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Henry.
05-08-2010, 07:44 PM
Have time to time wondered about if there would be any major problems by mounting a condenser that is built to be mounted laying down mounted standing up instead and now this all of a sudden have become a real issue to me.

I needed a condenser that had to be installed standing up but the only condenser i had left were one that were intended to be installed lying down. It's a waterchiller system to a friend of mine and the condenser are a little to big for the heatload anyway so it doesnt need to perfect in that aspect.

Several guys at work say that it could work but maybe not so good and some few even say it wouldnt work at all which i seriously doubt but no one had ever tested this so no one didnt new to 100%. But i think it could work quite all right if the orientation of at least the last row are in such way that the liquid can only flow down true these last coils? And this can be arranged on this condenser.

How the other two rows before this are oriented, since i guess most refrigerant as gas are present there, wouldnt really matter that extremely much in that case. But by orienting at least the last row in such way that it will be a downward flow of the liquid so couldnt any gas be able to go to the drier and cap as i see it, or might there be other things that i dont think about right now that would mess it all up anyway?

A new condenser are quite expensive but unless the one i have would be ok to use even if mounted in the wrong orientation but by the way i mention about the last row i will absolutely go with it. But i really need to now if it will be all right with say for example the only problem with a slightly lower capacity or so.

Brian_UK
05-08-2010, 09:14 PM
I suppose it does depend on the piping layout with regard to the liquid collection and discharge.

Sandro Baptista
06-08-2010, 01:22 AM
Send us a photo of the existing condenser regarding the circuit of tubes and the manifolds inlet and outlet.

Await news.

michaelm
06-08-2010, 03:06 AM
B”H

I agree with Brian and make sure that the liquid will drain out from the condenser.

chemi-cool
06-08-2010, 08:40 AM
Liquid will be pushed out any way, its the oil that I am worried about.

The outlet tube will have to be changed and placed at the bottom of the condenser.

Sandro Baptista
06-08-2010, 11:09 AM
Liquid will be pushed out any way, its the oil that I am worried about.

Yes, you right it will be pushed any way due to a superior pressure at upstream (discharge pressure). But as you know this will cause loss of condenser capacity for the same Tcond.

Henry.
07-08-2010, 12:28 AM
Yes of course oil distribution but i might then maybe just put a little more oil in the system to be sure in case i can use it because i guess quite much could gather especially in the coil in the middle if placed as mentioned below.

As seen its meant to be used laying down. Have used it for experiments before that i have forgot about therefore the valves and things on it since it contains gas.

On the left pic the tubes go from the upper right all the way down and then up in the middle and down to the far left bottom. If i would have inlet on top right as it stands now and outlet on the bottom left so should it be as good as it can and quite alright i hope since no gas can be collected at the outlet as it stands now only liquid.

Regards to oil distribution i dont really know but could the liquid drag the oil with it to the outlet anyway in such amount it would be ok? Should only be the case if the entire condenser where full of liquid which shouldnt happen.

Ill know it will loose some of its capacity but what could be a qualified guess on how much i will loose regards to its original capacity by using it in the wrong way, shouldnt be so extremely much?

Sandro Baptista
07-08-2010, 01:11 AM
Henry,

Please tell me the gas mass flow (kg/s), density at discharge pressure estimated, and the pipe DN.

Just for curiosity what's is the freón, refrigeration capacity, hear rejection capacity and conditions for the capacities you gave me (Tc, Tevap, sh).

Henry.
07-08-2010, 03:25 AM
Dont have any information about the condenser because the store i bought it from over a year back doesnt exist anymore. But what i do know are the tubes thats 10 mm OD and the condenser is around 16 x 3 x 10".

Refrigeration capacity will be designed to around 600 - 700W or so.

Since the system need to be really cheap i planned to use dirty simple bbq propane instead of clean expensive ref. grade type. I built this system to a friend that will only use the system for about 1 month and then never again so this is the reason to make everything as cheap as possible so i will hardly calculate anything and make a qualified guess for the rest and just use dancap for the captube and a little fiddeling to get it all enough to work ok.

