Looking to replace solar water heater

[ardcarmvk]

I've had my unit installed for 5+ years now and it still works awesome. April- Nov 1st I can actually turn off my Water Heater @ the breaker and only use solar. Thanks to all who were so gracious with their help. -Andrew

[MikeSolar]

The actually use water for the collector loop, and just rely on recirculation freeze protection.

http://www.linuo-ritter-usa.com/products/xl-solar-systems/technology/

They currently can't get OG-300 certification because recirc. is deemed too unreliable in the US. (Apparently the European grid NEVER has blackouts)

Food for thought - -

They install Millions of tubes per year, so you can't just say oh, they are making a mistake.

Yes, I have seen them years ago. I have one apartment building job with 18 of the 4.5m2 panels and SS tubing and a water treatment plant with 27 panels, and I think it is the best of the Chinese vacuum tubes, but it is still a vacuum tube and therefor it will have higher maintenance.

I haven't used any of the controls using pure water yet but it seems to work well enough.

[Art VanDelay]

The Biggest Installer of Evac Tubes Worldwide has Ditched Glycol

The actually use water for the collector loop, and just rely on recirculation freeze protection.

http://www.linuo-ritter-usa.com/products/xl-solar-systems/technology/

They currently can't get OG-300 certification because recirc. is deemed too unreliable in the US. (Apparently the European grid NEVER has blackouts)

Food for thought - -

They install Millions of tubes per year, so you can't just say oh, they are making a mistake.

[MikeSolar]

Just another reason I design systems around using plain old H2O, less maintenance, lower cost, higher efficiencies.
I won't use glycol unless I absolutely have to. I don't care who makes it, it's all crap to me.

I design drain back systems too but they don't work everywhere.

[LucMan]

Just another reason I design systems around using plain old H2O, less maintenance, lower cost, higher efficiencies.
I won't use glycol unless I absolutely have to. I don't care who makes it, it's all crap to me.

[MikeSolar]

There are lots of things I will experiment with but if the biggest solar companies in the world stock basically one product (Tyfocor G or GL) there must be a reason. I don't think it is wise to re-invent this wheel. Your local Buderus boiler supplier ,Viessmann supplier, Calefi dealer will have the stuff and if you only need 20-40L, it is a safe investment.

[inetdog]

I have a lot of concerns about things I have never looked at as well.

So now I have looked at it rather than just accepting what ardcarvmk posted. One problem with using a product meant for a different purpose to save money is that its formulation can change without your knowing it unless you pay attention.

The MSDS for Splash RV and Marine Antifreeze and Coolant (dated 2005) shows that it is essentially
14% propylene glycol (PG) and
10% ethanol.
Are your seals and other parts rated for exposure to ethanol?
Trace amounts of nasty stuff including Butyl Cellosolve.
But it gets better:

As of 2012, Splash seems to be selling (at least on their web site) only three formulations (all pink!) :

Splash -50 blend RV and and Marine Antifreeze and Coolant:
7% PG
7% Glycerine
<6% Ethanol
Traces of miscellaneous stuff including Butyl Cellosolve (nasty)


Splash -50 RV and Marine Antifreeze and Coolant:
<9% PG
<16% Glycerine
small amounts of additives, not harmful.


and Splash -100 RV and Marine Antifreeze and Coolant:
25% PG
25% Glycerine
small amounts of additives, not harmful.

If you are looking to replace "pure" PG with only a few additives for high temp, anti-scaling, etc. Splash is NOT the thing to use.

Hint: If you are having trouble figuring out the ingredients from the label (especially online) try to find the Material Safety Data Sheets (MSDS) for the product. If it is up to date, it should be authoritative.

[russ]

I have two concerns about Slash mix as described by ardcarmvk (I have not checked the specs myself).

I have a lot of concerns about things I have never looked at as well.

[inetdog]

One can buy the 'special' solar propylene glycol and pay a silly price.

The Slash stuff seems to fit the bill

I have two concerns about Slash mix as described by ardcarmvk (I have not checked the specs myself).

1. Propylene glycol < 9% --- That sure does not sound like a Propylene Glycol/water mix to me. At least not one good for very high temps as well as freezing.
3. Glycerine <16 % ---- What is that Glycerine doing? Acting as anti-freeze? What are its high temp characteristics? Is it there primarily to prevent evaporation in an open trap? "EVAPORATION RATE (BuAc=1): Slight". That does not seem like an important characteristic for a closed system!

