Anyone a self proclaimed hydronics/solar expert?

[ducpainter]

Idk-I'm not a thermal guy. 

Me too.

[rgramjet]

The "thermal guys" are going to say, "idk, we're not dhw and slab guys".

The suggestion to call Schuco wasn't any sort of "pitch" just a short path to the answer you seek.  They size new systems all the time and I'm sure they have it down to a boilerplate calculation.  The answer you are looking for might be but a phone call away......

Why a db system?

[The Architect]

I think you're on your own on this one Nate.

Here's the problem, those guys like/want hard numbers.  Even with the hard numbers it's a bit of witch craft.  When you create your own collector and storage tank that make its hard to provide accurate values.  i.e. how many btu's do you plan on getting out of your collector per day?

It would be best to talk to someone who has experience with this.

Based on my experience, if you can get that tank to 100 - 120 degrees and the insulation method your going to use will make heating that place a breeze.  And with the 1000 gallon capacity, you'll go many days without sun.

It's going to be a bit of an experiment for you.  If your home made collector isn't cutting it then you need to add more or modify it. 

My only recommendation would be to avoid fin tube radiators on the second floor.  You don't get much out of them at 100 degrees and they will needlessly draw a lot of heat out of the tank.  I understand you're reluctance for the radiant flooring but it is done everyday on wood structures.  You also have the option of using radiant boards. 

[Ddan]

The problem I see with radiant here is that it's inherently slow to react to temp swings, especially in the slab. ANother thing to consider is with this hybrid system you're proposing, you need to circulate different temps to make it work right.  As frank pointed out, fin tube needs more than 100 degrees to work at all, same with radiant in the slab.  Radiant in the floors above will likely need more than 100, but way less than the slab.  In trying to make this simple, you're getting pretty complex

[ungeheuer]

I havent been paying attention so if this has been covered.... well too bad....  . 

Have you considered a heat pump for DHW and adaption to hydronic heating?  I've been running an older version of the thing below for a few years now....  mine has 3 large evap panels externally mounted on the roof... so its a little more efficient (and less noisy) than the new "compact" fan driven models, but the technology is the same.....   Works well even in winter/at night (of course what I call winter almost never includes anything as severe as snow).



I like this as an idea for a larger do-it-yourself air-con>DHW conversion too:



It constantly annoys me that I own one heat pump to extract heat from the environment for storage inside a unit to heat water....... and another heat pump to expel heat from a storage compartment into the environment to keep beer cold.  Every household owns a fridge and a hot water service, these two units should learn to work together, dammit!

[ducpainter]

The problem I see with radiant here is that it's inherently slow to react to temp swings, especially in the slab. ANother thing to consider is with this hybrid system you're proposing, you need to circulate different temps to make it work right.  As frank pointed out, fin tube needs more than 100 degrees to work at all, same with radiant in the slab.  Radiant in the floors above will likely need more than 100, but way less than the slab.  In trying to make this simple, you're getting pretty complex

I don't think I'll have swings in the slab. I can make the system circulate water from the warm parts even if the system isn't calling for heat.

I'm not married to fin tube, I just don't want to be the guy to put a nail through the pex when the flooring goes down...do you?

You have to circulate 2 different temps with radiant on the second floor also. That's what mixing valves are for.

The "thermal guys" are going to say, "idk, we're not dhw and slab guys".

The suggestion to call Schuco wasn't any sort of "pitch" just a short path to the answer you seek.  They size new systems all the time and I'm sure they have it down to a boilerplate calculation.  The answer you are looking for might be but a phone call away......

Why a db system?

I didn't take it as a pitch.

I have to use either drainback or glycol and drainback is more efficient as it requires one less HX

I havent been paying attention so if this has been covered.... well too bad....  .  

Have you considered a heat pump for DHW and adaption to hydronic heating?  I've been running an older version of the thing below for a few years now....  mine has 3 large evap panels externally mounted on the roof... so its a little more efficient (and less noisy) than the new "compact" fan driven models, but the technology is the same.....   Works well even in winter/at night (of course what I call winter almost never includes anything as severe as snow).



I like this as an idea for a larger do-it-yourself air-con>DHW conversion too:



It constantly annoys me that I own one heat pump to extract heat from the environment for storage inside a unit to heat water....... and another heat pump to expel heat from a storage compartment into the environment to keep beer cold.  Every household owns a fridge and a hot water service, these two units should learn to work together, dammit!

You're trying to confuse me...huh?

[Ddan]

It's not the temp swings in the slab that are the problem.  It's not unusual we get nights that are sub-zero and days in the 30's.  The radiant just doesn't react fast enough and you wind up cold during the lows and hot when it warms up.  Your high R value will help, but it's still something to be aware of.  and mixing valves won't help if you need to circulate 160 water through the slab and you've only got 100.

I've put down lots of floors over tubing, and if you put a nail in it, either you or the plumbing installer screwed up.  A glue-down floor is also an option

[ducpainter]

It's not the temp swings in the slab that are the problem.  It's not unusual we get nights that are sub-zero and days in the 30's.  The radiant just doesn't react fast enough and you wind up cold during the lows and hot when it warms up.  Your high R value will help, but it's still something to be aware of.  and mixing valves won't help if you need to circulate 160 water through the slab and you've only got 100.

