[Equest-users] Unexpected Custom SHGC Results

[Chris Jones]

I apologize for not getting to this sooner but I wanted by make sure 
my analysis was "real".

The PVAV systems are set with COOL-CONTROL = CONSTANT.  That is 
driving up both the cooling energy and the reheat energy.

The zone air flows are self-sized and the minimum flow is too low for 
heating.  When you change the glazing in some of the windows, the 
zone air flows change, skewing the results.  I am pretty sure that a 
"real world" project would have fixed air flows to the zones.  In 
order to gain some understanding of how the change in glazing affects 
the building you would want to program the zone air flows to be the 
same between the three runs - Base Case, EEM 1, EEM 2.

There is no central heating coil.  As a result, air is delivered to 
the zones at much lower temperatures than required to meet the 
heating loads.  Hence the thousands of hours underheated.

First I fixed the zone air flow rates to the values reported in the 
Base Case run.  The results are more "real":
Cooling energy decreases in each EEM run, heating energy increases as 
expected - less heat in the windows, more heating required.
The fan energy also increases as expected, more run hours at higher 
zone air flows as this is a VAV system after all.

Interestingly though, the total energy remains exactly the same 
between all three runs.

Next I took the bold step of setting COOL-CONTROL = WARMEST, 
MAX-COOL-REHEAT-T = 70.
The base case total energy consumption dropped by 8.5%.

The two EEM runs again save cooling energy, the fan energy and 
heating energy increase.  The result is that EEM 1 saves 0.17% total 
energy.  EEM 2 saves 0.02% total energy consumption.


I hope that provides something a bit more real.


At 10:29 PM 15/07/2012, Peter Baumstark wrote:


>Wow, it looks like the airflow is throwing it off, somehow.  I ran a 
>case where I Auto-sized the airflow, and it's giving me more 
>reasonable numbers for energy "differences" in pre and post 
>case.  However the baseline energy use for the building (auto-sized 
>case) is about 25% below the building's actual usage.
>
>I have to think about how a reduction in airflow can make such a 
>difference when evaluating fenestration products.
>
>Pete
>
>
>From: Peter Baumstark <pbaumstark at sbcglobal.net>
>To: Chris Jones <cj at enersave.ca>
>Sent: Sun, July 15, 2012 6:21:29 PM
>Subject: Re: [Equest-users] Unexpected Custom SHGC Results
>
>Or actually here's a run with actual EEM runs, if that's more 
>straight forward to evaluate.
>
>Thank you,
>Pete
>
>
>
>From: Peter Baumstark <pbaumstark at sbcglobal.net>
>To: Chris Jones <cj at enersave.ca>
>Sent: Sun, July 15, 2012 6:09:40 PM
>Subject: Re: [Equest-users] Unexpected Custom SHGC Results
>
>Sure Chris, if you have a few minute to look at it, here it 
>is.  Thank you very much for your time.
>
>Pete
>



 >>
Christopher Jones, P.Eng.
Suite 1801, 1 Yonge Street
Toronto, ON M5E1W7
Tel. 416-203-7465
Fax. 416-946-1005
email cj at enersave.ca
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