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Old McDonald

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Posts: 66
Reply with quote  #1 

I lurked here for quite a while before registering. I like to know something about the people I deal with on forums, so here goes about us. I have given links to the websites of our “team” so you can use the info to learn more about us and the project site – my webpage shows some useful photos, particularly via Google maps to better understand my descriptions below. If you do access my site please ignore the sales part, I do not want my first post to be my last. It is a long post, but necessary to give the full info.

I live a few miles from the city of Castelo Branco in central inland Portugal and farm full time. I am an old peasant who has farmed in four different countries over six decades so have picked up a bit of experience and some ideas. I also claim to be well educated - a Bachelor of Business majoring in law and accountancy so I understand the written word and can crunch numbers – http://www.oldmcdonaldsolives.com  My son has two Masters and a PhD in astrophysics disciplines and works in astrophysics, so he understands all the equations and obviously has an in depth knowledge of the sun/earth relationship - http://www.jb.man.ac.uk/~mcdonald/  He is the only one of us to have visited the U.S.; giving a short series of talks at Cornell, Harvard, and NASA Washington and Baltimore in 2012.  My friend Patrick has a quinta (Portuguese for small farm) about 4 miles away, but is in an earlier stage of the development of his place than I am, and is only here part of the time. He has an excellent knowledge of just about most things electronic and mechanical plus experience of using solar applications. His website is currently offline whilst he revamps it.

The project is not imminent as I have others to complete, but I also like to plan ahead and the idea is to provide underfloor warming to the living area of the house. Not necessarily full heat, but enough to warm the floor slightly. Some heating is needed for up to 7 months of the year and cooling for up to 4. Both can be less but there is very little spring and autumn weather. We presently use a wood burning stove in the room used most - a typical farmhouse kitchen/dining/living room, plus have reverse cycle air con (mini splits in US?) in all rooms and sundry electric heaters for use when necessary.

The house has a footprint of 135sq m/1350 sq ft; is on three levels with the unfinished top level presently used for storage, although it could provide more bedrooms. The living area is the middle level – ground level at the front and one storey up at the back. The bottom level is partially underground in the style of southern European cellars and protected storages. That is in three separate rooms – an olive store (for equipment and olives) is half the area and a winery/wine cellar takes up most of the rest, with a cheese store the balance.

The ceilings of the bottom level are the floor of the living area. These ceilings are 12 feet and they are almost entirely clear of any obstructions.  Long term I had envisaged a system involving water storage and heat transfer, pumping to pipes across the whole of the area (divided into runs) but initially as a trial I would like to try direct pumping from a collector to the ceiling of the olive store to see what sort of gain we can achieve. If it is particularly successful I would set up the same for the rest of the house instead of a water storage system. In winter these cellars at floor and mid height are usually equal to or one degree above unheated rooms in the house averaging around about 12C or low 50sF.

In times past olives were stored under water in brick cement rendered bins and there are 3 in line of 2 cu m (just over 500 U.S. gallons) each. These days small boxes are used during olive harvest and transported more frequently to the buyer, so the bins are no longer required for their original purpose. There is also a lagar (a tank where the grapes are stomped) in the winery/wine cellar, also no longer used, and just over 3 cu m. The wine cellaring part is most definitely used!! So plenty of already built thermal water storage volume if I need it. I could have two systems – one for the living space above the olive store and one for the remainder. Water storage is easily increased by making the walls higher.

The whole house is stone, concrete and brick. Way back it was an olive mill. The ceiling is 18 to 20 cms thick, as near as I can measure, so an enormous thermal mass. Concrete beams in the shape of an inverted T carry specially shaped honeycombed bricks. The beams and bricks are topped by a cement screed and tiles. The ceiling of the living area is of similar construction.

Whatever I do it will not involve any internal disruption to the living area. All rooms have tiled floors and some either partially or totally tiled walls. As an initial experiment I would like to try direct pumping in a closed loop from a collector to heat pipes with aluminium spreader plates attached to the concrete beams in the ceiling of the olive store.

We know there is a long way for the heat to travel before it reaches the tiles, but provided some heat travels upwards it will eventually reach the floor of the living area, dissipating to some extent sideways before doing so. The length of time this takes is unimportant, and anything is better than nothing.

