Thank you all again for your input.
We made the decision on the design and will start ordering soon.
As per 1503's simulation we felt comfortable of installing control valve in the Hx1 downleg. This should solve the pressure problem and help reduce flow over Hx1.
We will also install a FCV...
Yes.
From what I gathered from the documents, the pump is from 1980.
RPM 1480, not sure if it's BEP but it's 85 % efficiency: head 60 m, Q 1050 m^3/h, power 195 kW (rated 260 kW)
Thank you very much, again, greatly appreciated!
I'd need to check that, at first glance even at 550 m^3 / h I...
Thank you very much!
We're currently in the construction phase of other projects and that consumes quite a bit of my days currently. So bear with me if my response times are a little bit slower than usual.
Orange = Distance in m
Red = Temperature in °C
The lengths are rough estimates, the...
Sorry for delayed response! I was preoccupied with other projects.
Above what return pipe? I could see if we have a LI for the tank (probably).
This was also one of the original ideas but to be flexible with changing operating conditions and the fact that the time frames in which can work on...
Thanks again for all the good input!
Earlier you mentioned
Bear with me here please, but I don't the woods from the trees.
We should install a vent like in your sketch, got that. This will raise pressure to 0 gauge and prevent the vacuum.
Then you talk about changing the leg A - B to 600 mm...
First of all thank you all for your valuable input!
I didn't have access to my system over the weekend so I couldn't get you all the information earlier. I updated the diagram (please excuse that I mistakenly thought the Hxn were in series when they in fact were in parallel, but they are still...
What do you mean by cascade flow? I couldn't really find an explanation.
This would mean V2 could be used to control the pressure in the system, I read from all the posts that this is not the case?
I get that you can still get increased pressure depending on the pump curve and cv. Did your...
I'll adress the other questions raised in depth tomorrow.
Just to clariy: There is no other flow control valve than V2. Currently V2 is a manual valve (flap?) and will be upgraded to an automatic rotary plug valve. Maybe this upgrade started the confusion that there maybe another flow control...
Thank you too!
Yes, with the exisiting V2 we want to be able to supply less water in order to reduce the cooling duty of the heat exchangers. Flow is measured with inductive flow meters. My diagram is one single state of which I got the most information. Occasionally up to 1000 m^3 / h are...
Thank you very much 1503-44 for your indepth answer!
So throttling V1 may actually help with the problem. Partial flow was the term I was looking for with stalling. What I took from your post is that it may be possible to find the sweet spot in throttling such that upstream pressure is...
Thank you all for your input! I also realized prior to looking back at this thread that my post may have been confusing and I wasn't wrong. Let's start again.
This is a recirculating loop, the tank is vented if the symbol I drew there isn't clear.
This is the current situation and I...
Hello,
we have the following problem: A heat exchanger (15 m) is fed by a pump (0 m). It is a pipe network where other heat exchangers on parallel pipes are located much lower. The pressure gauges read low to negative pressures right before and behind the heat exchanger. Throttling behind the...
What kind of pump is used? If you're not using a positive displacement pump I'd think the following:
Over time the flow resistance will increase, hence your operating point moves to a greater head / lower flow rate, hence X will change. So it could be used to control the pump. Except for the...
Just a remark: Shouldn't you avoid installing an elbow right in front of the suction side? You've give no diameters for the pipes, but at 160 m^3 / h I would guess from your model, that there's no uniform flow at the suction side. I stand to be corrected here, too.
Can't help with the rest...
You mean if suction friction loss is included in the calculation of NPSHA?
Can you elaborate on why your colleague would omit it? I've never heard of that and I don't omit the term. One _could_ argue, that omitting it would yield a more conservative result but honestly I don't see the point in...
Thank you for bringing up this additional consideration! The curves supplied by the manufacturer are specifically for the viscosity we supplied, but I will check back with them if the slip is really considered in that diagram.
Thank you all very much for your great replies! Really appreciated!
I'm trying to adress all of your input.
Great! So I just adjust these parameters in my calculations. Do I still need to factor in the added volume flow like I suggested?
Stream 3 and the end point, in this case indeed a...
Greetings!
Hopefully you can enlighten me on the following problem. Image a situation like depicted in the drawing. For the pump I'd like to calculate a system curve, so basically stream 1 and 3. I have trouble incorporating stream 2 into the equation for the following reasons:
- Stream 2 has...
