[esp-r] Emissvity and airflow network

[HUA SUO]

Hello ESP-r esperts, Could someone help me
with the following questions?

1.      
About the emissivity ,In
material database, we are provided with “Emissivity out” “ Emissivity in”  choices. I made a small test , for a given
material on a given surface, If I only reduce “ Emissivity out” , the simulation
results remains the same. If I only reduce ” Emissivity in”, leaving “Emissivity
out” the same as before, in result analysis the longwave radiation to sky will be
reduced, while the temperature for this surface increases. Does this mean that
if I change the “ Emissivity in” , “ Emissivity out “will be automatically
changed as the same value of “ Emissivity in”? What can I do if I want to
simulate an external Low-E coating to reduce the longwave to sky?

2.      
About the airflow network .I
coupled the simulation with an airflow network .However I found that the
ambient temperature from the output of .mfr is half an hour “earlier” respect
to the output of .res. While on the contrary I found when I inquire the heat
storage in the air , the output from .res is half an hour “earlier” respect to
the calculation from the .mfr output(I made the calculation based on the output
from .mfr). I run the simulation 1 step per hour with hourly result integration.

3.   Something very strange. I have
an airflow network including an fixed temperature node  with heating setpoint at 18 degree. It works well when I set this
fixed temperature node to be 20 degree ,but when I changed it to be 50 degree,
there is no flow anymore .This is the only parameter I changed. Why? I appreciate
if someone could give me a hand, also I can send you the model I made.







 

Best Regards,



Suo Hua
 
Ph.D Student in Tecnologia e Progetto per l'Ambiente Costruito/Technology and Design for Environment and Building
 
Il Dipartimento B.E.S.T.Dipartimento di Scienza e Tecnologie 
dell’Ambiente Costruito/ The Department of Building Environment Science 
& Technology
 
Politecnico Di Milano

Email:hua.suo at mail.polimi.it

 

 

 

 

 
 		 	   		  
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