Freezer Room PRV

[CCLPaul]

Years ago I had a quick spreadsheet calculation to determine the size of a room PRV, sadly that laptop is no more. Unfortunately, I dont know where I got the information from and have been asked to prove how I selected the number of PRVs installed. Can anyone help?

[chemi-cool]

Try www.totaline.com

they have some caculating sheets.

[Grizzly]

Hi cclpaul.
Sorry I have not found any software yet but I have found a written explanation of how to calculate relief Vales sizes etc.


The pressure relief valve, see Figure 9 equalizes internal and external pressures to reduce the possibility of these problems occurring. The number and size of the relief valves can be calculated using the following formula:
http://www.ishrae.in/journals/2002apr/article02/eq01.gif
Where A is the required venting area in m2, Q is the rate of heat production or extraction in the cold store in kW, T is the cold store temperature in °C and P is the allowable pressure difference from store to outside, in N/m2 or Pa.

It is recommended that at least the following Q values should be considered when determining the maximum possible value of Q to be used in the formula:

Maximum possible rate of extraction.
Maximum possible rate of heat input during defrosting.
Maximum rate of heat input during any possible transient conditions, such as might arise after a defrost, if cold air were blown through a hot finned cooler.
I hope this is of some assistance?
Grizzly

[chillerman2006]

Grizzly

Your a dark horse mate...been keeping your extra talents well hidden ;) well until now
I can gauge from that the sort of info you have stored upstairs

R's chillerman

[CCLPaul]

Thank you all, I will write it down at the front of one of my books this time.