, from a central power station.

However, the scale of new developments means this is impossible.

Small scale CHP is another possibility.
'medium' sized generators - 50kW-100kW are quite efficient, and properly plumbed in to heat exchangers mean that they have approaching 100% total efficiency - when heat is required.

Martyn1981

rogerblack wrote: »

District heating only really works when you can do whole districts.
This means that it works really well if, for example, you could build a whole new town, or suburb, putting in the very large required pipes at the same time as the sewers and other utilities, from a central power station.

However, the scale of new developments means this is impossible.

Small scale CHP is another possibility.
'medium' sized generators - 50kW-100kW are quite efficient, and properly plumbed in to heat exchangers mean that they have approaching 100% total efficiency - when heat is required.

There's also micro CHP for domestic use. Here's some spiel:

http://www.energysavingtrust.org.uk/Generate-your-own-energy/Micro-CHP-micro-combined-heat-and-power

http://www.baxi.co.uk/ecogen

There are larger domestic systems, that are 'on a pallet', but I've lost the link.

Mart.