Heating Help

What is in that tank?

@ March 7, 2012 8:51 AM in Solar storage tanks

The stuff you see in the tank is not algae, just residue that probably came off the copper as it aged. The big issue with the liner shown was the failure due to overheating.

Tank liners

@ January 12, 2012 12:28 PM in Solar storage tanks

EPDM can be a reasonable liner material for lower temperature tanks.
They do, however, break down over time.
Over the years, I have seen Solaroll (remember that one!), Entran 1,2 and 3
and various tank liners all fail due to their EPDM content.
Apparently the breakdown byproducts can affect copper heat exchangers causing premature failure.

Murphy's Law does rule the world. The image is of a 7 year old EPDM liner.

Vents

@ November 17, 2011 10:52 PM in Drainback Innovation?

We have done this type of drainback vent for over 20 years here in Maine.
It works well. If the vent is an open tube, there is some gurgling noise, but it is only near the tank and you know the system is working and good things are happening!

Tom in Maine
www.americansolartechnics.com

Algae

@ October 9, 2011 7:02 PM in Customer concerns about algae / growth in combi storage tank

If the tank temps go above 140F, most "stuff" that grows in these tanks will never develop.
The only time we have ever had a bad problem with stuff growing in tanks was with a solar tank that we used as a heat source for a heat pump. The tank was usually chilled down to 60F. When I opened it, I had what appears to be 600g of egg drop soup.
It was full of slime mold.
I cleaned it out, and did not get sick(!) The tank was otherwise fine.
Every other tank that we have been into has shown no signs of nasty stuff growing.
We have been doing this about 30 years. Although we used PVC liners up to very recently, we do get into EPDM lined tanks and if the EPDM is intact (we usually see them when the customer needs a new liner that is not EPDM) there is still nothing organic growing.

I would just follow the STSS pH recommendations to help prolong the liner life and keep it at 165-170F max.

Adding anything other than what the manufacturer recommends might void your warranty.

tom in maine

Aluminum Absorbers

@ October 9, 2011 6:54 PM in Aluminum Absorbers are Hot in Europe

We seem to see "new" aluminum heating components every couple years. They usually come from Europe. They come and then go as corrosion issues bring great expectations in reality.
It would be interesting if there is a lower cost absorber out there that is all aluminum.
I would not bet the farm on it until it is around for at least 5-10 years. There are too many aluminum baseboard and solar corpses out there.

Copper is still a good deal. It is serviceable, and even at the highest prices we have seen it is still not out of reach.

Tom in Maine

Another option

@ October 9, 2011 6:49 PM in solar tanks

We make 200g and up tanks that can have whatever you need for hx.
If you are tying two 119g tanks together, this might be an alternative.
Sorry for the commercial, but it is a fair bit less expensive and more serviceable.

Tom in Maine

Lotsa patents for bubbles

@ August 18, 2011 9:24 AM in Solar water bubble PUMP

The original "Geyser" pump was patented and trademarked by Eldon Haines and Bob Block from a company called Sunrise Research.
They manufactured the "Copper Cricket" for several years in Oregon.
The company folded but Eldon's patents are out there.

We were licensed for a while to manufacture them.
As Mark mentioned, Myles Movick made one and Wilfred Sorensen in Canada also makes one. Googling bubble pumps will get you a lot of hits.

One of the working features is the use of a vacuum to boil water at a lower temperature.
Mixing the water with alcohol (either ethyl or methyl) will help lower the boiling point and make it freeze tolerant.
The boiling water bubbles and lifts "slugs" of water in riser tubes to induce some flow in a closed loop.

We had mixed success with the design. At the time we licensed it, it was not quite ready for prime time.
I think it could lend itself to self pumping wood boilers, but the flow rates for solar are not really big.

It was fun, though! I still have the stuff we used to make the system work.

Of the three, I think the Sorensen design is the most viable, I am not sure about the energy cost (loss) associated with making the system self pump.

Tom in Maine
www.americansolartechnics.com

Maybe

@ April 21, 2011 5:38 PM in Dawn of a new age???

A water source heat pump would certainly help. One has to ask is this all worth the investment. Maybe yes, if it is cooling a PV system. You are keeping the efficiency of the PV's up and perhaps affording them more longevity. Considering the cost, color me skeptical. Many folks seem willing to spend the money without analyzing the cost/benefits very well.

No new age here

@ April 21, 2011 9:03 AM in Dawn of a new age???

The only thing the Dawn system has going for it is the fact you cannot see the collector.
The construction is basically a radiant floor on the roof before the metal roofing goes on.
This is a thermal disaster and the SRCC numbers back that up.

If one does not care about cost or payback, then this is their system.Wonder what happens if there is an abrasion leak on the PEX.
Yikes!

Tom in Maine

Tanks

@ December 23, 2010 1:05 PM in Solar DHW Tank Lifespan

We have been building unpressurized tanks for about 30 years. I just took one out of service (I wanted to check out the liner) after 24 years of service. It was fine and would have gone on for another long period of time.

An unpressurized tank has some merits that pressure DHW tanks do not have.
The big one is being able to rebuild it if it was every necessary.
The other one is cost and ease of installation. Our 200g tank is the same cost as most 100g pressure tanks with heat exchangers.

Sorry for the commercial, but I couldn't resist.

Merry Christmas.
A lot of tanks,
Tom
www.americansolartechnics.com

Self Pumping

@ December 23, 2010 1:00 PM in "Steam Pumping"

We actually manufactured these systems for a while. This was before the Copper Cricket.
The pumping action was finicky and we closed our business relationship. The principals went on to making their own unit, the Copper Cricket.
I think the systems eventually stopped pumping properly, either due to installation issues
or poor performance. They usually operated with large delta T's.

Most of our systems wound up being actively pumped with AC or PV's.

This is a variation on the theme:
http://www.bubbleactionpumps.com

You could use ethanol instead of methanol. Wouldn't that make work fun!

Tom in Maine
www.americansolartechnics.com

Liability

@ December 4, 2010 2:13 PM in ASHRAE Design Guide

I suspect that there are some other reasons for a preference to antifreeze or drainback systems.
If you ever have a leak, the leak is limited to the volume of the antifreeze in the system or the volume of the drainback vessel.
A direct system is going to leak water until someone discovers it.
I suspect there is some issue with cross-contamination(?)
We have had go rounds with code people in the US and Canada about our tanks using
single wall heat exchangers in either application. Since we (or more correctly--our customers) do not use toxic materials in their solar loops, there is little risk of the kind of cross-contamination that code is concerned with. And there is an exception to that rule in the code.

Wood Boiler Tanks

@ October 28, 2010 9:34 AM in Wood Boiler with thermal storage

We provide the square unpressurized tanks for Tarm USA (formerly BioheatUSA).
If you haven't already got plumbing diagrams, feel free to email me.

tom@americansolartechnics.com

Wood Boiler Tanks

@ October 28, 2010 9:33 AM in Wood Boiler with thermal storage

We provide the square unpressurized tanks for Tarm USA (formerly BioheatUSA).
If you haven't already got plumbing diagrams, feel free to email me.

tom@americansolartechnics.com