East/West facing solar water heating

umballah

Question for renewable energy guys out there.

I'm currently having a house built and have decided late to jump on the renewable energy band wagon with solar panels or evac tubes to heat domestic water.

Only problem is my house faces east-west and I have no roof to put it on that faces south. I've been told that I'll have to add a bit more - ~20% surface area for panels - to compensate for this. Does this sound reasonable?

The roof is 55 degrees inclined. I've heard 30 deg is the optimum? Any comments on that. Do I need to account for that somehow?

We are a family of 5 at the moment and won't be getting bigger. I've read that 5-ish m2 with a 300 litre tank should be sufficient to supply hot water to the household. Does this sound reasonable ignoring limitations above?

I haven't talked to my plumber in full about this but I like to be someway informed before talking to him (as a check on his competency really - he seems good and he mentioned that he had trained in this but it is new so....)

Thanks for your time.

CJhaughey

umballah wrote: »

Only problem is my house faces east-west and I have no roof to put it on that faces south. I've been told that I'll have to add a bit more - ~20% surface area for panels - to compensate for this. Does this sound reasonable?

East/west won't work you have to be at the least SE to SW you can maybe make a frame to hold the panels facing S/SW/SE at 40º otherwise it won't matter what size of panels you install.
I think for 5 people 6m2 and 300l could work but you would be better off going slightly larger maybe 400l tank
I have 6m2 flat panels facing SW with a 400L tank and it works well from now on.

BoozyBabe

I will have the same problem as this, & tbh I don't want to turn my house just for this reason as it'll mess up everything else.

If the solar panels are on the garage roof (if I can build IT south-facing) & the pipes are well insulated would there be much loss in heat or built up energy? (or whatever you want to call it!!!

AckwelFoley

CJhaughey wrote: »

East/west won't work you have to be at the least SE to SW you can maybe make a frame to hold the panels facing S/SW/SE at 40º otherwise it won't matter what size of panels you install.
I think for 5 people 6m2 and 300l could work but you would be better off going slightly larger maybe 400l tank
I have 6m2 flat panels facing SW with a 400L tank and it works well from now on.

East west is possible. Not ideal, but possible.

AckwelFoley

BoozyBabe wrote: »

If the solar panels are on the garage roof (if I can build IT south-facing) & the pipes are well insulated would there be much loss in heat or built up energy? (or whatever you want to call it!!!

Within 30m of the house, and on condition you use 3/4" pre insulated stainless steel pipe (assuming 36 tubes) you wuill have very very little - no loss.

NB. Its Imperative that the pipes are run through ducting that are completely water tight, if water gets in to the ducting and builds up in the ducting in a pool, there will be HUGE heat loss!

Baaaah! If you are building a house.. put in underfloor and use a Heat pump.. no need for solar then.

CJhaughey

snyper wrote: »

Baaaah! If you are building a house.. put in underfloor and use a Heat pump.. no need for solar then.

That is one way to do it, but there is also the problem that this this poster has with large electricity bills.
Solar DHW is a good practical solution, costs are relatively cheap compared with the installation of heatpumps and associated running costs.
I don't think that just writing off solar thermal and fitting a heatpump is a good solution.
Just make sure that what ever system you buy has a reputable company behind it, that is critical in todays environment where there are hundreds of so-called energy experts running around, funnily enough many of these "experts" seem to have appeared around the same time as the SEI grants...:rolleyes:

AckwelFoley

Well i certainly agree that particularly with heat pumps you need a reputable supplier.

The one thing that really pisses me off is theis issue of "running costs"

I feel like im going around in circles trying to explain that the costs are only a fraction of what ppl seem to be paying. But i hear too often ppl say "well insulated" Yet when in practice this is not the case. Id like to see a detailed breakdown of what insulation was used.

Heatpumps will use alot of electricity if there is a heat through poorly installed insulation, or a simple lack there of. Its not as simple as, "oh, id like a heat pump.. ill go buy myself one of them.." There is alot of planning involved on specifications and i would advise nobody consider getting a heat pump until they have done a Building energy assesment from the plans prior to building of the house.

Its pissing me off the bad rep that heat pumps are getting because of the poor workman ship of insulation installation or incorrect insulation being used,

Heat pumps are not new! They work sucessfully in colder climates than here.. but PADDY seems to be able to do things arseways as usual. :mad:

umballah

snyper wrote: »

Well i certainly agree that particularly with heat pumps you need a reputable supplier.

The one thing that really pisses me off is theis issue of "running costs"

I feel like im going around in circles trying to explain that the costs are only a fraction of what ppl seem to be paying. But i hear too often ppl say "well insulated" Yet when in practice this is not the case. Id like to see a detailed breakdown of what insulation was used.

