Energy Performance R-value - Part 3 Examples of Application to by vqa11744

VIEWS: 15 PAGES: 36

									Syracuse University
Mechanical & Aerospace Engineering




  Energy equivalent R-value
      Part 3: Application to metal assemblies
                                   assemblies




     Thomas Thorsell and Mark Bomberg
                              Bomberg

     Energy and Environmental Systems Lab
                                      Lab

 Wall tested in this project
                     project


‡ Referencewall – multi-component
 (MC) glass fiber in the steel frame
 system– nominal R23

‡ Selectedpanel system (PS) – exterior
 insulation with sheet metal
 protection – nominal R15.6
           Assembly 1, MC
• Multi Component (MC) Wall System
         Assembly 2, PS
• Selected Panel System (PS)
2D Modeling results, MC


          Horizontal section




                           Vertical section
          2D Modeling results, MC


-15.4°C          20°C

h=20             h=7.7
W/(m²K)          W/(m²K)




                           R18.9 ft²hr°F/BTU
   2D Modeling results, MC
Horizontal section
            20°C    h=7.7   W/(m²K)




            -20°C    h=20   W/(m²K)




   R10.4 ft²hr°F/BTU (nominal R23)
    2D Modeling results, MC
                         MC

Horizontal section
                         Temperature on
                         inside surface

                         Lowest surface
                         temperature

                          11.3 °C


 20°C, h=7.7   W/(m²K)




 -20°C, h=20   W/(m²K)
2D Modeling results, PS


          Horizontal section




                               Vertical section
2-D Modeling results, PS
          Horizontal section
20°C
h=7.7   W/(m²K)




-15.4°C
h=20 W/(m²K)




R13.6 ft²hr°F/BTU
          2D Modeling results, PS


-15.4°C        20°C

h=20           h=7.7
W/(m²K)        W/(m²K)




                                  R13.4 ft²hr°F/BTU
                         R11.5 ft²hr°F/BTU
Experimental data from climatic
          chambers




                              12
Measurements, implementation

Front side             Rear side            On the wall





• Temperature profile on
                                   • Heat Flux Transducer
  Vertical Thermal Bridge
                                     is built in the CBL
                      Test procedure
                                               Chamber        Lab
                      Air
                 Flow/Pressure              Temp      RH     Temp
Step Duration     [cfm or Pa]    Edges       [°C]     [%]     [°C]
 0     1 day                     Wall characterization
1a    3 days         0 Pa        Normal    -16 °C     Dry    room
1b    3 days         0 Pa        Sealed    -16 °C     Dry    room
2a    3 days         50 Pa       Normal    -16 °C     Dry    room
2b    3 days         50 Pa       Sealed    -16 °C     Dry    room
       3 or5
 3     days          50 Pa       Normal     40 °C    80 %    room
      1 + 3 or
      5 days                 Transition + period of drying
       2 day
 4      test         50 Pa        As is    -16 °C     Dry    room
 Surface temperatures, under CBL on
   drywall in inches from the stud
                            Multi-component wall
Exterior insulating panel
               Test results, MC
                             MC

STEP 1

Chamber          Room
                          Tested nominal
-16°C            20°C
                          R=14.7 ft²hr°F/BTU
+ 0 Pa           50% RH
Uncontrolled
                          Agrees with the model
RH                        results (18.9+10.7)/2=
                           14.8 ft²hr°F/BTU
      Effect of air pressure on MC
STEP 2

Chamber            Room

-16°C          ?   20°C     Measured R-value
+ 50 Pa            50% RH
Uncontrolled
                            12.4 ft²hr°F/BTU
RH                          (14.7-12.4)/14.7 = 15.6%



