georgedvf
22-10-2010, 10:55 PM
Hello!
I need help to get more info about this, the ASHRAE Refrigeration Handbook recommend this about Freezer insulation systems using air ducts:
"The air duct systems works well for smaller storages. For a larger storage, it should be supplemented with fans and a source of heat if the pipe is more than 30m long."
I've seen small Freezers using this method, using 4" PVC pipe underground. But in my case I have a very large Freezer room at -20ºC, 105m x 12m, and the PVC pipes can only be installed at the 105m long way, so I have lots of questions:
This system still works for this long of pipes?
How can I calculate the diameter of the PVC pipes?
How can I calculate the airflow that fans are supposed to trow?
How can I determine if extra heat source is needed?
Can you help me please?
P.D. I'll also use a 4" thick polyurethane foam and vapor barrier system not just the air ducts indeed.
Thanks.
Regards.
P.D. I mistake and post this thread on Practical Refrigeration forum and I don't know how to delete it.
I need help to get more info about this, the ASHRAE Refrigeration Handbook recommend this about Freezer insulation systems using air ducts:
"The air duct systems works well for smaller storages. For a larger storage, it should be supplemented with fans and a source of heat if the pipe is more than 30m long."
I've seen small Freezers using this method, using 4" PVC pipe underground. But in my case I have a very large Freezer room at -20ºC, 105m x 12m, and the PVC pipes can only be installed at the 105m long way, so I have lots of questions:
This system still works for this long of pipes?
How can I calculate the diameter of the PVC pipes?
How can I calculate the airflow that fans are supposed to trow?
How can I determine if extra heat source is needed?
Can you help me please?
P.D. I'll also use a 4" thick polyurethane foam and vapor barrier system not just the air ducts indeed.
Thanks.
Regards.
P.D. I mistake and post this thread on Practical Refrigeration forum and I don't know how to delete it.