eQUEST Heating Controls & Troubleshooting

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Hello,

I'm trying to model an existing building and have a few issues. The
building is in Canada (Regina) so predominantly heating climate; system is
VAV with reheat. The two main issues are some space heating occurring in
the summer and many unmet heating hours in winter. The heating hours may be
due to the fact that, from what I've seen, eQuest tends to under-size
baseboard capacities required for Canadian climates. (I don't have existing
building baseboard info). I have some general controls & trouble-shooting
questions:

1) Is it common to use seasonal schedules to lock-out summer heating? (or
is the summer heating a control issue that should not be occurring?)

2) Another thread indicated summer heating may be due to a reheat problem
with VAVs, which can be solved by controlling the cooling coil so that
minimum reheat occurs. If so, how can I do this?

3) Should the cold deck min leaving temp (or min supply temp) and the hot
deck max leaving temp be the same? Just wondering if the min cooling supply
temp is 55F and hot deck max is 65F whether this will cause excessive
reheat in the summer (assuming cooling is taking precedence and the leaving
temp is 55).

4) Looking at the SS-R report for the first time, many of the problem zones
(perimeter) with high unmet hours are at the minimum part load range
(50-60%) for 100% of the time. The VAV minimum flow is 50%, so I am
guessing those part loads refer to the VAV flow. That doesn't seem right to
me, unless I'm missing something.

5) What is the quickest way to check how the system is performing at a
specific time (e.g. check space temps at night)? Asking because one item
still lacking from my model is cycling heating + fans on at night. I take
it that, without allowing fans to cycle on, nighttime heating will be
provided by the baseboards only, and am curious to see the simulation
outputs for how this is performing.

Thanks all,
John

John Kopf, BEng, MASc, EIT, LEED AP BD+C
Sustainability Analyst
Stantec
200 - 325 25th Street SE Calgary AB T2A 7H8
Phone: (403) 716-8006
Fax: (403) 716-8049
John.Kopf at stantec.com

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WAY too many questions. However, try making your throttling range for a reverse acting t-stat from 4 - 6 DegF. The summer heating is probably being controlled by reheat.

Question 2 is answered by putting cooling-control on WARMEST.

That should solve your Summer problem.

Hello,

I'm trying to model an existing building and have a few issues. The building is in Canada (Regina) so predominantly heating climate; system is VAV with reheat. The two main issues are some space heating occurring in the summer and many unmet heating hours in winter. The heating hours may be due to the fact that, from what I've seen, eQuest tends to under-size baseboard capacities required for Canadian climates. (I don't have existing building baseboard info). I have some general controls & trouble-shooting questions:

1)Is it common to use seasonal schedules to lock-out summer heating? (or is the summer heating a control issue that should not be occurring?)

2)Another thread indicated summer heating may be due to a reheat problem with VAVs, which can be solved by controlling the cooling coil so that minimum reheat occurs. If so, how can I do this?

3)Should the cold deck min leaving temp (or min supply temp) and the hot deck max leaving temp be the same? Just wondering if the min cooling supply temp is 55F and hot deck max is 65F whether this will cause excessive reheat in the summer (assuming cooling is taking precedence and the leaving temp is 55).

4)Looking at the SS-R report for the first time, many of the problem zones (perimeter) with high unmet hours are at the minimum part load range (50-60%) for 100% of the time. The VAV minimum flow is 50%, so I am guessing those part loads refer to the VAV flow. That doesn't seem right to me, unless I'm missing something.

5)What is the quickest way to check how the system is performing at a specific time (e.g. check space temps at night)? Asking because one item still lacking from my model is cycling heating + fans on at night. I take it that, without allowing fans to cycle on, nighttime heating will be provided by the baseboards only, and am curious to see the simulation outputs for how this is performing.

Thanks all,
John

John Kopf, BEng, MASc, EIT, LEED AP BD+C
Sustainability Analyst
Stantec
200 - 325 25th Street SE Calgary AB T2A 7H8
Phone: (403) 716-8006
Fax: (403) 716-8049
John.Kopf at stantec.com

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