Electricity Supply
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Sounds counter intuitive but they do work. We had reversible air cons in an office I worked in and they worked well. The only problem was the distribution, the air blew across the ceiling so the heating wasn't even. And a bonkers control panel that even 6 programmers couldn't make any sense of
History shows it to be true. You need to think more globally."At least no one has suggested energy efficiency as a way to cut our emission, or keep the lights on.
Such ideas lead to more energy consumption"..
How does being energy efficient lead to more consumption?
That's nonsense.
My electric bill averages about £60 quid per quarter.
That's because I have no immersion, keep lights turned off, tv mostly off, pc on for a few hours per day.
Is that not being energy efficient?
Well if its not I'll just start and pull the trip everyday when I go to work.
And use the slaves in the evening to run the treadmill generator.
Energy efficiency improves quality of life (or increases profits for companies etc). When this happens, we consume more, which is good for GDP. When this happens, more energy is consumed.
Its called Jevons Paradox.
We have been becoming more efficient since the dawn of the industrial revolution, and yet global emissions have been going up, because we consume more and this is partly because of the benefits of improved efficiency.
.
Here we are wobs , a report that appears at least to contradict the whole Jevon's Paradox idea. Apparently the country is using less energy despite having a growing economy
If it's true then it's only good news , 10% less electricity consumption with practically no effort . It would certainly seem to validate the moves to ban 100 watt incandesants and latterly over powered vacuums , perhaps the next step is to phase out halogens. House insulation has improved so could be part of the picture .Of course the report doesn't make it really clear if this is consumption as a whole or more domestic and of course several factors could be coming into play. It could be an indication of a contracting industrial base for example , and seeing as we have been in virtual recession since 2008/9 the drop could be coming from reduced consumer spending and travelling. Any reduction in consumption is only good news but I'm keeping an open mind about this one , anyway the report,
www.bbc.co.uk/news/business-30518649
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History shows it to be true. You need to think more globally."At least no one has suggested energy efficiency as a way to cut our emission, or keep the lights on.
Such ideas lead to more energy consumption"..
How does being energy efficient lead to more consumption?
That's nonsense.
My electric bill averages about £60 quid per quarter.
That's because I have no immersion, keep lights turned off, tv mostly off, pc on for a few hours per day.
Is that not being energy efficient?
Well if its not I'll just start and pull the trip everyday when I go to work.
And use the slaves in the evening to run the treadmill generator.
Energy efficiency improves quality of life (or increases profits for companies etc). When this happens, we consume more, which is good for GDP. When this happens, more energy is consumed.
Its called Jevons Paradox.
We have been becoming more efficient since the dawn of the industrial revolution, and yet global emissions have been going up, because we consume more and this is partly because of the benefits of improved efficiency.
.
Here we are wobs , a report that appears at least to contradict the whole Jevon's Paradox idea. Apparently the country is using less energy despite having a growing economy
Any reduction in consumption is only good news but I'm keeping an open mind about this one , anyway the report,
www.bbc.co.uk/news/business-30518649[/QUOTE]
Thanks for that. The Jevons Paradox concept is often criticised by citing efficiency improvements in a region of country over a small number of years. They look at a too narrow a scope for the concept to apply. However, we live in a global economy. While is is true that the average household consumes less electricity (last time I looked it was the same as 1970), the figure does fluctuate. But that has little relevance to the issue at hand.
Remember I said (5th Dec, 4.26pm) that even if we consume less energy directly, the money we save would go on other things that will stimulate the economy. We buy more stuff from China etc, who burn more coal as a result (extreme example), or we save the money, and the bank use the money to loan to someone to help grow the economy further, increasing energy consumption.
That super efficient boiler we bought this year cost lots, and the company who sold and the fitter who installed it benefitted financially, and help grow the economy further.
We may see a temporary dip due to specific improvements (eg. insulation), but that helps growth globally, even if it takes time to trickle through the system.
I'm not saying its all a waste of time, or we shouldn't improve, but we shouldn't just assume that we are doing it for altruistic reasons.
Jevons Paradox reinforces the idea that energy efficiency (EE) should make financial sense. EE improves quality of life, but it can only really help slow AGW if it is controlled by some fiscal mechanism such as carbon tax, as GDP follows energy consumption rather closely.
Of course economic growth is not just driven by EE, but it is a significent factor.
Being pedantic..... its just Kelvin not degree Kelvin.
The degree prefix is only used with the Celsius & Fahrenheit scales.
late to the game as was on holiday when this was being discussed.
heat pumps work by the transfer of heat we can all agree on this
however with a cop of 4-1 the 'heat' is as follows
if we ignore the fan motors (approx 70w ea) and losses through the pipework, compressor body, from friction etc and assume the compressor pulls 1kw of electricity
1kw is spent by the machine running.
