REFRIGERATION-ENGINEER.COM - Newsletter (Iss. 14) - Sun 16th December 2001

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REFRIGERATION-ENGINEER.COM - Newsletter (Iss. 14) - Sun 16th December 2001
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Welcome to http://www.refrigeration-engineer.com the on-line global refrigeration community, 
joining thousands of refrigeration professionals' (from Managing Directors and Sales Managers to 
Design and Service Engineers) together in debate over anything and everything to do with the world 
of refrigeration.

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CONTENTS
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FORUM
DIRECTORY ENTRY
RECRUITMENT
ANSWER THIS?
ARE YOU INTERESTED?
MERCHANDISE
PSYCHOMETRIC TOOLS

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FORUM
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635 registered members (in addition to the thousands of 'guests' that pop in…).

Hot topics currently being discussed in the forum (amoungst the 448 active threads):

"Anybody know of any supermarket simulator programs to download?"

"Then, the main question I'm asking here, what if the valve selected was a little undersized and to 
meet the required capacity for a given dP and liquid temperature the superheat setting had to be 
reduced. For any subsequent low load condition such as fan failure or iced coil, would this 
undersized valve with a compensating low superheat adjustment have a greater tendency to floodback 
in comparison to a correctly sized correctly set TEV…?"

"What is the correct method to check subcool?   I take it for a correctly charged system subcool 
would be in the region 15K. Also how can one tell when an expansion valve is "hunting"?  I know 
these questions seem pretty elementary but subcool, superheat are two of the major aspects which 
control the stability and balance of a system, and also show up if the system is not designed 
correctly, ie: mismatch of components…"

Why not drop in & have your say? http://www.refrigeration-engineer.com/chat/ 

PLEASE NOTE YOU WILL NOT SEE ALL THE DISCUSSION THREADS UNTIL YOU REGISTER AS A MEMBER.  Register 
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DIRECTORY ENTRY
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visitors (over 1.6 million accesses since Feb 01) can easily contact you. 
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RECRUITMENT
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LOOKING FOR A JOB?  Service, Sales, Design, Management…?

Visit:http://www.refrigeration-engineer.com/jobs for 150+ jobs currently vacant in the UK, with 
salaries up to £40k.

We have agreed terms with further agencies and will be presenting an estimated 250+ CURRENT 
VACANCIES in the next couple of weeks (US vacancies are coming…).

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ANSWER THIS...?
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"Here is my problem...

I have 2 different freezer contractors quoting me two different equipment sizes for the same walk 
in freezer box.  Here is the backstory: 
Freezer will be 15x30x8 with floor. 4 inch urethane. 1 60x84 door.  The box will need to maintain a 
storage temp. of -20F for ice cream. Product will enter @ -10F. (200 lbs/day) for the purpose of 
storage w/low door traffic. 

On to the mechanicals: 
This will be a (2) Cond. unit / (2) Evap setup. (separate systems) Both contractors quoted with 5HP 
Low temp scroll cond. units (Russell # ML0500L44) that are rated at 13200 BTUH @ -30F Suction temp. 
@ 95F ambient for a total of 26400 BTUH.  The evaporater selection is where it gets tricky!  One 
Contractor choose the Russell # AE46-164B 4 fan /elec. defrost rated @ 15000 BTUH capacity @10 
Degree T.D. at a -30 Evap temp. total capacity = 30,000 BTUH (2 evaps).  The 2nd Contractor chose 
the Russell # AE36-140B which is rated @ 13,300 for a total of 26,600 BTUH at the same specs. 

Summary: System 1 Cond. units 26,400 
System 1 Evaps. 30,000 
=8.8 T.D. 

System 2 Cond. Units 26,400 
System 2 Evaps. 26,600 
=9.9 T.D. 

System 1 quote argues that 8.8 T.D. is acceptable with short pipe runs etc. for a freezer. 

System 2 quote says that 9.9 T.D. system is more efficient and is better matched. Also that I cant 
squeeze the extra capacity out of the evaps. if the condensing units cant provide it! 

O.K. which is the better designed system??  What are the pros and cons to each, or is it a matter 
of right and wrong?  I am in Western WA state where the average daily temp is 50F. these are 
outdoor units.(Box and Cond. units).  If anyone has the ability to run box load calculations on 
this set-up please do, as I wish to know if they are even sized right for my application. 

Thank you for any and all feedback!"
http://www.refrigeration-engineer.com/chat/showthread.php3?s=&threadid=500 

...Then why not visit the FORUM where this & hundreds of other similar questions are being asked: 
http://www.refrigeration-engineer.com/chat/

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ARE YOU INTERESTED...?
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Would you like to write for the site?  Do you or your company have an article they would like to 
share with the rest of the refrigeration community?  If yes, email: mailto:articles@refrigeration-
engineer.com and we will include it in our articles section.

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MERCHANDISE
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You can now get yourself identified as a proud member of the Refrigeration Industry with a 
selection of T-shirts, caps, mugs, and other neat gear from RE by clicking: 
http://www.cafepress.com/cp/store/store.aspx?storeid=refrig 

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PSYCHOMETRIC TOOLS
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Visit any one of the link sites offering various psychometric tools & calculators. 
http://www.refrigeration-engineer.com/chat/forumdisplay.php3?s=d6b3b7bc2d41ee58f40bb4f41f65cdaf&forumid=36 


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Received on Sunday, 16 December 2001 15:31:20 UTC