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2023-09-19 09:38:05 -0500 | received badge | ● Popular Question (source) |
2016-07-08 15:46:37 -0500 | asked a question | UNITARY SYSTEM COOLING RATE I followed the steps in the question "hvac template for standard split ac"to build up a standard split system. The only changes I made from the default are: Unitary - Single Speed DX cooling - Cycling - Elec reheat Controlling Zone or thermostat location: Τhe relevant zone Rated Total Cooling Capacity: 6156 W Rated COP: 3.21 Rated Air Flow Rate: 0.37188396 m3/s The results for the Zone Air System Cooling Rate, for the same thermostat setpoint and loads: For the Winter period: For the Summer period:
Thanks! |
2016-06-20 02:12:28 -0500 | received badge | ● Enthusiast |
2016-05-13 06:53:46 -0500 | commented question | ModelToIdf and EnergyPlus warnings @Julien - I really appreciate your help. I apologize for posting such a big error log. The reason I asked this question is to confirm that I can ignore some of the warnings.
As you mentioned the ground temperature warning could matter quite a lot. I 'v read up previous question but I don't understand why doesn't get the values from the weather file. |
2016-05-13 05:36:27 -0500 | received badge | ● Commentator |
2016-05-13 05:36:27 -0500 | commented question | Unitary system and OA system economizer does not leads to reduced cooling power @aparker Thanks for your comment. Reporting out the Air System Outdoor Air Economizer Status I see that economizers operation depends on climate conditions. The only time that operates when the dry bulb temperature is above 18 C. The recommended envelope is very restricted. I 'll consider wider envelopes. Thanks! |
2016-05-13 03:57:39 -0500 | asked a question | ModelToIdf and EnergyPlus warnings I want your help about warnings and how they can be eliminated (Although I understand, they are not all of them critical). Here 's my model: https://we.tl/5Cmmzhz0UY ModelToIdf Warnings: Warning: Both surfaces 'Surface 40', and 'Surface 27 reference the same construction 'Interior Wall' but it is not symmetric, creating a reversed copy. EnergyPlus Warnings: Warning : IP: Note -- Some missing fields have been filled with defaults. See the audit output file for details. In the out.audit file I see this Warning IP: IDF line~1976 Object=LIGHTS, name=189.1-2009 - OFFICE - CORRIDOR - CZ4-8 LIGHTS 1, entered with less than minimum number of fields. * ~~~ * *Attempting fill to minimum. * Add * 1.00000000000000 ! field=>Fraction Replaceable Warning: ProcessSchedulelnput: ScheduleTypeLimits='CONTROLMODE', Unit Type='CONTROLMODE' is invalid. Warning: ProcessSchedulelnput: ScheduleTypeLimits=ΊΙΝΕARPOWERDENSITY", Unit Type="LINEARPOWERDENSITY" is invalid. Warning: ProcessSchedulelnput: ScheduleTypeLimits='VOLUMETRICFLOWRATE", Unit Type=’VOLUMETRICFLOWRATE’ is invalid. Warning: GetHTSurfaceData: Surfaces with interface to Ground found but no 'Ground Temperatures' were input. Found first in surface =SURFACE 1 Defaults, constant throughout the year of (18.0) will be used. Warning: CheckUsedConstructions: There are 4 nominally unused constructions in input. For explicit details on each unused construction, use Output:Diagnostics,DisplayExtraWarnings; Warning: Output:Meter: invalid Name='GAS:FACILITY' - not found. Warning: Output:Meter: invalid Name='DISTRICTCOOLING:FACILITY' - not found. Warning: Output:Meter: invalid Name='DISTRICTHEATING:FACILITY' - not found. |
2016-05-11 07:04:15 -0500 | asked a question | Unitary system and OA system economizer does not leads to reduced cooling power I 'm trying to model a CRAC of a small Data Center and as you can see in the image its a Unitary system and OA system I followed "The third edition of ASHRAE’s Thermal Guidelines for Data Processing Environments" but the operation of the economizer does not leads to reduced cooling power rate. It has to do with the settings or has to do with the geographical location and the local climatic conditions (humidity, enthalpy etc.)? Here 's my model: Thanks in advance !!! |
2016-05-03 05:36:20 -0500 | edited question | Modeling a Standard Split AC with economizer I followed the steps in the question "hvac template for standard split ac"to build up a standard split system according to the technical data: http://www.inventorairconditioner.com... The only changes I made from the default are: Unitary - Single Speed DX cooling - Cycling - Elec reheat
Controlling Zone or thermostat location: Τhe relevant zone
Rated Total Cooling Capacity: 6156 W Rated COP: 3.24
Nominal Capacity: 6498 W Diffuser
Maximum Air Flow Rate: 0.236 m3/s (Air Circulation 850 CMH Max) My first question is if my settings are correct according to the technical data? The second Question is according to openstudio results summary. Using a Unitary - Single Speed DX cooling - Cycling - Elec reheat system the total calculated power consumption for cooling or heating is cooling/heating+fans consumption? The third question is if I can model an economizer, since the relevant zone is a IT room/Data center space and what are the appropriate settings for an economizer for such a space so as to estimate possible changes in energy consumption Thanks! EDIT------------------------------------------------------------------- The following error occurs: "Error: Sizing: Coil:Cooling:DX:SingleSpeed "1SPD DX CLG COIL 7": Rated air volume flow rate per watt of rated total cooling capacity is out of range. Min Rated Vol Flow Per Watt=[4.027E-005], Rated Vol Flow Per Watt=[8.196E-005], Max Rated Vol Flow Per Watt=[6.041E-005]. See Input Output Reference Manual for valid range." When all set to default (autosize), no error occured. Acording to the technical data, is it posible to be overrided this error? |
