DIY Hydronic Floor Heating

Hi Everyone, I read this thread with interest as we have just developed exactly what you were looking for Hacker. Check out www dot dshh dot info

I like to think of it as:

FREE HEAT FOR LIFE ;-)

We did the development in NZ, and now have interest from all over since we received Patent Pending status.

Our Digital Self-Heating Home system (DSHH) uses sun when available, stores excess summer solar under the slab, integrates log wetback (fireplace Boiler) AND hot water heat pump. In addition we integrated hot water into the package so the HW Heat pump heats the hot water first then the house.

We don't have a presence in the US yet, will be looking for regional key distributors sometime next year, but for now can get the specialized stuff. Realize the Thermal heat core storage is normally put in at time of foundation. It can be put in beside an existing home if the home is thermally efficient and the pipes are in the floor slab.

Any interest should be funneled through info at dshh dot info. We are gearing up for the 110V scenario at present due to interest from Canada.

Cheers for now,

Captron

[AC_Hacker]

Hello Captron welcome to Ecorenovator,

Originally Posted by Captron

Our Digital Self-Heating Home system (DSHH) uses sun when available, stores excess summer solar under the slab, integrates log wetback (fireplace Boiler) AND hot water heat pump. In addition we integrated hot water into the package so the HW Heat pump heats the hot water first then the house.

AC_Hacker here...

First off, I'm not the administrator of this blog, nor do I have privileged status of any kind here. Furthermore I can only claim to speak for myself and not for the other posters on this blog.

So, having said all that... it is my understanding that this blog is not a target for sales information (with the exception of the irritating insert adverts that diminish the usefulness of this blog for everyone). Rather it is a space where people with the skills and gumption and not unusually, very little money, share information about systems and structures that they have conceptualized or constructed or re-purposed, with the ultimate goal of reducing their energy consumption.

In short we are an innovative, resourceful, and relentlessly determined lot.

So, if you actually read a bit on this blog before you posted, you may well have already realized the kind of 'room' you were walking into before you spoke.

Having gotten all those bits of my own opinion out of the way, I looked at your web site and it looks like your company has learned many of the lessons of Passivhaus, regarding insulation, sealing, etc. I am interested in the details of your underfloor heat sink concept. I couldn't find enough info on your site to be of any use to me.

So for the sake of illustration, if you were building a home that was 2000 square feet in area, and the climate was such a severity that it required one Ton of conventional heating & cooling (1 Ton = 12,000 BTU/hr = 3.5 KW-h)...

• How much mass would you allow for the floor heat sink?
• Does your design system account for the large range of ground temperatures you might encounter in Finland, Alaska, Southern Spain, Caracas, etc.?
• Would you use regular cement or does your system also feature change of state additives (Phase Change Material)?
• If it does use PCM, what is the formulation?
• Are you running PEX through the slab for heat storage and heat reclamation?
• What kind of PEX spacing do you usually use?
• Are you running straight water or do you use antifreeze?
• How much insulation would you place under the floor to reduce loss?
• What percentage of heat do you estimate is nin-recoverable (lost) from your slab?
• How do you deal with interior summer heat while you are heating the thermal mass?
• Are you using radiant floor heating or have you placed an insulating layer over the heat sink structure and under the floor?
• Are you using inverter type mini-split heat pumps or are you going with inverter type central heat pumps and zoning the various areas of the house?
• Does your scheme use continuously variable brushless fans for ventilation?
• Are you employing HRV or ERV in the ventilating system?
• Are you using cross-flow, counter-flow or enthalpy wheel exchangers?
• How many airc hanges per hour do you design to?
• Do your wall structures use a separate, inside utility-wall to prevent insulation wall intrusion?

I'm sure there are many more questions...

Best Regards,

-AC_Hacker

Hi A.C., Yes, I hear ya, but think: How would you have introduced this to someone who has already expressed the need/interest when you had that ability sitting in your lap? It certainly wasn’t a "blatant" plug. You are being introduced to a product not yet in the states; we will be looking for a master distributor next year and you will hear much more about it then. Think you have been given an inside hint about what’s coming in an area you obviously love.

There are great questions, have a closer look at the site and our methodology will begin to make itself felt. It's not a "see all do all" solution for all locations, but for many places it is.

So for the sake of illustration, if you were building a home that was 2000 square feet in area, and the climate was such a severity that it required one Ton of conventional heating & cooling (1 Ton = 12,000 BTU/hr = 3.5 KW-h)...
• How much mass would you allow for the floor heat sink?

DSHH: We don’t tell everything on line or we cut our own throat, however: The design is a balanced system designed roughly for lowest cost in a give area with a give heat requirements. Sometimes this will only allow us to offset the heating load, which is why we added the Hot Water Heat pump and log wetback options.

