Pics of 2 DIY systems being built / Hot Air Collectors and Drainback System - Page 3

solarhotairpanels · 11-11-13, 05:24 AM

Sounds like you're good to go!

solarhotairpanels · 11-11-13, 06:30 AM

Sounds like a great plan.

Hopefully, the back of your house is facing south maybe?
I hope so cuz that would make things wayyyyyyy toooooooo easyyyyyy.

heck, if your solar collectors were mounted just below the level of your main living floor you might not even need FANS.

The hot air from the collectors will rise up into your home all by itself.

I HATE GUYS LIKE YOU that have perfect house arrangements for solar missions!

just not fair for the rest of us. :-)

skyking · 11-11-13, 01:44 PM

Thanks for some great write-ups, ideas, and humor

So I understand it better:
The drainback system starts up with dry collectors. Water is circulated up to them, and this can cause some steam, right? do you have a blowoff, or do the storage loops develop some pressure there?

solarhotairpanels · 11-11-13, 05:09 PM

Hi, thank you Sir,

Yes there may be a little steam in the pipe when the colder water begins entering the collectors however the pressure in the piping is relieved by an 'air vent' and 'vacum release' valve I've installed.

The vacum relief valve is at the highest point on the collectors outside 'right where the water exits the collectors'

The air vent is installed in the 3/4 copper pipe going into the top of my drainback tank.

I T'd off that 3/4 pipe just before it enters the drainback tank and installed a 1/2 inch 6 inch pipe straight up in the air off the 3/4 pipe.

On that 1/2 inch pipe I installed a ball valve which I leave cracked open at all times.

If I had no air release pipe the pressure would kick in during 'pump on' and 'stop' the water flo dead.

so the air vent solves that problem during pressure situations and the vacum release allows all the water to quickly drain back the second the pump shuts down.

Feel free to ask me as many questions as you want cuz I love talking about this solar stuff...

I'm not an expert on solar hot water systems by no means but did do one heck of a lot of research prior to putting my drainback system together.

so far.. everything is working like a clock.. no leaks (which was amazing) and I create hot water daily.

I installed a site glass on the side of the small 6 gallon electric hot water tank that I use for my drainback tank so I can keep an eye on water volume in the tank.

I have to remove the site glass to clean the ugly brown water out of it now and then but ya hardly 'ever' have to add water.

Just one circulator pump is used to heat up 2 tanks of water.
1 for domestic hot water use. (which is tied directly into my tankless hot water heater)

the other tank of hot water is used for heat distribution which I pump over to a radiator I installed in my family room. That's an independent variable speed Taco circulator pump that I use for that.

I stuck a thermostat in my family room dedicated to the heat distribution pump. All the thermostat does is send 24v to the little controller on the side of the pump which connects the 2 wire terminals together as it's calling for heat.

TIP: Ground water temp coming into your house from the street/well is normally 55 degrees at all times. SUMMER AND WINTER

It's cold ground water that 'replaces' the water in your solar hot water storage tank when water is removed for showers, etc.

That's not good cuz the water coming IN to your tank is cooling down that water big time.

SOLUTION:
If you run your cold water (ground water from street or well) thru a preheat tank located upstairs in a conditioned air space (68 to 71 degrees) PRIOR to running it to your solar hot water (COLD IN) pipe.. your solar hot water system doesn't have to work as hard to bring the water temps up to 120 degrees.

55 to 120 = not good - solar hot water system needs more hours to heat the water up.
68 to 120 = much better.. less hours needed to heat the water up..

Preheat tank does not need to be insulated.
The room air around it keeps it at room temp so actually 'no insulation' is even better.
Tank size = anything from 10 gallons to 20 gallons is all you need cuz most showers use only 8 to 10 gallons of water for each shower.

Once the shower is over and the preheated room temp water is now in your solar tank the water in your preheat tank immediately starts to warm again via the room temp air.

skyking · 11-12-13, 06:39 PM

All good stuff

I have electric everything, and a conventional water heater. I doubt I would ever go for an instant electric unit as they are pricey and draw huge loads to do what a natural gas unit does easily.
I can really insulate what I have to minimize storage losses. The solar would still do a great deal for me.
Now to show my wife pictures of your air collectors. We have a good south wall with no windows. If I can doll them up enough, she will probably go for it. I have 16 feet to work with

We have beloved giant trees all over, but that wall still gets a good bit of sun.

solarhotairpanels · 11-12-13, 10:10 PM

Hi SkyKing,

My tankless water heater does whole house heating and domestic hot water.

