Heating Help

Copper behind a wall

@ February 6, 2012 11:07 AM in I am stumped....

You're looking for a warmer stud bay. Since the wall isn't copper, you could "see" that.

BTW on bare pipes, you can use cheap flat white or black spray paint to fix the shinyness.

MFDs

@ February 5, 2012 2:39 PM in Best Recirc Demand Control for Multifamily

Mark, point us to that "other thread"
Thanks

Enovative

@ February 4, 2012 3:51 AM in Best Recirc Demand Control for Multifamily

Gary Klein, the hot water guru,
http://www.youtube.com/watch?v=8NglNLqaa6Q
recommends this solution, touted as "THE FIRST AND ONLY DEMAND CONTROLLED HOT WATER CIRCULATION SYSTEM FOR MULTIFAMILY BUILDINGS WITH CENTRAL WATER HEATING"

http://www.enovativegroup.com/

Wait a dang minute! They stole my idea from above, then went back in time and developed it!

ME weighs in

@ February 2, 2012 4:50 PM in Best Recirc Demand Control for Multifamily

In a brief conversation with Mark Eatherton today, he said use a timer and an aquastat.

But he is also apparently working on a better overall solution using a TRV, and Grundfos Alpha-style pumps. Can't wait to see it!

Agreed!!

@ February 2, 2012 2:41 AM in Best Recirc Demand Control for Multifamily

I've landed in the exact situation as you, "Art".

Only I have some experience owning and operating some 20 unit buildings, none of which had recirc.

I'm looking at some larger buildings now, and they ALL have huge pumps running 24/7.

I just started thinking about this today, but had a germ of an idea:

1. Install a flow switch on the water heater cold supply. Then the existing big ass pump will crank on the instant hot water is called for anywhere in the building.
2. Time how long the pumped hot water takes to reach the farthest fixture, and use a time delay relay to turn off the pump after that amount of time. A thermostat near the farthest fixture would prevent the pump restarting until the pipe temperature dropped to 110F.

Of course, insulate the pipes. It's worth it because if someone showers within 1/2 hour of the previous shower, the water is still hot enough, and is therefore not wasted. Without insulation, the water gets cold in 10 minutes. (All estimates are very rough and depend on many variables.)

OR

Install a timer. But the poor guy who needs to shower at 4am would have to wait for his hot water. That would take a LONG time with these uninsulated 1-1/2" pipes. The above system would have no 4am shower problem.

With the first scenario, the pump duty cycle would be cut down from 24/7 to maybe 10 minutes a day, saving at least $20/month.

Any thoughts? ME, how to you see it done around here?

Careful What you Wish For

@ January 29, 2012 4:26 AM in Solar Thermal Alliance of Colorado (STAC)

Yes, we're at the bullseye. But continued low prices for natural gas and high installed costs for solar leave us with an unhealthy solar hot water industry in CO today.

Subsidies, rebates, tax credits and incentives are dubious ways to assist an industry since they temporarily warp the market.

The development of simple, inexpensive, residential solar hot water systems has more long term value.

If you agree, and have some ideas, contact me ASAP. I will be presenting "simple solar ideas" at the World Renewable Energy Forum and ACEEE in May. http://ases.org/index.php?option=com_content&view=article&id=18&Itemid=147
http://www.aceee.org/conferences/2012/hwf

Powder Coat

@ January 23, 2012 12:33 PM in replacement baseboard covers

If the metal pieces aren't dented, take them to the local powder coater.
Or you (or a handyman) can spray Rustoleum on them.
Remember, the factory paint job will look like crap in 12 years, so do something better.

Never, NEVER use latex paint. It has water in it. Water rusts steel.

Torcelli Vacuum comes free in a closed system

@ January 18, 2012 4:23 AM in New steam mini tube system installed in my own house. (Iron Fireman style)

Then at every high point you'd have a Hoffman #60680074.
With those, the vacuum would be re-established with every heating cycle.

And if I'm thinking correctly, the steam generator just needs to be about 40 inches above the basement floor. Then you run a hose from the boiler drain to the floor and fill the system. Once the system is full, and most of the air is removed, then you open the boiler drain and remove water until it stops flowing.

At that point, you've established a good enough vacuum (40"H2O) to boil water at about 100F. I don't think you can pull a vacuum directly on a modern hydronic boiler because it has a low pressure cutout.

"Hartford Loop in the Air Relief Line"

@ January 18, 2012 2:18 AM in Drainback Innovation?

Larry,

If I understand your question correctly, the air relief line must go down after the Hartford Loop because it must go downstairs to the top of the storage tank. Remember, the air relief line must meet the collector return line above all the traps.

The excess air in a drainback system is always stored in the top of the tank during collection. When the pump stops, the air travels up to the collector loop return line to provide air that relieves the suction, and allows the collector loop to drain.

The reason for the Hartford Loop isn't obvious without direct observation: When the collector pump starts up, water wants to enter the air relief line. When steady state flow is reached in the collector loop, it means that a siphon has been established on the return side. When that happens, suction occurs where the air relief line meets the return line. Now air is continually sucked up from the tank and entrained in the return flow.

The Hartford Loop has prevented water from entering the air relief line and possibly getting stuck in a trap somewhere. Water trapped in the air relief line should be sucked out, but if it isn't, it causes pressure differences that pull water up the collector return.

