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U-Value KIT: Instruction Manual
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Table 1: Detailed explanations of the parameters used in the report
Designator
Description
How to calculate / formula
Measurement time
Total length of the measurement period
(measurement end time)
–
(measurement
start time)
Analysis period
Duration of the period used for data analysis (must be a
multiple of 24 h)
Measurement period rounded down to a
multiple of 24h. corresponds to:
(analysis end time)
–
(analysis start time)
Analysis start time
Since analysis period is shorter than measurement
period a part of the measurement data must be
discarded. The first part is discarded in our software
since it is usually more prone to fluctuations than the
last part of the measurement period
-
Analysis end time
Always corresponds to the end of the measurement
period
U-value (U)
U-value calculated by using the data of the full analysis
period
Where q
j
= heat flux at time j
T
ij
= inside air temperature at time j
T
ej
= outside air temperature at time j
U24
U-value calculated by using the data without the last
24h
See calculation of U-value
U2/3s
U-value calculated by using the first 2/3 of the analysis
period in days
Number of days of this period is calculated
using INT(2 /3* D), where D stands for the
duration in days of the analysis period
U2/3e
U-value calculated by using the last 2/3 of the analysis
period in days
Number of days of this period is calculated
using INT(2 /3* D), where D stands for the
duration in days of the analysis period
dU24
Deviation between U and U24
dU24 = 2*(U - U24) / (U + U24)
dU2/3
Deviation between U2/3s and U2/3e
dU2/3 =
2*([U2/3s] - [U2/3e]) / ([U2/3s] + [U2/3e])
R (not in report)
R-value calculated from U-value by assuming
standardized heat transfer coefficients of 0.13 (inside)
and 0.04 (outside)
R = 1/U - 0.13 - 0.04
R24 (not in report)
R-value calculated by using the data without the last
24h
See above
R2/3s (not in report)
R-value calculated by using the first 2/3 of the analysis
period in days
Analogous to U2/3s
R2/3e (not in report)
R-value calculated by using the last 2/3 of the analysis
period in days
Analogous to U2/3e
dR24
R-value deviation calculated from R24-value by
assuming standardized heat transfer coefficients on
0.13 (inside) and 0.04 (outside)
dR24 = 2*(R - R24) / (R + R24)
dR2/3
R-value deviation calculated from R2/3-value by
assuming standardized heat transfer coefficients on
0.13 (inside) and 0.04 (outside)
dR2/3 =
2*([R2/3s] - [R2/3e]) / ([R2/3s] + [R2/3e])
Test criteria:
1.
Measurement time >=72h
2.
Max (abs(dR24, dR2/3)) <= 5%
