MIXED Cooling and heating

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Dear eQUEST users

I have a fundamental question about my anomalous result. I modeling a
residential (high rise) building in normal way and use various weather
data but finally the summery result contains both cooling and heating
consumption during cold season. I change many options in the
definition wizard for example type of building, utilities energy per
area etc. but the result not changed so much.
I ask anyone who know about the reason to send me an E-mail about this issue.

S.P. Amid

Pouya Amid's picture
Joined: 2011-09-30
Reputation: 0


What type of HVAC system are you using? If you are mixing heating and cooling airflows, you are tempering the air, and thus having both heating and cooling loads.

Sending us the .INP and .PD2 files would be helpful to investigate it for you.

John R. Aulbach, PE, CEM

John Aulbach's picture
Joined: 2011-09-30
Reputation: 1

I have a building that gets chilled water and heating water from a district plant ? and they are trying to LEED certify the building. So I?ve been using the document ?Required Treatment of District Thermal Energy?, but we have been given the efficiency of the plant as a whole. The university meters the amount of energy they put into the plant and what they get out and gave us an efficiency for the heating plant at around 76% and 88% for the cooling plant. I?ve modeled the building with purchased water for Step 1 of the document, now I?m trying to model the building and plant for the proposed design in Step 2 (Aggregrate Building / DES Scenario).

I had hoped to be able to create a chilled water meter and heating (steam) meter and enter the equipment efficiency in where it asks for Source-to-Site Eff (shown in the screenshot). Unfortunately, no matter what number I put in there, the resulting ?Annual Energy Consumption by Enduse? stays the same. Interesting also that the default for the Equipment Efficiency for the chilled water meter is 1.5 and the default for the steam meter is 0.6. The help information on each is different too, one calls for the ratio of the site to source and the other calls for the ratio of source to site ? WHICH IS IT?
[cid:image003.jpg at 01CA9AAC.84346880]
Also, since the result doesn?t show up in the ?Annual Energy Consumption by Enduse? report, where can I get the results that show the inefficiencies in the plant? The only report I?ve found that is even remotely useful would be the PS-A Plant Energy Utilization report, but that doesn?t make sense. It shows the source energy as being 2.5 times the site energy. It seems like that has to be taking something else into account that I?m not realizing or something.

How can I enter the proposed design (existing plant) information if I have the overall efficiency of the plant and that?s all? (the real plant has multiple chillers of differing types and it would be impossible to model it how it runs, and same with the heating plant.)?

Once I have entered the information, where can I go to verify that it?s working right? Is there a report that I don?t know about that will show what I?m looking for better?

Any information would be appreciated.


Jason Wendel

jwendel's picture
Joined: 2010-10-05
Reputation: 0

It?s likely that you have core zones with internal gains and zero envelope losses which will require cooling even in winter.

Luka Matutinovic, B.A.Sc., LEED? AP

Matutinovic, Luka's picture
Joined: 2011-09-30
Reputation: 0