Capacity of condenser i dont know but would be interesting to know but i havent found a store yet on the Internet that mention the capacity or sizes of the ones they have so i could compare. But a guesstimate so should this be ok to handle the overall power with right fans but unfortunately i cant really give you any numbers about the rest. The evap will be put some degrees over freezing point.

mad fridgie
07-08-2010, 07:24 AM
Just remove the top and bottom return bends, split discharge into "3" at the top, same with the liquid at the bottom, ensure that the fans are in a cowl, 700 watts no problem

botrous
07-08-2010, 08:21 AM
Dear henry,
Please post the following data and i'll calculate the condenser capacity for you :
Height of coil
Lengh of coil
Number of rows or total number of tubes
Fin spacing
Airflow
Number pipes entering the coil (feeds)

Best reagards

Mike-Wadham
07-08-2010, 03:22 PM
as your condensing the liquid will fall to the bottom and have to be pumped back to the top of the condenser. have you tried positioning the condenser so the tubes run horizontally not vertically.

Sandro Baptista
07-08-2010, 03:45 PM
Dear henry,
Please post the following data and i'll calculate the condenser capacity for you :
Height of coil
Lengh of coil
Number of rows or total number of tubes
Fin spacing
Airflow
Number pipes entering the coil (feeds)

Best reagards


The capacity of the condenser will also depends of the ambient and the discharge pressure, which depends of the compressor/evaporator installed. An equilibrium of the system is necessary to determine the capacities of each equipment. That why I have post the last post so I can get information to know is there is a good drag of oil and condensed liquid.

Henry.
07-08-2010, 07:23 PM
Just remove the top and bottom return bends, split discharge into "3" at the top, same with the liquid at the bottom, ensure that the fans are in a cowl, 700 watts no problem

Yes thats absolutely one way to do, didnt thought about that. But i dont have the tubing required at home right now and i dont want to braze more then necessary due to time issue so it will be quick to put together later on but i will think on this anyway.



Dear henry,
Please post the following data and i'll calculate the condenser capacity for you :
Height of coil
Lengh of coil
Number of rows or total number of tubes
Fin spacing
Airflow
Number pipes entering the coil (feeds)
Best reagards

Thanks a lot! Ok here it is:

Height of coil: 10"

Length of coil: "width for me" 14.6" excluding the bends

Thickness so you have it all: 3"

Number of rows or total number of tubes: 10 rows high and 3 rows deep.

Fin spacing: ~0.13"

Airflow: will be using 2 fans with 8" 31 degree blades and 1500 rpm motors but i just dont know the CFM this combination could pump out just guesstimate it should be more then enough, but bettes safe then sorry. But well say maybe anyting beteen 500 - 800 CFM or so combined?

Number pipes entering the coil (feeds): only 1



as your condensing the liquid will fall to the bottom and have to be pumped back to the top of the condenser. have you tried positioning the condenser so the tubes run horizontally not vertically.

Yes i know this and thats the reason for this thread to get any light on if it might work anyway regards to oil distribution, the gas transportation it self didnt really seem to be an issue regards to one post if placed right. The condenser is ment to laying down but the problem is that it wont fit by placing it in that way because where i will put the system there is not much place at all so i have to put the condenser in a upright position but i only have this one to use as condenser.



The capacity of the condenser will also depends of the ambient and the discharge pressure, which depends of the compressor/evaporator installed. An equilibrium of the system is necessary to determine the capacities of each equipment. That why I have post the last post so I can get information to know is there is a good drag of oil and condensed liquid.

The calculation of the power the condenser can handle doesnt have to be so exact just so i get a ballpark indication to what these sizes can be used for power levels to see if this is alright as is for 700W or not. Any calculation can be off by say 15 % +- but that would be just fine as well.

Discharge pressure: Another system i put together a while ago with quite similar equipment had around 130 - 140 PSI and i dont think it would change to much in this one. But if the oil distribution in this condenser would work at say this pressure then i know that discharge shouldnt go much under this if its possible to calculate this anyway.

Ambient: 72

Compressor: Will be a SC12 i had laying around and that would be more then sufficient at the planned evap temp and power level so maybe then perhaps the little higher discharge pressure in that case.

Evap: Homemade design so unfortunately i cant give you any real data but its built based on what i guess would be needed to handle 700W.

Sandro Baptista
08-08-2010, 12:14 AM
The calculation of the power the condenser can handle doesnt have to be so exact just so i get a ballpark indication to what these sizes can be used for power levels to see if this is alright as is for 700W or not. Any calculation can be off by say 15 % +- but that would be just fine as well.

