[TRNSYS-users] Energyplus weather data and pump

[David BRADLEY]

Cathy,

> 1. I use the weather data(*.epw) downloaded from the webe of 
> Energyplus as the external files of Type15-2. When running simulation 
> of the project, there is no warning or error. But all the weather data 
> are not read out and shown as zero.
>
At one point, the energyplus weather file format changed and so we had 
to change TRNSYS to correspond. Please send me the *.epw file that you 
are trying to read (as well as which version of TRNSYS you are running) 
and I'll take a look at it.
>  2. In the water circulation, the flow rates of Single speed pump( 
> Type114) can be varied when the values of the inlet fluid flow rates 
> are different. What are the differences between  the Sigle speed 
> pump(Type114) and Variable speed pump(Type110)?
>
In TRNSYS almost all of the pump models set the downstream flow based on 
the value of the rated flow rate (a parameter) and the control signal 
(an input). They ignore the amount of flow that is coming into the pump 
from upstream except to do a mass-balance check. Type114 is designed to 
have a control signal of either 0 (off) or 1 (on). In fact if you give 
it a control signal of < 0.5, this is interpreted as 0 (off). If you 
give it a control signal > or = 0.5, this is interpreted as 1 (on). The 
flowrate out of Type114 will always be either zero or the rated flow rate.

With Type110, the rated flow rate (parameter) is multiplied by the value 
of the control signal input (which typically varies between 0 and 1) to 
give the outlet flow rate. You have to be a bit careful with Type110 
because it does not limit the input control signal to a maximum value of 
1.0. If you specify a control signal of 10, your output flow rate will 
be 10 times the pump's rated flow rate. We do not limit the control 
signal input to a maximum value of 1 because there are cases in which 
pump are intentionally run above their rated flow rate.

Kind regards,
  David

-- 
***************************
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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