[MikeSolar]

One can buy the 'special' solar propylene glycol and pay a silly price.

The Slash stuff seems to fit the bill

What do you buy? I never thought of Tyfocor as special, just appropriate for the use. It is about $4-5/L retail depending where you get it.

[russ]

One can buy the 'special' solar propylene glycol and pay a silly price.

The Slash stuff seems to fit the bill

[MikeSolar]

This is what I have Splash RV & Marine Antifreeze
Looks like the concentrations are a bit different Between the Harvey heat / Splash / Sierra

Harvey heat from plumbing supply has
Dipotassium Phosphate 1.0 -2.0%
Propylene Glycol 65.0 - 70.0

Slash RV stuff has
Propylene Glycol <9 percent
Glycerin <16 percent

Sierra has
Propylene Glycol 94-96 %
Water 3 %
Proprietary Additives 1-3 %

Slash data sheet has this as well.
APPEARANCE: Clear pink liquid
BOILING POINT: 370°F
ODOR: None
FREEZE POINT: 9°F
pH: 8.2
VAPOR PRESSURE (mm of Hg) <.01 @20C (68F)
SPECIFIC GRAVITY: (water =1): 1.01
VAPOR DENSITY (Air =1): 2.6
SOLUBILITY IN WATER: 100%
EVAPORATION RATE (BuAc=1): Slight

They are actually very different. I would google propylene glycol for solar (dow, tyfocor, etc). Many of these RV types are not for dynamic systems with rapid freeze/boil issues but for static protection of a toilet trap. Very different application so it is a different product.

[ardcarmvk]

This is what I have Splash RV & Marine Antifreeze
Looks like the concentrations are a bit different Between the Harvey heat / Splash / Sierra

Harvey heat from plumbing supply has
Dipotassium Phosphate 1.0 -2.0%
Propylene Glycol 65.0 - 70.0

Slash RV stuff has
Propylene Glycol <9 percent
Glycerin <16 percent

Sierra has
Propylene Glycol 94-96 %
Water 3 %
Proprietary Additives 1-3 %

Slash data sheet has this as well.
APPEARANCE: Clear pink liquid
BOILING POINT: 370°F
ODOR: None
FREEZE POINT: 9°F
pH: 8.2
VAPOR PRESSURE (mm of Hg) <.01 @20C (68F)
SPECIFIC GRAVITY: (water =1): 1.01
VAPOR DENSITY (Air =1): 2.6
SOLUBILITY IN WATER: 100%
EVAPORATION RATE (BuAc=1): Slight

[inetdog]

True, but the "normal" operating temps are in the 70-80C range. With auto there is a good amount of excess capacity built in. For natural proplyene glycol, you will not have a high degree of degradation below 130C which is why some systems (Thermo-dynamics, Enerworks etc) will use natural with no additives (It also helps to be able to call it food grade as well). They do not have high stagnation temps.

Thanks, Mike!

What sort of additives are often found in low-temp plumbing winterizing glycol mix? I would not expect any to be needed except maybe for anti-corrosion, coloring so you know it's there, and maybe some perfume?
On the same lines, what other than high-temp anti-corrosion additives are optional/desirable in a solar thermal glycol mix?

When you start with natural glycol, how important is it to use distilled, purified, or demineralized water to dilute it? I would guess it is far less important than for topping off batteries, but still an issue with high mineral or highly acidic or alkaline water?

Either a discussion or a pointer to some good writeups on the subject would be appreciated.

[MikeSolar]

Typical is one thing, but the reason that engine coolant systems are pressurized (up to ~15-20 psi) is to allow for the coolant to get above 100C under heavy loads. The "typical" temperature is at least as high as the thermostat setting on the system. It is true that you never expect the coolant to actually vaporize and re-condense however.

True, but the "normal" operating temps are in the 70-80C range. With auto there is a good amount of excess capacity built in. For natural proplyene glycol, you will not have a high degree of degradation below 130C which is why some systems (Thermo-dynamics, Enerworks etc) will use natural with no additives (It also helps to be able to call it food grade as well). They do not have high stagnation temps.