[Equest-users] VFD vs constant pump

[Sharad Kumar via Equest-users]

Dear Pramod,

Kindly have a go through the the following equation.

[image: Inline image 1]

As you know the rpm of the motor of the pump is dependent upon frequency
and number of poles.

The amplification by induction is used to change the frequency of the motor
and hence the frequency of the motor which results in the higher or lowered
rpm of the motor and hence variable speed of the motor of the pump and
hence on the help of micro processor controllers the resulting demand based
flow. Hence energy savings.

The energy savings have been brought about as the flow of the pump is as
per the demand based flow. When there is demand based flow the demand is
met properly as the constant flow does not determines the rate at which the
requirement has to be met so the VFD helps in meeting the requirement or
demand. If the demand is met at right time so the consumption would be
less. I mean for constant volume the flow is constant but the flow is
variable and hence the meeting demand can be best condition to fulfill the
wish of the intent to meet the demand.


Thanks,
Sharad.Kumar
Green Horizon Consulting LLP
Gurgaon
India.
.............................................................................................................
Today's Topics:

   1. VFD vs constant pump (Pramod .D via Equest-users)
   2. Re: [Bldg-sim] How to mirror a building in eQUEST
      (Keith Swartz via Equest-users)
   3. Re: [Bldg-sim] How to mirror a building in eQUEST
      (Xiangjin Yang via Equest-users)


---------- Forwarded message ----------
From: "Pramod .D via Equest-users" <equest-users at lists.onebuilding.org>
To: "equest-users at lists.onebuilding.org" <equest-users at lists.onebuilding.org
>
Cc:
Date: Thu, 28 Apr 2016 09:20:58 +0000
Subject: [Equest-users] VFD vs constant pump

Hi All,



I am simulating a model to see the savings provided by VFD pump connected
to the DHW plant loop. The energy used by the VFD pump is less compared to
constant volume pump. The problem is the energy usage of DHW increases if
constant volume pump is changed to VFD. Is this correct or am I missing
anything?  How does VFD pumps increases DHW usage?



Thanks!

Pramod
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