Liquid receiver connection

[heinasirkka]

Dear forum users,

I'm working on a closed refrigerant loop built for university experimental research. It has some unconventional and flawed features. There is a liquid receiver at the pump's (sliding vane pump) liquid suction line (thus, between the condenser and the pump). The receiver is to provide enough liquid to the pump. The design has a flaw since the receiver is expected to drain the liquid from the condenser and we'll lose the condensate levels, and will get very limited subcooling.

1 - We were thinking to connect the vertical receiver only from the bottom (liquid part), instead of inline series connection at the liquid suction line. By those means the condensate will not travel to the receiver directly, as we assume.
2- Another option can be putting a flow restriction (e.g. selenoid valve) means before the liquid receiver, as far as the available suction head is not too low.

I don't have a lot of experience in this. Can these solutions work by any chance? Any comments on these solutions are very much appreciated!
Greetings

 

[adammal44]

As more general advice, I would avoid declaring something "flawed" without understanding the design constraints/requirements that went into the initial design.

It may have just been a bad design - OR - it could have been a great design that also met arbritary cost/space requirements. End rant.

Can you provide a drawing of your system and the proposed alternatives? Small annotations of flow/pressure/line size would also help.

 

[heinasirkka]

Hello,

Thanks a lot for your answer adammal44. I called it flawed because I myself had to design and build it without enough expertise and know-how at the beginning, and without any supervision and with a hasty time constraint. And I cannot make the cycle work, so now I see that I missed some crucial points and I am trying to fix my mistakes. I think it is not an optimal design at all, but has hope for serving for research reasons.

It is an experimental closed cycle to observe the heat transfer properties of refrigerants. The drawing is included.

I understood that the first solution I mentioned will not work.

The main problem is that the liquid receiver drains the liquid phase from the condenser. This deteriorates our subcooling (also the condensate level inside the condenser). I was wondering what would be the way to keep the liquid phase inside the condenser while having a liquid receiver. Adding a secondary subcooler after the liquid receiver is not an option, because it would give subcooling, but won't solve controlling the liquid phase level in the system. By the way, all the tubes are half inch O.D.

 

[Compositepro]

Put a loop in the condenser drain line that goes above the condenser level before it goes to the receiver.