Using the thermosyphon effect for a floor water heating system

In summary, the grid power often dies, so the homeowner needs a backup power source and heat source. They think of installing water tubes in the floors and building a wood-burning water heater in a "stove house" down the hill from the house. This would be made so that the water circulates from the thermosyphon effect, without any pump. The stove house would be at 16m from the house, and it would be smart to put a couple CO detectors in the home.
  • #36
Would you cut and split the firewood for fun and exercise? My back tells me not to anymore and our firewood piles are shrinking. We could heat our house nicely without supplemental heat with our single wood stove (southeast Pennsylvania, house built in 53, maybe some insulation in walls) but lately I let the oil furnace do more and more of the heating.

If you don't need the exercise a backup generator might be cheaper in the long run?

https://www.google.com/search?q=bac.....69i57j0l5.4639j0j8&sourceid=chrome&ie=UTF-8

Did you tell us what is the main source of heat for your home currently?

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  • #37
Spinnor said:
Would you cut and split the firewood for fun and exercise?

I did until a month ago.
Fair Anne has complained for years about the dirt and leaves i tracked in

so i plumbed propane up to the fireplace and set one of those radiant heaters in front of it.
I am far happier with it than i expected - so after this heating season i think i'll change to gas logs inside the fireplace.
 
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  • #38
jim hardy said:
so i plumbed propane up to the fireplace and set one of those radiant heaters in front of it.

A few years back oil was relatively inexpensive, it still is not so bad. I burned a lot less wood then choosing to burn the less valuable fuel, heating oil.
 
  • #39
The idea of placing the stove 16 m from the house means 32 m of tubes that have to be isolated to minimize heat loses, and need to be somehow protected from freezing and rupturing.

Just another factor to consider.
 
  • #40
We used to have a relatively small and old house with poor insulation. The wood stove seen in this New Years Day picture was our only heat. It was a very comfortable and pleasant form of heat. When the temperature approached -40, it was not enough heat, so I would load it up with coal and that did the job.

But you need to put on extra blankets at night and get up to a cold house in the morning. My part of the marriage was to start the fire in the morning before my honey got up.:rolleyes:

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  • #41
Borek said:
The idea of placing the stove 16 m from the house means 32 m of tubes that have to be isolated to minimize heat loses, and need to be somehow protected from freezing and rupturing.

Yes, the pipes need to be buried beneath the frost line. That's true with all outdoor water piping including your city water or well water service.
 
  • #42
anorlunda said:
My part of the marriage was to start the fire in the morning before my honey got up.:rolleyes:

Hopefully her part was to get in bed at night first and warm it up. I think I sleep better in a cool bedroom.
 
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  • #43
Another potential problem with such system would be the resale of the house. In our neck of the woods for someone to get a mortgage for a house that house must meet certain minimum standards, your system may not and potential future buyers of your house might be hampered in getting a loan, just a thought. Also a future owner of your home might not want to deal with such a system, it might be a deal maker or breaker. It sounds like you are interested in doing work on your house, maybe time and thought spent making the home more energy efficient is a good project? If you do use a chainsaw and cut up a bunch of wood get some chainsaw chaps and all the other proper equipment.

shopping
 
  • #44
Spinnor said:
Another potential problem with such system would be the resale of the house.
As one who actually bought a house built with just a bit more creativity and bit less knowledge than ideal I have to agree.
All the homemade creative kludging feels tempting, but at the end the point when you finally need a handbook for your own house to keep it working is the point when it gets the title of 'need immediate and full restoration' on the market.
Nothing makes people respect simple and regular solutions more than living in a 'kludgehouse'.
 
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  • #45
Rive said:
kludgehouse
I like that word. :cool:
 
  • #46
anorlunda said:
I like that word. :cool:
Me too!

I'd never heard of "kludge" before. Did you also look up its history?

Merriam-Webster; "The first recorded use of the word kludge is attributed to Jackson W. Granholm, who defined the word in a 1962 issue of the magazine Datamation as: "an ill-assorted collection of poorly-matching parts, forming a distressing whole." He further explained that it was derived from the German word klug, meaning "smart" or "witty." Why Granholm included a "d" in his spelling is not known. What we do know is that speakers of American English have agreed to keep it silent, making the vowel pronunciation of kludge reflect the pronunciation of German klug (KLOOK). We can also tell you that not everyone agrees with Granholm on the "d" matter: the spelling "kluge" is also popularly used."​

Seems like adding too much "klug" stuff together makes "sludge", = kludge?

Anyways, I'm working on a similar problem, and have solved all the simple stuff, inserting my constants and variables where none were given.

House loses 160 watts/∆°C (common to both houses)
∆T = 44°C (OP, worst case. T_hot: 20°C, T_cold: -24°C)
power required = 7000 watts (OP, worst case)
area of floor = 84 m^2 (my house)
required temperature of floor = 34°C (my house in Norway)​

But I'm afraid my knowledge of thermodynamics & combustion of wood are too weak to be able to handle the details of this problem.

Example:

A $15,000 Woodmaster 6500, fully loaded, would "theoretically" heat my house in Norway for 2 weeks. But it's only rated for 12 hours. So this raises the question: How slowly can you burn wood?

According to this news account; "Trees can retain burning embers throughout the winter, she said, through snow and ice."

Ok then. A novel, well designed wood burning outhouse will work.​

But from here, as before, I'm finding the maths involved to be a bit tricky.
I'm used to thermal conduction solutions where the specific heats of the conductors are ignored.
But once I include them, I get quite confused.
I'm guessing this is a partial differential equations type thing.
Never did like them.

anorlunda said:
Prudent engineers always work in this order.
  1. Requirements
  2. Design
...