It's propane.
Electric is nuts in New England for what we pay for juice around here.

Yeah.. show you're wife the pics and maybe she'll give ya the heave ho.

but before that see what time the sun hits your south wall and what time it's useless later in the day. I actually monitored the hours of sun to make sure I was sticking them in the right place.

If you want them to look prettier you could go with the double wall polycarbonate. It's a smooth service / no wiggle strip insulation to goof with but 'does' cost a bit more.

Good Luck!

skyking · 11-12-13, 10:59 PM

over here on the west coast, the juice is cheap compared to propane. If we had natural gas in the street that is the best.
I checked out the double wall polycarbonate. That is not bad at all. She is interested!
There is only the one south wall so I don't have much choice. I will watch it next time I have some sun.

solarhotairpanels · 11-13-13, 07:02 AM

She likes the poly!
That's it! You're on your way!

Angle of sun is real low in the sky and gets worse at the end of Dec. which is why we all try to mount these hot air collectors as 'vertical' as possible for the winter sun.

Many times folks attach them right to a vertical 'wall' under an eave/overhang so in the summer when the sun is straight up in the sky the collectors are 'shaded' most of the day which is what you want.

Well keep me informed as you roll ok?
We can go over stuff along the way if need be.

skyking · 11-13-13, 08:12 AM

You bet. I may go at it with your materials, but build the whole thing in place on the wall. That way I can put the tubes through the PT plywood skirting (manufactured home) right at the start, build it up and finish it out. I have access to 4' shears and brakes, so some interior baffles are easy.
I can bring the hot in to the existing ducting under the house, and plumb the cool return into the return plenum above the electric furnace.
I'd need to fashion a damper in the main duct to keep things from just looping up through the electric furnace and right back out the return.
Probably end up with two dampers that way.
My system will be best flat on the wall as you describe. I have minimal eaves, the gutters do help. I can hang a rolled bamboo style screen in front of the system in the summer months to keep it cooler.

Mikesolar · 11-13-13, 08:13 AM

Hello solarhotairpanels,

I would reconsider the use of the air vent and vacuum break. There are 1000s of totally closed systems around that don't use them. A closed loop from panels to the HX allows the pump pressure created on the discharge side to be of help on the suction side of the pump. If the air vent is working, the pump will have to work harder to do the same job. If you are worrying about draining the panels, don't, as they will drain just fine with the slopes I see on your system.

Also, using an air vent and vacuum breaker means that you will have to monitor and fill the system more often which brings in more particulates and O2 which causes corrosion on the iron body pumps you have. Any potential failures in the system will come quicker and auto air vents are often the first to fail.

I cannot tell if the insulation you are using is closed cell (armaflex type) or open cell foam (used for insulating water lines in the basement and has a glue strip), but all insulation should be closed cell as the temp rating on the open cell is not high enough and it will melt to the piping in certain places near the collectors.

The tank arrangement looks good. Love the enthusiasm.