The depth of insulation below the pipes can be anything I choose given the high ceiling height, so heat loss downwards can be minimised, but insulation is not a strong point in Portugal. 30mm sheets of Wallmate are available locally, and not much else, but I will be looking further afield. DIY in general seems not to be a way to spend time, and sourcing supplies for many jobs is difficult. Sand, aggregate, cement, concrete beams and all sorts of bricks are easy, but apart from a few pv panels and domestic HWS there is not much evidence of solar. Wind is the main source for grid supplies of electricity.

I have kept weather records for the 13 years I have been here. Temperatures rarely drop below freezing, and then only by a couple of degrees on clear winter nights. We can go through a winter without a frost. Year round I wear only a short sleeved cotton shirt both indoors and out, no undershirt, no jumper, no jacket. At times indoors we have the common complaint of being hot from the knees up, and cold feet. 20ºC/68F is plenty warm enough for my wife and me in the main living rooms, and a few degrees less in our bedroom/bathroom - above the wine cellar. Our winter comfort (at least above knee height) is easily achieved with the woodburner and electricity, but I want to use solar.

Any fog lifts early in the morning and it is unusual not to get some sunshine in the day, with many days of all day sunshine throughout winter. I am more or less unlimited with space for collectors. As can be seen from the Google Maps link on my website (the olive store is on the north end of the building) the house is orientated so that collectors against the wall, or garden walls adjoining the house, would catch sun from mid morning and face directly into the afternoon mid winter sun. A street view from across the river shows the back of the house. A linked collector (possibly batch) could also be placed to catch the morning and early afternoon sun, being shaded by late afternoon.

I have spent a lot of time over a few months reading the info on this site, Build It Solar and anything else I have been able to find, and I am very grateful to you all for many hours of informative and enjoyable reading. This forum is outstanding, but there is only a little info about direct pumping.  I suppose it is not a common practice in places with cold winters. Thanks to the immense amount of info on here and BIS I do not have any questions at this stage. I will have later, but for now please feel free to comment upon or condemn my ideas.

netttech

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Posts: 720
Reply with quote  #2 
Welcome Old MC,

I have direct pumping from my solar panel to under the floor. I also supplies heat to a storage tank, but currently I'm not using it.

As you noted, heating the floor isn't an immediate type of heat. If I read your post correctly, your heating concrete. It will take time for it to heat-up & radiate into the room. However once the concrete is heated you should get the benefit during the evening hours. My wood floor is the same way. I can feel a difference thought during the day.

Do you have an idea what type (& size) of panel you would like to heat the water?

I'm currently using a DIY fixed parabolic trough panel. The pump begins to cycle (on/off) about 9:30am, until around 3pm. I don't fully trust the temperature gages to be accurate, it registers about 100-105 degrees (F) maximum on sunny days.

God luck on your project & looking forward to pictures.

Jeff
Central ILL
Solar air & water
stmbtwle

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Reply with quote  #3 
Welcome OMcD,

If you have any windows in your cellar you might be a good candidate for an air collector system at least for starters. Simply pump the warm air into the cellar through a window and let it rise to the ceiling and eventually it will heat the floor above. This would be a lot cheaper, and quicker to install than any kind of water based system. If this looks promising you could later convert your air-based collectors to ARETHAs
https://www.facebook.com/Aretha-Project-307885346030194/?fref=ts

With all your tankage in the basement you have lots of thermal mass, but it is not insulated. This could be to your advantage. If you fill them and heat them with ARETHAs or any water based collector, they will still lose heat to the air in the basement, which will rise to to the ceiling and heat the floor and rooms above in turn. You may be able to avoid the labor and expense of installing plumbing and spreader plates.

I would consider insulating the walls of the basement with Wallmate to avoid losing heat to the outside.

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Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
Old McDonald

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Posts: 66
Reply with quote  #4 
nettech, I knew about your system. I think I have read just about all the threads on the forum. Skipped a few that did not directly interest my plans at this stage, but will eventually get around to them all. 

We know that it will take time to warm up, and as I said that is not important. I read an article elsewhere that it can take a few weeks for such a big mass to warm right through, and it gives off heat for a long time after it has stopped being applied too. I suspect it was a theoretical article (Canadian govt if I remember right) rather than somebody who had done it, but even so, a bit of experimentation in late summer might be worthwhile. I think we can keep some heat going into the ceiling throughout the time we need it. 

