Hi all,
I am in the process of modeling a gymnasium that is served by two system types and I'm looking for the best way to model it. RTUs serve the space for cooling and ventilation purposes while hot water unit heaters supply the heating. The ventilation air from the RTUs tempered to 65degF during the heating months. Trying to figure out if there is a way to model it as a single system? I originally thought I could just mimic the RTU heating coil as the unit heater heating coil but got a ton of unmet hours. I have taken a powered induction unit with preheat as the approach now which has nixed my unmet hours but skyrocketed my heating energy consumption. Open to suggestions!
Thanks in advance,
Victoria
Victoria (Tsamis) Civitillo, PE, CEM, LEED AP BD+C, WELL AP
Sustainability Project Manager
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Stantec Consulting Services Inc.
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Hi Victoria,
Your gymnasium is a good application for taking advantage of the new DOAS system type in eQUEST 3.65 build 7175 running DOE-2.3. Model the RTUs as a DOAS system. Model the hot water unit heaters as a Unit Heater system (UHT) and assign the gymnasium zone(s) to it. Then assign the DOAS to the Unit Heater system using the DOA-SYSTEM keyword and set the DOAS-ATTACHED-TO the CONDITIONED-ZONES. You will want to enter the gymnasium ventilation rate in the gymnasium zone(s). The eQUEST UHT system type doesn't normally accommodate ventilation but it seems to work in this configuration.
Regards,
~Bill
William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer
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You can use baseboard heating to supplement an RTU, setup the parameters to be equivalent to the unit heater capacity, control, etc.
David
David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP
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Hi Victoria,
This sounds like a good case for utilizing the doe 2.3 engine with the most recent build. I think this will allow you to essentially model your AHU's as describes as a DOAS, and then to have them "attach" to another airside system which could explicitly simulate the operations of your unit heaters.
You would specify DOAS-ATTACHED-TO as CONDITIONED-ZONES to replicate the situation where the two systems are not directly piping air between each other, but instead draw separately from the mixed air of the conditioned space. You might review the reference entry for DOAS-ATTACHED-TO to see if that prompts you to consider defining a gym 'plenum' in further consideration of where these different units exist on the z-axis, in the event it isn't likely the whole volume is 'perfectly mixed.'
One thought: You might not be able to select and attach a system of type UH to a DOAS, considering UH by it's doe2 definition doesn't permit the introduction of ventilation air, but it may be worth a shot. If that doesn't work, you could likely define any number of other systems which permit the simple definition of a fan, heating coil, and ventilation air (multiple ways to skin the cat there).
~Nick
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Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Energy Performance Contracting
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Dang it Bill... I should have looked twice for your response =)!
[cid:image005.png at 01D515A3.47EDD880]
Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Energy Performance Contracting
D
M
F
E
913 . 564 . 6361
785 . 410 . 3317
913 . 564 . 6380
nicholas.caton at se.com
15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States
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