I've put down lots of floors over tubing, and if you put a nail in it, either you or the plumbing installer screwed up.  A glue-down floor is also an option

I'm aware of the slow reaction time. There are devices that can anticipate to a certain extent and minimize the delay

Do you have any idea how much I'm looking forward to sweating in the winter in the house?

Fin tube works at any temp over what you're looking for as room temp. It just doesn't work as fast. Plus I'm planning on having the solar water run through the fossil fuel device. It's easier to heat 100 degree water than 50 degree water.

I think Frank is right though about it killing the temp in the storage with it's requirements. I know wirsbo makes diffusers that not only increase floor contact, but also space the tubing off the deck. Maybe I'll just have you install the flooring. You don't seem scared.

[The Architect]

With the insulation system, even in the coldest of days, the slab will only require temps in the 80's.  Maybe the 90's if he turns off the system and wants to get it going again.  That is the beauty of the concrete slab.  If he decides to cover the slab with carpet or wood then that's a different story.  He will need higher temps.

His goal is to insulate well, get the mass up to temp, maintain the temp and boost the system if needed with propane.

The real difficulty will be getting the system as low maintenance as possible and the controls.  Ugh the controls.  Nate may have more patience than I.  So the controls may not be as difficult for him.  

Simple things to be cautious of; you don't want the propane to boost the storage tank, only the slab, you want to be able to temper the water in the warmer temps, where does the cooler water come from and you want to returnt hat cooler water to the storage tank, etc..................

[ducpainter]

With the insulation system, even in the coldest of days, the slab will only require temps in the 80's.  Maybe the 90's if he turns off the system and wants to get it going again.  That is the beauty of the concrete slab.  If he decides to cover the slab with carpet or wood then that's a different story.  He will need higher temps.

His goal is to insulate well, get the mass up to temp, maintain the temp and boost the system if needed with propane.

The real difficulty will be getting the system as low maintenance as possible and the controls.  Ugh the controls.  Nate may have more patience than I.  So the controls may not be as difficult for him.  

Simple things to be cautious of; you don't want the propane to boost the storage tank, only the slab, you want to be able to temper the water in the warmer temps, where does the cooler water come from and you want to returnt hat cooler water to the storage tank, etc..................

That is one of the reasons for a drain back system...low maintenance.

We have a resident control expert on the forum...his services will be utilized.

I think an anti scald valve will do all the tempering required for the DHW, and that valve requires no return as it only uses the volume of storage water required. A tempering valve does the same for the radiant heat. A back flow preventer will eliminate fossil fuel heating of the storage.

[The Architect]

We have a resident control expert on the forum...his services will be utilized.

Best move on your part   

And as far as the radiant heat on the second floor.  Worst case scenario; you drive a nail through the tubing, the nail will actually seal well and not leak, the project is completed, eight months later you notice a clear water stain, you look for roof leaks but find nothing, the leak gets worse, you open the ceiling and curse Dan and Frank, T is completely annoyed she has just lived through construction and the last thing she needs is to deal with demolition dust and drywall dust, you make the repairs and live life happily ever after...........

[Ddan]

With the insulation system, even in the coldest of days, the slab will only require temps in the 80's.  Maybe the 90's if he turns off the system and wants to get it going again.  That is the beauty of the concrete slab.  If he decides to cover the slab with carpet or wood then that's a different story.  He will need higher temps.

His goal is to insulate well, get the mass up to temp, maintain the temp and boost the system if needed with propane.

The real difficulty will be getting the system as low maintenance as possible and the controls.  Ugh the controls.  Nate may have more patience than I.  So the controls may not be as difficult for him.  

Simple things to be cautious of; you don't want the propane to boost the storage tank, only the slab, you want to be able to temper the water in the warmer temps, where does the cooler water come from and you want to returnt hat cooler water to the storage tank, etc..................

I agree the controls are going to be the key.  I don't think there are going to be off-the-shelf answers for what's going to be a very one-off system.  Somehow he's got to have enough adjustability to make it work with some trial and error.  

[Ddan]

Best move on your part   

And as far as the radiant heat on the second floor.  Worst case scenario; you drive a nail through the tubing, the nail will actually seal well and not leak, the project is completed, eight months later you notice a clear water stain, you look for roof leaks but find nothing, the leak gets worse, you open the ceiling and curse Dan and Frank, T is completely annoyed she has just lived through construction and the last thing she needs is to deal with demolition dust and drywall dust, you make the repairs and live life happily ever after...........

\

Or.  You do the floor above before the sheetrock below.  Problem Solved 

[mitt]

One of the other advantages I have read of a DB system versus a glycol is the number of walls you need in any HEX'rs that come into contact with potable water.  If you use a water DB all around, you can use single wall.  If you use glycol, you need a double wall HEX.  I can't remember if dp is planning on heating potable water with this system or just the slab???


mitt

[The Architect]

One more thought, the instant domestic hot water heater, make sure to purchase one of newer systems.  The older units are activated by a certain water flow and a delta water temp of 20 degrees.  Sending 101 degree water through the unit when your asking it to create 120 degree will not get it to fire. 

The newer unit look for a delta of 3 degrees and require much less flow (thanks to the new very low flow fixtures.)