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definition of District cooling, District Cooling:Facility and Heating Load

asked 6 years ago

updated 6 years ago

Sorry for the primary question, but I really cannot find the answer for that.

I have two output files:"Austin Energy Enduse Timeseries CSVExport" and "Zone Equipment Report". I have some questions about the definition/content of some terms.

(1) In "Austin Energy Enduse Timeseries CSVExport", what is district cooling("Cooling:DistrictCooling [kBtu]" )mean? I have three thermal zones in my model. This district heating includes the heating for all three zones? And does the district heating includes water heating?

(2)In "Austin Energy Enduse Timeseries CSVExport", what is the difference between "Cooling:DistrictCooling [kBtu]" and "District Cooling:Facility [kBtu]”?

(3) In "Zone Equipment Report", what is the definition of "Heating Loads" in "Zone Load Summary"?

I really need to figure out the definitions, Please help me :) Thanks in advance!

Sincerely,

Meiwen Zhou

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answered 6 years ago

hnagda's avatar

District heating and cooling are terms associated with the HVAC system of a building when it receives cooling and/or heating from a centralized source (eg. chilled water from a Chiller Plant which serves multiple buildings and steam from a Combined Heat and Power Plant)

  1. Yes, depending on the way you have set up your HVAC system, if all your thermal zones are served by the district heating system, then it includes heating for all three zones. As for the water heating (assuming you are talking about the service hot water loop), you can have it connected to the district heating.
  2. Unless you have multiple district cooling loops, the Cooling:DistrictCooling and District Cooling:Facility should have the same kBtu values.
  3. Heating load is basically the rate at which sensible and/or latent heat must be added to the space to maintain a constant space air temperature and humidity.
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  1. In my simulation, I use Ideal Air load for the three thermal zones. Ideal Air Loads means each zone has their own equipment. But district heating means centralized system. These two things seem contradictory to each other. In this case, why is there still a report for district cooling? There is no centralized system?
  2. what is the difference between heating loads and district heating?
meiwen.zhou@wur.nl's avatar meiwen.zhou@wur.nl  ( 6 years ago )

I think EnergyPlus models Ideal Air Loads somewhat similar to District Heating/Cooling, although I am not 100% sure and comments from experienced users are welcome.

Yes, an Ideal Air Loads means each zone has its own equipment and its 100% efficient. It is modeled as an ideal VAV terminal unit and it eliminates any inefficiencies at the plant level or in the distribution system. Even Dist. Heating/Cooling assumes heating/cooling is provided from a centralized source and it eliminates plant inefficiencies

hnagda's avatar hnagda  ( 6 years ago )

Thanks for replying me! I still have one question:).. What is the difference between district heating in "Austin Energy Enduse Timeseries CSVExport" and Heating Loads in "Zone Load Summary"? Because in my case, the two results (the number) have huge difference :(.( the unit of heating loads in "zone load summary" is kBtu/ft2 per Run Period. To get the total energy consumption, I use this number multiple the house area. The unit of district heating in "Austin Energy Enduse Timeseries CSVExport" is kBtu. But the result is presented by every hour. So I add all the number in the excel file)

meiwen.zhou@wur.nl's avatar meiwen.zhou@wur.nl  ( 6 years ago )

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Asked: 6 years ago

Seen: 612 times

Last updated: Mar 28 '18