1kw in =
3kw of heat transfer from outside to inside (HT)
1kw of Heat of compression by the compressor (HOC)
= 4kw of heat to the inside (HOC+ HT)
and 3kw of 'cooling' to the outside (HT)
HOC think of this like a bicycle pump which when you hold the base by the outlet -as you pump the tyre- it starts to get warm. This is HOC and this heat is also added to the total to make the COP
As outdoor air temperature falls the available free low grade heat falls (or current HP's ability to extract it) therefore HT falls so the COP falls too. HOC remains constant
There is a cut off point whereby the HP will actually reach a near equilibrium of 1-1. Many years back it was around 10c and all HP's had electric heaters installed
these days improvements have it around -15c
However a further complication is that at around 5c HP's will start to require regular defrosts of around 1 x 20mins every 4 hrs.
Defrosts work by reversing to cooling mode and extracting heat from inside to melt the ice on the outdoor unit. In which case there is a heat loss from the inside so the HP has to reverse again and make up that cooling of the inside then start heating the room again.
Most commercial air conditioning cooling is based on 125 w/m2.
In contrast heating is based nearer 80 w/m2
so with the added HOC the heat delivered is approx 150 w/m2 IE They are so oversized in heat mode which is why commercial air HP's seem great even when the outdoors is very cold. .
Domestic wet HP's
Domestic wet Radiator HP's are sized for the heat load only -This is why they insist you fully insulate your home when you install them becuase they cannot supply 30kw on the std mains supply to a normal house
Plus they are Kw rated at 12c not zero (as the cost would be considerably higher ) so they won't get the job. - They also often rate the rad water at 40+ which kills efficiency but reduces kit size
(Japanese water HP's with Inverters are really just air based units adapted for wet HP systems and inverters are only really helpful to reduce start current the COP's may look good on paper but it has long been considered the Japanese have been not quite totally honest about their COP figures....apparently )
Most domestic water HP salesmen are not very trustworthy. IMHO
Fundamentally air to water HP's work best when you need them least (spring) and worst when you do (winter).
Borehole geothermal gives the best year round COP
They need to get the COP up to around 7-1 before they really come viable alternative to gas. (I have spoken to a UK HP geothermal manufacturer who suggests this may be some time.. )
In big water chillers these sorts of COP's are being seen but the technology ( tubocor compressors if you fancy googling) remains very expensive and may take a few more years to trickle down to domestic or even small commercial level.
I have owned an ac company for 25 years or so and my house is heated by gas and will remain so until the government bans them...
heat pumps work by the transfer of heat we can all agree on this
however with a cop of 4-1 the 'heat' is as follows
if we ignore the fan motors (approx 70w ea) and losses through the pipework, compressor body, from friction etc and assume the compressor pulls 1kw of electricity
1kw is spent by the machine running.
1kw in =
3kw of heat transfer from outside to inside (HT)
1kw of Heat of compression by the compressor (HOC)
= 4kw of heat to the inside (HOC+ HT)
and 3kw of 'cooling' to the outside (HT)
HOC think of this like a bicycle pump which when you hold the base by the outlet -as you pump the tyre- it starts to get warm. This is HOC and this heat is also added to the total to make the COP
As outdoor air temperature falls the available free low grade heat falls (or current HP's ability to extract it) therefore HT falls so the COP falls too. HOC remains constant
There is a cut off point whereby the HP will actually reach a near equilibrium of 1-1. Many years back it was around 10c and all HP's had electric heaters installed
these days improvements have it around -15c
However a further complication is that at around 5c HP's will start to require regular defrosts of around 1 x 20mins every 4 hrs.
Defrosts work by reversing to cooling mode and extracting heat from inside to melt the ice on the outdoor unit. In which case there is a heat loss from the inside so the HP has to reverse again and make up that cooling of the inside then start heating the room again.
Most commercial air conditioning cooling is based on 125 w/m2.
In contrast heating is based nearer 80 w/m2
so with the added HOC the heat delivered is approx 150 w/m2 IE They are so oversized in heat mode which is why commercial air HP's seem great even when the outdoors is very cold. .
Domestic wet HP's
Domestic wet Radiator HP's are sized for the heat load only -This is why they insist you fully insulate your home when you install them becuase they cannot supply 30kw on the std mains supply to a normal house
Plus they are Kw rated at 12c not zero (as the cost would be considerably higher ) so they won't get the job. - They also often rate the rad water at 40+ which kills efficiency but reduces kit size
(Japanese water HP's with Inverters are really just air based units adapted for wet HP systems and inverters are only really helpful to reduce start current the COP's may look good on paper but it has long been considered the Japanese have been not quite totally honest about their COP figures....apparently )
Most domestic water HP salesmen are not very trustworthy. IMHO
Fundamentally air to water HP's work best when you need them least (spring) and worst when you do (winter).
Borehole geothermal gives the best year round COP
They need to get the COP up to around 7-1 before they really come viable alternative to gas. (I have spoken to a UK HP geothermal manufacturer who suggests this may be some time.. )
In big water chillers these sorts of COP's are being seen but the technology ( tubocor compressors if you fancy googling) remains very expensive and may take a few more years to trickle down to domestic or even small commercial level.
I have owned an ac company for 25 years or so and my house is heated by gas and will remain so until the government bans them...
