The Homemade Heat Pump Manifesto

[AC_Hacker]

Originally Posted by Xringer

If you wanted to add a small amount of thermal mass to your floor, without adding a lot of weight, you could add some stone-like,
heat absorbing material in those empty slots. Maybe some cheap Ceramic Tiles?

I was thinking something similar, like maybe some Sheetrock.

-AC_Hacker

[Vlad]

For DIY you are looking for something simple easy to do and inexpensive. Otherwise you hire the contractor, go to work and work 2-3 years to pay what he has done in 2-3 days . On other pictures I can see plywood cut round tubes are sitting in the slot. The advantages of "my" design are:

1 use 1x2 lumber (cheapest)

2 time saving (you cut 1x2 approximately, I can only imagine how much time it will take to cut all rounds and how much waist is left )

3 tubes do not contact subfloor(the bottom) they are suspended in omega shape heat transfer plates, because 1x2 is 3/4 inch high but 1/2tube OD is 5/8 of an inch.
Tubes and transfer plates contact the top layer of black painted plywood. Wood strips do contact the subfloor, but you have no choice. Ideally you want all heat to go up, heat that goes down is waist because it will heat up the structure, the sealing of the lower floor(if you have one) etc. As everybody knows the heat transfer rate depends on area. In my case the contact area part is only fraction of the whole area of the floor because it is only sum of areas of all 1x2.

4 the heat from tubes and plates (which are the hottest part) is reflected by foil toward upper layer of floor making system more efficient.

5 Tubes expend and contract. In my case they are free at the end and can do it.

[Vlad]

I used 1/2 oxybarier pex (the orange one). My runs are in 200-250 feet range. I have 10 zones and will buy 10 zone manifold. I did not finish connecting everything together. I did not buy pumps yet. I am too busy with my rig and other things outside of the house. Ideally I need to finish everything outside before rain starts. A/C Hacker thanks for the manual. Looks impressive.

The other part of heating is ventilation which people usually ignore. With hydronic system you have to set ventilation system. I am going to use HRV unit and I have large coil from walk-in cooler which will be used for circulating cold water(coolant) for cooling supply air in summer.

[Vlad]

Xringer, I might explained wrong about thermal mass. In my case I do not need it. Light (compare to 20 ton of concrete) system will allow to use set back. I will experiment it, it might be not practical to use. I built the whole house from scratch. I am not a builder and had to experiment a lot.

[Vlad]

Heat transfer plates is cheaper and easier to buy then build. You need omega shape. I bought few u-shape to try. U-shape will not hold the tubes you will need to hold tubes in place before cover them. In some places even with omega shape plates I had to use zep-straps to hold tubes down what a hassle.

[Xringer]

Originally Posted by AC_Hacker

I was thinking something similar, like maybe some Sheetrock.

-AC_Hacker

That would be easy to prepare if you had a table saw.. But dusty!
If it was thick enough, it might add to the solidity of the floor, give the top sheet some support.?.
The only thing that would cost less is clean river gravel..?.

[Vlad]

The hardest part of all was attaching the top plywood to the subfloor. I marked everything before the top plywood was in place. You have to be extremely accurate and consistent with you marking. when top plywood in place you can not see tubes. I used floor screws instead of nails. My floor feels like made of concrete. You can not even tell this is wood structure. Even floor in living-room which is 500 sqf and floor is suspended (no walls below for support) feels the same solid.

[Xringer]

You must have done a real good job with the screws, or you have super quality plywood on top. (or both).

I might have missed the details on the "omega shape plates".
They look perfect for collector builders and maybe even to cool the backs of my PV panels..
Did you make them, or buy them pre-formed?

[Ron342]

Vlad - Nice drill rig! Are you going to use 2" well pipe for your drill stems?? 1 1/2 is a lot lighter!

[Vlad]

Originally Posted by Xringer

You must have done a real good job with the screws, or you have super quality plywood on top. (or both).

I might have missed the details on the "omega shape plates".
They look perfect for collector builders and maybe even to cool the backs of my PV panels..
Did you make them, or buy them pre-formed?

With screws you just have to be accurate. I marked the line on the wall and the distance where to put screws. The plywood is just regular (non T&G) construction grade 5/8. I pressure tested every room (tubing) before moving to next room. I had no issues poking the tubing. Heat transfer plates I bought on Ebay. There are few really good pex stores there. There is no point to make your own plates. You will spend more on material. I live in Canada and for me to go to US is a big hassle. For you it is easiest way to shop. You order things and get them to your door.