We have an energy efficiency requirement to meet design parameters. It is engineered around certain fixed (Winter vs summer, temp expectations, thermal leak factor) & Variable parameters (Solar insolation factors, roof or adjacent real estate, water table level, earth type etc).

Based on the moderately high rate of loss given, this would be a moderate to cold climate in winter depending upon thermal efficiencies of the home. Missing from the equation is the heating window, for how long, or at what point do you no longer need to heat the home. These are just a few of the things we factor in.
In general we would ballpark this as 1.6CuM of Earthen thermal mass per SqM of warmed floor area. Thus for every SqM of floor space, we would design in roughly 1.5 SqM of thermal mass. This does not translate well into 1SqFt to 1 CuM.

To put this in perspective, for this guestimated design: One SqM = 1.5CuM of thermal mass. (3.29Sq Ft = 53Cu Ft) Thus we heat from the op an area about 1.6SqM deep for every SqM of Heated floor space. (5.25 deep per 1 Sq Ft)

• Does your design system account for the large range of ground temperatures you might encounter in Finland, Alaska, Southern Spain, Caracas, etc.?

Qualified Yes, however the law of diminishing returns forces us to assume a stance of offsetting the heat demand at a certain point, vs supplying all of it.

We are beginning tests in Canada next year in a location where winter temps get down to -45/-60c (-49f/-76f) in N Alberta. We have to figure out where to stop. In this area frost levels are 1.2M (4’) deep or more.

So far in NZ we have not had to add supplementary heat to any of our homes beyond solar and occasional use integrated log wetback use. We now have systems well into winter conditions of -15c (05f). As this is the only heat we have insisted they install a moderate How water heat pump which we also integrate into the hot water providing lower cost hot water on non solar days. We now are putting homes into one of the coldest towns in NZ, in the alpine region of the country.

• Would you use regular cement or does your system also feature change of state additives (Phase Change Material)?

No we use only require std 20MPa concrete and only in our ICF sub walls, we don’t specify the cement portion to the concrete at all.
We do have users who included insulation particles and air-entrainment, but with decent ICF thickness and the use of 90mm (3”) drain-flo EPS on the outside or inside of this thermal insulation levels are significant enough to contain most of the heat injected during the summer.

Remember, the bane of solar heating is not that it doesn’t work, but rather you need help over the dark days and bad weather. When you engineer the solar system to provide enough winter heat, you have huge summer overloads of energy, and rather than shut part of the system down in summer we inject the huge quantity of heat into a poor thermal mass which becomes saturated over time, doming down beyond 2.5M (8ft) below the insulation under the slab.

Visualize this as an 8 ft deep containment system the whole size of the house and you begin to get the feel of the huge area/qty of heat we are storing, usually just in time for winter if we have our calculation right, the thermal mass at the op sits in the 60-80c (140-175f) range after min 5 years of dumping vast amount of Kw of energy over every summer day and most of the should seasons, and much of the winter as well, as most of the solar array is quite large.

FYI I would guesstimate the solar array to be capable of min 13Kw, or over 280 Evacuated solar “U” tubes. These tubes still work well although at diminished capacity even down past 18c (0f)

• If it does use PCM, what is the formulation?

No, as it mentions on the website and above we use low cost in-situ earth, contained in ICF. It HAD to be low cost to work and be attractive, and not decrease carbon credits.

• Are you running PEX through the slab for heat storage and heat reclamation?

We run triple layered JH O2 proof pipe in both the slab and core, but at differing thicknesses and spacings.

• What kind of PEX spacing do you usually use?

We have to keep some things under our belt now don’t we ;-) Also we don’t normally use PEX

• Are you running straight water or do you use antifreeze?

Cold areas: System limited to 100c @ Min 35PSI use 50/50 Glycol

• How much insulation would you place under the floor to reduce loss?

Not much needed as it only serves to isolate the hot heat core from heating the slab in summer. Normally we use 90mm of HPDI special under floor high pressure steam popped EPS

• What percentage of heat do you estimate is nin-recoverable (lost) from your slab?

Very little is ‘lost’ from the slab, into the house excepted, if our specs are followed during construction. We loose about 50% from our heat containment in the early years improving by 50% more as years progress and the system reached stasis with the surround grounds outside the ICF containment area.

• How do you deal with interior summer heat while you are heating the thermal mass?

See above. It’s a balanced system. We will be getting an engineering firm or university to contract to ascertain many of the variables to be able to plug into a computer program. Right now we do it by and base educated guesstimates on experiences to date.

• Are you using radiant floor heating or have you placed an insulating layer over the heat sink structure and under the floor?

See above.

• Are you using inverter type mini-split heat pumps or are you going with inverter type central heat pumps and zoning the various areas of the house?

