Temperature coefficient conversion between C and K

[Koen]

Hi.
I am wondering how to convert PV module temperature coefficient from %/K to %/deg.C and vice versa?

[emartin00]

They are exactly the same.

[J.P.M.]

The coefficients of power, current and voltage are the same in either temp. system.

[discodanman45]

1 degree Celsius increase is exactly the same as 1 Kelvin increase. 20 to 21 degrees Celsius would be the same as going from 293.15 to 294.15 K. Math just gets weird with degrees Celsius when you have negative temperatures. Kelvin is also nicer for comparing energy. 400 Kelvin has twice the energy as 200 Kelvin. 40 degrees Celsius is not twice as energetic as 20 degrees Celsius. BTW, thank you for not writing degrees Kelvin! That drives me crazy. However, the absolute scale for degrees Fahrenheit still uses degrees Rankine.

[Koen]

Thanks all

[inetdog]

1 degree Celsius increase is exactly the same as 1 Kelvin increase. 20 to 21 degrees Celsius would be the same as going from 293.15 to 294.15 K. Math just gets weird with degrees Celsius when you have negative temperatures. Kelvin is also nicer for comparing energy. 400 Kelvin has twice the energy as 200 Kelvin. 40 degrees Celsius is not twice as energetic as 20 degrees Celsius. BTW, thank you for not writing degrees Kelvin! That drives me crazy. However, the absolute scale for degrees Fahrenheit still uses degrees Rankine.

Using Kelvin rather than degrees Kelvin is technically correct, but makes it more difficult to distinguish between references to absolute temperature measurements and references to differences in temperature.
From a dimensional units perspective there is no difference, but there has long been a useful but not universal convention that an absolute temperature is measured in degrees Fahrenheit or degrees Celsius, while temperature differences are described as so many Fahrenheit degrees or Celsius degrees instead.

[gbynum]

BTW, thank you for not writing degrees Kelvin! That drives me crazy.

Is the difference from 20C to 30C temperatures "10 Kelvins" or "10 Kelvin degrees"? Do we use a degree symbol or the word degree at all in the Kelvin temperature system?

[discodanman45]

Is the difference from 20C to 30C temperatures "10 Kelvins" or "10 Kelvin degrees"? Do we use a degree symbol or the word degree at all in the Kelvin temperature system?

When it was first introduced they did use degree Kelvin. However it was omitted and it is just Kelvin now. We never use the word degree in Kelvin. By omitting degrees from degree Kelvin, we are just saying that the unit Kelvin doesn't have an arbitrary reference point like Celsius or Fahrenheit.

Fun fact 1 - Anders Celsius defined the boiling point of water as 0 and the freezing of water as 100. Backwards of what we use today.

Fun fact 2 - Water freezes at 32 degrees and boils at 212. Subtract the two and you get 180 degrees of separation!

Fun fact 3 - In May this year we are redefining Kelvin and Celsius in terms of the Boltzmann constant.