refrigerant weight

[PaulLag]

Hi there

hope everybody is fine.

Please, I'd need an hint as follows.

is there a literature reference or formula in order to calculate thew weight of refrigerant contained in a condenser and an evaporator ?

Ex:
In a condenser with condensing temperature of 122F, with R410A, how much is the weight of refrigerant ?

it can't be the volume for specific weight, since I have a phase change.

Please, can anybody help me ?

thanks !

 

[IRstuff]

You still have conservation of mass, so whatever was inputted to the system is the volume, hence the weight.

TTFN
I can do absolutely anything. I'm an expert!
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[PaulLag]

Hi !
Thanks for the answer.
I am afraid that I'd need more help.
My point is: I know a mass flow, but I don't know the mass or the volume that has been inputted.
Would you be so kind and make me an example of calculation ?

Thanks !

 

[gruntguru]

The mass flow past any point in the (recirculating) system will be identical.

The volume flow at any point is simply the mass flow times the specific volume.

Specific volume is available from tables except for saturated mixture states (eg condenser and evaporator) where quality is unknown but could be inferred as linear between 0 and 1 whit distance travelled along the heat exchange path. The section of the HX where mixed phase exists can be approximated since T will be constant throughout that section.

je suis charlie

 

[PaulLag]

Many thanks
@ gruntguru
I have a massflow (mass/unit of time).

1) It is not clear to me how to pass from mass flow to mass.
2) shall I then make an integration along the condenser length on quality ?
3) how shall I consider the calculation for refrigerants with glide ?

Many question, but thanks to your help things are getting step by step more clear !!

 

[gruntguru]

To estimate total mass you can probably ignore sections containing vapor. Calculate the total volume of sections containing liquid and divide by the specific volume of the refrigerant.

je suis charlie

 

[chicopee]

Gruntguru has the approach but I'll go a little further to his approach. Shut down the refrigeration system for a period of time so that the system is under constant pressure and temperature, the ladder of which may be a little difficult depending where the equipment is located. Knowing the type of refrigerant, you can approximate the specific volume from chart or graph and then calculate the mass.

 

[lilliput1]

The equipment manufacturer would have the data on the required refrigerant charge for the system. Clarify from them how much correction to add for longer refrigerant pipe runs than their normal allowance.