[TRNSYS-users] calculation of unmet hours

Mayank mayank.23aug at gmail.com
Thu Mar 22 23:00:24 PDT 2012


Hello Sir,

 

Thank you very much for quick reply.  I have a question about Power
Coefficient of Pumps and Fan. This is a parameter which is required for
calculation of power consumption of Pump and Fan. It is a user defined
value. My question is : How can I calculate the power coefficient or there
is some standard value for constant speed and variable speed pump and Fans?
Please guide me. If there is some literature about it please specify.

 

Regards,

Mayank 

 

From: David BRADLEY [mailto:d.bradley at tess-inc.com] 
Sent: Thursday, March 22, 2012 10:34 PM
To: Mayank
Subject: Re: [TRNSYS-users] calculation of unmet hours

 

Mayank,
  If you have access to the TESS Utility Library, you can use the "zone
temperature watcher: Type584." When zone temperature exceeds the setpoint,
you have an "unmet hour." If you do not have Type584, you can write an
equation that has a value of 1 if the zone temperature exceeds the setpoint
temperature.

  On a related note, he first important thing to do is to define what you
mean by "unmet hours." In the industry, most often people refer to "unmet
load hours" If you are running your Type56 in energy rate control mode
(where you define a setpoint temperature and HEATING and COOLING types
inside TRNBuild and use the QSENS NTYPES to predict your sensible energy
loads) then you have the choice as to whether you limit or do not limit the
capacity of your idealized heating and cooling system. If you limit the
heating or cooling capacity then an unmet load occurs whenever the Type56
zone temperature exceeds the cooling setpoint temperature or falls below the
heating setpoint temperature. 

  If your building is operating in temperature level control (where you
define a thermostat, an actual HVAC system and the zone temperature reacts
to what the HVAC system is doing) then "unmet load hours" are meaningless
because the "load" is never calculated at the space level (the space reacts
to the HVAC system's operation, it only indirectly commands the HVAC
system). In this case, we typically redefine "unmet load" as time spent
outside the throttling range of the thermostat (ie above or below the
deadband). Again Type584 is used to total the amount of time.
Kind regards,
 David

On 3/19/2012 03:42, Mayank wrote: 

Hello Everyone,

 

I need to calculate unmet hours of my system. Is there any component in
TRNSYS 16 or I have to make manual calculation.

 

Please guide me.

 

Regards,

 

Mayank Bhatnagar

M.Tech.(Energy Engineering)

Malaviya National Institute of Technology, 

Jaipur (INDIA)

Ph.: +91-9983816468

 






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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA
 
P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com
 
http://www.tess-inc.com
http://www.trnsys.com
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