High cooling consumption before lights level are decreased

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Hi Fakeha,

This is the second mail today.

You might be knowing that when you decrease the lighting schedule the
lighting load decreases so as the heating part of lighting load.
There is no normal reason behind what are the real factors causing it.
Following can be the cases:

1. Due to low cooling set-point as well as higher lighting fraction
schedule there can be easy way to know why there is higher cooling energy.

2. Maybe as the lighting fraction and the cooling set-points are matching
in the case of 2 pm to 5 pm to have the low cooling consumption.

3. May be the duration between 11 am and 2 pm is the time where there is
too much possibility to have the higher cooling consumption as the
condition matches to have the higher cooling load but you are unable to
resolve it so might be it depends upon your model or something so that in
this case of 11 am to 2 pm the cooling consumption is higher.

4. Another reason can be that there can be the possibility in this case
that the duration, schedule, time ans set-point is such that that it is
able to have the cooling consumption going higher in this case.

I'm unable to predict more but others can may help.

*Thanks,*
*Sharad.Kumar*

---------- Forwarded message ----------
From: Fakeha Sehar via Equest-users
To: via Equest-users
Cc:
Date: Tue, 31 Jan 2017 18:41:50 +0000 (UTC)
Subject: [Equest-users] High cooling consumption before lights level are
decreased
Hi,

When I raise my building's cooling set points from 2pm to 5pm,I observe for
a summer day that the cooling consumption goes low during this time; which
is fine. Now when I reduce the lighting schedule values (in order to reduce
the lighting load) from 2pm to 5pm lighting consumption goes low during
this time but for some reason the cooling consumption gets higher before
around 11am to 2pm, why?

Regards

via Equest-users's picture
Joined: 2016-07-15
Reputation: 400

Hi Fakeha,

As you decrease the lighting schedule the lighting power decreases, true.
As when the lighting power decreases and hence the heating goes down due to
the lighting power reduction, understandable.
Now when the heating due to the lighting power goes down there is less
cooling required and hence less cooling consumption should be there so you
are right.

But the possibility can be as follows:

1. You are required to observe that the lighting load decreases in the case
of 13:00 to 17:00.

2. But the cooling consumption is rigorously high in the case of 9:30 to
23:30.

4. Hence there can be some other more rigorous reasons as per me behind the
fact that why there should be more cooling consumption in this case then
the fact of the lighting loads factor.

Following can be the factors:

a. It is the day-time schedule of the project so can be that there are
other factors responsible for this as this can be the general schedule for
all type of purposes like equipment, cooking, refrigeration, HVAC, and
other factors.

b. May be this is the day-time when there can be higher atmospheric DBT and
WBT so might be this is the case of higher cooling consumption.

For more help from me you can attach the model (.pd2 and .inp) and weather
files next time.

May be other can also help.

*Thanks,*
*Sharad.Kumar*

---------- Forwarded message ----------
From: Fakeha Sehar via Equest-users
To: "equest-users at lists.onebuilding.org" ,
"equest-users-request at lists.onebuilding.org" onebuilding.org>
Cc:
Date: Thu, 2 Feb 2017 14:05:49 +0000 (UTC)
Subject: Re: [Equest-users] Equest-users Digest, Vol 107, Issue 1
If I only control lights, i.e., lower light schedule values from 2pm to
5pm, the lighting power consumption goes down as shown in Fig1 below.
[image: Inline image]
Fig 1 Light power consumption with and without light control

What I don't understand is why the cooling consumption goes higher as shown
in Fig 2, it should decrease due to decrease in lighting load.

[image: Inline image]
Fig 2 Cooling power consumption with and without light control

via Equest-users's picture
Joined: 2016-07-15
Reputation: 400