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Info added on July 27th: PowerFacAging calculator is now on-line! You can use it just right here
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This year one of our projects is to create a simple on-line calculator which would make it possible for the visitors to:
* evaluate the energy savings obtained with capacitor bank (Power Factor Correction)
* estimate the cost for the required capacitor bank
* view the corresponding payback timeWe do believe that worlwide there is still a lot of energy savings to catch with the help of Power Factor correction solutions, so this small tool could help increase the awarenees about it.
We didn’t see any such tool on the web (as far as we could see), only tools to calculate the size of the capacitor banks (kvar).
As usual, to make this calculator usual for our community, we would like to get your inputs about it:
* do you know any existing calculator with these functionalities?
* do you have some ideas about how this calculator should be working (inputs, outputs …)?You can tell us your interest in this topic or send us your ideas as a comment to this dedicated forum topic.
Moderators teamJust a point to watch. I have seen a number of people install power factor correction equipment in the hope of making savings and see next to no saving in their electricity costs simply because they were on a kW tarrif rather than a kVA tarrif. There should be something in the calculator to alert people to thoroughtly understanding their tarrif structure.
Some utilities providers charge for a minimum level of KVA and therefore any reduction of KVA below that minimum level will not result in any saving on the lectricity bill (some for example charge a minimum of 70KVA and other 100KVA.
We have two very good calulator programs for power factor correction (to where should I meail them?)@Peter Cohen said:
We have two very good calulator programs for power factor correction (to where should I meail them?)
Thaks for your proposition to share your calculators, you can e-mail them to the engineering community mail: engineering@electrical-equipment.org
No..the energy saving is by reducing the losses in the system also. However, saving from Max demand reduction may be higher than the saving by reduction in losses in case of small installations.
@Smithy said:Just a point to watch. I have seen a number of people install power factor correction equipment in the hope of making savings and see next to no saving in their electricity costs simply because they were on a kW tarrif rather than a kVA tarrif. There should be something in the calculator to alert people to thoroughtly understanding their tarrif structure.
There will be some energy saving that is why I said “next to no savings” rather than none but lets us keep it in perpective.
If you had a 1MW load at 0.8 power factor and install correction to 0.95.
1MW @ 0.8 = 1.25MVA
1MW @ 0.95 = 1.05MVA
If one assumes ohmic losses in the cabling system of 5% then the power saving due to current reduction would be approx (1.25-1.05)/1.25 or approx 16%
16% of 5% is approx 0.8%
On a kW tarrif your savings would be approx (0.008 x 1.25)/1 =.001 or 1% of the power bill which is purely the loss reduction saving.
If you were on a KVA tarrif the saving would be the Power factor improvement as well as the loss reduction and would exceed 16%
If you were on a kW tarrif your max demand in kW would only reduce in the order of the loss reduction but if you were on a kVA tarrif the MD kVA reduction would be significant.
Understand the tarrif.
@anilsabaji said:No..the energy saving is by reducing the losses in the system also. However, saving from Max demand reduction may be higher than the saving by reduction in losses in case of small installations.
@Smithy said:Just a point to watch. I have seen a number of people install power factor correction equipment in the hope of making savings and see next to no saving in their electricity costs simply because they were on a kW tarrif rather than a kVA tarrif. There should be something in the calculator to alert people to thoroughtly understanding their tarrif structure.
@Laurent said:
@Peter Cohen said:
We have two very good calulator programs for power factor correction (to where should I meail them?)
Thaks for your proposition to share your calculators, you can e-mail them to the engineering community mail: engineering@electrical-equipment.org
Thanks Mr.Peter. Would you please mail them to dasmsg@gmail.com Thanks
We have now chosen a name for this project: PowerFacAging calculator.
Why this name?
Well, “PowerFac” stands for … Power Factor of course !
With “Aging” at the end because to make a fair estimation of the savings, it is important to look at the complete life cycle of the capacitor banks and their real efficiency to compensate :
* capacitors are a bit like batteries, charging and discharging them makes them progressively less efficient, they are getting older and at some moment might not be able to compensate properly anymore
* the electrical installation itself will most probably evolve along the time (new loads added …), making the existing capacitor bank no more adapted to the new installation requirements, if it is not upgraded
To keep you posted with this project, below is a first idea of the typical result which we want the tool to provide:
* a clear view of the yearly cost savings obtained when installing PFC
* an estimation of investment cost and payback time (not yet implemented here)
* and also an idea of how these cost savings will evolve during installation time==> please tell us what you think about it
Moderator team
What happens to the power factor capacitors, if the magnetic starters in the motor control centre are converted to VFD’s?
@Laurent said:
We have now chosen a name for this project: PowerFacAging calculator.To keep you posted with this project, below is a first idea of the typical result which we want the tool to provide:
* a clear view of the yearly cost savings obtained when installing PFC
* an estimation of investment cost and payback time (not yet implemented here)
* and also an idea of how these cost savings will evolve during installation time==> please tell us what you think about it
Moderator team
In order to evaluate the PFC savings (how much I should replace them? how do I detect when I shall do it?),
I need to understand well the impact of age on performance of capacitors and also a proper selection of the automatic power control system of the Capacitor bank, if it`s going to have fixed and step modules.
Capacitor`s age of seven to ten years, counted since manufacture date or installation is a good estimation?
The other relevant aspect is related to the voltage and KVAR of capacitors: I knew changes in dimensions, distribution of elements and level of protection in case of failure, in less than 7 years. I have had to replace units because are no longer available, for other ones from different manufacturers.
The last comment is related to the performance of load connected in parallel to these PFC units:
Without PFC connected to the network, the voltage drop and current increase will be registered inmediately in comparison with the PFC on. This factor will be considered also for calculation of savings.
I really appreciate if I can share the previously announced calculation tools to daniel.diaz_AT_emerson_DOT_com
Thanks
I just wanted to announce, in case you are not already aware, that the PowerFacAging calculator is now on-line!
You can use it just right hereDon’t hesitate to send us your feedback after testing it, here in this topic !
@Laurent said:
I just wanted to announce, in case you are not already aware, that the PowerFacAging calculator is now on-line!
You can use it just right hereDon’t hesitate to send us your feedback after testing it, here in this topic !
Laurent,
Thank you for the PowerFacAging calculator. I had previously done some calculations for a large refrigeration business that has a 150 kVA maximum demand and Power Factor of 0.75.
The electricity grid in Australia is undergoing rapid investment and expansion. As a result the cost per kVA has jumped from $6 / month to $10 / month over the last year. Your calculator limits the price to $10 / kVA. A higher upper limit will soon be needed in Australia.
The calculator also limits the price of PFC systems to $50 per kVAR. Quotes received for installation so far in Australia are near $70-$80 / kVAR.
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