That also explains why the air relief line must be significantly smaller than the collector loop piping. If the air relief line were the same size as the collector loop, any traps in the air relief line wouldn't get sucked dry when the collector pump stops.

Failure Mode?

@ January 12, 2012 9:34 PM in Solar storage tanks

Tom,

Is that algae? What caused the failure?

Right

@ January 7, 2012 9:31 PM in Checking Glycol

But if you live in an area that never sees subzero F temperatures, it's a more "definite" way of checking the freezing point, and can be used to make sure that your $30 hydrometer is telling the truth.

dp

@ January 6, 2012 1:46 PM in Drainback Innovation?

Cheapest Way

@ January 6, 2012 11:45 AM in Checking Glycol

Here's how Thermomax describes a glycol test:

"- To check antifreeze/inhibitor concentration, draw off a small sample at the drain cock and place in the freezer compartment. Remove when frozen then measure temperature at “slush” stage i.e. when ice and liquid are both present. Temperature should be the same or lower than the minimum expected for the locality."

Extra credit to the first Wallie who identifies the problem with this procedure.

Better Explanation With Pictures

@ December 17, 2011 2:43 AM in Drainback Innovation?

Since Gary Reysa at Build it Solar (BIS) is interested in drainback systems, he picked up on this idea.  I provided him some photos and schematics describing the strategy in more detail, and now it is posted on his website.  BIS is rapidly becoming the essential knowledge base for drainback solar as well as hundreds of other home energy saving topics:
http://www.builditsolar.com/Projects/WaterHeating/DBAirLine/DBAirLine.htm

Needs purging

@ December 16, 2011 11:47 PM in solar sand box

Purging the air out is required. Get out the old bucket, a gallon or so more collector fluid, and pump.

After a few weeks, more air will come out of solution and might airlock the pump again. It helps if your pump is at a low spot also. Most closed systems have air removal accessories.

Air line location rules

@ November 20, 2011 10:40 AM in Drainback Innovation?

1. The air line must be installed on the downcomer (return line). It can be at the very highest point in the piping.

2. The connection must be above the first trap by a few feet. (How many feet is one of the design criteria I'm trying to develop)

3. All traps must be inside the heated space, including any traps in the air line.

4. The air line can be uninsulated.

The theory behind this is that water seeks its own level only if the air pressure on both ends of the tube is the same. This air line should equalize the air pressure.

It acts to "break the siphon", so the lower it is, the higher the flowrate can be. If it is at the very top, then the collector pump is operating at maximum head, which is high up on the pump curve. (Maximum head means minimum flowrate). If the air line is connected, say, 5ft. down from the top, then the pump will operate at maximum head minus 5ft., plus the pipe friction head loss.

Matt, having level headers makes sense to me, but I'm not sure it will always work with evacuated tube/heat pipe collectors. Those usually have a header pipe that is larger than the supply and return pipes. That would trap a risky amount of water.

Grumman

@ November 13, 2011 10:14 AM in Drainback Innovation?

"nothing new under the sun" applies here. Do you remember if they put the air line at the highest point on the system, or just somewhere on the return?

Drainback Innovation?

@ November 12, 2011 2:15 AM in Drainback Innovation?

The #1 rule for drainback solar collection loops has always been that both the supply and return must be sloped continuously back to the tank with a minimum slope of 1/4" per foot. That means no traps.

Well...... sometimes the job just can't accommodate rule #1, and we've found ways to break it. You can run a 1/4" air line from the top of the tank (assuming closed loop drainback) to some point on the collector return line above all the water traps. This provides reliable drainback and no possibility of freezing if none of the traps are outside the heated envelope.

With an atmospheric tank, it's a bit simpler, the air relief line can just be a stand pipe about 24" long somewhere on the return line inside the heated envelope.

My question is has anyone you seen systems with traps that work fine, or have you experimented with this problem? Perhaps some design criteria can be developed.

Dead Men Live On

@ November 12, 2011 1:49 AM in Latest Intrepid/EZ-Gas Steamer

I love the natty apron and the old-timey facial hair!

Aluminum Absorbers are Hot in Europe

@ September 21, 2011 9:17 AM in Aluminum Absorbers are Hot in Europe

According to Sun and Wind Energy Magazine, EU manufacturers supplying Al absorbers now outnumber the copper manufacturers. Obviously it's a cost thing.

SWE also says drainback systems are gaining market share in Europe.

Are they compatible? Some of them have all-aluminum wetted surfaces.

Complete darkness = no algae?

@ September 21, 2011 9:07 AM in Customer concerns about algae / growth in combi storage tank

Come to think of it I have seen some sort of algae or plant growing in high temperature hot springs. Temps above 150F even. Never seen it in any solar tank, though.

My working theory is that since algae is a plant, it needs at least a little bit of light to grow.

(But don't mention that fungus likes the dark.)

Vented or closed Drainback?

@ September 21, 2011 1:37 AM in Steamback System Design

A closed drainback system can build up pressure, but an atmospheric tank wouldn't.
So this must have been a sealed system?

We are very interested in hearing more about evacuated tube reliability. Please start a new thread, and by all means, name the manufacturers.