No idea without reading your EPlus IDF entries. I have not used eQuest.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: randymaddox@xxxxxxxxxxx
Date: Thu, 17 Feb 2011 23:14:53 +0000
Subject: [EnergyPlus_Support] Packaged VAV Cooling Coil
I'm a real beginner at this, so if you can help, please talk down to me.
I'm modeling an existing building with a 70 ton packaged VAV with reheat. An eQUEST model of the same building used a minimum design flow rate of 0.5 cfm/sf = 8 m^3/sec. I'm told that 1 ton of AC capacity translates to 350--500 cfm of airflow, so I used 425 cfm, which is approximately 14 m^3/sec. I converted 70 tons to approx 246kW, and used a sensible heat ratio of 0.75.
I can see that the minimum volumetric flow rate per watt is too small, but even if I change 8 to 12, I still get exactly the same error with the same (rated) number:
"At low speed 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=[3.790E-005], Max Rated Vol Flow Per Watt=[6.041E-005]."
Tweaking both max and min numbers only confuses me. If I change them to 15 and 14, respectively, I get:
"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=[6.093E-005], Max Rated Vol Flow Per Watt=[6.041E-005]."
Can someone tell me what's going on here?
Randy
I'm modeling an existing building with a 70 ton packaged VAV with reheat. An eQUEST model of the same building used a minimum design flow rate of 0.5 cfm/sf = 8 m^3/sec. I'm told that 1 ton of AC capacity translates to 350--500 cfm of airflow, so I used 425 cfm, which is approximately 14 m^3/sec. I converted 70 tons to approx 246kW, and used a sensible heat ratio of 0.75.
I can see that the minimum volumetric flow rate per watt is too small, but even if I change 8 to 12, I still get exactly the same error with the same (rated) number:
"At low speed 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=[3.790E-005], Max Rated Vol Flow Per Watt=[6.041E-005]."
Tweaking both max and min numbers only confuses me. If I change them to 15 and 14, respectively, I get:
"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=[6.093E-005], Max Rated Vol Flow Per Watt=[6.041E-005]."
Can someone tell me what's going on here?
Randy
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