Pramod, see the discussion here
.
This was regarding Energy Plus and a HHW loop, but the reason for the
heating increase is the same.

Aaron

From: "Pramod .D via Equest-users"
To: "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