Using solar pipes as shadebars - Any visually nice options?

[MikeInSoCal]

We are in the final stages of building a pool (16'x36') and guesthouse. We'd like to add solar heating. We also need to add shade bars on the eaves of the guesthouse, so we're thinking we can combine these two by making the shadebars out of waterpipes. The problem is that black pvc pipe is kinda ugly, especially compared to the more traditional shadebar choice of wood. Plus the pipes have to turn a corner, which means using clunky looking pvc elbows.

We though about using 1"x1" or 1"x2" stainless steel tubing and painting them dark brown, but a little Google research seems to say that chlorine is bad for stainless steel. (Although I think we're going with a salt system, but my understanding is that that has chlorine in it, too.) From another thread here, it looks like copper is out as well.

We cant just put massive commercial panels on these eaves, because we don't want complete shade. Instead we're looking for a more decorative trellis look, like 1" width of wood, alternated with 1" width of open. Except with water pipes instead of wood.

Any ideas on how to do this and still look nice?

Below are links to a couple pictures of the guesthouse with the bare eaves. Contrary to what the pictures might suggest, the guesthouse gets continuous sun after 9:00 a.m.. The lengths of these eaves is 56". The front width of the guesthouse is 23' and the side where the eaves are is 17'. This gives a potential area of about 30% of the pool area. Not optimal, obviously, but it's the best we've got and better than nothing.

http://realitone.com/images/Guesthouse1.jpg

http://realitone.com/images/Guesthouse2.jpg

[inetdog]

We are in the final stages of building a pool (16'x36') and guesthouse. We'd like to add solar heating. We also need to add shade bars on the eaves of the guesthouse, so we're thinking we can combine these two by making the shadebars out of waterpipes. The problem is that black pvc pipe is kinda ugly, especially compared to the more traditional shadebar choice of wood. Plus the pipes have to turn a corner, which means using clunky looking pvc elbows.

We though about using 1"x1" or 1"x2" stainless steel tubing and painting them dark brown, but a little Google research seems to say that chlorine is bad for stainless steel. (Although I think we're going with a salt system, but my understanding is that that has chlorine in it, too.) From another thread here, it looks like copper is out as well.

We cant just put massive commercial panels on these eaves, because we don't want complete shade. Instead we're looking for a more decorative trellis look, like 1" width of wood, alternated with 1" width of open. Except with water pipes instead of wood.

Any ideas on how to do this and still look nice?

Below are links to a couple pictures of the guesthouse with the bare eaves. Contrary to what the pictures might suggest, the guesthouse gets continuous sun after 9:00 a.m.. The lengths of these eaves is 56". The front width of the guesthouse is 23' and the side where the eaves are is 17'. This gives a potential area of about 30% of the pool area. Not optimal, obviously, but it's the best we've got and better than nothing.

http://realitone.com/images/Guesthouse1.jpg

http://realitone.com/images/Guesthouse2.jpg

One problem you will have is that most efficient solar thermal panels require a covering over the collection tubes and a black, light-absorbent, backing which covers the space between the tubes too. I am not sure whether your idea of isolated pipes (or even spaced pipes with a clear cover in front and back) will pick up enough heat to justify the effort. I will leave that question to those with more solar thermal experience. You do not want to lose heat from the pipes either to the top or the bottom, or to the surrounding air.

[Naptown]

Actually pool collectors are generally unglazed plastic numbers. Solar Industries or Aquatherm are two makers. Well actually one who brands under two names.
You can use a metallic piping to do what you want to do. the down side is it is titanium to withstand the pool chemicals. Copper is certainly out and stainless is better but will not last 20 years.
Titanium is a difficult material to work with and requires some specialized equipment to weld. You will not be soldering it with standard solder and a torch.
Oh and it is very pricey and hard to find also.

[MikeSolar]

There are some nicer PVC 90s that can make a good heater and it won't deform in the heat. Black is way better than brown for absorbing heat. Pools with salt are vary hard on stainless so all heat exchangers are titanium/stainless such as this one:

http://www.pahlen.com/our-products/heating-heat-exchangers/heat-exchanger-hi-flow-titanium.html

The most efficient pool panel according to SRCC is the:

http://www.techno-solis.com/

[MikeInSoCal]

Titanium is a difficult material to work with and requires some specialized equipment to weld. You will not be soldering it with standard solder and a torch.
Oh and it is very pricey and hard to find also.

But other than that, it's the way to go, right?

Okay, so titanium is off the list, too. This Pahlen heat exchanger is intriguing, though. I assume this means I can run regular water through my pipes (so I could use stainless,) then the heat exchanger transfers heat from that water to my pool's salt/chlorine water? That seems pretty slick, but I wonder how efficient it is at getting all the heat transferred. I need every btu I can get.

Our architect (not a solar expert) had another idea. What if we put pvc pipe inside stainless steel tubing? A 1" pvc pipe inside a black 1 1/4" square stainless tube, for instance. Obviously there's an insulating factor that comes into play, but as the day wears on and a temperature equilibrium is achieved, I wonder if the pvc inside would be the same temperature as the pipe anyway? Kinda like how the cold water pipes inside my south facing wall (uninsulated) give me warm water on a hot day.

