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A_L

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Everything posted by A_L

  1. A_L
    First, try measuring the flow of the shower (bucket and stopwatch). To raise 15l/min by 30°C takes 31.32kW, so the boilers are going to struggle! Second, to raise 250ltr of water by 50°C takes 14.5kWh of energy, so 14.5/30 or 0.483hrs, but only if the cylinder heat exchanger can transfer 30kW to allow continuous operation Third, if your house as described requires more than 5 to 7.5kW of continuous input under extreme conditions I would want to know why!
  2. A_L
    Just in case you are unaware, some micro-hydro generators have a built in dump load that can take all the output and heats the flowing water.
  3. A_L
    based on the BBA cert http://www.radflek.com/downloads/BBACertificate.pdf with a 25mm void on one side it is about the same thermal resistance as 11mm of PUR for ceilings, 17mm for walls and 20mm for floors
  4. A_L
    Remember that when you add in the voids either side of the insulation it is effectively 100mm thick. Also it is normally still used in conjunction with 100-150mm PUR See BBA Cert https://www.roofingsuperstore.co.uk/user/u/files/tlx-silver-bba-certificate-roofing.pdf
  5. A_L
    @ProDave , is 50Pa not about 5mm on a water gauge? (5.1mm to be over picky ) Edit: or were you taking 2mm up and 2mm down on other side?
  6. A_L
    The roof/wall insulation will keep it sufficiently warm to prevent any condensation. If the MVHR/outside world exhaust/supply pipes run through the space they should be insulated with water vapour impermeable insulation (also if elsewhere).
  7. A_L
    not exactly what you were looking for but falls into the 'old but good' category, see page 18 of attached pdf Small_Buildings_Structural_Guidance.pdf
  8. A_L
    @joe90 iso_bloco-hf - https://www.iso-chemie.eu/en-GB/sealing-solutions/sealing-products/pre-compressed-joint-sealing-tapes/
  9. A_L
    I am with Mr Punter on this, your radon barrier is also likely to be DPM. Certainly the one from Visqueen is http://www.visqueenbuilding.co.uk/products/gas-membranes/radon-membrane So another one not needed.
  10. A_L
    hello @hmpmarketing assuming the same type of insulation as in the SIPS panel (usually EPS or PU) then you will need an amount equal to 80-90% of the thickness of the insulation in the SIP panel as the blockwork will only contribute around 20% of the overall thermal resistance for approximate parity
  11. A_L
    @IanR -hello, strictly speaking I think this is correct:- from http://www.peterwarm.co.uk/a-guide-to-volume-calculations-for-passivhaus-air-tightness-testing-and-the-difference-with-the-uk-method/
  12. A_L
    @ProDave Suitably sized centralised mechanical extract ventilation (MEV) should be sufficient on its own https://beta.gov.scot/publications/building-standards-technical-handbook-2016-domestic/ Section 3.14.11 (bottom of page 196) @JSHarris Is the m2 term not the total external surface area of the house? (ceiling + walls (including openings) + floor)
  13. A_L
    hello @Cpd, my understanding is that thermal resistance of vertical cavities is pretty constant from 25mm and up. Certainly BR_443 (page 11) only gives one value. BR_443_(2006_Edition).pdf
  14. A_L
    hello @Gorlando, foil works as an insulation because it has a low emissivity of infrared (heat) radiation. For this to work there must be an air gap (of at least 25mm) in front of the shiny surface,. If the foil is in contact with a solid the heat is transferred by conduction. as mentioned by others the foil used for this is vapour impermeable and should not without careful consideration be used on the cold side of other insulation as there is a danger of interstitial condensation
  15. A_L
    Given the low level of extraction with a passive slab type house I do not think there would be much danger of the ground actually freezing, with the summer to recharge and the intermittent nature of heating superinsulated houses it should be O.K. Might have to watch it if year round DHW was also provided by this source. Remember the floor heatlosses will be higher because of the lower ground temperature so possibly somewhat counter productive. This may provide some information tonyshouse
  16. A_L
    @JamieM, Why?, you appear to be putting insulation where there is already insulation. Even if not, with apparently a floor U-value of 0.13 this small amount will have a tiny/ insignificant effect.
  17. A_L
    The whole house is cheap-rate at the appropriate times so all you need is a timer, possibly integrated on the appliance, one period for the off-peak and a manual override/boost for the on-peak use (or additional timed periods if use is regular).
  18. A_L
    Taking a wall of 105mm brick/200mm cavity/100mm lightweight block (lambda 0.11) wall gives U-values of 0.151/0.134 W/m2.K for dritherm 37/dritherm 32 full cavity fill respectively. The difference of 0.017 represents an energy saving of very much less than 1 kWh/m2/annum in a central England climate (probably around 0.4kWh/m2/annum). I do not have costs for dritherm 32 but it is rarely worthwhile paying for the premium versions of any insulation.
  19. A_L
    To get ECO funding the finished wall has to achieve 0.3W/m2K. Hope the cavity is unventilated.
  20. A_L
    Anthracite has a calorific value around 9.2kWh per kg. True efficiency of a closed stove could range from 20% to 80%. Without supporting evidence I would tend to the bottom half of this range.
  21. A_L
    hello, @oranjeboom, assuming lambda values of 0.022W/mK for celotex and 0.038W/mK for EPS then for floor areas from 100m2 to 400m2 and a P/A ratio of 0.449 the U-value for your 100mm Celotex and 160mm EPS is 0.09W/m2K
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