RE: [EnergyPlus_Support] Heating/Cooling Changes Drastically with Occupancy

The hourly evergy value is correct. 288000 w sould read 480 w.

The sum of the sensible and the latent heat equals to total heat, which is the value you have entered for the activity. Radiant plus covection heat squal to sensible heat value. The component values for the Winter and Summer period are different, but the total value remain constant as the entered value.

These are my observations on the spread sheet. I do not know how the numbers are used in the table calculation for the annual total.

I ran the DesignDay simulations only with CTF, 4 peple in DesignDays and 2 people in CustomDays, and timestep = 6, and did not run the annual simulation.

When the number of people is reduced, the all the numbers are proportionally reduced..

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: nirajpdl@xxxxxxxxx
Date: Mon, 6 Aug 2012 17:45:20 -0400
Subject: Re: [EnergyPlus_Support] Heating/Cooling Changes Drastically with Occupancy

Dear Dr. Li.

I will try to validate using equipment and lighting as well. And from your spreadsheet it does seem that the results in Watts does not make much sense. I will keep you updated on what results I get with the validation.

Thank you for taking the time to run the simulations and preparing the spreadsheet. I really appreciate it.

Sincerely yours'

Niraj

On Mon, Aug 6, 2012 at 3:22 PM, YuanLu Li <yli006@xxxxxxxxxxx> wrote:

You may want to try the validation using equipment and lighting as well.

People object is a little complicated. The attached spread sheet show that the values are different for the Winter and Summer seasons. There are four components to made up the total. It appears that there is a bug on the Total value. The Joule value seems correct, and the watt value is too large.

If the watt value is used for your annual value calculation, then the result would be wrong.

I used designDay objects for 4 people and CustomDay objects for 2 people, so that more data can be obtained in one run. If you add Sunday for one, and Monday for none, then all four contitions can be verified by editing the Office Occupancy Schedule with 1.0 0.5, 0.25, 0.0. for the four daytypes.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: nirajpdl@xxxxxxxxx
Date: Sun, 5 Aug 2012 16:52:28 -0400
Subject: [EnergyPlus_Support] Heating/Cooling Changes Drastically with Occupancy

Dear all,

I have modeled a very simple one zone building in Eplus Version 7.1:

a) 1225 sq ft.
b) 15% glazing window/wall ratio.
c) No infiltration, No ventilation, No Lights, No Equipment.

d) Heatbalance algorithm - Conduction Finite Difference with 60 timesteps per hour.
e) HVAC - Ideal Air Loads System - always ON. (Heating Setpoint: 21 Degree Centigrade and Cooling Setpoint: 25 Degree Centigrade)

f) Heating and Cooling Availability always ON.

Okay now here is the problem:

When the number of people progressively increases in the building the annual heating and cooling energy changes drastically (more than expected) :

Zero People:
Annual Heating: 1.4969E+10 Joules
Annual Cooling: 4.064E+9 Joules

1 Person (Activity Schedule is always on and the activity level is 120 Watts per person):

Annual Heating: 1.3882E+10 Joules
Annual Cooling: 5.303E+9 Joules

2 People (Activity Schedule is always on and the activity level is 120 Watts per person):

Annual Heating: 1.2853E+10 Joules
Annual Cooling: 6.509E+9 Joules

Could anyone help me pinpoint what is going on here. I would appreciate any insight on this issue. Thanking you.

Sincerely yours'
Niraj

--
Niraj Poudel, Architectural Engineer.
PhD student, PDBE Program.
Clemson University, Clemson, SC.

Niraj Poudel, Architectural Engineer.

PhD student, PDBE Program.

Clemson University, Clemson, SC.

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