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    • CommentAuthorjoconnor
    • CommentTimeOct 17th 2007
     
    I am currently working with a developer on a site for 16, two bed, single storey apartments (for rent) and the building is likely to be up to six storeys high. The site is only 12 metres wide but over 70 meters long and the narrowest elevations face east and west. There is a four storey building to the south to a depth of 2/3rds of the site and a single storey building to the north to the site depth.
    I want to minimise space heating, yet provide apartments which have comfortable internal temperatures throughout the year (the Architect will be providing a thermal model in Ecotect). Quality of the build, budget, minimal maintenance, trying to meet code level 3 of the CSH. I am looking for suggestions for the structure. (note we are more than likely to opt for a steel frame).
    We have almost ruled out complete timber frame due to the impossibility of making the exterior faces water-tight adjacent to the party wall buildings and also the problems of over-heating.
    Other considerations are i. exterior face of masonary with internal face of timber frame and a faily deep screed on the floors and dense concrete interior block walls; ii. tradional cavity, beam and block floors and stud partitions; iii. some form of heavy mass modular system for the exterior walls, which is weather-tight.
    • CommentAuthortony
    • CommentTimeOct 17th 2007
     
    Solid blocks to all internal walls and like you say concrete floors -- how about planks? I would forget the steel frame and if you really cant build with blocks and bricks then how about pouring it all?

    Wide fully filled cavities --- solar panels on the roof and an inter seasonal thermal store -- passive solar design and thence no boilers or heating needed.

    Hope it gets off the ground.
  1.  
    Tony,

    it's been shown many times on this forum that an inter-seasonal thermal store is impractical for single buildings. You'd never get enough thermal mass (even using water) and if you did, it would be impossible to control passively leading to a very uncomfortable living environment. Steel framing is good if you need large spaces, but is certainly more expensive than timber frame at the current price of steel. As for the original poster's assertion that it is impossible to make the exterior faces water-tight adjacent to the party wall of other buildings - I don't think I undertstand the problem. How is a steel frame going to help here?

    Paul in Montreal
    • CommentAuthortony
    • CommentTimeOct 17th 2007
     
    What do you think an inter seasonal thermal store is then? like the ones in Alberta or N Europe but smaller could easily work. All I was thinking of was a water tank underground under the building.
    •  
      CommentAuthorfostertom
    • CommentTimeOct 17th 2007
     
    Posted By: Paul in Montrealit's been shown many times on this forum that an inter-seasonal thermal store is impractical for single buildings
    No it hasn't - discussion elsewhere on this forum is all about doing it. Sure, water's not practical for interseasonal - needs to be vast. Subsoil is the way. Here's the original texts:

    http://www.primedesign.us/self_heating_houses/pahs_article_1.html - all you need to know, really, about John Hait's PAHS, the purist no-machinery concept
    http://www.primedesign.us/self_heating_houses/self_heating_houses_files/frame.htm esp frame 18 of this Powerpoint by Engineer Joe Anderson
    http://www.EinsteinCode.info to buy the ebook

    http://www.greenershelter.org/index.php?pg=3 - all you need to know about Don Stephens' AGS, which judiciously uses machinery to make it work better, in more situations
    http://www.greenershelter.org/TokyoPaper.pdf - ditto
    http://www.greenershelter.org/index.php?pg=2 - comparison between PAHS and AGS

    Thanks to others' original steer on this forum, esp. James Norton and/or Jeff Norton (NZ), I'm currently designing extension and re-ordering of a client's house in Devon, on AGS lines, which we'll Tas-model before pressing GO (and before convincing the Bldg Insp). I'm in touch with John Hait, who is sadly not well enough to provide me with consultancy; still trying to contact Don Stephens.
  2.  
    Tony,

    for an apartment building a reasonable store could be put in place with an internal swimming pool - it could be solar heated in summer and a heat pump could extra heat in the winter. However, if you do the calculations, it's surprising how much water is needed for an entire season - infeasible for most houses that's for sure. I did post the calculations on an earlier thread but the search function isn't showing it.

