VFD application on Pump
VFD application on Pump
(OP)
Hello Everyone,
Can anybody suggest me whether it is useful of adding VFD in Boiler feed pump in a power plant.
I gone through the details. I understand the advantages of VFD but not sure about the overall burden of VFD on O&M cost.
The overall cost of VFD is almost equal to the cost of Motor itself. 1t increase the overall budget cost. Therefore, it is important to understand the Energy saving, ROI, and O&M difficulties.
Please suggest the VFD effect on the above mention parameters.
The plant detail is as follows
BFP motor rating : 900kW
Frequency : 50Hz
Please note that the plant is Solar thermal and it has cycling operation means pump will start every morning and shutdown in the evening.
Can anybody suggest me whether it is useful of adding VFD in Boiler feed pump in a power plant.
I gone through the details. I understand the advantages of VFD but not sure about the overall burden of VFD on O&M cost.
The overall cost of VFD is almost equal to the cost of Motor itself. 1t increase the overall budget cost. Therefore, it is important to understand the Energy saving, ROI, and O&M difficulties.
Please suggest the VFD effect on the above mention parameters.
The plant detail is as follows
BFP motor rating : 900kW
Frequency : 50Hz
Please note that the plant is Solar thermal and it has cycling operation means pump will start every morning and shutdown in the evening.





RE: VFD application on Pump
In general i believe that a boiler feed might be a suited application - but then again: Some system uses constant flow and som constant temperature - only for the latter VFD is suited.
Best regards, Morten
RE: VFD application on Pump
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: VFD application on Pump
Any "saving" on energy needs an alternative to compare it to 9usually this is a fixed speed drive which then needs throttling to prevent pump over run and hence "lost" potential energy of the fluid turning into heat. VFD is not always less energy - there are some significant extra losses in the VFD units and your pump may not be operating close to the BEP. However VFD in your case may be the only way to maximise your head / flow and stay within the limits of your system and VFDs are good at that.
Far too many variables for a forum like this to advise.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: VFD application on Pump
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: VFD application on Pump
RE: VFD application on Pump
he was.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: VFD application on Pump
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: VFD application on Pump
VFD's on BFW pumps are almost always a waste of money. Most of the energy goes into producing head, not producing flow. The control range from full flow to no flow will be a few percent of the operating speed, so your control is lousy. Use the money to buy a decent control valve and actuator.
Artisi - really? Wow.
RE: VFD application on Pump
look at the OP other very recent posts, This is not a standard boiler feed water pump...., but a solar array
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: VFD application on Pump
what operating pressure does a solar boiler operate at? It's obviously a decent size boiler to require a 900kW BFW pump.
RE: VFD application on Pump
No pump data has been posted - so we are all crystal ball gazing and who would know what the answer is likely to be.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: VFD application on Pump
Its 3000 RPM (please see the 1st post Frequency is mention as 50Hz). Does it matter whether its 50Hz or 60Hz frequency?
The pump flow rate is 150 m3/hr. it's a BB5 pump.
Let me know if any more details needed.
RE: VFD application on Pump
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: VFD application on Pump
It's all far too confusing for my elderly brain - how about sitting down and putting something together that is meaningful to all interested parties.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: VFD application on Pump
You are combining 2 different posts..
This VFD is for Boiler Feed Pump while the other pump was HTF (High Temp Fluid) pump..So both are independent and flowing different liquid in different circuit.
RE: VFD application on Pump
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: VFD application on Pump
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: VFD application on Pump
Thanks BigInch, Yes you are correct.
There are 2 streams
Stream 1: Heat Transfer Fluid : HTF Pumps it through solar field, get some heat, and then passes through the Steam Generator and transfer energy to Water/Steam
Stream 2: Water : BFP pumps water to Steam Generator.
Steam Generator is the heat exchanger which transfer energy from HTF fluid to Water..
From VFD point.. Both pumps (HTF Pump and BFP) are big pump with consuming huge MW and both have to start/stop everyday..That is the reason I wanted to know the consequences of using VFD.
RE: VFD application on Pump
But for the BFP, as BigInch explained, it is mostly static head (pressure),It is a relatively flat system curve.
You need to maintain the pump discharge pressure at 110 Bar + piping friction loss at what ever flow. You can not reduce the speed much to have meaningful power saving. Bear in mind the VFD has power loss also and can be costly to maintain.
If you are concern about the daily start stop use a soft starter instead.
RE: VFD application on Pump
Hence your issue is how to do this change of flow rate effectively. More (3 or 4) smaller flow fixed speed pumps would be better on a BFW supply than a single VFD unit as they don't work well on fixed head variable flow duty. This would also reduce your starting current and only be using power when you need to.
If your flow is somehow fairly constant, then size your pump or pumps correctly and get the highest efficiency you can and forget about a VFD on BFW pumps. If starting current is your issue there are other ways to soft start large motors without using a VFD
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: VFD application on Pump
http://www.volker-quaschning.de/articles/fundament...
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: VFD application on Pump
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: VFD application on Pump
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: VFD application on Pump
What many eventually find out, is that they spend 5 to 10% more energy when using a VFD, because they add them into a system that had a control valve before and then run them where the control valve would have served just fine by itself, and/or they forget that the VFD gives off heat into a space that they then have to cool. Electrical losses + HVAC load....
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: VFD application on Pump
RE: VFD application on Pump
RE: VFD application on Pump