               ?
               Measured results, SPS
                                 SPS

STEP 1

Chamber             Room
                             Nominal R-value
-16°C               20°C
                             10.1 ft²hr°F/BTU
+ 0 Pa              50% RH
                             i.e.
Uncontrolled
                             much less than expected,
RH
                             let us go back to the model
                             and check the effect of
                             stainless steel chamber
                              on flanking loss from the
                             metal wall
 Effect of flanking loss from the
metal panel in stainless chamber

            Mounting strip above the wall




             Middle part’s R= 13.3 ft2 hr oF/ Btu
                          26.3% reduction
               Average wall R= 9.8 ft2 hr oF/ Btu
               Measured results, SPS
                                 SPS

STEP 1

Chamber             Room
                             Nominal R-value
-16°C               20°C
                             10.1 ft²hr°F/Btu
+ 0 Pa              50% RH
Uncontrolled
                             Compare to
RH
                             14.7*0.737 =
                             10.8 ft²hr°F/Btu
               Effect of air flow on PS
                                     PS

STEP 2

Chamber	             Room

-16°C            ?   20°C	     Measured R-value
+ 50 Pa              50% RH	   9.3 ft²hr°F/BTU
Uncontrolled
RH	                            so the effect of air flow is
                               0.8/10.1 about 8%
                 ?
   Measured temperature profile
on the wall surfaces, no air pressure
  Top level of the wall, vertical thermal bridge




                                                   PS

                                                   MC
     Measured temperature profile
on the wall surfaces, no air pressure -2-
                                      -2­
               Middle level




                                 PS



                                 MC
     Measured temperature profile
on the wall surfaces, no air pressure -3­

                Bottom level


                                  PS

                                  MC
Effect of air infiltration
     Top position




                             MC

                             PS
Effect of air infiltration
      Middle position


                             MC




                             PS
Effect of air infiltration
    Lowest position




                             MC

                             PS
  Measured temperature profile
                         profile

on the wall surfaces -conclusions
                     -conclusions

  ‡ Surface temperature in deg C :
  Without air infiltration - with ΔP=50 Pa
  Top     13.7                    23.4
  Middle 12.2                     26.4
  Bottom 15.6                     25.5
  So, with the inflow of cold air into the
   assembly we draw warm air into the
   insulation or air cavity in the wall
  Interim concluding remarks -1-
                             -1­


‡ Exterior  insulated panel is superior to
   MC in the following ways:
1) Calculated temperature depression is
   from 20 deg C in air to 11.3 deg C on the
   surface (much lower in the corner)
2) Under CBL (uniform layer with R3)
   measured temperature depression is
   about 13 deg C while the corresponding
   value for SPS is only 2 deg
General discussion:
instrumented plates
  General discussion continue :
effect of hot & humid conditioning
General discussion: mold as the
effect of hot and humid exposure
       Conclusions -2-
                   -2­


‡ PS is more reliable in avoiding
  condensation than MC
‡ The impact of sealed and unsealed
  drywall is significant. In case of
  sealed drywall 35-45 % of the
  pressure drop was across the
  drywall. The pressure drop was more
  than 80 % when the drywall was not
  sealed.
         Conclusions – 3-
                       3­


(1) Nominal R-values ft²hr°F/BTU
(2) multi-dimensional heat transfer
(3) air flow
        (1)     (2)     (3)    air % total %
MC R23          14.7 12.4 16 % 46%
PS R15.8 13.6* 12.5* 8 % 21%
*/ correcting for effect of flanking loss
    in stainless steel climatic chamber
                                chamber

    Different start but at the end
                               end

    there is the same Ree - value

‡ MC nominal R23 energy equivalent
                        equivalent

 12.4 (46% reduction)
‡ PS nominal R16 energy equivalent
                        equivalent

 12.5 (21% reduction)
          Acknowledment
          Acknowledment

This research was not supported by grants;
  the following companies supported it for
3 years:
‡ Centria Corporation
‡ Greenfiber Corporation
‡ Huber Engineered Wood
2 years:
‡ Fortifiber Corp
‡ Jeld-wen Corp

								
To top