Forum menu
Ah - I thought you meant passive heating standards.
there is certainly a huge amount that can be done in commercial buildings. Local CHP is one good one I believe and better control of lighting and heating would help .
😆
Control is the most often neglected TJ, you are absolutely correct.
CHP can be good but must be sized according to heating load (great for swimming pools). Modern buildings are so efficient thermally and densely populated that many still have the chillers running even now, in November!
A typical household gets through about £250's worth of gas just for hot water. The bill will be higher if you use electricity.
The Energy Saving Trust say you're wrong.
As an aside, my last two quarters were a total of £85, and that includes cooking, but the heating was turned off. Family of three.
Show me any system that's worth it when looked at from a purely financial payback point of view.
Insulating my walls and loft. Replacing light bulbs with CFLs.
If someone asks me for advice on energy efficiency, I would never advise them to spend several thousand poinds on a system that will save them less than £100/ year. Maybe that's just me.
What are the un-subsidised costs and payback periods of those, in financial terms?
Let's not forget, it's not just about the money.
wreacker - if they are thermally efficient they wouldn't need chillers!
What are the un-subsidised costs and payback periods of those, in financial terms?
Let's not forget, it's not just about the money.
Irrelevant diversion. You asked me for examples that payback and I gave them to you.
Next!
wreacker - if they are thermally efficient they wouldn't need chillers!
What's your proposed solution?
Irrelevant diversion. You asked me for examples that payback and I gave them to you.
You actually haven't, have you? Anything that is subsidised is going to have an unfair advantage.
Maybe we could have an extra bit tagged on to the end of the weather forecast? "well everyone, its going to be windy tonight, so don't forget to turn your washing machines on when you go to bed"
Why not?
We already set our dishwasher and washing machines to come on during the middle of the night, not because it saves us money, but because we know that all of that important "base load" generation isn't really doing much at that time, so that it is probably better for us all in the long run to try and help run it efficiently.
What annoys me about all the short sighted people who trot out the usual line about wind/renewables being intermittent and that we therefore need all this back up capacity to replace them when it is not windy, is that they conveniently forget that demand isn't constant either.
The smart way to use electricity is to use more of it for non time critical things at times when there is more of it available. No?
Control of passive / solar gain, decent ventilation systems.
Not necessarily TJ. The sensible and latent heat gains from occupation, lighting and equipment are huge and since the fabric U-values are so [s]high[/s] low and there is no natural ventilation due to air tightness, the heat must be mechanically removed. In most cases, the mech vent isn't man enough to do this as it's sized to supply the fresh air and not as the primary heating/cooling source.
We already set our dishwasher and washing machines to come on during the middle of the night, not because it saves us money, but because we know that all of that important "base load" generation isn't really doing much at that time, so that it is probably better for us all in the long run to try and help run it efficiently.
This is dynamic demand as I mentioned earlier. Companies are currently being paid (per kWh switched) to turn their machinery on at low loads so that the power companies don't have to turn the power stations down as it's expensive.
Control of passive / solar gain, decent ventilation systems.
Details, how?
Do you mean high or low for the U-values, wrecker?
So provide some natural ventilation in a size that will do the job? Vents that open when it hot and close to return to the air tightness when cold.
I am sorry - building a "passive" building that requires air con is summer is missing the point and target by a mile
Well spotted DS. Low!
mcboo said,
If the events in Fukushima did anything they proved that even if you have a reactor that is decades out of date and of questionable safety you can site it right on a major geological faultline and hit it with a massive tsunami.....and it still doesnt do anything like the damage that Greenpeace would lead you to believe.
I just find this attitude unbelievable.
80,000 people have been evacuated from their homes and are unlikely ever to be allowed to return.
What would be your threshold for seeing a problem?
You actually haven't, have you? Anything that is subsidised is going to have an unfair advantage.
You asked for examples of measures that pay back in pure financial terms. And I gave them to you. If you want a different answer, ask a different question.
This is dynamic demand as I mentioned earlier. Companies are currently being paid (per kWh switched) to turn their machinery on at low loads so that the power companies don't have to turn the power stations down as it's expensive.
And we can all do it domestically right now at zero cost.
What's your excuse?
So provide some natural ventilation in a size that will do the job? Vents that open when it hot and close to return to the air tightness when cold.I am sorry - building a "passive" building that requires air con is summer is missing the point and target by a mile
Get designing TJ, I've not seen one that the occupier is happy with yet!
So provide some natural ventilation in a size that will do the job? Vents that open when it hot and close to return to the air tightness when cold.
That's where everyone's been going wrong. The solution really is that simple, I wonder why no-one has already thought of that. You should be ashamed of yourself wrecker.
Got the design in my head right now 🙂 YOu able to get it out?
Again of course it needs energy to be much more expensive so people have more of an incentive to save it - possibly a sliding tarrif so the more yo use teh more expensive it gets
First the LED bulbs:
I've got a bathroom mirror that came with 3 x 40w bulbs. I replace with 3 x 9w "economy" which were dimmer so put one 40w back. I then replaced the 40w with a 3w LED and found it to be brighter than both the 40w and 9w economy. Logically there are now 3 x 3w LEDs.
