Designing a Cooling System with a Plate Heat Exchanger – Pump & Flow Control Advice Needed

[thomx5]

Hi everyone,

I'm working on designing a cooling system for a small test lab using a plate heat exchanger (PHE) since we have access to cold water. The system needs to cool a black box that outputs up to 4 kW of heat into water. The pressure drop across the black box is:

• 0.2 bar at 7 L/min
• 0.5 bar at 10 L/min

The current system works by bypassing part of the hot water past the PHE using a 3-way valve to achieve the desired temperature. It uses a centrifugal pump to circulate water.

The Problems:​

1. The current pump is too weak – it can only achieve 3 L/min at max power, but we need 10 L/min while being controllable from 1 L/min to 10 L/min.
   • The pump curve indicates a 0.75 bar pressure drop, but I suspect it’s actually twice that in practice.
2. Flow control challenge – I need a way to precisely control the flow rate between 1-10 L/min.

My Questions:​

• What type of pump would be best for this setup? Should I be looking into a centrifugal pump with a VFD (variable frequency drive)?
• Are there better alternatives for fine flow control? Would a solenoid valve or some other method work better?
• Are there other technologies I should be considering that I might not be aware of?

I've also sketched a diagram of the current system, which includes a PI controller attached to the 3-way valve.

Any advice or insights would be greatly appreciated! Thanks in advance.

 

[LittleInch]

Is this the same system as you've posted inthe pump forum but with more details?

Add this info to the pump form post and delete this one please. We can't have two posts on the same subject.

 

[thomx5]

Is this the same system as you've posted inthe pump forum but with more details?

Add this info to the pump form post and delete this one please. We can't have two posts on the same subject.

I rewrote my first post because after posting I couldnt find it. Turns out it has to be reviewed first, thats on me haha.