DIY Hydronic Floor Heating - Page 31

Drake · 03-26-13, 10:41 PM

Sorry randen, first floor will be a 4" poured engineered double arched floor spanning 16' resting on a load wall. Second floor radiant area will be poured atop steel pole barn metal deck(which someone else from europe has also done). When tiled it will be 1.5" thick. The warm board approach is also a good way to go I just want the thermal mass for passive solar storage.

My heat will be from a number of sources but will all be stored in at least one buffer tank. Still researching open vs closed floor loop. I am not doubting anyones experience, expertise or recommendations as to which is better but there are very passionate aurgements for both which I want to explore before deciding. I will only need a two loop system so I want to keep it as simple as possible. It would be must easier for all of us that are trying to DIY conserve home energy if there was just one same thing for all of us everywhere. The variables of what we are starting with, where we live and what we want in the end, our skills can be many. So in the attempt to share info and experience to lend a hand to each others goal we are trying to determine what is constant from what is variable on the edge of what is yet not even fully defined. I thank anyone that throws me a bone in my journey to better energy saving.

I also thought the warmmfloor staple up application looked sparse but the heating info in slabs appear reliable(unless they doctored the IR photos).

AC_Hacker · 03-27-13, 12:41 AM

Quote:

Originally Posted by Mikesolar

That "warmmfloor" company has some big mistakes in the picture alone. One is that the plates are spaced way too far apart to be effective, you need 2 runs per joist space to be effective...

Could you please explain what you mean here? I'm having a difficult time making any sense of what you have written.

-AC

Mikesolar · 03-27-13, 05:20 AM

Quote:

Originally Posted by AC_Hacker

Could you please explain what you mean here? I'm having a difficult time making any sense of what you have written.

-AC

That's the easy part. It may be no problem to heat a floor in some parts of the the US where the heat load is 5btu/ft2 but when you get to MN or Toronto, that won't do. Staple up starts with inferior conductivity of wood (and maybe more wood on top), spread the heat out so that it is quite difficult to meet that load with 90F water so we have to bump up to 120F (which removes the Heat pump as a viable heat source).

All the tables I have seen start with no more than 12" spacing, and that is in concrete. One tube in one joist space is 16". IIRC, this wide a spacing is not in the manuals because it cannot produce much heat. I will find the sheets and post them.

AC_Hacker · 03-27-13, 08:05 AM

Quote:

Originally Posted by Mikesolar

That's the easy part...

Oh, so you weren't even commenting on Warmboard at all...

Sorry,

-AC

Mikesolar · 03-27-13, 09:31 AM

Quote:

Originally Posted by AC_Hacker

Oh, so you weren't even commenting on Warmboard at all...

Sorry,

-AC

Nope, the company in the link above is not the same as the one who makes "warmBoard". Warmboard is an OK product......I still like cement tho....

michael · 03-30-13, 12:51 AM

Apropos of nothing, I'd like to report on some recent work on our radiant system. Strange that I've never done this before, and the system has been in place 25 years, but I suppose reading all these posts has made me curious to know more about how these things work. Ours has 2000 LF of 1/2" polybutylene plus a few feet of larger pipe in and around the manifolds. I calculated that the water content of the entire system is approximately 22 gallons, that is, on the floor side of the heat exchanger. Water enters the floor at 110 degrees and exits at 85, a 25 degree drop. The Taco 007-F5 pump is rated to move 0 to 23 gpm up to a maximum head of 10'. I put a flow meter in the return line and clocked the results. There's a lot of momentum in that 22 gallons, and it took moving about ten gallons through the line before the water movement stabilized at 2.2 gpm, and there it stayed for the next ten minutes. That means the resistance to flow in those pipes comes to an effective head of around 9.5'. It takes about ten minutes for the contents of the system to make one complete circuit, and in that circuit roughly 4500 BTUs are transferred from the water to the floor. In an hour of operation (circulator on), roughly 27000 BTUs are delivered to the house. I have installed a clock on the Taco, so that every time the pump runs, the clock will run as well, and I've started a list of high and low temperatures for the day, and I'm going to observe the relationship between run time and outdoor temps. This is just for fun, but it may in some way help me design the next system, and it may help me decide how large a heat pump will be required when this system is switched from oil fired water heater to heat pump.

