Liquid Receivers Vs Air Cooled Condenser Coils

[karim]

6454Hi Guys

I would like to know if it possible to reeuce the size of my air cooled condenser in my commercial refrigeration unit by addind a liquid receiver ahead of my DX evaporator coil ?

You know tube-fin coils with copper are getting very expensive and what would the ratio between liquid receiver and condenser coil size to keep my system within pressure range .

My system is a 10 ton medium temp.system
+20 f sst / 105-110 f condensing
R404 A / 25 LBS ***** AIR COOLED CONDENSER

REGARDS AND THANKS IN ADVANCE !

[install monkey]

liq recievers are designed to store liquid refrigerant when the system is pumped down and ensure liquid flows to the tev-where a condenser is designed to reject heat and change vapour to liquid,is also sized against the capacity of the evaporator duty

[monkey spanners]

Condenser needs to be sized to suit the expected heat rejection of the system not desinged on price.
If you let customers dictate prices you'll soon end up with a very cheap system with no actual parts....

[Magoo]

Some manufacturers design condensers to hold the reserve liquid charge and acts as a subcooling effect as well. By adding a liquid receiver, you will only add more refrigerant to system, for little effective change due to headering and pass arrangements in condenser.
With an average SDT of 110'F what is the problem. ? To lower that add more fan HP and air flow across condenser. Too much air flow will compound things as too higher velocity can be counter productive. [coil dwell time ].

[lana]

Hi there,

As said by the others, liquid receiver and condenser have different duties in the system. You can not select one bigger and the other smaller.

Air cooled condensers must be selected for the highest ambient temperature and system heat rejection rate. Receivers on the other hand are for storing additional refrigerants when TEV operates and also for pump down.

In theory, inside volume of the condenser and receiver must be equal to the total refrigerant charge. I said in theory, because in design stage you can not estimate the total charge needed.

Cheers

[mad fridgie]

looking at the OPs attachment, he seems to be confused!
the reciever is a combo "reciever/accumulator" where you can possibly get some extra sub cooling, hence possible extra duty, in a similar way that we use a liquid line/suction line heat exchanger

[Magoo]

Mad F
could you edit your last post, suggest the shakes have got to you. Who would live in ChCh., 20K have shifted to Auckland / jafa town. And we live on top of 20 plus volcanoes. Holy hell. Word has it that NZ will be 4 islands, guess where the split in the south island is. Around about Christchurch, you could end up with a coastal frontage and park your boat at your back door.
Have a nice day, magoo

[karim]

It sounds very sustainable ! so air cooled condensers should just be able to condense and reject heat ! cause i worked in a company that oversized the condenser coils 150 % of the evaporator tu subcool ! but copper and fin stock were 1.5 $ a lbs and .6 $ a lbs respectively ! I guess I have to make sure I match evap. duty ! and use liquid receivers to hold ref. for pump down and monitor cfm !