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Re: [TRNSYS-users] Glazed air collector



Dear David
Thank you for your valuable advice. I agree with you that using type 33 (together with type 539) is somehow important to predict the air properties at the outlet.
Best Regards
Nidal Abdalla
From: David BRADLEY <d.bradley@tess-inc.com>
To: Nidal Abdalla <nidalabdalla@yahoo.com>
Cc: Matt Duffy <duffy@tess-inc.com>; "trnsys-users@cae.wisc.edu" <trnsys-users@cae.wisc.edu>
Sent: Monday, October 29, 2012 5:47 PM
Subject: Re: [TRNSYS-users] Glazed air collector

Nidal,
  There are a couple of things you need to be a little bit cautious about in this. First, Type539 only accounts for sensible heating and cooling. The assumption is that the absolute humidity ratio of the air entering and leaving the collector is the same. During daytime, this is likely not a problem but because the temperature changes through the collector, you'll need to put a Type33 at the outlet in order to correctly recalculate the outlet air relative humidity. Second, Type539 does not take into account longwave radiation loss that typically happens at night. Your working fluid will only cool down to ambient, not below it. While this is true for both water and air based collectors, the impact is a little more important for air-based collectors because, as I mentioned in the first caution, the Type only handles sensible energy so while in real life you might get some condensation occurring inside the collector at night, this effect will not be seen in the model.
Best,
 David
 

On 10/26/2012 17:33, Nidal Abdalla wrote:
Dear Matt
 
Thank you v.much for your reply.
 
Nidal Abdalla
 
 
From: Matt Duffy mailto:duffy@tess-inc.com
To: Nidal Abdalla mailto:nidalabdalla@yahoo.com
Cc: trnsys-users@cae.wisc.edu
Sent: Friday, October 26, 2012 7:26 PM
Subject: Re: [TRNSYS-users] Glazed air collector

Dear Nidal Abdalla,
 
I have used Type539 (Glazed Flat Plate Solar Collector from TESS Solar Library) with success for a solar air collector. Since the solar air collector was here in the states, they had the SRCC rating numbers for the efficiency and IAM's, so I could simply enter those numbers into the parameters of Type539.  Since this solar collector model and many others in TRNSYS assume a constant fluid specific heat, you can implement solar air heating simulations with them.
 
Best regards,
 
Matt Duffy
 
On 2012-10-16 16:15, Nidal Abdalla wrote:
Dear all
 
I am trying to simulate glazed air collector for space heating using TRNSYS 17 with TESS libraries. Anyone can recommend the best choice for collector type can be used? I found at the TRNSY archives 2010 that  Mr. David had mentioned that there are a number of air-based solar collectors available in the TESS Solar Component. In fact, I found only unglazed air collector in the TESS lib. I am wondering if someone can help me.
 
Regards
 
Nidal Abdalla
 
National Energy Research Center
Amman - Jordan 
 
 




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