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Hi every one :p:p:p
i 've one problem that did we've any standred to charge refrigerant R134a in any system
how much we charge ???? :confused::confused::confused:
speacial attention to :cool:
Mr. MG PONY
MR. BRAIN UK
MR.ICE MAN
MR. JOSIP
MR.NIKE
thanks and best regrads
JAHANGIR AHMAD KHAN
LAHORE PAKISTAN
You need to charge by superheat and subcooling regardless of refrigerant.
Correct superheat ensures that there is no liquid at compressor suction (because liquid cannot be compressed) and if it is to low compressor could be damaged and if it is to high, evaporator capacity is lowered, because that excess superheat is not useful.
Correct subcooling ensures that liquid is present at inlet of expansion device, and if it is low, some evaporated refrigerant enters in expansion device lowering device capacity and, also, could damage it (TXV). High subcooling uses higher part of condenser for storing liquid refrigerant, and lowers his heat rejection capacity.
Refrigerant charging must be balanced in that manner that is in all working conditions ensured minimum superheat and minimum subcooling and in same time that useless subcooling and superheat is also minimal.
Amount of superheat and subcooling is dependent on construction of appliances and working conditions in time of charging.
Good guide for AC is Jim Wheeler charging article:
http://tinyurl.com/56jrzl
For refrigeration I don't have any link or table
I will appreciate any friend to tip me or suggest what to be done to design the industrial water chiller, for tank capacity 5000gallon, ambient temp.45deg.C and design temp will be 20deg.C , I would like to know if cooling load estimation can be done through cold storage design software or there is special software related to water cooling load?, I like to share experience of friend on this , as it is the first time this come to me as challenge and i preffer to have great idea instead of biten about the bush, any idea is welcome,and I am appreciating software and other tips , thanks in advance;)
AoA
MR.IBRAHEEM
what is this
i've problem in charging and u reply with your problem
you make a new thread for your problem
don't ask your problem in other s thread
i think u understand it
thanks for ur coopration
thanks a lot
jahangir ahmad khan
Lahore pakistan
As Nike has said, there is no "standard" charge, the charge must be tuned to your fridge.Quote:
Originally Posted by jahangir.ahmad
Add refrigerant till you just begin to see frost on the suction line, then with this charge allow the fridge to pull down to the temperature of 2C, then you adjust the charge to get proper super heat and sub cooling.
After this you will watch it and test it at several different condensing temperatures to ensure it is good then seal it off.
Good luck to you and your venture, I am sure you will succed.
Good after noon
thanks a lot
for such a nice information MR.MG pony and same to u
JAHANGIR AHMAD KHAN
LAHORE PAKISTAN
I'M ALSO waitingFOR THE COMMENTS OF .
MR JOSIP
MR.Brain uk
I'M WAITIN FOR REPLY
JAHANGIR AHMAD KHAN
LAHORE PAKISTAN
goood morning
i'm still waiting the comments of MR.JOSIP AND BRAIN UK
IF U READ IT AND DON'Y HAVE ANY INFORMATION ABOUT IT KINDLY REPLY ME SIMPLY
REMEMBER I'M STIL WAITING FOR YOUR REPLY
THANKS AND REGRADS
JAHANGIR AHMAD KHAN
LAHORE PAKISTAN
hi good morning
some of mine friends told me the thumb rule ' that fill your tube 70% and see that back pressure is must be zero (0)
send me your comments about it
attn: MR JOSIP
THANKS
JAHANGIR AHMAD
LAHORE PAJISTAN
Then, you just listen those friends of you.Quote:
Originally Posted by jahangir.ahmad
good morning
i'm asking your suggestion
this is just a thumb rule
i'm asking that did we have any thumb rule or not like this
don't to be angry i'm just telling u to confirm it
if u r not agree then its wrong
clear
thanks for reply
Jahangir Ahmad Khan
Lahore Pakistan
I'm Request To
I am not angry.Quote:
Originally Posted by jahangir.ahmad
Learn to work without rules of thumb, because they could mislead you.
If you had carefuly read that article I sent you in post no. 2, then you would understand why my answer to your question it is such as it is.
Quote:
In literally hundreds of visits to problem jobs, I’ve found most air conditioners/heat pumps to be overcharged with refrigerant. Why? Because incorrect charging techniques are too commonly used in the field. I remember my first training on charging a residential air conditioner. The technician I worked with said: “Just add refrigerant until the high side is about 250-psig and the low side is about 60.” And that’s how I did it for the first six months of my career as a hvacr service technician.
Unfortunately, this is the same training many others in our industry received during the building rush of the early ‘70s.
It’s comforting to know that few still use that method today, but some are even worse! The “Gifted Finger” technique: Adding refrigerant until the suction line turns cold – is one. Another is called the Amprobe Method: you add refrigerant until the compressor reaches rated amps.
And let’s not forget the Add 35*F approach: this is a little more scientific. You add refrigerant until the saturated condensing temperature is 35*F above the outdoor ambient.
I know that by now some of you are sitting back and laughing, while others are wondering what’s so funny. I really don’t want to hurt your feelings if you use one of these methods- you certainly aren’t alone or in the minority- but each of these techniques result in an overcharge, and often a GROSS overcharge.
Back when I used to work as a training manager for a Carrier distributor, I found it strange to find contractors filing claims for 10-lbs. Of refrigerant on systems that only held 6-lbs. However, after several field calls I found many actually WERE putting 10-lbs. Of refrigerant into a6-lbs. systems!
It’s a common misconception among some technicians [and a few managers] that if you increase refrigerant beyond the specified charge, you increase system capacity. Actually, the opposite is true. Refrigerant added beyond the proper charge reduces capacity. This is because, on capillary or orifice metered equipment, as you add refrigerant you also raise the evaporator temperature.
The problem with some of these common charging methods, and the reason they shouldn’t be used, is because they fail to address such factors as:
· Temperature relationships
· Proper superheat
· System operating conditions
· Condenser efficiency
An overcharge is far more likely to damage the compressor than an undercharge. With capillary and orifice metering devices, excess refrigerant is returned to the crankcase as a constant floodback, reducing capacity, efficiency, and compressor life.
I only know two ways to properly charge non-TXV [Thermostatic Expansion Valves] systems. Both are simple to use and generally universal in application. They include: the Weight Method and the Superheat Method.
Weight Method: Weighing charge is simple, quick, and certain. The weight of the factory supplied charge is found on the model/serial number nameplate. If the system has 25-ft. of line [on split systems], the lines aren’t over or undersized, and there’s no field installed liquid line filter dryer, simply weigh the amount shown.
GOOD AFTERNOON
MR.NIKE
I 'VE NO WORD S TO SAY THANKS
THIS IS GOOD EXPERINCE IN YOUR LIFE
thanks a lot
This quote is not my experience, it is quoted text of Jim Wheeler.Quote:
Originally Posted by jahangir.ahmad
who is jim wheeler?????Quote:
Originally Posted by nike123
ok thanks again for your kind information
one question which company you r working ??
jahangir ahmad khan
lahore pakistan
Did you ever read post no.2 in this thread?:eek:Quote:
Originally Posted by jahangir.ahmad
Jim Wheeler is an award-winning writer and teacher with more that twenty-five years in the field of HVAC.
http://tinyurl.com/3q3bv6
I am selfemployed!
in which country ???? and company also and designation tooQuote:
Originally Posted by nike123
thanks
jahangir ahmad khan
lahore pakistan
No company, no designation! I work from job to job for cash money (tax free :D).Quote:
Originally Posted by jahangir.ahmad
Why do you ask that?