Heating Help

Great Steamback Article by Fortunat

@ August 15, 2011 2:27 AM in Steamback System Design

http://www.renewableenergyworld.com/rea/news/article/2011/08/steamback-shows-promise-for-solar-water-overheating

Sunnovation

@ August 12, 2011 5:30 PM in Passive Pumping Part II

Anyone else put one of these in recently?

New Geyser Pumps

@ August 1, 2011 1:41 AM in Solar water bubble PUMP

I recently installed a Sunnovations geyser pump. It was very simple, very versatile, and is working well.

Thus far, it's not compatible with evacuated tubes, but works with just about any harp-style flat plate collector.

We dissected it pretty well on this thread:
http://www.heatinghelp.com/forum-thread/135984/Passive-Pumping-Part-II

Downspouts

@ July 24, 2011 10:02 AM in Outdoor pipe wrap

Downspouts from Home Depot look great and are cheap.
Just slit them down the back, then pop them on, friction holds them in place. Elbows are only a couple bucks each, If you need to change the color, a coat of Krylon should last at least 15 years, then the housepainters will take over.

If you use the next larger size (5") then you can inject the final product with Great Stuff for added R value. I just can't believe they can charge $10/ft for that preinsulated wrinkly black stuff. Ugly.

EPDM tanks are labor intensive

@ July 23, 2011 6:54 PM in Solar storage tanks

Very few systems inside the home would require this much labor, so I dislike them for that reason. Lots of fiddly details to get right, and all failure modes are costly.

The best overview on building them: http://www.builditsolar.com/Projects/SpaceHeating/DHWplusSpace/TankDesign.htm

Commercial style tanks CAN easily be used for unpressurized drainback:
http://www.solarheatexchangemanufacturing.com/NewFiles/products.html
But they only go up to 120gal.

One issue that I think hasn't been decided is whether to use dip tubes or bulkhead fittings. Dip tubes on the suction side of a circulator pump will eventually airlock the pump, but a bulkhead fitting in an EPDM tank is risky.

pipe size?

@ June 30, 2011 5:31 PM in a new twist on an old cap

Nice looking job, hr, how many feet of 1/2" pipe is recommended on the downcomer?

First system in

@ June 12, 2011 2:36 AM in Passive Pumping Part II

I installed a Sunnovation system this past week, and it's percolating just fine.
I did a one collector system for a single person, so the flowrate is probably a bit low, but the collector outlet temperature did seem a bit high

No Vacuum

@ June 7, 2011 10:37 PM in "Steam Pumping"

I didn't draw a vacuum, but I don't see how it would help. I had no trouble generating steam. (250F at 1 psi)

I need something to condense the steam bubble quickly. Just like what you don't want in a steam heating system. In this case I want the steam hammering, because each time a steam bubble collapses, cooler water would be drawn into the inlet of the solar panel.

I think it would look just like a european syle bottle trap. Back to the lab/backyard.

Drake Landing Good

@ June 7, 2011 10:23 PM in groundsource heat-dump solar trickle-charger?!?

None of the other interseasonal schemes have worked very well.
Drake Landing was big, expensive, and complicated, however.

training schedule

@ May 23, 2011 3:26 AM in schoolin'

http://solarprofessional.com/email/training/
This is mostly PV, but Solar Thermal should be on the schedule as well.

Keep them as is

@ May 14, 2011 1:42 AM in Single vs double glazed flat panel collectors

I worked for Solaron in 1982-1983. By then we made our own single glazed liquid panels. Hot air panels usually had double glazing.

Depending on the construction, removing the inner glass panel could be difficult and you might compromise the water tightness. Of course you don't want to remove the outer glass because you'd make a little swimming pool. As Rod indicated, some double glazed panels are built like window glass, and both pieces of glass are hermetically sealed to each other, making removal of one pane nearly impossible.

Assuming a four person family, if you have only two panels, remove a pane and tilt them at latitude. If you have 4 panels, tilt them at latitude plus 15 and keep all the glass. You will get more in the winter but still have plenty in summer. If you have 3 panels, then play with Fchart to decide what to do.

Where do you live?

@ May 10, 2011 6:13 PM in Single vs double glazed flat panel collectors

And what's the collector tilt? A high tilt favors keeping the two panes, a low tilt favors removing one pane.

Your climate would be considered a "heating climate" if your heating degree-days (HDD) are greater than 3-4000/yr.

If you're in a warm climate or "cooling climate" you should remove one pane of glass.