Mike

11-11-13, 05:24 AM	#21
solarhotairpanels Helper EcoRenovator Join Date: Mar 2012 Location: Warwick, Rhode Island Posts: 92 Thanks: 22 Thanked 29 Times in 18 Posts	Sounds like you're good to go! __________________ Pat from Warwick, RI Please Note: Comments and/or suggestions I make here at the forums on 'your' projects as well as my own have all been carefully and scientifically calculated by 'the seat of my pants' To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-11-13, 06:30 AM	#22
solarhotairpanels Helper EcoRenovator Join Date: Mar 2012 Location: Warwick, Rhode Island Posts: 92 Thanks: 22 Thanked 29 Times in 18 Posts	Sounds like a great plan. Hopefully, the back of your house is facing south maybe? I hope so cuz that would make things wayyyyyyy toooooooo easyyyyyy. heck, if your solar collectors were mounted just below the level of your main living floor you might not even need FANS. The hot air from the collectors will rise up into your home all by itself. I HATE GUYS LIKE YOU that have perfect house arrangements for solar missions! just not fair for the rest of us. :-) __________________ Pat from Warwick, RI Please Note: Comments and/or suggestions I make here at the forums on 'your' projects as well as my own have all been carefully and scientifically calculated by 'the seat of my pants' To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-11-13, 05:09 PM	#24
solarhotairpanels Helper EcoRenovator Join Date: Mar 2012 Location: Warwick, Rhode Island Posts: 92 Thanks: 22 Thanked 29 Times in 18 Posts	solar hot water collector steam.. Hi, thank you Sir, Yes there may be a little steam in the pipe when the colder water begins entering the collectors however the pressure in the piping is relieved by an 'air vent' and 'vacum release' valve I've installed. The vacum relief valve is at the highest point on the collectors outside 'right where the water exits the collectors' The air vent is installed in the 3/4 copper pipe going into the top of my drainback tank. I T'd off that 3/4 pipe just before it enters the drainback tank and installed a 1/2 inch 6 inch pipe straight up in the air off the 3/4 pipe. On that 1/2 inch pipe I installed a ball valve which I leave cracked open at all times. If I had no air release pipe the pressure would kick in during 'pump on' and 'stop' the water flo dead. so the air vent solves that problem during pressure situations and the vacum release allows all the water to quickly drain back the second the pump shuts down. Feel free to ask me as many questions as you want cuz I love talking about this solar stuff... I'm not an expert on solar hot water systems by no means but did do one heck of a lot of research prior to putting my drainback system together. so far.. everything is working like a clock.. no leaks (which was amazing) and I create hot water daily. I installed a site glass on the side of the small 6 gallon electric hot water tank that I use for my drainback tank so I can keep an eye on water volume in the tank. I have to remove the site glass to clean the ugly brown water out of it now and then but ya hardly 'ever' have to add water. Just one circulator pump is used to heat up 2 tanks of water. 1 for domestic hot water use. (which is tied directly into my tankless hot water heater) the other tank of hot water is used for heat distribution which I pump over to a radiator I installed in my family room. That's an independent variable speed Taco circulator pump that I use for that. I stuck a thermostat in my family room dedicated to the heat distribution pump. All the thermostat does is send 24v to the little controller on the side of the pump which connects the 2 wire terminals together as it's calling for heat. TIP: Ground water temp coming into your house from the street/well is normally 55 degrees at all times. SUMMER AND WINTER It's cold ground water that 'replaces' the water in your solar hot water storage tank when water is removed for showers, etc. That's not good cuz the water coming IN to your tank is cooling down that water big time. SOLUTION: If you run your cold water (ground water from street or well) thru a preheat tank located upstairs in a conditioned air space (68 to 71 degrees) PRIOR to running it to your solar hot water (COLD IN) pipe.. your solar hot water system doesn't have to work as hard to bring the water temps up to 120 degrees. 55 to 120 = not good - solar hot water system needs more hours to heat the water up. 68 to 120 = much better.. less hours needed to heat the water up.. Preheat tank does not need to be insulated. The room air around it keeps it at room temp so actually 'no insulation' is even better. Tank size = anything from 10 gallons to 20 gallons is all you need cuz most showers use only 8 to 10 gallons of water for each shower. Once the shower is over and the preheated room temp water is now in your solar tank the water in your preheat tank immediately starts to warm again via the room temp air. __________________ Pat from Warwick, RI Please Note: Comments and/or suggestions I make here at the forums on 'your' projects as well as my own have all been carefully and scientifically calculated by 'the seat of my pants' To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by solarhotairpanels; 11-11-13 at 05:20 PM..

