# PH_Rev01.txt

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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
 Author: Anonymous ID: 248788 Card Set: PH_Rev01.txt Updated: 2013-11-24 14:31:21 Tags: Passive House Revision 01 Folders: Description: Passive House Revision 01 Show Answers: