Dump the plumbing and use PV to heat water? - Page 7

Themitchells04 · 03-31-15, 02:33 PM

dragging up an old thread in hopes of updates

Xringer · 03-31-15, 02:44 PM

The hotwater from PV has been working when the sun is out..
But, when it's cold outdoors, the panels make a lot of power.
So, now the problem is over-heating the storage tank..

I've been working on it this week.

http://ecorenovator.org/forum/solar-...v-array-3.html

AnneWindsor · 08-03-15, 05:24 PM

I’m remodeling my home with solar panels from solteksolar.com. They’ve been here in the CA Central Valley for over 15 years, and the advantages of solar energy here is that I can heat my pool year-round without crazy high electric bills.

Xringer · 08-03-15, 07:20 PM

When I started this thread back in 2009, I envisioned heating my hot water with PV panels.
What I've found since then, it works! It's not the best setup, but it's simple and it works.
Of course using PV to heat a pool with PV would be nuts.. Way too costly..

Anyways, I looked at the SolTek Solar building in Clovis (Google map) and there aren't any solar panels on the roof.. Nice flat roof, covered with about 17 AC units..
With PV panels on part of that roof space, they could power all those AC units.
It would be good advertising to have some panels on the roof..

jeff5may · 08-04-15, 10:53 AM

Quote:

Originally Posted by AnneWindsor

I’m remodeling my home with solar panels from solteksolar.com. They’ve been here in the CA Central Valley for over 15 years, and the advantages of solar energy here is that I can heat my pool year-round without crazy high electric bills.

Solar thermal panels would be much more cost effective for heating pool water. In a low temperature application, thermal panels are highly effective compared to pv. For domestic hot water, there is another 40 degF to overcome, so the effectiveness is more even between the two.

Acuario has built both ways to heat his pool, be sure to check out his threads. His latest concoction is a hybrid thermal/pv/heat pump that does it all for his home and pool. He was surprised a few times by the performance of his DIY creations as well as the price difference between them and prefab equipment.

Good luck, start a new thread and take pictures along the way.

nibs · 08-25-15, 10:15 PM

Xringer, you could just slap a snap switch on the tank that goes open when the tank reaches a high temp, a second snap switch could redirect the power to batts or ???
Cheap & simple, tho with that much pv (grrr) you might need relays.

I used to control my hot tub pump,that way, when we heated it with propane.
Now we heat the tub with wood so we no longer pump, it thermo syphons, now we control the temp by using the stove door.

Xringer · 08-25-15, 10:53 PM

Those type of switches are okay for low amperage use.
But, I couldn't use one for PV, since it's DC and at over 100 volts at about 7Amps..
Any contact surfaces have to be large, with a large gap when open, fast moving,
and be self cleaning (wiping action). Otherwise the DC arcing will eat them up..

Regular 240vac 30amp hotwater heater controls didn't last long at all..

I'm just using manual control now. I monitor the temp and use use some hot water if the tank starts getting too hot..
And when we are out of town, I cut the power, out at the panels.
I could have my CAI system email and message me and my wife when the tank starts to gets too hot,
but I've not written the routine yet.
I can have the CAI system turn the A7 heat pump on or off,
but controlling the PV power is going to be more difficult..

nibs · 08-26-15, 09:56 AM

I am impressed with snap switches, they are like me cheap &.......
You still could use them to drive a contactor. But then, I am telling a pro,

Xringer · 08-26-15, 10:17 AM

I purchased a golf kart contactor and it lasted a while..
But, when the contacts started getting a little resistive,
it started heating up and eventually melted the nylon(?) insulators..

What I need is a contactor rated for EV use..

But those cost more than I want to pay.. Yeah, I'm cheap..

jeff5may · 08-26-15, 07:14 PM

Methinks mosfets are cool. They don't arc or spark like relay contacts do. If a couple can run an arc welder or plasma cutter, switching your solar panel array should be no problem. Just beware of the datasheets:

FET Current Ratings -- Chuck's Robotics Notebook

If mosfets seem wimpy, there's always the almighty IGBT. For when heavy-duty isn't good enough. These go in EV power modules and Tony Stark's toys and such. Super duper duty.

