Two Condensers in the same unit

[Cewek ITS]

Dear All,


Can we use two condensers in the same system at the same time? If can, is there any requirement on the connection of the condensers?

[The MG Pony]

Could you please elaborate as to the system and why the need or desire to have two? Thanks.

[Cewek ITS]

Hello MG,

I am still learning about refrigeration system, I only know from theory that two evaporators can be instaled in one system and how about condensor ?. I still try to improve system if it's possible.

Is it possible or not ? What's the reason

[The MG Pony]

It is indeed possible for things like heat recovery, or for winter loading.

Lets say you need 5Kw of heat rejection during the summer, in winter you'd need half of that, hard to do with one big one. If we take two 2.5Kw condensers and make it so we can turn one off, we can reduce its capasity to match the winter load on the system.

Or you can have a condenser placed inside the store and recover heat from the system befor going to the out side coils.

There is no real simple answer, can it be don? Yes it can be, and depending on the aplication it will be easy or very hard.

With out a goal it is next to impossible to realy answer in any one way as it is the end goal that determins the system used.

[Cewek ITS]

MG,
So it's possible. But do we have to place two units in the same ambient air ? Because we have to ensure condensing temp in same condition and mass flow can flow in balance, is it right? Or may be there is some regulation for this case.

[monkey spanners]

Some Zannoti units have two condensers, at either end with the compressor in the middle. they are on the same level, same size and just 't'ed into the discharge pipe with thier outlets 't'ed also. These are small packaged capiliary systems for cutting into coldroom roofs.

Jon

[The MG Pony]

MG,
So it's possible. But do we have to place two units in the same ambient air ? Because we have to ensure condensing temp in same condition and mass flow can flow in balance, is it right? Or may be there is some regulation for this case.

There is no answer unless we know the system and we know the end goal.

With out a perpose and an objective we can go 8 ways to any where.

You must have a foundation befor you start on the roof!

[Josip]

Hi, Cewek ITS :)


Hello MG,

I am still learning about refrigeration system, I only know from theory that two evaporators can be instaled in one system and how about condensor ?. I still try to improve system if it's possible.

Is it possible or not ? What's the reason

Yes, it is possible to install more then only two condensers on the same system, also more then two evaporators and also more compressors....., but please, can you explain us what you are trying to improve....what is not good or you think you can improve...

Reason to install more units (evaporators, condensers, compressors) because single one is not enough...

Please come with some more info...maybe we can help more...

Best regards, Josip :)

[Cewek ITS]

Dear All,

The reason is the single one not enough. So we want to make paralel connection. Is there any added equipment to be installed ? Or any added special regulation ?

Thanks

[Josip]

Hi, Cewek ITS :)


Dear All,

The reason is the single one not enough. So we want to make paralel connection. Is there any added equipment to be installed ? Or any added special regulation ?

Thanks

That one was not enough from the day one or you notice some problems couple of weeks or months later?

There are some rules regarding parallel connection of condensers....

Please can you specify more, the system you have, DX or flooded evaporator/s, capacity, refrigerant, condenser type-air coled, evaporative, shell&tube...maybe to copy-paste/upload scheme of your plant...without that we can give you wrong advices...


Best regards, Josip:)

[momo]

Playing with ideas for a condenser unit of an old Carrier air conditioner: twin compressor outdoor unit from the business's archiving store (old junk!) - the question arose: if using the two condensers in parallel to serve one indoor unit: what would the results be?

Some thoughts:
Use the two systems in full parallel or one compressor onto two condensers
increased condensation efficiency especially at peak heat loading
more subcooling
oil circulation problems: one is above the other, therefore the lower one would have to be used continuously
low liquid pressure (liquid sloshing around in condenser)
problems with balancing the charge with a fixed capillary or use a TXV?
Inceased Energy Efficiency Ratios or waste?

Also:
How should the excess cooling capacity be cut out? Electro-valve on inlet or outlet of 2nd condenser
one way valve on outlet...
control of 2nd condenser...

These are evidently questions that coincide with the initial post and lead to discussion: note the this is a simple system, then if extended to multiple (switched) evaporators and compressors like in supermarket systems the question of the controlled connection of condenser arises - and we are not talking about controlling fan speeds of a single unit...

Time has left these "academic" questions in the air until the unit is removed from a current quick install to save somebody money during a crisis!

[Cewek ITS]

Hello Josip,

The system is DX. I wants to use two condensers because they need 600KW condensation capacity for one system with a temperature difference of 7K only. One condenser can not reach this capacity at 7K temperature difference. Type condensor is air cooled. Refrigerant R404. Please your advice about connection in detail.

Thanks
BR,
Cewek ITS

[assane608-adsl]

Hello
two condensers in the same unit, it is possible.But what for? You could have many reasons. If your system need to condense more because it don't reject a maximum of warm from gas,or your air condenser location is not enough cool. In all case you can connect two condensers but be sure about the reason. About connection you have to connect one outlet to one inlet condenser.the outlet of one of the two condensers must be connected to the liquid bottle.In this case the outlet air from condensers must be less hot than in the case of one condenser.You could have the same result about the high pressure.
good luck

[Josip]

Hi, Cewek ITS :)


Hello Josip,

The system is DX. I wants to use two condensers because they need 600KW condensation capacity for one system with a temperature difference of 7K only. One condenser can not reach this capacity at 7K temperature difference. Type condensor is air cooled. Refrigerant R404. Please your advice about connection in detail.

Thanks
BR,
Cewek ITS

please check this..

http://www.evapcoeurope.net/uploaded-net/documents/eu/Piping%20131-E_0706.pdf
http://www.heatcraftrpd.com/resources/install/H-IM-43B.pdf (figure 13)
http://www.ishraepune.org/Claes-Stenhede_CO2/PHE-as-Condensers.ppt

Best regards, Josip :)

[Josip]

Hi, assane608-adsl :)


Hello
two condensers in the same unit, it is possible.But what for? You could have many reasons. If your system need to condense more because it don't reject a maximum of warm from gas,or your air condenser location is not enough cool. In all case you can connect two condensers but be sure about the reason. About connection you have to connect one outlet to one inlet condenser.the outlet of one of the two condensers must be connected to the liquid bottle.In this case the outlet air from condensers must be less hot than in the case of one condenser.You could have the same result about the high pressure.
good luck

I was thinking we can connect in serial (ahead of condenser) only desuperheater (heat exchanger)...,

but two condensers in serial, :confused:, please, can you post some link where we can see this type of connection and of course some explanation why that is good...

Best regards, Josip :)

[cakabo28]

hı cewek,
ıt ıs possible to use two condenser in one unit,
you must use 1 fan and 2 compressor.
ıt is easy but problem is main pcb so you need perfect software to control system !!!

[walden]

When using two condensers in parallel, the refrigeration contractor often asks me that two fans, one on each condenser, are switched on together from the electrical control panel first and then the fans are to be switched on singly, one on one condenser the next on the other condenser. Why the two fans to start?

[John Hunter]

Condensers in series is nonsence .Condenser and sub cooler yes.
Condensers in parallel present no operational problems provided they are piped up and controlled correctly. To describe how to do it is too involved for this post, but there are plenty published sourrces explaining the requirements. Where two condensers are coupled in parallel you want to have a simmiliar pressure drop in each at the same time so fan control is important. Today most new condensers have VSD drive fans based on preset headpressure. If the fans are manual with only one fan on and the other off the condenser with the fan on could liquid lock. On large units specially designed liquid outlet leg traps overcome this problem .

[jwhytock]

if correctly tubed main point would be to use an invertor to stage all condensor fans evenly to ensure even saturation