Snyper,

I agree with what you're saying to some extent and I always wanted to put in geothermal but for me I saw some risks i.e. extra costs, reports of pumps failing regularly (which may sound like conspiracy theory but this is someone I know 3/4 & 6 years pump failed). I know this is not down to the technology itself but rather poor installation/insulation/understanding etc etc. but from a consumer point-of-view I don't need the hassle of worrying if I'm paying extra money (at least 10K) for a system that might end up costing more or breaking or whatever.

And I don't want to have to pay extra money to get energy assessments done either.

Maybe a safe boring point-of-view but I'd prefer to insulate well, try to supply hot water with solar panels (which aren't great economically either but I think just about make it in my book) and use solid fuel burners/oil for the winter.

AckwelFoley

umballah wrote: »

Snyper,

Maybe a safe boring point-of-view but I'd prefer to insulate well, try to supply hot water with solar panels (which aren't great economically either but I think just about make it in my book) and use solid fuel burners/oil for the winter.

Well, i cant convince everybody to do it, but i think if you do use adequet insulation and used a condenser boiler along with underflooring you will reduce you costs of running your home.

The issue with poor installation is why i personally promote the purchase of the Daikin air to water units. They are better than the conventional air to water systems because they can more efficently produce heat than other air to water pumps and are now as effective as geothermal.. and are far less costly, the only slight drawback is the fitting. There is refridgeration tec involved and a refridgeration pipe to be connect between the outdoor and indoor unit and you need a qualified refridgeration tec for that.

But all in all, i do acknowledge your point, and t the end of the day you need to be happy with your home, so its best to be at ease with your own decisions rather than somone trying to ram heat pump tec down your neck!

Carlosthejakal

I have the same problem, my roof faces only east ( back ), west (front ) i have a mate that does research for solar companies and he asked one of the big importers / distributors.

He said it is not as effective as south facing but a 10-20 % increase in surface area should compensate for it. West is better than east ( sun is warmer by early afternoon ). he mentioned something about a special boiler to maximise effeciency !! cant remember have it in an email somewhere.

You will need an installer and product both on the sei list to qualify for the grants.

Carlos

AckwelFoley

Carlosthejakal wrote: »

I have the same problem, my roof faces only east ( back ), west (front ) i have a mate that does research for solar companies and he asked one of the big importers / distributors.

He said it is not as effective as south facing but a 10-20 % increase in surface area should compensate for it. West is better than east ( sun is warmer by early afternoon ). he mentioned something about a special boiler to maximise effeciency !! cant remember have it in an email somewhere.

You will need an installer and product both on the sei list to qualify for the grants.

Carlos

You made one good point with the facing of the panel, west is better than east. But its not because its warmer.. solar does not use heat, its sunlight intensity

Carlosthejakal

I am a self confessed idiot about these things but your man made alot of sense about what he said about solar.

I just wish the SEI would pull its finger out make it simplier, easier and more straightforward to learn, get reviews on products and suppliers, installers so everyone could benefit form those that are good and close the cowboys that just sign up !!

AckwelFoley

Carlosthejakal wrote: »

I am a self confessed idiot about these things but your man made alot of sense about what he said about solar.

I just wish the SEI would pull its finger out make it simplier, easier and more straightforward to learn, get reviews on products and suppliers, installers so everyone could benefit form those that are good and close the cowboys that just sign up !!

Trust me.. id love if there was a way the sei could weed out the cowboys..
But the problem is, that SEI are an Independant body and are not therefore allowed to be seen to "promote" companies. Its a pity, but only fair..

The bottom line is that one needs to do plenty of research and go with companies that have a recognised industry reputation..

sinnerboy

snyper wrote: »

The bottom line is that one needs to do plenty of research and go with companies that have a recognised industry reputation..

OR ... it would be a big help if SEI would populate it's HARP database for
- solar thermal panlels and
- heat pumps

They are "waiting for the industry" to "issue data"

"The industry" , based on many e mail enquiries I have made , are not interested in playing ball .

SEI need to raise their game here . Stop subsiding this lot .

SEI have no problem in publishing what can be seen as a league table for boilers in the current HARP database . So why not to follow suit with the infinately more expensive renewable technologies ?

If anyone wants to start to research I have yet to be told where better than the first post here - any other suggestions Snyper ?

http://www.boards.ie/vbulletin/showthread.php?t=2055263818

Gtec

Going back to the OP's question about east west solar, there are east west controlers available on the market where you put panels on both east and west facing roofs and there are 2 pumps for solar circulation. I don't have all the details as it was never an issue for me (my roof faces pretty close to due south), but they exist. this crowd do them (look for DeltaSol E controler) Resol

Gtec

AckwelFoley

Gtec wrote: »

Going back to the OP's question about east west solar, there are east west controlers available on the market where you put panels on both east and west facing roofs and there are 2 pumps for solar circulation. I don't have all the details as it was never an issue for me (my roof faces pretty close to due south), but they exist. this crowd do them (look for DeltaSol E controler) Resol

Gtec

All suppliers do them