[Equest-users] Fan Night cycling and chiller operation

[Sharad Kumar]

Hi Rushi,

The meaning of night cycle control is regarding the fan shall might operate
in the night time in unoccupied time.
Regarding this the fan will be switched ON during the night time when the
temperature is below or above the throttling range which in your case is 70
to 75.2 degree Fahrenheit.

The superscript for the night cycle control is as follows:

[image: image.png]

[image: image.png]

This might mostly can be due to the just prior time of the occupied hour
reason when there is the case such that the space might require heating or
cooling so as the space should be at the marginal temperature range that
the occupied person might be comfortable soon with the temperature of the
space at the first-cum occupancy hours.

This might cost high electrical consumption but can might be used for the
above perusal reason.

Hope this might help.

*Thanks and Regards,*
Sharad.Kumar
Freelancer.
India.

....................................................................................................................................................


---------- Forwarded message ----------
From: Rushi Quest <rushiquest at gmail.com>
To: equest-users at lists.onebuilding.org
Cc:
Bcc:
Date: Thu, 23 Apr 2020 13:15:06 +0530
Subject: [Equest-users] Fan Night cycling and chiller operation
Dear E-questers,

I am working on a nine hours, five days a week office building operated by
chillers to meet HVAC demand.
As per ASHRAE 90.1-2010 appendix G, fans must be cycled during unoccupied
hours to meet the heating and cooling loads.
Now my query is that if night cycle fan control is kept on Cycle on Any
then it is observed from the hourly reports that chillers are operated
during night time and even on holidays, but this is not the actual case as
chillers (or even the electric heating) won't be on during night hours or
holidays.

I have checked the schedules and thermostat set points in zones and they
seem to be fine. The temperatures are considered 75.2F and 70F respectively
for cooling and heating in occupied hours and 82F and 64F in unoccupied
hours.

So please let me know if it is correct that chillers are cycling on during
unoccupied hours?  If no, then what should be done to operate them only in
occupied hours.

Note: I tried to give on/off schedule to chilled water loop but it gives
unreasonable amount of unmet hours.

Thanks in advance.

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