Staple up radiant and a woodstove

Steven_4

We are working with efficiency VT trying to make this building as energy efficient as possible. I posed the question of plates to them and they said that in a house this tight, it would not make much of a difference. They suggested leaving a 2" gap between the insulation and the tubing. We have not yet priced the sytem with plates but are also looking into Buderus panel rads. With the staple up, would you recommend a floor sensor?

Steven_4

Can these two work together?

We are looking into either using staple up radiant on our first floor or buderus panel rads. We will incorporate a wood stove into our floor plan because of the endless supply of wood on our property. Can anyone help us by answering which system would work better with a woodstove. The woodstove would not be run 24/7 but enough to help cut down on the LP bills. We are leaning towards the staple up but would appreciate any help.

ALH_3

Wood

Design the heating system as if the woodstove is not there. There's nothing like deciding you don't want to run the woodstove in a few years and having inadequate heat in the room. Maybe you'll sell the home one day and the future owners won't want to burn wood.

When you run the woodstove the thermostat on the heating system will satisfy and the floor/radiators will shut off. This is where it saves you on the LP bill.

If you'd like to use wood for your hydronic system there are wood boilers available. They're relatively easily incorporated into the heating system with LP backup. They're not necessarily inexpensive or compact.

I'd also steer you away from staple-up and toward extruded aluminum plates. Use the panel radiators if extruded plates are too expensive. They'll work more reliably.

-Andrew

ALH_3

Plates

If you're using a floor covering that is particularly sensitive you might consider limiting the floor temperature.

Plates decrease the response time and increase the potential output of the radiant floor. You can take advantage of modulating, condensing boilers better with the plates because of the lowered fluid temperature.

If the budget doesn't allow plates everywhere, you might want to use plates in the bathroom/kitchen areas and radiators elsewhere. Size the radiators appropriately and you can run them at lowered temperatures. Combination systems work very well.

At lease that's how I would approach the system.

-Andrew

S Ebels

Design difficulties

One of the considerations a free standing wood stove brings into the picture is that it often throws a great deal of heat into one area of the home. This being the case, the ability to zone the main heating system will of more importance to you than rads vs. plates. Keeping this in mind will likely help you make your decision as to which heat emmitter to go with. My personal preference would be panel rads running on outdoor reset for the simple fact that zoning them is a no-brainer. They offer great comfort and excellent controlability. If you have some hard surface floor areas that you want to warm, it might be possible (your heat loss will tell you) to throw a single loop of tube into the associated joist bay just to provide a little floor warming. You may be able to just let these run wild on the reset curve if your system designer pays attention to rad sizing and maximum water temp in the system at outdoor design.

So many options........ Wish I could be there to help. I think these combo systems I described above are my favorite though. They give you all the benefits, great control and response and ooooohhhhhhhhhh, such great comfort.

Nick Dearing

Yes,

if you want to heat your hydronics part with wood, look into wood gasification from newhorizoncorp.com. There models run about $3500 depending on what size you need. They have efficiency ratings of as high as 87%! Wonderful technology.

Bob Gagnon plumbing and heating

I'm going to put plates

in the walls and ceiling around my wood stove to help carry the heat away from that area, but I'm using lower temperature solar heated water. Make sure you have makeup air for the wood stove. Bob

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NORTHEASTER

PLATES

Staple up is a much easier installation. While the plates do reduce the ability of the pex to expand, contract and make noise, and the pex is cheaper, the hose is MUCH easier to install. Pull two loops of each and tell me which is better. Plates are no better than staple up. The heat loss, infiltration and the floor covering dictate water temps and response times.

wetheat1_2

???????????

Puts your hands in the air and step away from the crack pipe! Where did you get this load of non sense? Plates will out perform staple up. The issue is what does the system need not what is easy to install.

Design the system as if the wood stove is not there and then look at the water temperatures needed and what is available. Staple up may or may not work if you are much over 20 btu a square foot or so or if you have high floor covering r values.

NORTHEASTER

Pex plates will perform better than stapled up PEX. If you are using hose and it is inulated properly, the response times and ability to heat the floor are almost parallel. Hose water temps are higher because it is a thicker walled material. The mass of the floor is what ultimately determines our response times and water temps. Can somebody tell me how the plate creates more heat? Do you plug it in, is it magic? No, it is simply a means for us to create constant conact and conducution for our pipe. My point was, if they perform the same (and if you do your homework, they do) why not go with something that saves on labor? Also, hose can be used at much higher than 20 btu's a square, actually even 40 - 45. I don't don't smoke crack, I do my homework.

Mike T., Swampeast MO

Can somebody tell me how the plate creates more heat?

They can't create heat, but they can and do transfer heat in a larger quantity.


You answered your own question as to how, "it is simply a means for us to create constant contact and conduction for our pipe".

Conduction will trump both convection and radiation every time.

To achieve a given surface temperature of the emitter in identical situations of bare vs. plated, bare must have one, some or all of the following situations true:

1) less heat loss per unit of emitter area

2) more surface area of tube

3) higher average temperature of the heating medium

Situation 1) is the best and IMHO is the main reason that bare-tube works in some cases. At definite and not-too-distant points it becomes impractical to add additional tube or increase the temp of the heating medium.

Tony_8

Homework

You better do some more

Plates and PEX, bare PEX, bare "hose" all at 140F water temp. Which transfers more heat to the panel per hour ?

Bonus question : Plates and PEX at 120F, "hose" at 180F. Which uses more energy to get the job done ?

Every method has it's time and place.

ALH_3

Controls

How are you controlling the woodstove heat recovery? How are you making sure it's warm enough to deliver heat to the solar tank? Is it enough btu's to worry about?

Just curious. Have had people ask for this sort of thing, but it's not as easy to control as it seems on the surface and it comes with some potential problems.

-Andrew

Bob Gagnon plumbing and heating

I'm not sending the heat to the storage tank

I'm hoping the radiant in the ceilings and walls will help move the heat from the woodstove area. Bob

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Steven_4

Thanks

to everyone for all of the help. It sounds like the panel rads are the way to go, especially when we factor in the cost of the plates. We will still use staple up in the bathrooms and mudroom, which will be tiled. Just for the record, the crack pipe comment made by WH1 was great.

Dave Yates (PAH)

While we debate

the issue regarding lower water temps resulting in energy savings, other countries are adopting codes and regulations mandating the upper liomits for hydronic systems because they know the answer.

Next ish of Contractor Magazine on ISH has the second of three feature articles & part two includes that info.

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