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planning:thermal_protection:windows:window_certification:start

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planning:thermal_protection:windows:window_certification:start [2020/10/27 15:57] – naman.sukhija@passiv.deplanning:thermal_protection:windows:window_certification:start [2022/02/15 19:54] (current) – admin
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 Important factors in determining a window's energy balance include the thermal values for the glazing (U<sub>g</sub> and g-value) and the frame (U<sub>f</sub> and glass edge thermal bridge coefficient Ψ<sub>g</sub>) along with the window frame surface area A<sub>f</sub>. All of these parameters are important because, on one hand, the frame tends to have a worse U-value than the glazing and, on the other hand, no direct solar gains are possible through the frame. From the parameters U<sub>f</sub>, Ψ<sub>g</sub>, and A<sub>f</sub>, relative to the length of the glass edge l<sub>g</sub>, we can derive the indicator Ψ<sub>opaque</sub>, which describes losses from the opaque component. The smaller Ψ<sub>opaque</sub> is (that is, the lower losses are along the edge of the glass), the greater potential solar gains through the window are. PHI used this parameter to determine classes from phC to phA+, which have been used to evaluate Passive House windows since early 2011 (cf. [[planning:thermal_protection:windows:window_certification:start#references|[Krick 2011]]], [[planning:thermal_protection:windows:window_certification:start#references|[Krick 2011a]]]):\\ Important factors in determining a window's energy balance include the thermal values for the glazing (U<sub>g</sub> and g-value) and the frame (U<sub>f</sub> and glass edge thermal bridge coefficient Ψ<sub>g</sub>) along with the window frame surface area A<sub>f</sub>. All of these parameters are important because, on one hand, the frame tends to have a worse U-value than the glazing and, on the other hand, no direct solar gains are possible through the frame. From the parameters U<sub>f</sub>, Ψ<sub>g</sub>, and A<sub>f</sub>, relative to the length of the glass edge l<sub>g</sub>, we can derive the indicator Ψ<sub>opaque</sub>, which describes losses from the opaque component. The smaller Ψ<sub>opaque</sub> is (that is, the lower losses are along the edge of the glass), the greater potential solar gains through the window are. PHI used this parameter to determine classes from phC to phA+, which have been used to evaluate Passive House windows since early 2011 (cf. [[planning:thermal_protection:windows:window_certification:start#references|[Krick 2011]]], [[planning:thermal_protection:windows:window_certification:start#references|[Krick 2011a]]]):\\
 \\ \\
-<latex>+$$
 \Large{\varPsi_{opaque} = \varPsi_{g} +\dfrac{U_{f}\cdot A_{f}}{l_{g}}} \Large{\varPsi_{opaque} = \varPsi_{g} +\dfrac{U_{f}\cdot A_{f}}{l_{g}}}
-</latex>+$$
  
 After the certification program, the introduction of this classification system proved to be the second major incentive to continue improving the energy efficiency of windows. The trend toward wider frames and, in turn, worse Ψ<sub>opaque</sub> values turned around within a year after the classes were introduced. In 2013, 44 percent of newly certified frames received Class A designation (with one frame earning Class A+); except for a few aluminum frames, no products were designated Class phC in 2012 and 2013 (see Figure 1).\\ After the certification program, the introduction of this classification system proved to be the second major incentive to continue improving the energy efficiency of windows. The trend toward wider frames and, in turn, worse Ψ<sub>opaque</sub> values turned around within a year after the classes were introduced. In 2013, 44 percent of newly certified frames received Class A designation (with one frame earning Class A+); except for a few aluminum frames, no products were designated Class phC in 2012 and 2013 (see Figure 1).\\
planning/thermal_protection/windows/window_certification/start.txt · Last modified: 2022/02/15 19:54 by admin