2016-05-02 12:09:00 -0500 | commented question | Run period simulation with modified weather file @macumber, No I don 't get the correct days. I forgot to mention that original weather file has been purchased from whiteboxtechnologies.com. Here is my model and the original weather file before modified : |
2016-05-02 04:55:13 -0500 | commented question | Run period simulation with modified weather file After some tests I noticed that if I set the run period a few days before e.g. from 6th to 15th of August the input values are correct to the corresponding days (10th to 15th of August) ....! |
2016-05-02 04:46:44 -0500 | commented question | Run period simulation with modified weather file As you can see I edited my question. The calendar year settings changed after setting the epw file. If I set run period from 1/1 everything is ok. My second thought is that the openstudio sticks on Wednesday because is the first day of the year 2014 and for some reason it keeps this value for Day of Week for Start Day for every run period. I think one simple solution is to set annual run period and get the results from the period that I 'm interested to. |
2016-04-30 17:10:27 -0500 | asked a question | Run period simulation with modified weather file I modified a weather file of year 2005 using elements software tool. I set the value 2014 in the Reference Year field and some of the time-series data. In openstudio I set the value 2014 in the Callendar Year field in the schedule tab/Year Settings . I created a new run period profile from 10th to 15th of August. I checked if the input values are correct to the corresponding days (in result viewer) and I see that the values are not correspond to the respective days. I opened the in.idf file (path: ....\run\2-ModelToIdf-0) and I see that the value Day of Week for Start Day is Wednesday which is not the right value for year 2014 as the 10th of August is Sunday. I think for some reason openstudio uses 2005 as the reference year Why is this happening? EDIT ---------------------- If I change the epw file openstudio change the year settings |
2016-04-15 00:50:01 -0500 | commented answer | Run period profiles I have a last question. As shown in the diagram of the result viewer the first day of the run period has the maximum value of the electric power. This is not a major problem because if I set the run period a day before (from 24th) the results seems to be fine from the period of 25th to 30th. I am getting the simulation data with the XesoView program and I make the diagrams WITH EXCEL, so the wild variations isn't a problem for me I think its OK to close the question. Thanks! |
2016-04-14 17:16:05 -0500 | received badge | ● Supporter (source) |
2016-04-14 17:09:36 -0500 | commented answer | Run period profiles First of all I want to thank you for the time you spent for my question Julien! I think I found the solution for my problem. For all priorities I set the date range I am interesting for. For example I am interesting for the date range of 25th to 30th of December. Setting this period for each priority, only set the day corresponding to each priority. Then I set the run period from 25th to 30th of December. (Have a look at my last edit). What do you think? Thanks! |
2016-04-14 00:58:20 -0500 | commented question | Run period profiles |
2016-04-10 13:34:22 -0500 | answered a question | Run period profiles The Default profile works fine! The question is why overrides priority profiles results |
2016-04-06 13:05:48 -0500 | commented answer | Run period profiles As you can see I edited my answer. I use openstudio 1.8.0. In space tab/loads I set the schedule for the electric equipment load as "IT Room Equip" (2nd image) similar to your image |
2016-04-06 13:00:22 -0500 | commented question | Run period profiles As you can see I edited my answer. I use openstudio 1.80. I added more images of Facility tab where there is the corresponding zone and assigned as 189.1-2009 - Office - IT_Room space type. It seems like the default run period overrides all others. What else should be checked? I apologize for not tagging my question |
2016-04-06 12:50:43 -0500 | received badge | ● Editor (source) |
2016-04-05 15:59:23 -0500 | asked a question | Run period profiles Hi, I 'm using openstudio 1.8 In the loads tab I set the maximum design level for the electric equipment load: In space tab/loads I set the schedule for the electric equipment load as "IT Room Equip" In schedules tab/schedules I set hourly fractional run period profiles according to the variations of electric equipment load for specific days of the year In schedules tab/schedules sets I set Electric Equipment as "IT Room Equip" In ResultsViewer I see no variation of Zone Electric Equipment Electric Power. It seems like the default run period overrides all others. Why is this happening? (why not taking account the power variations of electric equipment) Edited--------------------- The Facility Tab, sorting by space type and Thermal zone
Edit --------------------------------------------------------------- The Default profile works fine! The question is why overrides priority profiles Results EDIT--------------------------------------------------------------
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2016-03-25 18:50:18 -0500 | commented answer | Modeling a Standard Split AC with economizer Q#1 The answer from the vendor was not helpful .... Q#2 I was not sure if the HVAC fan consumption is separated from the total cooling/heating consumption. Besides there is no HVAC system other than that in my model, and is rather reasonable. So I figured that is separated. Q#3 I'm searching ... Thanks! |