    Just to put it into perspective, a 10,000l heat store made out of water requires 11.6kwh to raise it by 1C. So a 20C differential will give you 233kwh - that obviously won't last very long. OK, let's say you have a swimming pool that's 10m long, 3m wide and 1m deep on average (that's a fair sized pool btw). That's only 30,000l and so a 20C differential will store 700kwh. If your heatload is only 5kw, that's enough heat for just over 5 days. See the problem? It takes a huge amount of thermal mass to make inter-seasonal storage possible. For fun, I recently calculated the thermal mass of the cylinder of rock that surrounds the borehole of the ground source heat pump that I use for heating. Allowing the cylinder to touch the property line gave a mass of around 40,000 tonnes - the heat capacity of this was just enough to supply all the heat I need for winter after making some simple assumptions on the termperature differential from the start of the season to the end (it's more complicated in reality due to ground water movement etc. - I just wanted to see how much heat was stored in that cylinder of rock). This gives you an idea of how much thermal mass is required for inter-seasonal storage at least in my climate (which, of course, is more severe than the UK - but not by as much as one might imagine in terms of heating degree days per year). 40,000 tonnes of limestone is equivalent to 1752381l of water (correction for different temperature differentials used) - this is a cube of water 12m per side (not too bad I suppose) or a swimming pool 29m x 29m x 2m deep. This might just be feasible for an apartment building (though a pool 100 feet by 100 feet would be pretty large!).

    Paul in Montreal.
    • CommentAuthortony
    • CommentTimeOct 17th 2007
     
    In my dreams, though you are rather spoiling them, I'm thinking of 150m^3 pond 3m below the house and this would be heated during the summer by solar hopefully to a nice warmth. The house itself will not need any formal heating system as it will be be built to a higher standard than passivhaus or your Canadian standard. I am expecting that the heat wont run out before spring. My heat losses are a lot less and my store bigger.

    The capacity of the thermal store is not just that of the water in it but of that plus its structure plus quite a bit of the ground arround it.

    In my nightmares I get concerned about the whole thing getting too warm to live in :-)
  3.  
    Tony,

    sounds interesting! How do you plan on extracting the heat from your pond? Presumably you're not going to let it cool below the minimum you want inside your building if you're going passive. Problem is as the store gets cooler, the rate of extraction of heat also becomes less in a fully passive system - could make for some chilly days in early spring. Your 150,000l will store 3500kwh if you heat it by 20C - you might get by if your heat loss is really low - 3500kwh will give you an average of 1.6kw continuously over 90 days. Have you done any modeling? Charging the pond may be an issue in the less-than-sunny UK climate. Preventing overheating should be straightforward - but it depends on what your heat delivery system is. I'm currently looking at RETScreen (this is a renewable energy modeling package from Natural Resources Canada) and hopefully will be attending the training course in Montreal in January - it would be interesting to see what can be done with this kind of localized inter-seasonal store. Any more info you can provide would be appreciated.

    Paul.
    •  
      CommentAuthorfostertom
    • CommentTimeOct 17th 2007
     
    tony, what's the thinking behind part-liquid, part-subsoil as the storage medium? - assuming I'm right that your tank's going to be uninsulated in the subsoil? Is the tank's purpose really as a large-surface heat-exchange surface between the heat collection/distribution liquid and the solid storage medium? I think its temp will be too low to really function as an instant-heat-supply buffer tank. If it's there as a heat exchanger, there must be much easier ways of creating that much exchange surface - e.g. an array of pipes in the ground! Good thinking, all - we're getting closer to the measure of what's needed.
    • CommentAuthortony
    • CommentTimeOct 17th 2007
     
    I cant make my hot 2000 do anything useful for me. Walls -- 100mm solid concrete / 300mm fibreglass batts in cavity/ 100mm brick or concrete block. roof mega insulated exceptionally low air leakage, MHVR, triple glazed low E (our way round) windows, below ground insulation down the outside of the walls of the basement to 2.2 m then horizontal for 2 m sideways with the second level lower part of the basement 10m x 6m x 2.5m deep filled with water as thermal store. Basement floor insulated to try to stop heat coming up from the thermal store. Solar hot water system too. Rainwater shower, washing machine and composting WC.

    Do I have any hope -- weather aprox as London England. House facing SE solar porch outside thermal envelope front roof 45 with roof windows to bedrooms and 1.25m high walls. Overhanging front eves to give summer shading with the possibility of additional active shading, sun screens to roof windows and fans from porch to/from house.

    The porch will be oak framed and likely single glazed -- interested Biff?
    •  
      CommentAuthorfostertom
    • CommentTimeOct 17th 2007
     
    Posted By: tonyI cant make my hot 2000 do anything useful for me
    Howdya mean? Tried Hot3000?
    • CommentAuthortony
    • CommentTimeOct 17th 2007
     
    No but if i cant get 2k going how will i make 3000 work for me?
  4.  
    Tony,

    what are the dimensions of your house and the window locations and dimensions? I can put together a hot2000 file for you if you like. This will at least give you an estimate of the heat loss to a first order approximation. The more info you can give me the more accurate it will be - you can send me email if you'd prefer - it's in my profile.

    Also, how are you getting the heat out of your store? I'm guessing there's a heat exchanger in your MHRV to do this? Anyway, first thing to do is calculate the heat load. How many occupants? What's your estimated occupancy? What's the base load like on a daily basis (appliances, lights etc.). The more accurate these are, the better. Hot2000 accounts for the heat generated by the occupants which is why the occupancy percentage is needed.

    Paul.
  5.  
    Posted By: fostertomThanks to others' original steer on this forum, esp. James Norton and/or Jeff Norton (NZ), I'm currently designing extension and re-ordering of a client's house in Devon, on AGS lines, which we'll Tas-model before pressing GO (and before convincing the Bldg Insp). I'm in touch with John Hait, who is sadly not well enough to provide me with consultancy; still trying to contact Don Stephens.


    I bought the John Hait book, good read and in simple terms so I can understand it!
    • CommentAuthortony
    • CommentTimeOct 19th 2007
     
    What is the title of John Hait's book please?
    •  
      CommentAuthorfostertom
    • CommentTimeOct 19th 2007
     
  6.  
    tony,

    "Passive annual heat storage, improving the earth sheltered home" by John Hait

    I ordered from here http://www.earthshelters.com/Catalog.html
    • CommentAuthortony
    • CommentTimeOct 19th 2007
     
    Thx
    •  
      CommentAuthorfostertom
    • CommentTimeOct 20th 2007
     
    Tell us if it's worth buying - also John Tait's book about Resonant Fields - anyone read that?
    • CommentAuthorcaliwag
    • CommentTimeOct 22nd 2007
     
    There's a secondhand copy of "Passive Annual Heat Storage" from an American bookseller for £15.79 on www.abebooks.co.uk
    • CommentAuthorjoconnor
    • CommentTimeDec 14th 2007
     
    The debate seems to have moved on past my original questions.
    We are looking at steel frame as the structural support grid vertically and horizontally. There are now four blocks ranging from three to eight storeys. Our architect is familiar with passive solar design, but the surrounding buildings provide a great deal of over shading.
    A heat store in the ground would be difficult due to the ground conditions, neither would passive annual heat storage as developed by John hait and used on Mile End Visitor Centre in london and the Archeolink vsitior centre in Scotland.
    I am aware of John Hait's book 'passive annual heat storage' which relies on using 'umbrella', that extends six metres beyond the perimter of the building.
    Talking about dynamic thermal modelling package TAS above I attended the recent IBPSA conference at plymouth university and saw designbuilder presented. Wo, it is as good as TAS if not better.
    having visted ZED factories latest project at Northampton in November we are looking at whether we can similar principles which is based on glulam columns and beams with internal 2000x45x400 concrete planks as the mass in the walls and concrete planksin the floors and ceilings and extrenal inuslation.
    • CommentAuthorjon
    • CommentTimeDec 15th 2007
     
    Difficulty with trying to meet level 3 is that information available is patchy and contradictory. It may be a better strategy to go for tradable points from other sections
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