I really appreciate the responses, by the way. This is very helpful. As far as the SI., Aquatherm or Techno-Solis panels go, I wish I could use those, but we don't have a place for them.

[Wy_White_Wolf]

Someone would need to research the idea but:

Could you attach clear corrigated panels on top of the eaves and use the corrigations to lay black painted pex tubing in?

[Naptown]

But other than that, it's the way to go, right?

Okay, so titanium is off the list, too. This Pahlen heat exchanger is intriguing, though. I assume this means I can run regular water through my pipes (so I could use stainless,) then the heat exchanger transfers heat from that water to my pool's salt/chlorine water? That seems pretty slick, but I wonder how efficient it is at getting all the heat transferred. I need every btu I can get.

Our architect (not a solar expert) had another idea. What if we put pvc pipe inside stainless steel tubing? A 1" pvc pipe inside a black 1 1/4" square stainless tube, for instance. Obviously there's an insulating factor that comes into play, but as the day wears on and a temperature equilibrium is achieved, I wonder if the pvc inside would be the same temperature as the pipe anyway? Kinda like how the cold water pipes inside my south facing wall (uninsulated) give me warm water on a hot day.

I really appreciate the responses, by the way. This is very helpful. As far as the SI., Aquatherm or Techno-Solis panels go, I wish I could use those, but we don't have a place for them.

You would run the pool water through this, all piping would be plastic.
Generally speaking you will need about 50% of the pool surface area in collectors if the pool is in full sun. If it is 100% shaded between 9 and 3 during the day you would use 100% and linear proportions in between. This is the basic formula we use in the Mid Atlantic where I am for a swim season from 5/1 - 9/30.
This will give you a pool temperature about 10 degrees above average ambient air temperature.

[green]

This may sound silly but I always err on the side of caution. You are talking about using those cantelevered beams that stick out, correct? I was just going to mention make sure (and I'm sure you did) make sure they are as strong as they look, and that they are not just decorative. Panels and pipes full of water are quite heavy and a cantelever of that length would require a very strong connection to the structure. They look very strong, but look can be decieveing.

Just thought I'd mention that before you got to far along.
Green

[Sunny Solar]

The roof of the concrete building is it used for anything? If not could it be covered with a big coil of black plastic pipe also? Those short extended beams are certainly more than adequate in size to support anything you are ever likely to put on them.
Its hard to tell exactly the spacing but mabe you could use the same plastic piping I suggest for on the roof? IF the distance is not to great it should not get excessive sag?? If spaced 1in apart that would let light go below and their relatively small dia should not look to ugly??

[green]

Those short extended beams are certainly more than adequate in size to support anything you are ever likely to put on them.

I think better advice would be to make sure they are adequate to support anything you put on them. You are refering to size, I am refering to structural support.

Green

[russ]

Someone would need to research the idea but:

Could you attach clear corrigated panels on top of the eaves and use the corrigations to lay black painted pex tubing in?

From what I have read about it I don't believe PEX is UV resistant - a different plastic might be better.

[Wy_White_Wolf]

From what I have read about it I don't believe PEX is UV resistant - a different plastic might be better.

That's why you paint the PEX. Gary covers this at Builditsolar. He has build several solar collectors using PEX.

[MikeInSoCal]

Thanks for the responses, guys. There are some good ideas here I hadn't thought of. Plus I didn't know about builditsolar.com. I've just skimmed it so far, but it looks like there's a lot of good stuff there.

The clear corrugated panels with PEX is worth looking into, although I don't know if my wife will go for it. Aesthetics over functionality is going to be a battle. I wonder, though, what would be the advantage of PEX over PVC?

As far as the beams go, they're decorative, not structural (they don't extend through the building,) but they're intentionally built to hold a lot of weight because this solar thing has always been the plan. I'm meeting with the architect today, though, so I'll double check anyway, just to be sure.

The roof can't be used for solar, because it's a deck. Although I suppose a black floor (walk-on solar panels?) might be kinda interesting. It's a weird idea and probably really difficult, but I'm half serious about at least considering it.

As far as shading goes, we get 100% sun on this building from 9:00 until sunset. The eaves area is only about 30% of the pool area, though, and even with the cover, we're still underpowered. But we're taking whatever we can get.

I'm thinking about doing some experiments to test how effective pvc inside a painted square metal tube would be. I'd compare with black pvc and painted black metal. Maybe even compare black paint versus brown. But before I try to reinvent a wheel that someone else already invented, has anyone already done tests like that somewhere?

[russ]

That's why you paint the PEX. Gary covers this at Builditsolar. He has build several solar collectors using PEX.

The paint stays 100% over time? Bad idea!

[russ]

I'm thinking about doing some experiments to test how effective pvc inside a painted square metal tube would be. I'd compare with black pvc and painted black metal. Maybe even compare black paint versus brown. But before I try to reinvent a wheel that someone else already invented, has anyone already done tests like that somewhere?

Think about it for another 5 minutes then discard the line of thought - my opinion.