You asked for examples of measures that pay back in pure financial terms. And I gave them to you. If you want a different answer, ask a different question.
I just don't see that financial payback is relevant (unless you don't have the money) - the main thing is that it makes sense in carbon terms.
Most of what we spend our money on isn't financially sensible.
At the time you spend your money on a Rolex you are trading a lot of money for some sort of satisfaction at a rate that you set and that is personal to you. You could just buy a cheap Casio to get the same functionality. Financially it makes no sense. We're currently having some walls internally insulated as part of a refurbishment project and I haven't even bothered to work out the extra financial cost - it probably won't pay back in pure financial terms, but I am sure it will save carbon, and that will make me feel good, which is why I don't mind spending money on it.
It's great that you are in that position, but for the majority I suspect the financial aspect of installing solar heating, insulating a home etc is a fairly important factor.which is why I don't mind spending money on it.
My gas consumption for the first year I occupied this house was 602m3, about 800e at current prices including the standing charge. Last year I cut the gas off. There has been an increase in the elecricity bill due to topping up the hot water in winter, say 50e and the wood I burn would be worth about 120e if I had to pay for it. Saving: 630e/year.
So 630e a year saved thanks to all the money invested (pesimistic guesstimates):
Roof insulation 750e
Solar hot water heater (home made) 1100e
Wall insulation 900e so far
secondary double/triple glazing and insulating doors/shutters 400e
Under floor insulation (in progress) 700e
More economical appliances 450e
Wood burner 1000e
Tools (I owned them but the ones you'd need) 750e
Total 6050e. Time to pay for all the investments 6050/630 = Under 10 years. If you DIY it is economically viable.
I haven't included the photovoltaïque which will pay for itself in 6.5 years.
I like making things so I've enjoyed doing it. It's also nice walking across a warm floor barefoot and not having clothes go mouldy in the wardrobe.
It's great that you are in that position, but for the majority I suspect the financial aspect of installing solar heating, insulating a home etc is a fairly important factor.
Come off it. This forum is filled with people agonising over which new £3000 bike to buy.
I've had a good look through the Energy saving Trust site, Ransos. The only reference to £55 I can find is the figure given for what you can save by properly insulating your hot water tank and lagging the hot pipes. Now if you can save £55 I suggest the total typical consumption figure must be somewhat higher. Could you link your source please.
What does that have to do with the demographics of the UK?Come off it. This forum is filled with people agonising over which new £3000 bike to buy.
I just don't see that financial payback is relevant (unless you don't have the money) - the main thing is that it makes sense in carbon terms.
Solar thermal saves only a small amount of gas. Gas produces 1/3 of the carbon electricity produces per KWh. So I don't think it makes much sense in carbon terms, either.
I've had a good look through the Energy saving Trust site, Ransos. The only reference to £55 I can find is the figure given for what you can save by properly insulating your hot water tank and lagging the hot pipes. Now if you can save £55 I suggest the total typical consumption figure must be somewhat higher. Could you link your source please.
http://www.energysavingtrust.org.uk/Generate-your-own-energy/Solar-water-heating
"Based on the results of our recent field trial, typical savings from a well-installed and properly used system are £55 per year when replacing gas heating "
Insulating your loft/roof is a no-brainer really.
In the grander scheme, we need to be reducing electrical energy use.
Not only is it more expensive, it's a good bit more carbon intensive. Look at your lamps (there's a variety of CFLs on the market with different start up times and CCFs so do some research and buy the correct type for you) look at appliances, plug-top timers are cheap and easy to set up, buy AA+ rated kit.
http://www.energysavingtrust.org.uk/Generate-your-own-energy/Solar-water-heating
Your link Ransos, sorry it's in full, the buttons have vanished to link it. I know how much hot water three very economical people use and a saving of only £55 is nonsense. It assumes the solar water heater only contributes 20% to water heating which anyone who has used a solar hot water heater will tell you is wrong. They (Energy Saving Trust)reckon you can save as much just by lagging your tank.
Edit: I found it eventually. 🙂
We're currently having some walls internally insulated as part of a refurbishment project and I haven't even bothered to work out the extra financial cost - it probably won't pay back in pure financial terms
If you're doing it as part of a bigger project it might well payback, because the trades are all onsite anyway. The other benefits are a more pleasant home environment and reduced mould/ condensation.
I haven't included the photovoltaïque which will pay for itself in 6.5 years.
Thank god for that, because if you had I would be asking:
Where were the working bits of the PV made? (I'd guess either somewhere like China or Japan). How do you make silicon (or CdTe if they are of that form). Its not exactly a low energy process. Panels roughly "break even" on energy (in terms of kWh required to produce the panel) in something between 2 and 8 yrs depending on the panel design and the latitude its mounted at. Paying for itself financially and in energy terms is not the same thing since there are better rates for PV. But here is the point people seem to miss: if the panel was made in China it was made using dirty coal power. So the global environmental impact of making the panel is much worse than using clean coal (or other western power) in Europe for the entire payback period. If the panel is Japanese in origin then it almost certainly relied heavily on nuclear power to make it - which most of the people who fit them seem uncomfortable with. In addition, for reasons nobody has ever explained PV panels are exempt from ROHS regs and so potentially a "disposal timebomb" full of lead, cadmium etc...