Discharge pressure: Another system i put together a while ago with quite similar equipment had around 130 - 140 PSI and i dont think it would change to much in this one. But if the oil distribution in this condenser would work at say this pressure then i know that discharge shouldnt go much under this if its possible to calculate this anyway.

Ambient: 72

Compressor: Will be a SC12 i had laying around and that would be more then sufficient at the planned evap temp and power level so maybe then perhaps the little higher discharge pressure in that case.

Evap: Homemade design so unfortunately i cant give you any real data but its built based on what i guess would be needed to handle 700W.

Still many unknows parameters: Refrigerant, Suction pressure, the rest of parameters you told me are estimations, (what's SC12)...so I can calculate the vapor velocity in the first sector of the pipes (upward sector)...I would suggest you take the risk...after all we are talking about a mini-refrigeration plant...it will not be a big deal if it doesn't work...buy a new condenser designed as you want. We are talking about how much cost? 250...400 Euros?

Sandro Baptista
08-08-2010, 12:16 AM
Still many unknows parameters: Refrigerant, Suction pressure, the rest of parameters you told me are estimations, (what's SC12?)...so I can calculate the vapor velocity in the first sector of the pipes (upward sector)...I would suggest you take the risk...after all we are talking about a mini-refrigeration plant...it will not be a big deal if it doesn't work...buy a new condenser designed as you want. We are talking about how much cost? 250...400 Euros?

Peter_1
08-08-2010, 10:14 AM
Haven't read all the posts but you condenser was made to lay down/flat, (turn it 90° to the left in your 1st picture)

Henry.
08-08-2010, 04:17 PM
Haven't read all the posts but you condenser was made to lay down/flat, (turn it 90° to the left in your 1st picture)

Yes, but it also have to do with the airflow to cool the compressor which are just a hair above whats needed with the fans im going to use because bigger wont fit so that part have to be pretty much perfect.

By changing the condenser to pretty much any other position that in front of the comp would not be possible regards to the placing of the fans and airflow and space for the compressor. Its a really small space to put the system at so unfortunately there isnt really any room to place it in any other way then standing up in front of the compressor regards to cooling the compressor and the space for the condenser and the fans.

--

Btw i just found another condenser on the attic but thats only slightly bigger then half the size in width then the one on the picture but this one is at least oriented right but i dont think this alone could handle 700W? But if i find another similar one so would that be great because then i can just put these two in series or maybe parallel with each other. Otherwise i just buy one smaller one so will it be cheaper so i can starting to build this thing and hope my friend accept the little higher sum.



Still many unknows parameters: Refrigerant, Suction pressure, the rest of parameters you told me are estimations, (what's SC12?)...so I can calculate the vapor velocity in the first sector of the pipes (upward sector)...I would suggest you take the risk...after all we are talking about a mini-refrigeration plant...it will not be a big deal if it doesn't work...buy a new condenser designed as you want. We are talking about how much cost? 250...400 Euros?

Refrigerant did i mention before as R290.

About the SC12 so does it say Compressor on the left on the same line. Someone asked about the compressor im was going to use.

Suction pressure: ~30PSI

I dont know if you need any other parameters so just tell me what you need and i will try to give you as many as i can.

No its not estimations they are taken from another system i built once that was very similar to the one i built now so any measurement i did from that one, the ones i have wrote down that is, can pretty much be used to this non built one. Any slight differences wont be so big that it will make any problems so ill go with the measurements from the other as for now.

As you say its a small system and that will only be used for about 1 - 2 month so as long as it might work i would use this condenser anyway as long as the oil issue wont be a bigger problem wich are the issue.

Henry.
08-08-2010, 04:21 PM
I know i mentioned R290 before but cant find it so that didnt get in the final text in some way. But "dirty bbq propan" did i however mention in a post at the beginning which might not be that easy to se.

Sandro Baptista
09-08-2010, 01:21 AM
Some calculations I have done according with your information:

Refrigerant: R290 (C3H8)

Suction pressure (relative): 2,07 bar (-14ºC evaporating temperature) The real value will depend on the compressor, evaporator and water temperature, flow of water, etc.

Discharge pressure (relative): 9,7 bar (+30ºC condensing temperature) The real value will depend on the condenser, ambient temperature, compressor regimen, equilibrium with the evaporator, etc.