At this stage I am thinking a serpentine PEX collector although I have not decided on the size as yet. This is where my boy begins to do his physics equations. We are heating concrete, but the bricks in between have some insulating value. There is a lot air trapped in there. About 75% to 25% walls of brick. We do not have a reliable figure to work on yet. 

I thought maybe a batch type collector for the linked one facing the early morning sun - the thinking being it might start off the day slightly warmer than a tube collector. 

stmbtwle, It is easier to type Willie, if that is OK with you. Thanks for the suggestions, much appreciated that you took the time to do so, but we do not want the bottom level to be heated.  

The current ambient temperature in these storage areas is what is needed. The wine in particular must not be warmed up. I am creating a "cellar" of Vintage Ports, Moscatel de Sétubal, a fortified wine that goes well with nuts after the cheese and Port, as well as long lived Portuguese wines for my son and grand children. We also store olives for a few days during harvest (late Oct/early Nov when we need heat in the house) and again we want them kept cool. 
Garage_Hermit

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Reply with quote  #5 
Nice reading, Mac, welcome on board  !

Quote:
I would consider insulating the walls of the basement with Wallmate to avoid losing heat to the outside.


Dead right, Willie - IMHO, cellar insulation must be the first course of action here (external walls, NOT roofs, then floors.)/

Wine store obviously excluded !
(will in any case probably require insulating from rest of cellars...).


Before building any "add-on" collectors, explore use of the building envelope first... Such as draft-chasing; improved doors & windows... ).

After that, a solar site survey (off BIS) - I am thinking of hot-roof collection, with circulation of hot air to push heat into thermal mass in the (newly insulated...) basement.

Plus whole-house fan, to mitigate stack effect...

Details HERE... http://www.builditsolar.com/Projects/SpaceHeating/SolAirHtSysBook/Chap02.pdf

Would not even contemplate any hydronics until air options exhausted.

G_H


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stmbtwle

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Reply with quote  #6 
OMcD,
Willie is fine.

I can understand your not wanting to heat the wine!

I wouldn't either, so I will go with that. Suppose you were to come down a bit from the concrete beams and install a false ceiling of insulation board, it could be suspended with wire as with any suspended ceiling, probably as you have already considered. Then circulate hot air from air collectors above the insulation. This will keep the heat near the ceiling where you want it and leave the lower part cool. As warm air rises anyway, you might get away with thin plastic film to prevent it mixing with the air below.

The main advantage of a water-based system is heat storage, but if you aren't going to use that feature I don't see much point. Water-based systems are expensive and tedious to build, and you probably have plenty of heat storage in the concrete already. I just feel that an air-based system would be much cheaper and easier to install, and may work just as well.

A quick non-solar approach would be to install ceiling fans in the living space to move heated air from your wood stove down to the floor, heating it from above. This would increase your energy consumption though.

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Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
solardan1959

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Reply with quote  #7 
I agree with Willie, I was thinking the same thing when you said you did not want to heat the basement.
Plenty of hot air right to the beams, especially since you get a lot of sunlight seems ideal.  a vent up above to blow the hot air across the top of the floor and right into the living area even better but that may generate too much heat.   An air diverter\valve to switch it back and forth depending on your needs would work nice to.
Dan
gbwillson

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Reply with quote  #8 
Welcome OMcD!


I have my air heater warming the basement as it is ideal since the open ceiling allows the heat to be absorbed by the wood floor joists and subfloor. This absorbed heat is quite effective at keeping the upstairs warm until bedtime. In fact, on a sunny day my furnace only turns on only once per day in the early morning hours until the sun turns on the solar heaters. Also, as has been mentioned, I strongly suggest you insulate the basement walls and make sure to seal every air leak. Pay particular attention to the rim joist as this is one of the biggest air leaks in most houses. Air leaks before insulation, otherwise it's like wearing an unzipped winter coat and complaining about the cold.

Greg in MN[wave]
stmbtwle

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Reply with quote  #9 
Greg, 
Probably no need to insulate the basement walls as he does NOT want to heat the basement/wine storage.  Maybe the top couple feet above the false ceiling...

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Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
gbwillson

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Reply with quote  #10 
Willie-

Yup, I should have said to insulate above the ceiling tiles if the warm air is directed there. Sealing leaks still applies.

Greg
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