Working on the international system. Im confused

[elgue]

Hey how u doing?

I’m moving soon from US to down under and I’m trying to get my mind used to work in the international metric system so I have a couple of question and I 'd appreciate for your help.

Ok I know that temp is measure with C Celsius instead of F. But I've been reading some posts and articles on the net and when they talk about subcooling or superheat they talk about "K" ???

For example this is from an article “liquid subcool values of say 1K to 3K”. What do they mean by this?? Is this 1 kelvin to 3 kelvin? Why are they using Kelvin instead of Celsius?

I’ve seen also that in some articles they use celsious and Kelvin interchangeably.
But 23 C are not the same as 23 K, are they?? I thought that C=K-273

Can someone help me to digest this please.:confused:

I have 2 more questions.
1. What unit is used in Aussie to measure refrigerant pressure? Psi??
2. How is airflow measured in Aussie? CFM??
Thanks.

[charlie n]

Forget about American units of measure. They aren't used anywhere else except sometimes in Canada. Pressure is recorded in bar or kpa. Degrees Kelvin is an absolute scale starting at -273 C but one degree C difference is the same as 1 degree K. Air flow is recorded in cubic meters per second or per hour. Water flow is recorded in litres per second or lcubic meters per hour. refrigeration effect and motor power are in kW. The best way is to start using the international units & don't try to convert everything. The calculations are way easier & you'll fit in and become comfortable much faster.

[Josip]

Hi, elgue :)


Hey how u doing?

I’m moving soon from US to down under and I’m trying to get my mind used to work in the international metric system so I have a couple of question and I 'd appreciate for your help.

Ok I know that temp is measure with C Celsius instead of F. But I've been reading some posts and articles on the net and when they talk about subcooling or superheat they talk about "K" ???

For example this is from an article “liquid subcool values of say 1K to 3K”. What do they mean by this?? Is this 1 kelvin to 3 kelvin? Why are they using Kelvin instead of Celsius?

I’ve seen also that in some articles they use celsious and Kelvin interchangeably.
But 23 C are not the same as 23 K, are they?? I thought that C=K-273

Can someone help me to digest this please.:confused:

I have 2 more questions.
1. What unit is used in Aussie to measure refrigerant pressure? Psi??
2. How is airflow measured in Aussie? CFM??
Thanks.

Welcome to RE forums ....

you can find and learn a lot by searching RE forums....

use key words like superheat, subcooling, measuring units, Kelvin etc...

read this thread:

http://www.refrigeration-engineer.com/forums/showthread.php?t=23821


of course, welcome back with any new doubt you have;)

good luck down under....

Best regards, Josip :)

[Toosh]

Hey how u doing?

I’m moving soon from US to down under and I’m trying to get my mind used to work in the international metric system so I have a couple of question and I 'd appreciate for your help.

Ok I know that temp is measure with C Celsius instead of F. But I've been reading some posts and articles on the net and when they talk about subcooling or superheat they talk about "K" ???

For example this is from an article “liquid subcool values of say 1K to 3K”. What do they mean by this?? Is this 1 kelvin to 3 kelvin? Why are they using Kelvin instead of Celsius?

I’ve seen also that in some articles they use celsious and Kelvin interchangeably.
But 23 C are not the same as 23 K, are they?? I thought that C=K-273

Can someone help me to digest this please.:confused:

I have 2 more questions.
1. What unit is used in Aussie to measure refrigerant pressure? Psi??
2. How is airflow measured in Aussie? CFM??
Thanks.

Here is si units


http://www.gordonengland.co.uk/conversion/thermcon.htm

[michaelm]

B”H
Charlie,

Engineers like to work in bars.

[marc5180]

Hey how u doing?


Ok I know that temp is measure with C Celsius instead of F. But I've been reading some posts and articles on the net and when they talk about subcooling or superheat they talk about "K" ???

For example this is from an article “liquid subcool values of say 1K to 3K”. What do they mean by this?? Is this 1 kelvin to 3 kelvin? Why are they using Kelvin instead of Celsius?

I’ve seen also that in some articles they use celsious and Kelvin interchangeably.
But 23 C are not the same as 23 K, are they?? I thought that C=K-273



Even though K normally stands for Kelvin, people use the term K on the end of a number to express temperature differences.

For example Saturated Condensing temp of 56DegC and the actual temperature of the liquid line is 48DegC, this would give you 8DegC subcooling or 8K ( temperature difference.

[Toosh]

B”H
Charlie,

Engineers like to work in bars.


Haha is that your local bar or pressure :off topic:

[charlie n]

Haha is that your local bar or pressure :off topic:

Your choice. I like both.

[elgue]

Hey Thanks to everyboby for taking the time to answer my questions.

Does anyone know where I can find a P/T chart on the web for Celsius and bar or Kpa??? I've been trying to find one and all I find are P/T charts with F and Psi.

By the way any good HVACR book (basics) with the SI system you would recomend?

[Chef]

Try this
http://www.et.web.mek.dtu.dk/Coolpack/UK/download.html

[marc5180]

By the way any good HVACR book (basics) with the SI system you would recomend?

Kotza Refribase

[charlie n]

here's a PT guide for the "400" refrigerants. I have one for ammonia, R22 & R507 but it's too big to upload

[Toosh]

Hey Thanks to everyboby for taking the time to answer my questions.

Does anyone know where I can find a P/T chart on the web for Celsius and bar or Kpa??? I've been trying to find one and all I find are P/T charts with F and Psi.

By the way any good HVACR book (basics) with the SI system you would recomend?

Try this

http://fridgetech.com/calculators/