We don’t have access to inverter Hot Water heat pumps as yet. We would prefer them though. Right now we use 6-10kW HW units, a good deal as it heats the hot water as well at less cost than other fuels as a rule. We h\are installing one now in a very cold area where we put in 2 6kW units simply staged for cold weather. We estimate the 2nd one will only been needed occasionally when ambient insolation is obscured for long periods, even in winter.

• Does your scheme use continuously variable brushless fans for ventilation?

No supplemetary ventilation included we simply heat the slab fro warmth. It is not yet a full on package – later maybe. It use continuously variable brushless fans and low cost air-to-air heat exchangers.

• Are you employing HRV or ERV in the ventilating system?

No, customers choice. We don’t even recommend these with our full energy efficient designs as they typically blow cold air during winter nights. They do have their place.

• Are you using cross-flow, counter-flow or enthalpy wheel exchangers?

Nope, See Above.

• How many airc hanges per hour do you design to?

Non, we focus on the warmth aspect.

• Do your wall structures use a separate, inside utility-wall to prevent insulation wall intrusion?

Our current maximum spec for the EE home (not to be confused with the DSHH system) involves 200mm (8x2) with 95mm (2x4) offset studs, 12mm (1/2”) plywood sheathing with building wrap. In locations where external temps dip below freezing for more than 2 weeks at a time we add in a std vapour barrier. They glue gypsum boards here, and this drives them crazy.
To avoid this entirely we are now doing more homes & commercial completely out of ICF:

1. Built in concrete thermal mass
2. Double insulation excellent R values, improved thermal efficiency
3. 90mm of Drainflo EPS almost doubles the thermal value
4. No risk of rotting timbers
5. No risk of wind ingress
6. Fantastic noise containment or rejection
7. All owners rave about their homes being warm and solid
8. Fast erection

time


Hope this helps, it won't work in every situation to eliminate alternate heating, we can calculate how much solar heat we can generate which will offset other forms of heating.

Cheers,

Ron @ DSHH.info

[lt190b]

proper technique for radiant heating | BreaktimeA C Hacker check out this blog post from PhillK hope this works lt190b

[AC_Hacker]

Originally Posted by lt190b

A C Hacker check out this blog post from PhillK http://forums.finehomebuilding.com/c...comment-732109 hope this works lt190b

lt190b,

I clicked the link and got a "Page Not Found" message.

Could you try again?

-AC_Hacker

[lt190b]

AC Hacker i think the edited link will work now. lt190b

[AC_Hacker]

Originally Posted by lt190b

AC Hacker i think the edited link will work now. lt190b

Yes, it's working now. Good info.

However, many people are commenting on the wonderful photographs...

Are you able to see the photographs?

-AC_Hacker

[lt190b]

Originally Posted by AC_Hacker

Yes, it's working now. Good info.

However, many people are commenting on the wonderful photographs...

Are you able to see the photographs?

-AC_Hacker

No! seems there are some problems with changes made to forum lt190b

[AC_Hacker]

I found a hydronics design Spreadsheet that was created by SlantFin.

It could be useful in estimating heat loads and designing hydronic systems.

AVAILABLE HERE

...it could also be useful in developing your own special-purpose spreadsheet.

-AC_Hacker

[Piwoslaw]

AC_Hacker asked me to post what I know about how hydronic floor heating allows a heat pump system to be more efficient, compared to normal wall radiators.

A heat pump system gets more efficient when the water temperature is lower, which can be had by increasing the area of heat exchangers (radiators). This means either increasing their size, or their number, or going with a totally different approach and using the whole floor area for heating. This brings the water temperature down from a max of 85°C to a max of 55°C. Normal temperatures in a floor heating system are usually closer to 40°C. This is also good for increasing the efficiency of a system with a condensing furnace, since it only condenses (efficiency above 100%) when the temperature of the returning water is below the dew point.

A side effect of using hydronic floor heating is that heat is distributated much better than with wall mounted radiators, allowing the room temperature to be 1-2°C lower, which leads to further savings.

As for how to plan and build such a system, the only "real" info I found was: when laying the water tubes, there should be at least 8 meters of tubes in each square meter of floor area, you may want slightly more in "cold" areas, ie close to doors and windows. I could not find anything about what type of tubing to use or what diameter (I assume there is only one standard diameter?). Of course, the tubes should be in loops, plumbed in parallel, not series, to distribute the heat more evenly and to reduce pumping losses. There should be a reflective layer underneath, and foam insulation under that. Tiles are good for covering it, wood is not.

Another thing that increases the efficiency of almost any heating system with radiant floors is a heat buffer. The buffer allows the heat pump (or whatever other heat source) to work at its most efficient speed/setting, while heat is taken from the buffer only when it is needed. Low temperature (floor) heating allows the buffer to give up more heat before needing to be charged again. Great for when you have a cheap source of heat (solar, electric with night tariff, etc.). It also allows zoning of the heated part of the house, which allows you to save by reducing heat use in unoccupied rooms.