Hi...
I have a problem regarding the equest output & I need your help so that I
can complete the project on time.
At the first step to remove the proposed case unmet hours,i have increased
the cfm of same zone by diverting the cfm of other zone which is having
zero unmet hour, in order to maintain the design CFM of particular system
throughout the model.
After simulate the model, the unmet hour of same zone has been reduced
without affecting the zone from where the CFM was diverted, but the output
of space cool consumption comes in negative. I have attached the pics of
before & after the simulation of monthly energy consumption graph.
For your information, this is the hospital project consist of ground+7
floors+3 basements and for cooling & heating, there are two water cooled
screw chiller, two hot water generator are used on site.
Hi...
I have a problem regarding the equest output & I need your help so that I
can complete the project on time.
At the first step to remove the proposed case unmet hours,i have increased
the cfm of same zone by diverting the cfm of other zone which is having
zero unmet hour, in order to maintain the design CFM of particular system
throughout the model.
After simulate the model, the unmet hour of same zone has been reduced
without affecting the zone from where the CFM was diverted, but the output
of space cool consumption comes in negative. I have attached the pics of
before & after the simulation of monthly energy consumption graph.
I just want to know that why is this space cool output consumption showing
in negative and how to make it correct?
For your information, this is the hospital project consist of ground+7
floors+3 basements and for cooling & heating, there are two water cooled
screw chiller, two hot water generator are used on site.
Regards,
Nitin Harjai
Sustainability Engg.
Would you mind sharing your INP and PD files?
Hi Nitin,
I suspect there are inadvertent changes beyond those you?ve described moving CFM?s around. Comparing a before/after save file case could prove enlightening if that?s available.
I searched the archives a bit ? past instances of ?negative cooling? have reportedly involved:
- Misapplied CHW loop reset scheduling
- Drastically undersized chiller capacities (review units, try auto-sizing)
- Drastically undersized heat rejection / towers, in a similar vein
- Custom chiller curves gone awry
Some other observations, beyond the negative cooling:
- Electric heating is more than doubling
- Electric fan energies are altogether slightly higher
- Gas heating is a full magnitude larger
From the above I?d suspect one or more edits to inputs on the hydronic side are playing a role?
Best regards,
~Nick
---------------------------------------------------------------------------------------------------------------------------------------------
Nick Caton, P.E.
Senior Energy Engineer
Energy and Sustainability Services
North America Operations
Schneider Electric
D 913.564.6361
M 785.410.3317
E nicholas.caton at schneider-electric.com
F 913.564.6380
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Suite 204
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