Excel Question

[ad.dias]

Greetings,

I’m currently writing a dissertation about how building envelopes behave in cold climates, specifically, I’m having trouble interpreting a wall’s resistance to freeze/thaw cycles. I have the following data:


I have two columns with 40 000 rows of data.

Colum A is the Time (Number of hours after the experiment starts, 1, 2, 3, 4, 5…)

Colum B is the Temperature (In Celsius)


Example:

(A) (B)

1 -5

2 13

3 16

… …


I need to create a function, or something similar, that can return the number of freeze/taw cycles that occur. Freezing takes place when the temperature is below 0ºC, and thaw takes place when the temperature is above 0ºC. However, I need to take into consideration the following two aspects:

1)The freezing of the wall must take at least 2 hours to occur (There needs to exist 2 consecutive hours, where the temperature is below 0ºC to occur freezing)

2)Two consecutive freeze/thaw cycles must be separated by, at least, 2 hours to occur.


Could someone with a little more expertise help me out on this? I would be very grateful

Kind regards

 

[Hui]

Can you post a sample file with say several cycles and highlight them

 

[ad.dias]

Hi Hui, thank you for your response
Here is a more detailed example on how a freeze/thaw occurs

(A) (B)
1 -10 (Freezing hour 1)
2 -15 (Freezing hour 2, hence, freeze cycle occurs)
3 10 (Thawing hour 1)
4 -6 (Freezing hour 1, remember, thawing has to occur for two consecutive hours in order for a thawing cycle to occur, so this resets the thawing count for the cycle to occur)
5 6 (Thawing hour 2)
6 7 (Thawing hour 3, given that 2 consecutive hours of thawing occur, a thawing cycle occurs)
7 -10 (Freezing hour 1)
8 -11 (Freezing hour 2) (freeze cycle occurs)
9 5 (Thawing hour 1)
10 -10 (Freezing hour 1)
11 7 (Thawing hour 2)
12 9 (Thawing hour 3) (thawing cycle occurs)

I hope this helps =)

 

[p45cal]

It helps a bit, but it's always useful to have a file with real figures to experiment with.
What is 'thawing'?
1. A tempersture above 0 degrees? or…
2. A temperature higher than the previous hour's temperature?

 

[Hui]

Real Data is so much better, and would have speeded up your solution



see attached file:

 

[ad.dias]

Much obliged Hui !!

 

[bobhc]

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