Subject line has it all, really...

Everyone I know in the low energy game (e.g. the directors of www.aecb.net) think it's a load of b*llocks. As far as they're concerned do anything and everything you can to reduce demand. They're equally scathing about grey water/rain water recycling, reduce demand first, then worry about anything else.

I've just had a hunt but couldn't find any relevant threads on their forum:

http://www.aecb.net/forum/index.php

Sign up, as a member you'll get a free sub to Green Building magazine which is really interesting.

You may find this useful:

http://www.electricityinfo.org/

People here seem to think Good Energy are OK:

http://forum.downsizer.net/viewtopic.php?p=774790#774790

There'll probably be quite a few similar threads on Downsizer.

In what way? The whole proposition of reducing my carbon emissions by buying "green electricity"? The idea that these suppliers really are using renewable sources? Or something else?

My thinking was that, if I pay slightly over the odds for carbon-neutral electricity, this would have two effects: 1. I'd feel less guilty, and: 2. They'd have more money to invest in more carbon-neutral generation.



At some point, that requires changing my lifestyle. Yes, I know that I should really do something about that too, but that takes time. This'd be a quick win, if it was feasible.

To clarify:

• We recycle as much as we can -- Ealing Council are probably one of the best at allowing plastics in the recycling box. I assume that they do something with it later.
• We've changed our boiler for a newer, combi boiler.
• We've had our loft insulation checked; it's not quite up to spec, but it's not far off. We're looking at a loft conversion, so we'll bring it up to grade at that point.
• We can't have cavity wall insulation: we have no cavities.

On the negative side, we do leave far too much stuff in standby...

All of the above, there are pages of discussion about this on the AECB site. Here's a linky to one of the discussions and a related article:

Green Electricity Illusion

Here are some other useful ones:

A++ Appliances

Water Consumption

Low flush loos

Energy efficient refurb

As here most of the AECB bods are really helpful, and know their stuff.

I'd also say that even a simple change in your food shopping habits (don't buy ready meals, stuff in plastic packs, airfreighted fruit & veg) and gardening regime (don't use chemicals, don't water your lawn, grow some food) will have a much greater impact than buying green leccy. Eating less meat is also usefuil

Someone's just pointed me at this:

Unsecured loans for commercial energy efficiency improvements

Might be useful for someone

Done all of that, as far as realistically possible.



Don't really have enough space or time to do that, unfortunately...

Well, don't feel so guilty then! Are you driving a 5.0 V8? (I used to)

You might find this useful:

http://ecoterrace.co.uk/blog/

There's plenty you can do to enhance the performance of your house.

You can create some. Nail or glue some furring strips onto your bare walls, install insulation between them, probably some sort of foil-backed foam board, then install drywall, nailing into the furring strips.

2002 Ford Focus 1.6. It's only got 40K miles on the clock.

I've done it all, barring the cavity wall insulation as my walls are 2ft. stone. After the boiler was installed, I read that it will averagely take 12 years to recoup the investment - but I'm not convinced that I've saved myself anything on energy bills.

I think that we have to radically re-think the way we run our homes to make real savings, most are run on lines Queen Victoria would have found familiar!

1. Water is a poor conductor, so we heat it up enough to heat radiators twice a day. The water we want to use for washing we then have to dilute down to a manageable temperature, added to which, in most systems, we waste as much as we use waiting for the hot to draw through after the cold. Most houses have one thermostat to decide how warm our whole house should be.

Why don't we just have an instant water heater at each sink, like the shower ones, and only a cold water system throughout the house? In our house, we all shower daily, so we don't need a bath's worth of water heated twice a day. For heating, we have the technology for a PC not just to monitor the temperature of each room, but also the habits of the household, thus building up a pattern to switch electric/gas heaters on, strictly when needed.

2. Most electrical appliances in our houses work, or could be adapted to work, on 5,6,9,12 volts. Surely it would be easier to wind or sun generate and store say a 12volt system*, rather than all the rigmarole of feeding power back to the grid, which I understand power companies are lukewarm about anyway.

*Yes, I know from another forum that the wiring would be as thick as water pipes!

Well, it doesn't sound like you're raping the planet to me. Make sure you insulate as well as you can when the extension gets done, support orgs like the AECB, buy more efficient appliances, poke people gently in a better direction. IMO all of these are more useful than buying green electricity.

Do you have a separate heater for each room? You have to figure out how to heat each room independently.

This is doable, depending on how your house is heated, but there's more to it than just monitoring. There's retrofitting involved. It might be as simple as vents that can be opened and closed by a computer, or it might be as complicated as installing additional heating units.


There are a couple of points here. There are a huge number of devices, especially electronics, that waste energy converting AC to DC. Even devices that don't have an external transformer have power supplies that do that conversion. That said, unless you can get all of your devices to expect the same input voltage, you're still going to lose energy to conversion.


Photovoltaic cells generate DC current, so that makes sense for them. Turbines generate AC, though. That said, I don't know the voltage, but I doubt it's 110, much less 220.

But you can certainly store your excess electricity in an array of lead-acid batteries. "Many" people do so; there are existing solutions. But the power grid is an excellent battery, it already exists, so you don't have to deal with massive amounts of batteries in your basement (though lead-acid batteries are very recyclable), and regardless of how you store your energy, you're going to be losing some of it to conversion.

I'm sure that power companies are lukewarm about it, though. Effectively, they're buying power from you at consumer rates. One would assume that when they produce it themselves that it costs them less than that. On the other hand, if you store it yourself, you're still reducing your consumption by that same amount.

That's my thinking, if you can use them precisely when needed.
Individual Heaters versus Ducts/radiators, I would think to be easier to install, especially if they are electric.

