Re: Simulating a GrassRoof

["Anil Misra" <anil_misra@xxxxxxxxxxxxxxxx>]

Dear Ajit,

I received your mail some time back but could not reply earlier.
You have yourself answered your first question that you did not
understand my problem because you are not familiar with TRNSYS.
Then how you received my mail?

Cutting solar radiation by shading the roof is a good measure to
reduce cooling load because 40% cooling load in summer could come from roof.
However, if the cover is there on the roof even at night, then natural
cooling of
roof will not take place at night, and would leave the roof much warmer on
the next morning. Polythene cover is not transparent to longwave radiation,
and
would block the reradiation from roof at night.

I have explained the function of the grass roof in my mail. Certainly grass
roof is
much more effective mean to reduce (almost eliminate) cooling load from
roof.
In addition, the evapotranspiration by grass modifies the climate arounf the
building,
thereby reducing the solair temperature.

I hope this answers your questions.

Best regards,

Anil Misra

----- