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A_L last won the day on October 12 2017

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About A_L

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  1. A_L

    Is our winter generation amount about right?

    @MikeGrahamT21PVGIS for Leeds in February gives about 30kWh/month for 1kWp on East and West 35° slopes and 50kWh/month for South 35° slopes. So I do not think anything is seriously wrong. I would expect the outperformance to be proportionately higher on sunny days and less on cloudy ones.
  2. A_L

    Perimeter insulation

    @vfrdave, not unless there is a high thermal conductivity pathway (i.e. masonry) from the floor slab through the area insulation to a stub wall/footing
  3. Only because of the design of current thermal stores. See tank B in attached pdf. A store charged to 60°C provides close to 120% of its volume at 43°C TZS_10.pdf
  4. A_L

    Nail sealing foam strip

    how about this then http://www.caravan-components.co.uk/Caravan-Sealant-Mastic-IDL99-Cream-in-400ml-Tube
  5. A_L

    Nail sealing foam strip

    AC50 12 for £22.90 inc vat https://www.sealantsandtoolsdirect.co.uk/silicones_and_sealants/intumescent_fire_and_acoustic_sealants/everbuild_everflex_ac50_acoustic_sealant_adhesive_c4_380ml_box_12_P23506.html
  6. Sorry, do not really understand this, I have given heatloss for 20°C inside 0°C outside. If you want greater capability then heating to 20°C when -10°C outside then add 50% to heating load. An oil filed radiator with timer and thermostat, about £40 from Lidl/Aldi will achieve this, even if only interim solution. An aircon unit (air to air heat pump) maybe £500 - £1000 will solve this. They can even be DIY'ed (just an example, heating output about 1.7kW) http://www.cooleasy.co.uk/categories/diy-air-conditioning/unico-air/unico-air-8-hp.html I can confirm that a professional install would be in this ballpark (at least) If this is anything like accurate then you need to look at low power alternatives.
  7. Look at it from a heatloss point of view. Assuming an outside/inside differential of 20°C then with 150mm of PIR or equivalent on all six surfaces the heat loss is about 340watts, plus say 180watts for 6m2 glazing, ventilation of 0.5ach with no heat recovery is about 200watts. So about 720watts, then subtract input from solar/bodyheat/appliances. Do you really need a GSHP?
  8. A_L

    Cold weather observation - ASHP

    Unfortunately the amount of heat stored in any fixed volume of air is too small for this to work. ASHPs process several hundred cubic metres of air per hour to obtain their energy and one/two passes would almost certainly reduce the temperature to no higher than the outside. After this it would be colder than ambient air.
  9. A_L

    Roofing membrane

    The manufacturer says Majcoat can be exposed for upto 8 weeks while Majcoat 150 can only be exposed for upto 4 weeks.........so https://www.siga.swiss/global_en/catalog/majcoat
  10. A_L

    What type of boarding above rafters

    Not sure I would be happy using OSB/OSB2 for sarking. https://www.norbord.co.uk/media/1297/sterlingosb-brochure-24pp-2015.pdf pages 5 &7 http://wpif.org.uk/uploads/PanelGuide/PanelGuide_2014_sect2-6.pdf page 1
  11. from section 6 of BBA cert, '1.24 m2·K·W–1 R value for SuperFoil SF19 (41.9 mm thick) with no air gaps either side ' wiith air gaps the thermal resistance will vary with orientation, as suggested here https://www.roofingsuperstore.co.uk/product/superfoil-sf19-multi-layer-foil-insulation-15m-x-10m-roll-15m2-1.html?gclid=EAIaIQobChMIs5GD97OR4AIV6Z3tCh16IQxeEAQYAyABEgJHufD_BwE although I do not know where the R values come from
  12. Here is the BBA Cert for the product. According to this the SF19 variant is 42mm thick and has the insulating effect of about 55mm of ordinary loft roll. It is also to be considered a VCL with a vapour resistance of 1200Mn.s.g (Polythene is normally about 300 IIRC) Superfoil BBA Agrement Certificates Roof and Wall.pdf
  13. @willbish , 15/5°C is the CIBSE defaults for this calculation. I am not entirely sure why they have a positive condensation rate at the interface in layer 2. The vapour pressure is lower than the saturation vapour pressure and the structural temperature higher than the dew-point temperature. Certainly my own CRA software (operating to the same BS5250 standard) does not indicate a problem, even with chipboard added and a 20/-5°C temperature scenario.
  14. A_L

    Flexible pipe .

    Search for 'polybutylene pipe', JG Speedfit/Hep2O and others, very flexible. Oh! and welcome!
  15. A_L

    Spray foam insulation

    no, unless there is a layer more vapour resistant than the insulation on its cold side, good ventilation on the cold side would reinforce this. What is the thermal conductance and vapour resistance of the insulation? a (non-tenting) water vapour permeable membrane at this point is really there to act as a backup should the final layer (i.e. slates etc.) have a fault and let water through