I'm thinking we may have different definitions of "Design".
My definition would be; "Solve all the maths involved, down to the last partially differentiated detail."
But, I may be overthinking the problem.

Here's another problem I haven't worked out:

What's the optimal way to not have hot spots on the floor?
I'm guessing the initial high differential temperature at entry is going to resolve itself because less heat is going to flow when that section of floor mass warms up.

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  • #47
OmCheeto said:
How slowly can you burn wood?
The efficient solution is to burn it very fast at high temperature and add a buffer to store the heat. For an internal stove it can be a big piece of masonry, for external ones a big bucket of water with some heat exchangers. For an efficient combination of stove and floor heating, these kind of buffer tanks are necessary.

Ps.: around the same link some pointers can be found about floor heating limits, control and pipes.
 
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  • #48
Rive said:
The efficient solution is to burn it very fast at high temperature and add a buffer to store the heat. For an internal stove it can be a big piece of masonry, for external ones a big bucket of water with some heat exchangers. For an efficient combination of stove and floor heating, these kind of buffer tanks are necessary.

Ps.: around the same link some pointers can be found about floor heating limits, control and pipes.

I calculate that we need a 2700 liter (700 gallon) tank for a 24 hours period. (7000 watts * 24 hours)
Kind of big, but the https://1q11xr3but6322f0iz1d1vp6-wpengine.netdna-ssl.com/wp-content/uploads/2015/01/24397_15-WM-Classic-BRO-Web.pdf has a built in 1900 liter (500 gallon) tank. So, I guess if the experts do it, it must be necessary.
 
  • #49
I am surprised that no one has mentioned the problem of the "heating water" freezing whenever the fire goes out (sickness, vacation etc.). My house is relatively new and we have done everything by the book (heavily insulated, using a rock-to-water heat exchanger etc.) and we still use a frost-free liquid (glycol and water) in the system.

BTW: Retrofitting an old house with floor heating is more expensive than building a new house (I know, because I got a quotation in 2007). We built a new house instead.
 
  • #50
Svein said:
I am surprised that no one has mentioned the problem of the "heating water" freezing whenever the fire goes out

Tom.G said:
Don't forget antifreeze in the system, otherwise you can't leave for a couple days without draining the whole system.

I believe that's not the only time it was mentioned.
 
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<h2>1. How does the thermosyphon effect work in a floor water heating system?</h2><p>The thermosyphon effect is a natural process where heated fluid rises and cooler fluid sinks, creating a continuous flow. In a floor water heating system, the heated water from a boiler or heat pump is circulated through pipes under the floor. As the water heats up, it rises and is replaced by cooler water, creating a constant flow and evenly distributing heat throughout the floor.</p><h2>2. What are the benefits of using the thermosyphon effect for floor water heating?</h2><p>Using the thermosyphon effect for floor water heating is an energy-efficient and cost-effective option. It eliminates the need for a pump, reducing energy consumption and maintenance costs. It also provides a more even distribution of heat compared to traditional heating methods.</p><h2>3. Can the thermosyphon effect be used for any type of flooring?</h2><p>Yes, the thermosyphon effect can be used for any type of flooring, including tile, hardwood, and carpet. It is a versatile heating method that can be adapted to different types of flooring and building structures.</p><h2>4. Are there any potential drawbacks to using the thermosyphon effect for floor water heating?</h2><p>One potential drawback is that the thermosyphon effect relies on the temperature difference between the heated water and the cooler water to create the flow. If the temperature difference is not significant, the flow may be slower, resulting in uneven heating. Additionally, the system may be more susceptible to freezing in colder climates.</p><h2>5. How can I ensure the efficiency and effectiveness of a floor water heating system using the thermosyphon effect?</h2><p>To ensure the efficiency and effectiveness of a floor water heating system using the thermosyphon effect, it is important to properly size and design the system according to the specific needs of the building. Regular maintenance and monitoring of the system can also help identify and address any potential issues. It is also recommended to consult a professional for installation and any necessary adjustments to optimize the system's performance.</p>

1. How does the thermosyphon effect work in a floor water heating system?

The thermosyphon effect is a natural process where heated fluid rises and cooler fluid sinks, creating a continuous flow. In a floor water heating system, the heated water from a boiler or heat pump is circulated through pipes under the floor. As the water heats up, it rises and is replaced by cooler water, creating a constant flow and evenly distributing heat throughout the floor.

2. What are the benefits of using the thermosyphon effect for floor water heating?

Using the thermosyphon effect for floor water heating is an energy-efficient and cost-effective option. It eliminates the need for a pump, reducing energy consumption and maintenance costs. It also provides a more even distribution of heat compared to traditional heating methods.

3. Can the thermosyphon effect be used for any type of flooring?

Yes, the thermosyphon effect can be used for any type of flooring, including tile, hardwood, and carpet. It is a versatile heating method that can be adapted to different types of flooring and building structures.

4. Are there any potential drawbacks to using the thermosyphon effect for floor water heating?

One potential drawback is that the thermosyphon effect relies on the temperature difference between the heated water and the cooler water to create the flow. If the temperature difference is not significant, the flow may be slower, resulting in uneven heating. Additionally, the system may be more susceptible to freezing in colder climates.

5. How can I ensure the efficiency and effectiveness of a floor water heating system using the thermosyphon effect?

To ensure the efficiency and effectiveness of a floor water heating system using the thermosyphon effect, it is important to properly size and design the system according to the specific needs of the building. Regular maintenance and monitoring of the system can also help identify and address any potential issues. It is also recommended to consult a professional for installation and any necessary adjustments to optimize the system's performance.

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