Currently, I am made to wonder if the Taco circulator is undersized. A higher rate of circulation would warm the floor faster, but since the floor is never allowed to cool more than just the daytime thermostatically controlled shut down due to warm weather, it doesn't seem like a problem. The Taco isn't working any harder than it would if the water were moving faster as far as I can tell.

I have some photos of the set up, and I'll see if I can't get them to post here after I switch to another computer. The photos show the set up with the flow meter, the tempering valve, water temps before and after the tempering valve and a bad shot of the clock.

Mikesolar · 03-30-13, 08:31 AM

Quote:

Originally Posted by michael

Apropos of nothing, I'd like to report on some recent work on our radiant system. Strange that I've never done this before, and the system has been in place 25 years, but I suppose reading all these posts has made me curious to know more about how these things work. Ours has 2000 LF of 1/2" polybutylene plus a few feet of larger pipe in and around the manifolds. I calculated that the water content of the entire system is approximately 22 gallons, that is, on the floor side of the heat exchanger. Water enters the floor at 110 degrees and exits at 85, a 25 degree drop. The Taco 007-F5 pump is rated to move 0 to 23 gpm up to a maximum head of 10'. I put a flow meter in the return line and clocked the results. There's a lot of momentum in that 22 gallons, and it took moving about ten gallons through the line before the water movement stabilized at 2.2 gpm, and there it stayed for the next ten minutes. That means the resistance to flow in those pipes comes to an effective head of around 9.5'. It takes about ten minutes for the contents of the system to make one complete circuit, and in that circuit roughly 4500 BTUs are transferred from the water to the floor. In an hour of operation (circulator on), roughly 27000 BTUs are delivered to the house. I have installed a clock on the Taco, so that every time the pump runs, the clock will run as well, and I've started a list of high and low temperatures for the day, and I'm going to observe the relationship between run time and outdoor temps. This is just for fun, but it may in some way help me design the next system, and it may help me decide how large a heat pump will be required when this system is switched from oil fired water heater to heat pump.

Currently, I am made to wonder if the Taco circulator is undersized. A higher rate of circulation would warm the floor faster, but since the floor is never allowed to cool more than just the daytime thermostatically controlled shut down due to warm weather, it doesn't seem like a problem. The Taco isn't working any harder than it would if the water were moving faster as far as I can tell.

I have some photos of the set up, and I'll see if I can't get them to post here after I switch to another computer. The photos show the set up with the flow meter, the tempering valve, water temps before and after the tempering valve and a bad shot of the clock.

I only have a moment to comment at this time but the first thing I would say is that the dT will be highest when responding to a cold slab and it should reduce as the slab warms. Second, polyB tubing, does have issues with erosion due to higher flow rates so I would keep the rate where it is or even reduce it a bit. Don't worry about the time to heat up the house. Floor heating in a slab is not supposed to have a high degree of set back (or any at all) at night so it shouldn't be a big issue.

AC_Hacker · 03-30-13, 05:29 PM

Quote:

Originally Posted by michael

...I'd like to report on some recent work on our radiant system...

Thanks for the post and I'm really interested in any additional information, too.

I'd be interested to know what your loop spacing is, and I'd also like to know if your loop is all one circuit, or if it's composed of parallel branches.

You did mention that there was a slab involved. Since you didn't indicate otherwise, I assume that your slab in on the ground. Is there any insulation under the slab? If yes, how much?

Do you have any information about the insulation in your house? Walls? Ceiling? Window configuration? Single glass? Double or even triple glass?

I did a Heating Degree Day check. Ukiah was the closest I could find, and your average HDD is 4886. Which is pretty moderate, not so different from Portland, my fair city.

Best,

-AC

Drake · 03-30-13, 05:29 PM

Can different diameter pex be run off the same manifold if each loop has near equal flow resistance? Are there numbers for # of feet of various dia tubing for flow resistance? Like ?' of 1/2" is same as ?' of 3/4". Would the flow restriction of a max 1/2" loop be same as max 3/4" loop?

Mikesolar · 03-30-13, 05:37 PM

1/2" of PEX is only slightly different than 1/2' of PB so, yes, you can run what you would like but the flow rate for 3/4" is quite different and is typically only used in large commercial buildings, warehouses and the like. There will be a hard time getting consistent floor surface temps with 3/4" tubing.

