Solar Thermal on West Facing Roof???

monster · Post by **monster** » 02 Jan 2008, 19:15

We have a west (well west, south west - just) facing roof and would like to get solar thermal for hot water. Does anyone know if its worth it. Most sites I read say you really need anything between south south east, to south west to be worthwhile - does anyone out there have one on a west facing roof - otherwise the roof is completely unshaded by trees/buildings etc and we live on south coast (Brighton).

Thanks for any help.

hardworkinghippy · Post by **hardworkinghippy** » 02 Jan 2008, 22:29

Monster,

I had solar panels on due west and east roofs in Essex (2 on each) and they worked fine. Brighton's a bit sunnier and your roof's southish, so they should contribute quite a bit to your water heating.

I took the panels with me to France, (The new owner didn't want them!

) and still use two of them almost 30 years later.

biffvernon · Post by **biffvernon** » 02 Jan 2008, 22:42

West is especially good if you like your bath in the evening.

RenewableCandy · Post by **RenewableCandy** » 03 Jan 2008, 09:41

I'd say no worries, get your Solar HW!

Sorry I can't find the diag on the web but it's in my CAT course notes (consults notes...), it says at the best roof slope angle (about 30 deg to the Horizontal), due West gives you about 85% of the energy that you would get if your panel were facing due South. The winter performance would go down more than the summer performance. But you dould do a MrE and get a woodburner with boiler...

The most critical factor in efficiency of a Solar HW system is, insulation of tank and pipes. It really does make a HUGE difference.

Adam1 · Post by **Adam1** » 03 Jan 2008, 10:30

Mine face a fraction south of east and they work fine too. From memory, you get about 70% - 80% of what you would get with the same panel surface area if they were facing due south. If you increase the area of panel accordingly (say an extra 25% to 30%) you'll compensate - assuming there is as much sun in the afternoon on average as in the morning.

mobbsey · Post by **mobbsey** » 03 Jan 2008, 13:24

Adam1 wrote:From memory, you get about 70% - 80% of what you would get with the same panel surface area if they were facing due south.

That's in summer. The more significant problem is that the heating season is reduced because the sun is at a much lower angle relative to the panels in spring/Autumn.

You could always wall-mount then. Although the installaers might moan as bit as they'll have to find somewhere lower down in your house for the expansion vessel (to stop them freezing up in Winter).

monster · Post by **monster** » 03 Jan 2008, 16:21

Thanks for all your replies - they seem to be worth it from what you all say

Now to get some quotes - we currently have a gas combi which is seven years old and not a condensor so will replace - are we best going with a standard hot water tank or a thermal store (there are two of us in the house if that helps) ???

JohnB · Post by **JohnB** » 03 Jan 2008, 17:53

The company I used to part own installed one vertically on an end wall, and did several where there was a panel on the east and west facing roofs, although that adds to the complexity (and cost) of the controls. We also did a few on frames in the garden. I don't know how effective they were compared to a south facing roof.

careful_eugene · Post by **careful_eugene** » 04 Jan 2008, 09:26

monster wrote:Thanks for all your replies - they seem to be worth it from what you all say

Now to get some quotes - we currently have a gas combi which is seven years old and not a condensor so will replace - are we best going with a standard hot water tank or a thermal store (there are two of us in the house if that helps) ???

http://www.powerswitch.org.uk/forum/vie ... highlight=

I asked a similar question in this thread and received some excellent advice.

monster · Post by **monster** » 06 Jul 2008, 15:23

Just to give some feedback.

We had a solar thermal system installed on our west facing roof six weeks ago (thermomax evacuated tubes that were rotated slightly in a southerly direction) and we have only had the boiler on for two hours in the past six weeks for hot water!!

On average one bath and one shower a day and washing.

hardworkinghippy · Post by **hardworkinghippy** » 06 Jul 2008, 15:49

Monster,

I'm so glad you posted that, people just think I'm a flippin' hippy who says anything...

Solar thermal works well and will even help to increase the temperature in your hot water tank out of season. Ideally, it can be used on the same circuit as another source of energy.

Try taking fewer baths and showering less too. It's not healthy to wash too often.

Adam1 · Post by **Adam1** » 06 Jul 2008, 20:07

Nice one Monster, it is very satisfying getting your hot water free (or nearly free if you include the little bit of electricity for the panel pump).

hardworkinghippy wrote:Try taking fewer baths and showering less too. It's not healthy to wash too often.

... or just turn the water on and off as you need it in the shower, particularly if you have a powerful shower. That saves us loads of water and heat. Nothing beats a daily shower! Enjoy it while you can!

Bozzio · Post by **Bozzio** » 07 Jul 2008, 11:50

Adam1 wrote:... or just turn the water on and off as you need it in the shower, particularly if you have a powerful shower. That saves us loads of water and heat. Nothing beats a daily shower! Enjoy it while you can!

These little devices are an excellent way to save water yet maintain the pressure in a powerful shower. I'd recommend the lowest litre/min flow that you can tolerate so you may care to experiment. They simply fit in line on the shower hose, usually between the hose and the head. They're not suitable for low pressure systems and can cause a slight noise if the water pressure is high but this is easily remedied by turning the flow down a little on the shower itself.

Shower Flow restrictor

Mind you, I've put an 8 litre/min restrictor on my shower and my wife can still use most of the hot water (150 litres) if I'm not there to stop her!

Adam1 · Post by **Adam1** » 07 Jul 2008, 12:08

Bozzio wrote:
Adam1 wrote:... or just turn the water on and off as you need it in the shower, particularly if you have a powerful shower. That saves us loads of water and heat. Nothing beats a daily shower! Enjoy it while you can!
These little devices are an excellent way to save water yet maintain the pressure in a powerful shower. I'd recommend the lowest litre/min flow that you can tolerate so you may care to experiment. They simply fit in line on the shower hose, usually between the hose and the head. They're not suitable for low pressure systems and can cause a slight noise if the water pressure is high but this is easily remedied by turning the flow down a little on the shower itself.

Shower Flow restrictor

Mind you, I've put an 8 litre/min restrictor on my shower and my wife can still use most of the hot water (150 litres) if I'm not there to stop her!

Looks interesting, and portable. Can it be used with any shower, for instance gravity fed with 3bar pump?

BTW, I see you've moved out of the big smoke. Well done! Only wish we could escape too.

Post by **mikepepler** » 08 Jul 2008, 08:05

Bozzio wrote:
Adam1 wrote:... or just turn the water on and off as you need it in the shower, particularly if you have a powerful shower. That saves us loads of water and heat. Nothing beats a daily shower! Enjoy it while you can!
These little devices are an excellent way to save water yet maintain the pressure in a powerful shower. I'd recommend the lowest litre/min flow that you can tolerate so you may care to experiment. They simply fit in line on the shower hose, usually between the hose and the head. They're not suitable for low pressure systems and can cause a slight noise if the water pressure is high but this is easily remedied by turning the flow down a little on the shower itself.

Shower Flow restrictor

Mind you, I've put an 8 litre/min restrictor on my shower and my wife can still use most of the hot water (150 litres) if I'm not there to stop her!

Can you use them in a power shower? Our rented house has a shower that's like a bucket of water emptying on you, and I've already turned the pump down to minimum.