Ambient temperature: +22ºC

Refrigerant capacity: 700 W
Mass flow sucked to get 700 W: 0,002394 kg/s (it also depends of the useful and non useful superheat)


At 60ºC discharge temperature inlet at condenser and 9,7 bar and OD pipe 10mm the vapor superheat has ~2,4 m/s. At saturated temperature vapor (condensing temperature) the velocity is 2,0 m/s. The minimum velocity based on a correlation for a riser is ~1,7 m/s (aprox. the same for the both cases). Supposing that the correlation draw the reality so on the superheat zone no liquid is condensing and only oil must be carry on. Then the liquid starts to condensate and less saturated vapor is available to carry on the oil and the liquid.
Watching the picture at the left I would dare to say that in the first column of pipes (the fluid go upwards) no problem will happen (desuperheating and condensing will occur), then on the second column of pipes (the fluid go downwards) and no problem will happen (condensinga will occur). At the last column, the third column (the fluid go upwards), much of the refrigerant has be condensed and sure there is insufficient vapor to carry on the liquid and oil.

CONCLUSION: The third column will certainly be full of liquid and oil but both of them will be pushed out of the condenser. Of course there will be a loss of the condenser capacity...maybe of about 20% and the discharge pressure will be higher than if the liquid could be naturally drained (by gravity).

However as I told you before on a previous post I would take the risk and would connected to the plant.

Sandro Baptista
16-08-2010, 09:40 AM
Henry,

How is the condenser working on its new position?

Henry.
17-08-2010, 07:05 PM
The same day you posted the message before your last post i posted a long message where i among other things thanked you and the other guys here, but nothing of this has been posted i see now dammit.

The system however is built and installed at my friends house for about a week ago. Unfortunately so didnt i really have time to check it all as much as i wanted because i was running out of time and i was late to finish it up before i needed to install it. But i had at least time to have it running and testing for about an hour and it worked pretty much perfect after a little twiddling with the capillary length.

The compressor didnt get any warmer then it should be during this time so i guess the oil distribution worked just as you said at least during this hour. But he have now had it running for about a week almost 24/7 and it is still going strong and perfect as he said and the compressor isnt warmer then it should either so he is very happy and so im i. I also put in a little more oil in the compressor when i built it all just in case and the maybe 20% less efficiency of the condenser isnt any problem at all but i didnt think that either due to its size.



By the way do you think it could be possible to calculate the maximum power this condenser could dissapate? Dont know what numbers needed though to calculate this. I havent found a similar condenser to compare with either which suprise me but it have to exist somewhere. My guess is that it might could be able to dissapate around 1.2KW or so with two 20cm fans maybe little more, its a guess but i pretty much need to know.

Planned to use it to another system after he is done with it but then i need to know how much it could handle because i think it could be on the border. This time there will be enough space so it will be lying down as it should.



But thanks a lot for the info and calculations and to the other guys here for the help and tips in this errant it was highly appreciated!

Sandro Baptista
18-08-2010, 08:34 AM
By the way do you think it could be possible to calculate the maximum power this condenser could dissapate? Dont know what numbers needed though to calculate this. I havent found a similar condenser to compare with either which suprise me but it have to exist somewhere. My guess is that it might could be able to dissapate around 1.2KW or so with two 20cm fans maybe little more, its a guess but i pretty much need to know.

Planned to use it to another system after he is done with it but then i need to know how much it could handle because i think it could be on the border. This time there will be enough space so it will be lying down as it should.



It all depends on the exterior environment conditions you have and discharge pressure (condensing temperature) you can admit.

Presently if you have 700 W of refrigerant capacity at -14C/+30ºC (exterior ambient temperature +22ºC) and R290 you are maybe dissipating about 1,0 kW.

So with the condenser on the correct position and with the same conditions -14ºC/+30ºC and +22ºC and R290 maybe you can get 1,2 kW, as you said. Even if the condensing temperature be +35ºC it is very acceptable and the condenser will give more heat rejection capacity.

Henry.
19-08-2010, 08:43 PM
Very interesting to see and the pressures and so on would be about the same so they work to be used. And this is really good to know this now because then i have a "base" to go on.

Thanks once again!

Regards Henry

Sandro Baptista
19-08-2010, 10:50 PM
Keep give us feedback about this subject, okay? Does the condenser still working good on the "lay down" position? What are the condensing pressure, and ambient temperature of the refrigerant plant where is currently installed?