[TRNSYS-users] Decrease of temperature with Type 56

[Aaron J. Danenberg]

Augustin,

 

You infiltration rates seem relatively high (0.6ACH), if it is this high I
would assume you are in a windy location, or the building is old and leaky
(or you include some mechanical ventilation in this number).  Since the
building is well insulated, I would assume the problem lies within your
control (signal) scheme, or double checking your ACH assumption against the
results of a blower door test.  I use the data reader and TMY2 weather data
to define the conditions for external walls.  I did not understand how you
defined your conditions for the external walls, that may be something you
want to double check on, I cannot say if it is incorrect or correct, but may
be a likely source of your problems.  

 

Aaron J. Danenberg

Graduate Research Assistant

University of Hartford

 

From: Augustin CUQ [mailto:augustin.cuq at gmail.com] 
Sent: Monday, June 06, 2011 10:03 AM
To: trnsys-users
Subject: [TRNSYS-users] Decrease of temperature with Type 56

 

Dear all,

I sent a mail two weeks ago to expose the problem I had but it was not very
clear. So I have made an Excel file to illustrate it.The model has been
simplified. 

It represents a two rooms building, with no internal gain. The outside
temperature remains constant to 0°C and all the other parameters used by the
.bui are equals to a default value: 0.
The only parameter which is a variable input of the model is a heating
power. It remains constant until the steady state is obtained and then it is
put to 0.

The variation of the temperature, for the three time steps following the
stop of the heating device seems to be weird. The decrease of the
temperature is very fast, then it increases (???) before going down with an
acceptable derivative value (around 0.3°C/hr).
Find attached the model I have used.

Can anyone explain to me the reason of this phenomenon?
Thanks in advance.

Best regards.

-- 
Augustin CUQ 

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