PH_Rev01.txt

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Author:
Anonymous
ID:
248788
Filename:
PH_Rev01.txt
Updated:
2013-11-24 09:31:21
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Passive House Revision 01
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Passive House Revision 01
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  1. Outline the steps in calculating the thickness of insulation to give a required improved u-value
    • 1/Exist u-value = Re
    • 1/Improved u-value = Ri
    • Required additional resistance Rr = Ri - Re
    • Thickness Extra insulation = Rr x Thermal Conductivity of insulation
  2. Calculate the thickness of extra insulation to give a required improved u-value of 0.15W/m2K for existing u-value of 1.5W/m2K. Given Thermal conductivity of the insulation = 0.04W/mK
    • 1/Exist u-value = Re
    • = 1/1.5W/m2K = 0.67
    • 1/Improved u-value = Ri
    • = 0.15W/m2K = 6.67
    • Required additional resistance Rr = Ri - Re
    • = 6.67 - 0.67 = 6.0
    • Thickness Extra insulation = Rr x Thermal Conductivity of insulation
    • = 6 x 0.04 = 0.24m
  3. Gt = ?
    Heat Degree Hours
  4. What is Gt for Dublin?
    60 kKh/a = 60 kilo Kelvin hours per annum
  5. What is the Energy Balance Formula?
    Heat Losses = Heat Gains
  6. What Heat Losses are considered for the Energy Balance?
    Losses: Windows + Walls + Floor + Roof + Air Leakage
  7. What Heat Gains are considered for the Energy Balance?
    Gains: Solar + Internal + Heating (Heat Demand)
  8. Annual Heat Demand for Building = ?
    = GFA x ??kWh/m2/y
  9. Annual Heat Demand for 200m2 Building with Heat Demand of 15kWh/m2/yr= ?
    = GFA 200m2 x 15kWh/m2/y = 300kWh/yr
  10. Calculate Annual Heating Costs if Annual Heat Demand = 3000kWh/yr at cost of €0.10/kWh
    Cost = 3000 x 0.10 = €300
  11. Dublin GrassTetany = ?
    60kKh/a (kilo Kelvin hours per annum)
  12. Calculate Gt for Jan given the average external temp = 5 deg K
    • Heat Degree Hours Jan = Gt January
    • = ( 24h x 31d x (20K - 5K) ) / 1000
    • = 11.16kKh
  13. Source for average external temperatures?
    MetroNorm
  14. Qt = ?
    Elemental Heat Losses
  15. Qv =
    Ventilation Losses
  16. Qi =
    Internal heat gains
  17. Qs =
    Solar Gains
  18. Qh =
    Heat Demand
  19. Formula for Qh =
    • Qh = (Qt + Qv) - (Qs + Qi)
    • or
    • Heat Demand = (Element Heat Losses + Ventilation losses) - (Solar gains + Internal gains)
  20. Calculate the Heat Demand for Jan through 100m2 of wall with a u-value of 0.15w/m2K and a Jan Heat Demand of 11.16kKh
    • Qt Jan = A x U x ft x Gt
    • = 100m2 x 0.15W/m2K x 1 x 11.16 kKh
    • = 167.4 kKh (for Jan)
  21. Calculate the Annual Heat Demand through 100m2 of wall with a u-value of 0.15w/m2K and a Gt of 60kKh
    • Qt = A x U x ft x Gt
    • = 100m2 x 0.15W/m2K x 1 x 60 kKh
    • = 167.4 kKh

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