Certainly, I was more thinking of the building industry going forward in a greener way.

Glad you mentioned that one: Surely the grid doesn't store*, but can switch supply from multiple sources to meet demand? One of the proponents of wind power, which our politicians see as the way forward, when asked what happened when there was no wind, said that then the traditional power stations take over: Ignoring the fact that our coal/nuclear installations are largely becoming obsolete, with no firm replacement policy in use.

Good argument and one I hadn't thought of.

*There's a hollow mountain in Wales that pumps water up and, when the peak demand arises, releases it back down to generate electricity, I don't know of any other storage method, but if we're going to rely on wind power, we desperately need to think of one!

I'm not an HVAC engineer, but I imagine that efficiencies would go down significantly with multiple smaller unit, as opposed to a single larger unit. In addition, you'd be talking about electric heaters (as you probably don't want point-of-use gas-fired heaters pumping CO into your living room), which tend to be less efficient than fuel-fired heaters, mostly due to the fact that, ultimately, you're using heat to generate electricity, which is shipped across the country, and then used to generate heat, with losses all along the way. I'm sure that the power plants are more efficient at gathering heat than a residential heating unit, but still. Of course, if your infrastructure moves to (far?) less fossil-fuel, there may be other considerations.


My understanding is that the transmission lines are huge enough that their capacitance is more than able to deal with the small amounts of energy we're talking about being pushed back from consumers. In addition, power companies already deal with varying consumption rates; there's no reason that they can't just include that information in their procedures.

My arguments are based on water circulating radiators, which are effectively multiple small units supplied by water (As I've said a very poor conductor) versus electricity through wires, very good conductors. I'm not a HVAC engineer either, so I was floating a discussion point more than anything else.

The UK has 3 large pumped storage stations, two in Wales and one in Scotland.

There are other large scale storage options, including flow batteries, compressed air, fly wheels, hydrogen generation etc

Most of them still need some work though.

http://en.wikipedia.org/wiki/Grid_energy_storage

That is apparently the theory on which the heating system in my house was put together (long before I bought it). There's a single boiler, a single primary water circuit, and a single timeswitch, but instead of a central thermostat switching the radiator pump on and off, the pump runs all the time the heating is on, and each radiator has its own thermostatic valve.

It's an appealing theory, but the problem is that all the pipes to and from the radiators remain hot even in rooms where the radiator is off; in other words the problem isn't with the low conductivity of the water, it's with the high conductivity of the (no) insulation on the copper pipes. If the electricity flowing round my house were equally poorly-insulated, it'd be a deathtrap!

Peter

If they're on the radiator: An HVAC engineer once told me that their a waste of time, as they are monitoring the heat at the radiator, not in the room. Most houses he visited just kept them on full, which is effectively leaving them out of the circuit. The only way to make them work is to have electric valves, controlled by radiators on the opposite wall.
In my suggested system, they'd probably be on the wireless network, reporting back to the PC.

They make radiator thermostats that have remote temperature sensors that are driven by thermal expanding wax (like your car's thermostat) and connected to the radiator valve by a capillary tube. More efficient than an electricity-powered wireless remote sensor.

Oh, your argument was that water's poor heat conduction was a failing? It's not.

Imagine if the distributed fluid was an excellent heat conductor. The heat that entered the fluid would leave it immediately, and by the time that it reached the radiator, it would have no heat left. That would be phenomenally inefficient.

The reason that radiators are shaped the way they are is so that the surface area of the contained water is as large as possible, so as to speed up the heat transference. On the other hand, cylindrical tubing gives the water as low a surface area as possible.

Yeah, copper was probably a bad choice for this, seeing as how it is an excellent heat conductor. Based solely on the heat properties, they probably should have used the same cast iron they use for the radiators, but that's brittle, heavy, and likely to corrode. Iron is actually a relatively poor heat conductor, which means it retains a lot of heat and releases it slowly, which makes it ideal for things like radiators and skillets. There's no reason that the copper pipes feeding your radiators can't be insulated, though.

I wasn't aware of those, but it backs the point that Honeywell agree with my bloke, that mounting them on the radiator isn't effective.

I haven't noticed that being a problem, to be honest. Unless the radiator is situated so poorly that its convective current doesn't reach the whole room -- in which case, it scarcely matters how hot it gets -- the air temperature at the bottom of the radiator will be the heat in the room. Or at least, will be monotonic with the heat in the room, which is all you actually need it to be (that Honeywell thing is a neat idea if you don't like bending down to fiddle with the thermostat, but notice that it's calibrated 1-5, not in celsius or fahrenheit).

Peter

I don't think the Honeywell one is unique, and they probably just don't want to spend the time to calibrate the wax. You could easily do it yourself once installed, though. Actually, they ought to include a sticker with temperatures printed on it. Or have a rotating scale. I'd be surprised if the expansion isn't consistent between batches.

I take your point, maybe if it wasn't for the potential for a leak, we would have an oil filled central heating system! However, without research, I still think that a carefully controlled system of electric radiators meeting a precise need might well be more efficient.
It may just be in the UK, but I have a feeling that, despite making the engineer's life a misery, my boiler is doing very little less water heating in the summer, than the winter, in my mind I think that these systems are thinking that we are all taken luxuriant baths, twice a day - this era ended when my daughter moved out, it's now her beau's problem!

Yeah, there's the same issue with "hot water heaters" in the US. It's still a big tank that it keeps hot all the time, and it's by far the most commonplace hot water system. On-demand heaters are becoming available, to the point where it's an obvious consideration, but most people (myself included) are too lazy to replace a working unit.

Also, there are electronically controlled valves specifically designed for radiator systems, which would help prevent heat wastage from pipes to unused radiators.