11-12-13, 10:10 PM	#26
solarhotairpanels Helper EcoRenovator Join Date: Mar 2012 Location: Warwick, Rhode Island Posts: 92 Thanks: 22 Thanked 29 Times in 18 Posts	Tankless water heater Hi SkyKing, My tankless water heater does whole house heating and domestic hot water. It's propane. Electric is nuts in New England for what we pay for juice around here. Yeah.. show you're wife the pics and maybe she'll give ya the heave ho. but before that see what time the sun hits your south wall and what time it's useless later in the day. I actually monitored the hours of sun to make sure I was sticking them in the right place. If you want them to look prettier you could go with the double wall polycarbonate. It's a smooth service / no wiggle strip insulation to goof with but 'does' cost a bit more. Good Luck! __________________ Pat from Warwick, RI Please Note: Comments and/or suggestions I make here at the forums on 'your' projects as well as my own have all been carefully and scientifically calculated by 'the seat of my pants' To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-13-13, 07:02 AM	#28
solarhotairpanels Helper EcoRenovator Join Date: Mar 2012 Location: Warwick, Rhode Island Posts: 92 Thanks: 22 Thanked 29 Times in 18 Posts	She likes the poly! That's it! You're on your way! Angle of sun is real low in the sky and gets worse at the end of Dec. which is why we all try to mount these hot air collectors as 'vertical' as possible for the winter sun. Many times folks attach them right to a vertical 'wall' under an eave/overhang so in the summer when the sun is straight up in the sky the collectors are 'shaded' most of the day which is what you want. Well keep me informed as you roll ok? We can go over stuff along the way if need be. __________________ Pat from Warwick, RI Please Note: Comments and/or suggestions I make here at the forums on 'your' projects as well as my own have all been carefully and scientifically calculated by 'the seat of my pants' To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-11-13, 01:44 PM	#23
skyking Helper EcoRenovator Join Date: May 2011 Location: Western Washington Posts: 91 Thanks: 47 Thanked 20 Times in 13 Posts	Thanks for some great write-ups, ideas, and humor So I understand it better: The drainback system starts up with dry collectors. Water is circulated up to them, and this can cause some steam, right? do you have a blowoff, or do the storage loops develop some pressure there?

11-12-13, 06:39 PM	#25
skyking Helper EcoRenovator Join Date: May 2011 Location: Western Washington Posts: 91 Thanks: 47 Thanked 20 Times in 13 Posts	All good stuff I have electric everything, and a conventional water heater. I doubt I would ever go for an instant electric unit as they are pricey and draw huge loads to do what a natural gas unit does easily. I can really insulate what I have to minimize storage losses. The solar would still do a great deal for me. Now to show my wife pictures of your air collectors. We have a good south wall with no windows. If I can doll them up enough, she will probably go for it. I have 16 feet to work with We have beloved giant trees all over, but that wall still gets a good bit of sun.

11-12-13, 10:59 PM	#27
skyking Helper EcoRenovator Join Date: May 2011 Location: Western Washington Posts: 91 Thanks: 47 Thanked 20 Times in 13 Posts	over here on the west coast, the juice is cheap compared to propane. If we had natural gas in the street that is the best. I checked out the double wall polycarbonate. That is not bad at all. She is interested! There is only the one south wall so I don't have much choice. I will watch it next time I have some sun.

11-13-13, 08:12 AM	#29
skyking Helper EcoRenovator Join Date: May 2011 Location: Western Washington Posts: 91 Thanks: 47 Thanked 20 Times in 13 Posts	You bet. I may go at it with your materials, but build the whole thing in place on the wall. That way I can put the tubes through the PT plywood skirting (manufactured home) right at the start, build it up and finish it out. I have access to 4' shears and brakes, so some interior baffles are easy. I can bring the hot in to the existing ducting under the house, and plumb the cool return into the return plenum above the electric furnace. I'd need to fashion a damper in the main duct to keep things from just looping up through the electric furnace and right back out the return. Probably end up with two dampers that way. My system will be best flat on the wall as you describe. I have minimal eaves, the gutters do help. I can hang a rolled bamboo style screen in front of the system in the summer months to keep it cooler.

11-13-13, 08:13 AM	#30
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	Hello solarhotairpanels, I would reconsider the use of the air vent and vacuum break. There are 1000s of totally closed systems around that don't use them. A closed loop from panels to the HX allows the pump pressure created on the discharge side to be of help on the suction side of the pump. If the air vent is working, the pump will have to work harder to do the same job. If you are worrying about draining the panels, don't, as they will drain just fine with the slopes I see on your system. Also, using an air vent and vacuum breaker means that you will have to monitor and fill the system more often which brings in more particulates and O2 which causes corrosion on the iron body pumps you have. Any potential failures in the system will come quicker and auto air vents are often the first to fail. I cannot tell if the insulation you are using is closed cell (armaflex type) or open cell foam (used for insulating water lines in the basement and has a glue strip), but all insulation should be closed cell as the temp rating on the open cell is not high enough and it will melt to the piping in certain places near the collectors. The tank arrangement looks good. Love the enthusiasm. Mike