solar panels

[Mary Fisher]

What exactly do you mean by solar cells?

Are you talking about solar water heatinig or pv panels?

Mary

[Bioboffin]

I wasn't really drawing a distinction. I guess that currently solar water heating is the more usual, because it is cheaper to install. On the other hand, you can end up with overheated water in the summer.

[David Hansen]

On Sun, 24 Sep 2006 11:05:29 GMT someone who may be "Bioboffin" wrote this:-

Only if the system is badly designed and/or installed.

[Andy Hall]

Notwithstanding that they are plug ugly and ruin the exterior appearance of a property almost as much as stone cladding.

[Dave Liquorice]

Modern kitchen, bathroom etc fall into the "decoration" category for me and are very much down to individuals tastes. Certainly estate agents rarely recomend spending any money on those things if you're intending to sell. The "blank slate" is more attractive that some new and flash that isn't in the buyers taste range.

Thermal Solar panels and a reasonable control system would be a good positive selling point IMHO.

[Mary Fisher]

There are huge distinctions!

No, it's because it's efficient in Britain, which PV can't match.

What makes you say that?

Mary

[meow2222]

For roof mounted panels, snow will prevent any output at all, as it blocks the light. For wall mounted panels, snow increases output since you've got sun and skylight bouncing off the snow onto the panel as well as direct light.

NT

[meow2222]

drain heat exchangers can pay back fairly well, though maybe not if you have to take the bath out to get one in. HRV is worth a look too.

It'll be interesting to hear you explain that.

Night time temperature has nothing to do with it, nor does the absence or presence of a desert. The relevant difference between desert conditions and our winters is direct vs diffuse sunlight. Flat panels work with diffused light. To achieve good temp gains the design may need to be slightly different, but not by much. The same process is going on, and in either case the same big advantage of space heating is there, the high panel efficiency.

Why do you think panels can not work in winter? Its fairly basic science. Certainly there will be more output at the ends of the heating season than the middle, this is true for all solar thermal systems.

Surely what you get depends on what solar system you design and build? How does house design affect the panel output? It doesnt, as long as the panels point the right direction.

Yes... and thats precisely why space heating yields more return. Theres only so much DHW a house uses. Much more space heating energy is used, thus much bigger potential paybacks are available there. Plus setup cost is much lower.

I hope it will change greatly one day, but it isnt likely to be any time soon. There is nothing significant in the research pipeline. Energy prices wont change the equation by a lot, as the cost of system purchase depends on energy cost.

NT

[Bioboffin]

Personal experience.

[Mary Fisher]

It hasn't been ours even in this year's very high temperatures. I think you've had the wrong type.

[David Hansen]

On 24 Sep 2006 06:46:37 -0700 someone who may be [e-mail] wrote this:-

Please indicate where I said they do not work in winter.

The question is how well their output matches heating demand.

It is a matter of engineering rather than science.

I'm glad you have now adopted this more realistic line, rather than your earlier one that such systems would heat all of a building all year round in the UK.

Assuming it does.

Indeed, which is why matching is important.

Correct.

That does not necessarily follow.

Perhaps, if one is converting a wooden barn in a desert. However, a UK building is rather different.

[David Hansen]

On Sun, 24 Sep 2006 14:20:15 GMT someone who may be "Bioboffin" wrote this:-

Overheated water in the summer means the system was badly designed and/or installed. Which was it in the system(s) you are thinking of?

[David Hansen]

On Sun, 24 Sep 2006 12:23:28 +0100 someone who may be Andy Hall wrote this:-

In your opinion. Not everybody shares it.

[David Hansen]

On 24 Sep 2006 06:18:51 -0700 someone who may be [e-mail] wrote this:-

Thick snow will. Thin snow will probably not, for various reasons.

[Andy Hall]

You think they're things of beauty?

The most likely outcome is that the house would become harder to sell to people who think that they are ugly or will complicate the heating system, which are probably the majority. Perhaps they might appeal to geeks.

At best, saleability would have been reduced for little or no ROI.

Pointless in other words.

[Bioboffin]

It wasn't actually me - it was a friend. It was, I think, a home installed unit - and worked fine, but did produce very hot water this summer. Her comment was that she was finding it difficult to use all the hot water produced, and that the tap water was becoming unacceptably hot. No doubt this is not a serious issue to fix.

I am certainly attracted to the technology, and I plan to implement it in the house we buy after this one. I just have a feeling that doing a lot now would (a) cost a lot of money which I can't afford and (b) not help the sale prospects for the house in the city where we live. (Peterborough).

I might well be wrong!

[Mary Fisher]

Sadly, all energy (and water saving) systems are much easier and cheaper to build in at the design stage. Retro-fitting is much more expensive. That doesn't mean it's undesirable but space heating from solar isn't for us, sadly.

Mary

[Mary Fisher]

Ah - so it wasn't personal experience.

You don't HAVE to use it all!

That is a problem with most domestic water heating systems unless there's some kind of thermostatic control. It has to be diluted from the cold supply. It's not a fault. I made use of the very hot water to launder items such as washable pillows, duvets and other bedding which is normally left - in my inefficient way - until when we need it. I have said here and the makers say in their literature that it makes sense to organise routines to make best use of the free hot water.

I think you are but it's your choice.

>

[Mary Fisher]

I didn't see this post - WHAT are plug ugly? Surely not solar water heating panels? Ours looks like a roof light from the street.

Mary

[Mary Fisher]

That's true. But, David, some people are so dead set against it and think they know more than anyone else that they're not going to listen to those of us with direct experience.

Mary