03-31-15, 02:44 PM	#62
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	The hotwater from PV has been working when the sun is out.. But, when it's cold outdoors, the panels make a lot of power. So, now the problem is over-heating the storage tank.. I've been working on it this week. http://ecorenovator.org/forum/solar-...v-array-3.html __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

08-03-15, 07:20 PM	#64
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	When I started this thread back in 2009, I envisioned heating my hot water with PV panels. What I've found since then, it works! It's not the best setup, but it's simple and it works. Of course using PV to heat a pool with PV would be nuts.. Way too costly.. Anyways, I looked at the SolTek Solar building in Clovis (Google map) and there aren't any solar panels on the roof.. Nice flat roof, covered with about 17 AC units.. With PV panels on part of that roof space, they could power all those AC units. It would be good advertising to have some panels on the roof.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

08-25-15, 10:15 PM	#66
nibs Apprentice EcoRenovator Join Date: Jun 2010 Posts: 206 Thanks: 1 Thanked 18 Times in 17 Posts	Xringer, you could just slap a snap switch on the tank that goes open when the tank reaches a high temp, a second snap switch could redirect the power to batts or ??? Cheap & simple, tho with that much pv (grrr) you might need relays. I used to control my hot tub pump,that way, when we heated it with propane. Now we heat the tub with wood so we no longer pump, it thermo syphons, now we control the temp by using the stove door. Last edited by nibs; 08-25-15 at 10:19 PM.. Reason: added the hot tub stuff

08-25-15, 10:53 PM	#67
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Those type of switches are okay for low amperage use. But, I couldn't use one for PV, since it's DC and at over 100 volts at about 7Amps.. Any contact surfaces have to be large, with a large gap when open, fast moving, and be self cleaning (wiping action). Otherwise the DC arcing will eat them up.. Regular 240vac 30amp hotwater heater controls didn't last long at all.. I'm just using manual control now. I monitor the temp and use use some hot water if the tank starts getting too hot.. And when we are out of town, I cut the power, out at the panels. I could have my CAI system email and message me and my wife when the tank starts to gets too hot, but I've not written the routine yet. I can have the CAI system turn the A7 heat pump on or off, but controlling the PV power is going to be more difficult.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

08-26-15, 10:17 AM	#69
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I purchased a golf kart contactor and it lasted a while.. But, when the contacts started getting a little resistive, it started heating up and eventually melted the nylon(?) insulators.. What I need is a contactor rated for EV use.. But those cost more than I want to pay.. Yeah, I'm cheap.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

03-31-15, 02:33 PM	#61
Themitchells04 Lurking Renovator Join Date: Dec 2013 Location: Arkansas Posts: 5 Thanks: 4 Thanked 0 Times in 0 Posts	dragging up an old thread in hopes of updates

08-03-15, 05:24 PM	#63
AnneWindsor Lurking Renovator Join Date: Aug 2015 Location: Clovis, CA Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	I’m remodeling my home with solar panels from solteksolar.com. They’ve been here in the CA Central Valley for over 15 years, and the advantages of solar energy here is that I can heat my pool year-round without crazy high electric bills.

08-26-15, 09:56 AM	#68
nibs Apprentice EcoRenovator Join Date: Jun 2010 Posts: 206 Thanks: 1 Thanked 18 Times in 17 Posts	I am impressed with snap switches, they are like me cheap &....... You still could use them to drive a contactor. But then, I am telling a pro,

08-26-15, 07:14 PM	#70
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	Methinks mosfets are cool. They don't arc or spark like relay contacts do. If a couple can run an arc welder or plasma cutter, switching your solar panel array should be no problem. Just beware of the datasheets: FET Current Ratings -- Chuck's Robotics Notebook If mosfets seem wimpy, there's always the almighty IGBT. For when heavy-duty isn't good enough. These go in EV power modules and Tony Stark's toys and such. Super duper duty.

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