[Equest-users] Cooling Load not met!

Siddharth V siddharth.v at tcs.com
Fri Sep 17 04:29:11 PDT 2010


Hi All, 

I have created a System, which has only one zone(25000 sqft) using DX 
coils for cooling, Furnace for heating; and system type is CAV Packaged 
Single Zone system. 

I have set the COOLING-CAPACITY = 1500.00 kBTU/hr. 

When I was going through the HOURLY reports, I found the following data.

Below are the Peak Cooling Report Summary, followed by the HVAC Cooling 
load for the peak day(Jun 21) and the current zone temperatures/ 
Thermostat Temperatures for that same day. 


MY Queries are: 

If my HVAC system is designed to remove a heat load of 1500kBTU, and the 
total Heat to be removed on Jun21 (8am) was 1004375+44188 = 1048563 BTU/hr 
only, why wasnt the HVAC system unable to remove it? The first doubt was 
about insufficient CFM (of the used constant volume system). But the same 
CFM is able to handle higher loads at other times.

Please see the SS-J Report during the particular hour the load was never 
met. 

Please resolve my confusion regarding this sufficient cooling capacity vs 
unmet load scenarios.

I am attaching the inp, weather file for your reference (in case it 
helps).



REPORTS:
  
REPORT- SS-J Peak Heating and Cooling for   Sys1 (PSZ) (G.1)     WEATHER 
FILE- EPW New Delhi,Delhi,
---------------------------------------------------------------------------------------------------------------------------------



          - - - - - C O O L I N G - - - - -       - - - H E A T I N G - - 
-       D A Y   C O O L I N G   P E A K

                        JUN 14                              JAN 19    JUN 
21


          HOURLY                                    HOURLY        HOURLY
         COOLING    SENSIBLE    DRY-   WET-        HEATING    DRY-   WET-  
     COOLING    SENSIBLE    DRY-   WET-
            LOAD        HEAT    BULB   BULB           LOAD    BULB   BULB  
        LOAD        HEAT    BULB   BULB
HOUR      (KBTU)       RATIO    TEMP   TEMP         (KBTU)    TEMP   TEMP  
      (KBTU)       RATIO    TEMP   TEMP



   1       0.000       0.000    93.F   74.F          0.000    49.F   48.F  
       0.000       0.000    89.F   79.F
   2       0.000       0.000    95.F   74.F          0.000    48.F   47.F  
       0.000       0.000    89.F   78.F
   3       0.000       0.000    96.F   73.F          0.000    47.F   47.F  
       0.000       0.000    87.F   78.F
   4       0.000       0.000    95.F   74.F          0.000    47.F   47.F  
       0.000       0.000    86.F   78.F
   5       0.000       0.000    89.F   76.F          0.000    47.F   47.F  
       0.000       0.000    85.F   79.F
   6       0.000       0.000    89.F   77.F          0.000    48.F   47.F  
       0.000       0.000    84.F   80.F
   7    1100.896       0.763    89.F   77.F          0.000    48.F   48.F  
    1065.103       0.708    85.F   80.F
   8     988.670 *     0.732    90.F   78.F          0.000    49.F   48.F  
    1004.375 *     0.685    86.F   80.F
   9     996.547       0.747    92.F   78.F          0.000    51.F   50.F  
     988.282       0.686    90.F   81.F
  10     982.636 *     0.731    94.F   79.F          0.000    52.F   51.F  
    1006.017       0.678    92.F   81.F
  11     987.969       0.734    97.F   79.F          0.000    54.F   52.F  
     988.014       0.678    95.F   82.F
  12     998.494       0.711    99.F   81.F          0.000    55.F   54.F  
     989.553       0.669    97.F   83.F
  13    1004.154       0.694   100.F   82.F          0.000    57.F   54.F  
     990.271       0.662    98.F   84.F
  14     979.070       0.691   100.F   83.F          0.000    59.F   55.F  
     955.878       0.668    99.F   83.F
  15     934.561       0.711   100.F   81.F          0.000    59.F   55.F  
     942.959       0.676   101.F   83.F
  16     863.300       0.735   100.F   78.F          0.000    59.F   55.F  
     899.941       0.683   101.F   82.F
  17     737.102       0.770    99.F   75.F          0.000    58.F   55.F  
     814.377       0.687   102.F   82.F
  18       0.000       0.000    97.F   75.F         -6.497    56.F   53.F  
       0.000       0.000   101.F   81.F
  19       0.000       0.000    96.F   74.F          0.000    53.F   52.F  
       0.000       0.000   100.F   81.F
  20       0.000       0.000    94.F   76.F          0.000    51.F   50.F  
       0.000       0.000    98.F   81.F
  21       0.000       0.000    93.F   77.F          0.000    49.F   49.F  
       0.000       0.000    98.F   82.F
  22       0.000       0.000    91.F   78.F          0.000    48.F   48.F  
       0.000       0.000    96.F   81.F
  23       0.000       0.000    90.F   78.F          0.000    48.F   48.F  
       0.000       0.000    95.F   81.F
  24       0.000       0.000    89.F   78.F          0.000    49.F   48.F  
       0.000       0.000    93.F   81.F
        --------                                  --------     ---------
SUM     10644.770
MAX     1100.896                                    -6.497


