Does anyone have ASHRAE's HVAC/R handbook of fundamentals and can tell me what the load factor is for cooked meat is in a blast cooler application is? Thanks in advance.
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Does anyone have ASHRAE's HVAC/R handbook of fundamentals and can tell me what the load factor is for cooked meat is in a blast cooler application is? Thanks in advance.
Take the same as non-cooked meat, this will make not a difference.
Load 'factor', what do you mean with 'factor' ?
The heat which is in the meat must be taken out the meat and transferred to the refrigerant
I gave you the figures on the other thread you were writing.Quote:
Originally Posted by Freezon
Meat has a specific heat content.
If you want to make it hotter or colder you need to add or remove heat.
Find the specific heat, eg water is 4.19 Kj/Kg per degree.
If I wanted to cool water by 10 degrees C I would have to remove 10 X 4.19 Kj/kg
and that is the heat load for water when I cool it by 10 K.
Just do the same for the meat.
taz.
.
I wish I could explain this better. In this KEEP- RITE or TRENTON refrigeration sizing software that is free to the working stiffs, it automatically fills in two categories once u select your type of product. It gives an "above" and a "below spc. Ht" value. Below those two boxes is a "LOAD FACTOR". The default is #1. The only advice or tip offered is "If this is a blast cooler or freezer, please locate the correct value fom ASHRAE fundamental Handbook". If you change 1 to 2 it dbl's the total btu load and 2 to 3 and so on. As u Stated earlier, I can see if you oversize the eqpmt, It wiil pull the temp down quicker than it can suck th moisture. Its Tuesday now and I'll try giving the software folks a call. I just figured it was a common # to be had since they were directing me to the specific book. Thanks again.
I have a copy on a backup disc at home let me look at it tonight and if I can shed any light on it I will :)
All the best
taz
.
Thanks. If you would like, I can e-mail you the job info and you can drop it in possiby. I did call Trenton and got no where. It appears this program is for your standard app's. and the content individual I spoke with refused to venture out of his box. I sized the eqpmt for the heaviest part of the load which was 140 degree to 70 degree( in 2 hours), the lightest load being 70 to 40 in 4 hours. Again, I'm just trying to see what size of equipment needs to be installed. Its beginning to look like the box can barely handle the girth of the equipment. Thanks for your input.
I think you will find if you choose the the right refrigerant, allow for a floating suction pressure that process will balance out as per the specification.
"Example only" a Copeland on R134a at 25C SST and 50C SCT, will give you 91Kw of cooling, the same comp at 0C SST and 50C will give you 35Kw.
So in practice, you need to reheat the room before product enters (to stop condensation falling onto the product)
So the trick is sizing the evap and refrigerant control (expansion device) for the large variants in duty.
The best way to understand your process is to is to break down into smaller time segments.
for example (these figure shown are only for illustration and have not been calculated in any form)
Start air temp 40C, SST 25 C, split 15C, duty 90kw
15 min air temp 35C, SST 22C, split 13C duty 83Kw
30 min air temp 31 C SST 19C, split 12C duty 77Kw
45 min ---------------------- and so on
You need to understand your application, a computer program is only as good as the information that you put in, and most of the programs available base calculations on a number of steady state variables ( fixed ambient, pressures, temps etc)
Hi Freezon.
as per your other post, ambient coolers will knock a huge amount of heat out of product initially.
.
Freezon, I have had a look through my backups and can't find what you are looking for.
It sounds like the free software relies heavily on chargable information and the way they
make their money is on you having to buy the extras so you can do the calcs.
Just go back to basics and work it out longhand, you would have done it by now and
saved yourself all this hassel.
All the best
taz
.
I agree! The screwed up thing is I would have bought a program just to avoid the math but I swear on my life "i could not find one". I searched the I=net and could not find a software program for refrigerated boxes. Go figure. Thanks for looking and your efforts are truly appreciated.
In the UK there is a product called Mistral, search it and see if itQuote:
Originally Posted by Freezon
meets your needs but I know that it calculates
Loads
sizes
pipe runs
flow rates
pipe sizing
types of equipment
and many many more
I have used it for a college assignment and used the free version that limits you to one or two
goes before you have to buy the licence.
It will do multiple calculations for differant systems and it draws all the schematics and
other things aswell.
http://us.mistralassociates.com/
some of the software is freeware and others you have to pay for.
See what you think.
All the best
taz
.
.
Coldroom design
http://us.mistralassociates.com/coldwind.html
All the best
taz
.
Thanks Taz. I'm looking into it now and it does look promising. Thanks my friend.
Off topic - needed removing