03-30-13, 12:51 AM	#306
michael Michael Join Date: Feb 2013 Location: mendocino, california Posts: 67 Thanks: 7 Thanked 2 Times in 2 Posts	Apropos of nothing, I'd like to report on some recent work on our radiant system. Strange that I've never done this before, and the system has been in place 25 years, but I suppose reading all these posts has made me curious to know more about how these things work. Ours has 2000 LF of 1/2" polybutylene plus a few feet of larger pipe in and around the manifolds. I calculated that the water content of the entire system is approximately 22 gallons, that is, on the floor side of the heat exchanger. Water enters the floor at 110 degrees and exits at 85, a 25 degree drop. The Taco 007-F5 pump is rated to move 0 to 23 gpm up to a maximum head of 10'. I put a flow meter in the return line and clocked the results. There's a lot of momentum in that 22 gallons, and it took moving about ten gallons through the line before the water movement stabilized at 2.2 gpm, and there it stayed for the next ten minutes. That means the resistance to flow in those pipes comes to an effective head of around 9.5'. It takes about ten minutes for the contents of the system to make one complete circuit, and in that circuit roughly 4500 BTUs are transferred from the water to the floor. In an hour of operation (circulator on), roughly 27000 BTUs are delivered to the house. I have installed a clock on the Taco, so that every time the pump runs, the clock will run as well, and I've started a list of high and low temperatures for the day, and I'm going to observe the relationship between run time and outdoor temps. This is just for fun, but it may in some way help me design the next system, and it may help me decide how large a heat pump will be required when this system is switched from oil fired water heater to heat pump. Currently, I am made to wonder if the Taco circulator is undersized. A higher rate of circulation would warm the floor faster, but since the floor is never allowed to cool more than just the daytime thermostatically controlled shut down due to warm weather, it doesn't seem like a problem. The Taco isn't working any harder than it would if the water were moving faster as far as I can tell. I have some photos of the set up, and I'll see if I can't get them to post here after I switch to another computer. The photos show the set up with the flow meter, the tempering valve, water temps before and after the tempering valve and a bad shot of the clock. Attached Thumbnails Last edited by michael; 03-30-13 at 01:06 AM..

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03-26-13, 10:41 PM	#301
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	Sorry randen, first floor will be a 4" poured engineered double arched floor spanning 16' resting on a load wall. Second floor radiant area will be poured atop steel pole barn metal deck(which someone else from europe has also done). When tiled it will be 1.5" thick. The warm board approach is also a good way to go I just want the thermal mass for passive solar storage. My heat will be from a number of sources but will all be stored in at least one buffer tank. Still researching open vs closed floor loop. I am not doubting anyones experience, expertise or recommendations as to which is better but there are very passionate aurgements for both which I want to explore before deciding. I will only need a two loop system so I want to keep it as simple as possible. It would be must easier for all of us that are trying to DIY conserve home energy if there was just one same thing for all of us everywhere. The variables of what we are starting with, where we live and what we want in the end, our skills can be many. So in the attempt to share info and experience to lend a hand to each others goal we are trying to determine what is constant from what is variable on the edge of what is yet not even fully defined. I thank anyone that throws me a bone in my journey to better energy saving. I also thought the warmmfloor staple up application looked sparse but the heating info in slabs appear reliable(unless they doctored the IR photos).

03-30-13, 05:29 PM	#309
Drake DIY Guy Join Date: Jan 2011 Location: Mpls,MN Posts: 315 Thanks: 2 Thanked 17 Times in 17 Posts	Can different diameter pex be run off the same manifold if each loop has near equal flow resistance? Are there numbers for # of feet of various dia tubing for flow resistance? Like ?' of 1/2" is same as ?' of 3/4". Would the flow restriction of a max 1/2" loop be same as max 3/4" loop?

03-30-13, 05:37 PM	#310
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	1/2" of PEX is only slightly different than 1/2' of PB so, yes, you can run what you would like but the flow rate for 3/4" is quite different and is typically only used in large commercial buildings, warehouses and the like. There will be a hard time getting consistent floor surface temps with 3/4" tubing.