Whilst over a 20+ yr lifetime of a panel it will save energy they aren't 'saving' energy from the day they were installed due to the invested energy within them. Financial investments, recovered over several years may make sense. I'm not so sure that makes sense for carbon.
Quite frankly PV panels, certainly in the UK are just Eco-bling.
I know how much hot water three very economical people use and a saving of only £55 is nonsense.
This was the result of a field trial. You're confusing evidence with personal anecdote.
Here's my personal anecdote, which is the opposite of yours:
My last two quarters' gas bills were a total of £85, no heating was on during that period. From my annual non-heating total of £170, we subtract gas for cooking and the inefficiencies of the solar panel (let's assume it provides an average of 50% year round, and we use say 20% of the gas for cooking). Then we subtract the cost of the electricity for running the pumps.
£55 is absolutely spot on.
What does that have to do with the demographics of the UK?
Sod all.
But so what?
I just kind of took it for granted that I was addressing the users of this forum, not the nation as a whole.
these threads are like some kind of stw hormone cycle that comes around every couple of months. I don't have the energy (wahey!) to get involved in them any more.
Poly he is further south but I tend to agree with you - photovoltaics are not really a part of the solution in the UK at present efficiencies / manufacturing cost / lifetime environmental penalty
Taking 50l/person/day [url= http://webarchive.nationalarchives.gov.uk/+/http://www.berr.gov.uk/files/file16568.pdf ]from here[/url] thats 200l per day for a family of four, or 73 000l per year.
start temperature of water is 10°C. Final temperature 50°C, change 40°C
Q = 73000 x 4184 x 40 = 14966168000J
= 4157 kWh (assuming perfect lagging and no heat losses.
At 8p per kWh that's £332
The Energy Saving Trust either can't do maths or think that solar panels provide less than 20% of hot water needs.
You aren't going to get water at 50°C for more than a couple of months in the UK. Average winter temp is 4.4°C and our winters are loooong.
Gas isn't 8p/kWh, more like 4 or 5p/kWh.
Regardless of insulation, there will always be heat losses.
The Energy Saving Trust either can't do maths or think that solar panels provide less than 20% of hot water needs.
Your calculation is irrelevant. It's a theoretical example for a specific case. By contrast, EST did a proper field trial. When you've done one of those, come back with the results, and we can discuss it.
In any case, your savings calculation is way off. It's nearly double the total amount of non-heating gas I use in a year. Family of 3.
My Solar World panles were made in Germany as was the rest of the system. They've already paid for themselves in embedded energy terms.
Using your own figures Ransos. £170 for the year based on summer hot water and cooking use. I assume you have a couple of weeks holiday and the water takes more heating in the winter. Say £190 per year for hot water and cooking and you've forgotten to add in the water heater in the washing machine (and dish washer if you have one) so we can add another £20.
£210 - 20% for cooking = £168. 70% produced by solar = £117
Using your own figures Ransos. £170 for the year based on summer hot water and cooking use. I assume you have a couple of weeks holiday and the water takes more heating in the winter. Say £190 per year for hot water and cooking and you've forgotten to add in the water heater in the washing machine (and dish washer if you have one) so we can add another £20.£210 - 20% for cooking = £168. 70% produced by solar = £117
You really should stop making assumptions. No holiday this summer. Year-round efficiency of solar panel likely to be less than 50%. Dishwasher and washing machine are cold fill only, like most of the population.
£170 year-round less 20% cooking = £136. Less 50% efficiency (optimistic) for panel = £68. Less electricity for running the pumps, let's say £10 = £58.
£58 against the EST figure of £55. Time you learned to add up...
I've done a proper field trial too with a system designed by a bunch of solar fans and plumbers on a forum.
It uses two tanks:
the solar tank heated only by a heat exchanger fed from the solar panel. The system thermosyphons as the tank is above the panel, thus requiring no pumps or control gear and eliminating risk of back-syphoning. It's all double lagged. The solar tank feeds the house direct in Summer (six full months this year).
The second tank is a small (50l) conventional tank with an immersion heater. In Winter the water pre-heated by the solar tank enter the second tank and we switch on the immersion heater as needed. Most of the heating is still solar except for a month either side of the Winter solstice.
I know many commercial sytems use only one tank, are insufficiently insulated, run energy greedy pumps and simply don't deliver their promises. However, I feel an organisation such as the Energy saving Trust should base their findings on a system at least as good as a monkey with blow torch can cobble together in his shed.
Should EST base their study on a) a custom-designed highly unusual system or b) the type of system most people have or would buy?
Even if your system supplied 100% of my hot water, it would still only save £136. If a typical installation costs £4,800 (EST figure) that's a 35-year payback! So a more typical installation is perhaps a 70-year payback. Wouldn't that be longer than the operational lifespan of the equipment?
Carbon saving is also low.