[Equest-users] Cooling Load not met!
Paul Diglio
paul.diglio at sbcglobal.net
Fri Sep 17 05:03:38 PDT 2010
Siddharth:
It would help if you attach the .pd2 file also.
Paul Diglio
________________________________
From: Siddharth V <siddharth.v at tcs.com>
To: equest-users at lists.onebuilding.org
Sent: Fri, September 17, 2010 6:29:11 AM
Subject: [Equest-users] Cooling Load not met!
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
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