Ultra-Fin Up Date

cnmdesign

Hot Rod

Any chance of getting this post reopened and get some up dated information on Ultra-Fin.
Did you ever post your results from the below link?
https://forum.heatinghelp.com/discussion/100204/ultra-fin-whats-the-deal

You don't really bet the farm on this product, but on the other side you don't really shoot it down.

Thinking of using this in the winter of 19-20. My hardwood floor ranch is 35x50 with 40 straight totally open joist bays. Perfect for this application. Not looking for specifics directly related to my home , just a general thought out consensus on the concept and some up dated real life results with up dated equipment.

After listening to and watching all of your Coffee with Caleffi vids (some as many as 3 times), I've seem to come to place your opinions and answers on here above most if not all the others. Thanks for all you do.

P.S. To all others on here, I do value your professional opinions and take them into account as well, just a little bias towards HR.

hot_rod

It has a place, it will warm the joist bay which in turn warms the floor. Requires higher SWT to get convection currents moving.

Really the best output of a radiant floor, wall, ceiling is directly related to the surface temperature.

That surface really doesn't know how it was warmed or care.

I think we all agree that air is a less desirable way to move energy, conduction with plates is a stronger transfer.

Here is a look at start up, after a few minutes, and the floor from above. Pretty clear that it is warming the surface.

Always the best flooring is thin and hard surface, carpet and pad or throw rugs not so good.

The room by room load calc will indicate what you need from the floor to git er done.

cnmdesign

hot rod said:

It has a place, it will warm the joist bay which in turn warms the floor. Requires higher SWT to get convection currents moving.

Do you remember what the floor surface temp ended up being and what your sq/ft btu requirement was on this project? Was 106 your SWT? No biggie if you can't remember. My sq/ft btu requirement is 23. Will try to use 145* to start with and hope it's lower. Theoretically, is this possible with this system? I live in SE Ohio.

hot_rod

You will get 2 btu/ square foot output for every degree difference between the floor surface temperature and ambient air

82F floor surface -68F = 14X2= 28 btu/ sq.ft.

Or if you prefer warmer space 82- 70 = 12X2= 24 btu/ft

The question becomes what supply temperature will get you to 82F surface.

That depends on floor surface, downward loss thru the under slab insulation, and transfer between the tube and concrete in the slab.

Tight ∆, like no more than 15° will help get you a consistent floor surface temperature, as will tighter tube spacing, 6" is nice for even floor surface temperature and lowest SWT.

As I recall you mixed some foam in the concrete? Now we will see if, or how much that cost you in heat transfer to the floor surface.

cnmdesign

hot rod said:

You will get 2 btu/ square foot output for every degree difference between the floor surface temperature and ambient air

82F floor surface -68F = 14X2= 28 btu/ sq.ft.

Or if you prefer warmer space 82 -70 = 12X2= 24 btu/ft

The question becomes what supply temperature will get you to 82F surface.

Thanks
Looking for the 82- 70.

Am I understanding this right?
It takes 28 btu/sqft to heat a room to 68* and only 24 btu/sqft to heat it to 70*? I think there is some training I'm missing. I understand the math and results, just not the lower temp requiring the higher BTUs.

Hoping the Ultra-Fin doesn't require a SWT higher then 149* to achieve the 24 btus, so I can get some benefit out of my condenser.
The whole first floor will be one zone. Should help with the cycling.

No concrete involved fins are in floor joist. Think that was someone else.

hot_rod

cnmdesign said:

hot rod said:

You will get 2 btu/ square foot output for every degree difference between the floor surface temperature and ambient air

82F floor surface -68F = 14X2= 28 btu/ sq.ft.

Or if you prefer warmer space 82 -70 = 12X2= 24 btu/ft

The question becomes what supply temperature will get you to 82F surface.

Thanks
Looking for the 82- 70.

Am I understanding this right?
It takes 28 btu/sqft to heat a room to 68* and only 24 btu/sqft to heat it to 70*? I think there is some training I'm missing. I understand the math and results, just not the lower temp requiring the higher BTUs.

Hoping the Ultra-Fin doesn't require a SWT higher then 149* to achieve the 24 btus, so I can get some benefit out of my condenser.
The whole first floor will be one zone. Should help with the cycling.

No concrete involved fins are in floor joist. Think that was someone else.

Sorry, I was thinking about another post.

The heat output, any heat transfer depends on a temperature difference, called a delta T.

the laws of thermodynamics state , hot goes to cold, and the rate of transfer depends on the delta T.

The wider the delta between the two, the more the heat transfer. So a cooler space with the same temperature emitter will have a higher output. As the temperatures get closer together, less delta.

The output you ending up needing constantly changes as then load on the space changes. On the coldest day you will probably need the highest temperatures, less than design days lower temperature.

When the temperature indoor and outdoors is the same, your delta is zero, no heat transfer is possible or required.
that will be your lowest SWT condition and the most efficient operation condition.