[Equest-users] T-Stat is acting Screwy

[Rob Hudson]

Thanks for your thoughts and here is your answers:

1) yes, but there is no night set back time.
2) everything is 100% oa and constant volume 24/7/365
3)no exhaust heat recovery, and steam preheat.  the thermostat is set for 70
- 73 heating and cooling and the set back is to 60 and 80 at night for my
parametric run.
4) the cooling comes from a central chilled water plant for the entire
campus, and i just created a chilled water loop, added a meter and a pump
and it seems to be running happily.
5) the fans run all the time, day and night
6) I do have internal loads with latent heat, and it cycles down at night to
almost nothing.  These loads are currently the same for the model and the
parametric run.
7) i have set humidity levels to 20% and 53%, which also do not change with
my parametric run.

hope this give you enough information.

thanks again

On Wed, May 19, 2010 at 11:13 AM, David Bastow <
dbastow at mcclure-engineering.com> wrote:

>  Rob,
>
> I have a number of questions:
>
>    1. Do you have many lab hoods?  And are exhaust and make-up air revised
>    for the lab hoods at the night set back time?
>    2. What is the percent of outside air to the lab?  Does this percentage
>    change during the night set back time?
>    3. Do you have a pre-heat or exhaust heat recovery and pre-cooling on
>    your make-up air?  What is the temperature setting of this pre-heat or heat
>    recovery and pre-cooling?  Does the temperature settings on these change at
>    the night set back time?
>    4. Do you utilize an air or water side economizer for 1st stage
>    cooling?  Does this use change any at night set back time?
>    5. Does the fan run continuously day and night?  Have you ran models
>    with the fan running continuously, and with fan cycling based on demand at
>    night and off completely at night, to see how the results compare?
>    6. Do you have a internal load watts per square foot and latent load on
>    the space from interior lighting and equipment?  Do these loads change at
>    the night set back time?
>    7. Are you adding humidification or dehumidifying the space based on
>    some humidity settings?  Does the humidity settings change during the night
>    set back time?
>
>
> One of these things is probably causing the increased chilled water cooling load.  Often if you have high internal loads, even at night, then changes to the fan cycling and the amount of outside air brought inat night,
>  will increase the chilled water cooling load.  I would review all of these areas and run various test models to see how they each affect your energy usage when modified.
>
> Our firm just completed modeling some very large lab facilities with more
> than 55 exhaust hoods in the building, with high internal loads 24/7 and
> 100% outside air.  As long as the models are set up correctly they are
> normally right.  It takes some real design and thermal dynamic thought and
> often may models to really get your mind right with what is truly going on
> with the facility.  Its important to keep an open mind to what is going on.
> Having been doing computer hourly modeling for over 17 years, it is often
> easy to think you have a handle on what is going on with the building, but
> it is important to keep an open mind and investigate all the different
> avenues that you can think of until figure out what is going on.  I have 99%
> of the time that I have blamed the screwy program having problems that I
> have found that I just didn't look at all the different angles enough.
>
>  *David A. Bastow *
> *McClure Engineering, Inc.  *
>  <http://www.mcclure-engineering.com/>
>
>  ------------------------------
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Rob Hudson
> *Sent:* Wednesday, May 19, 2010 7:46 AM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] T-Stat is acting Screwy
>
> I have a lab space that is kept between 73 and 70 degrees all year long.
> One of my parametric runs has the cooling and heating T-stat schedules
> changing to have night time setbacks to 80 and 60, respectively.  When i use
> these, i get more energy spent overall.  specifically, i have a chilled
> water meter, steam meter, electric meter and hot water meter to monitor
> everything.  The chilled water increases while the others slightly decrease
> when i use the set back schedules.  Any ideas?
>
> --
> Rob Hudson
>



-- 
Rob Hudson
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