              SYSTEM-TYPE         PSZ                      SQFT/TON  544.9
              COOLING PEAK          22.02 (BTU/HR- SQFT)   HEATING PEAK    
-0.13 (BTU/HR- SQFT)
              SUPPLY AIR PEAK FLOW   0.53 (CFM/SQFT)       MIN-OA/PERSON   
   35.00 (CFM )
              OA FRAC AT CLG PEAK   0.164                  OA FRAC AT HTG 
PEAK   0.164

              * ASTERISKS INDICATE HOURS LOADS NOT MET
---------------------------------------------------------------------------------------------------------------------------------------------------

          BUILDING      Zn (G.1)
          -HVAC 
          COOLING       LOAD NOT
          LOAD          MET 
          BTU/HR        BTU/HR 
 
          ----( 1)      ----(16)
 621 7      1065103.            0.
 621 8      1004375.        44188.
 621 9       988282.            0.
 62110      1006017.            0.
 62111       988014.            0.
 62112       989553.            0.
 62113       990271.            0.
 62114       955878.            0.
 62115       942959.            0.
 62116       899941.            0.
 62117       814377.            0.

 DAILY SUMMARY (JUN 21)


-------------------------------------------------------------------------------------------------------------------------------------------------
       Zn (G.1) Zn (G.1)
 
       ZONE     THERMOST
       TEMP     SETPOINT
       F        F 
 
       ----( 6) ----( 7)
 621 7     76.9     76.0
 621 8     79.4     76.0
 621 9     76.9     76.0
 62110     77.0     76.0
 62111     76.9     76.0
 62112     76.9     76.0
 62113     76.9     76.0
 62114     76.8     76.0
 62115     76.8     76.0
 62116     76.7     76.0
 62117     76.6     76.0


 DAILY SUMMARY (JUN 21)





Regards,
Siddharth Venkataraman
Tata Consultancy Services
Mailto: siddharth.v at tcs.com
Website: http://www.tcs.com
____________________________________________
Experience certainty.   IT Services
                        Business Solutions
                        Outsourcing
____________________________________________
=====-----=====-----=====
Notice: The information contained in this e-mail
message and/or attachments to it may contain 
confidential or privileged information. If you are 
not the intended recipient, any dissemination, use, 
review, distribution, printing or copying of the 
information contained in this e-mail message 
and/or attachments to it are strictly prohibited. If 
you have received this communication in error, 
please notify us by reply e-mail or telephone and 
immediately and permanently delete the message 
and any attachments. Thank you


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100917/8385787b/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Input.zip
Type: application/zip
Size: 66516 bytes
Desc: not available
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20100917/8385787b/attachment.zip>


More information about the Equest-users mailing list