Escort iMiniPlus User Manual page 44

42
Select this option to display the Mean Kinetic Temperature of the iMiniPlus readings in the 2D graph legend.
There are some products and materials that
exist which have accelerated rates of
degradation at higher temperatures. For
example, perishable
pharmaceutical products and many forms of
bacteria can grow/degrade exponentially as
the environmental temperature increases.
Mean kinetic temperature is a calculation that accommodates the non-linear thermal effect temperature can
have on products. Mean kinetic temperature is represented as the equivalent temperature the product was
thermally subjected to during the period of time the
various temperature readings were recorded. As an
illustration of how the MKT calculation will affect an
expressed mean for a yearly calculation (important for
the long term storage of critical drugs and chemicals),
here is an illustration:
If the temperature is constant for an entire year, but is
"off" for a single month of that year, there will be a
difference in the calculated arithmetic mean (the sum of
all of the measurements divided by the number of
measurements--a simple mean) and the kinetic mean.
The following graph and table show the differences which
are calculated by both methods:
Effect on Kinetic and Arithmetic Mean Temperatures on storage for one month at other than 25° C.
Temperature (one month)
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Although the effect is not dramatic, it is clear that the MKT method weights the higher temperatures in a
series more than the lower temperatures.
Growing Degree Day
GDD are calculated by taking the average of the daily maximum
and minimum temperatures compared to a base temperature,
(usually 10 °C). As an equation:
food items,
Mean Temp.(Kinetic)
24.48
24.51
24.54
24.58
24.62
24.67
24.72
24.78
24.85
24.92
25.00
25.09
25.18
25.29
25.41
25.53
Mean Temp.(Arithmetic)
24.17
24.25
24.33
24.42
24.50
24.58
24.67
24.75
24.83
24.92
25.00
25.08
25.17
25.25
25.33
25.42
T
,
base