Double pane liquid panels are extremely rare, which means the manufacturers typically didn't think the extra cost and added weight were worth the extra energy collected. But it should help performance when the temperatures are lower.

These are just rough guesses. A much more accurate answer could be obtained with an f-chart simulation, but you'd need lab test results for the collector in question. The lab report for a similarly constructed panel might be close enough for a decent simulation.

ECO switch Opens at 180F

@ May 9, 2011 10:40 PM in Simple question

And it must be manually reset.

It Didn't Work

@ May 9, 2011 8:19 PM in "Steam Pumping"

For what it's worth, I set up a test for my steam pumping idea. Although I achieved steam with the e-tube collector, I didn't get any steam bubble collapsing and percolating like I had postulated.

It happened pretty much like Gordan had predicted, it just steadily did the steamback thing.

Airlock equals no flow

@ May 7, 2011 6:44 AM in Frostproofing evacuated tube SHW

Bubbles usually get flushed out of hydronic systems by fast -moving water.

The fluid velocity in a drainback solar panel is relatively low during the filling phase. If the there's a bubble, there's no heat collection. Steam bubbles could be another problem with u tubes.

Any pipe smaller than 1/2" is risky to drain if it has a low slope. 1/4" can hold several inches of water due to surface tension/capillary action.

If you are developing a relationship with sunmaxx, they have a few engineers on staff you could ask.
Monday's webinar is the perfect place to ask if they recommend u-tubes in drainback:
http://www.solarwebinars.com/solar-hot-water-webinar-schedule/

Remember, evacuated tubes are only preferable to flat plates when you need water over 160F all the time.

doubt it

@ May 6, 2011 2:20 AM in Broken evac tube.

I think he believes that this fluid doesn't expand on freezing. Since I'm sure that It's mostly water, I don't. But since I found just a few drops, and surface tension draws water up the sides of the pipe, there isn't any room for an ice plug. But that's way too hard to explain in Chinglish.

U tubes

@ May 5, 2011 9:41 AM in Frostproofing evacuated tube SHW

SunMaxx is a Chinese collector, like all the e tubes. But they have invested a ton of money in their US distribution and support. Apricus has been around longer, but don't seem to be as well organized.

A U tube collector on its side might work, but I'd want to test it with filling it during dry stagnation. Also, getting the tilt just right would be very tricky. Tilt it one way it might airlock, tilt the other way, it won't drain.

Antifreeze

@ May 4, 2011 3:43 PM in Frostproofing evacuated tube SHW

If you use u-tubes, you're probably stuck with antifreeze. If you use antifreeze, you should plan on "steamback":
http://www.solarwebinars.com/fundamentals-in-steamback-design-11082010/

The reason I wouldn't use drainback with u-tubes is because they won't drain right side up, and they won't purge the air reliably if they are mounted upside down.

But back to your original issue, heat pipes will not have freeze damage unless you get a bad batch, heaven forbid.

Heat pipe fluid mystery cont'd

@ May 4, 2011 3:34 PM in Broken evac tube.

After I drained a heat pipe, I put the fluid in the freezer. It freezes solid.
So the small amount of fluid is really the freeze protection method.

The vapor pressure of the fluid is higher than pure water, though, so there probably is a little alcohol. Just not enough to prevent freezing at 0 deg. F. There's more condensation on the sides of the storage bottle I have it in, than in similar bottle with only water.

I have a building

@ April 26, 2011 2:00 PM in vapor heating system with naturally induced vacuum

Igor,

I'd love to convert my 22 unit apartment building to to VHSNIV.
It's in Denver though.

The vacuum part of it is what eluded me in a previous train of thought on the subject:
http://www.heatinghelp.com/forum-thread/127890/High-Efficiency-Steam-boiler-thought-experiment

15-100

@ April 26, 2011 9:06 AM in Drainback booster pump question

HR,
Then what wattage does the 15-100 use for steady state pumping?

Vacuum could take the boiler efficiency from 80% to 98%

@ April 25, 2011 12:21 PM in New steam mini tube system installed in my own house. (Iron Fireman style)

A condensing boiler can be used for the heat source if you employ a steam generator of some sort. Vacuum could take the boiling temperature right down to the sweet spot of today's condensing boilers. The steam generator could be a partially filled sidearm water heater, with boiler water circulating thru the coil.

The water in the sidearm could be rapidly boiling away at 140F, but the condensing boiler would still be in it's desired pressure range, say 12psi.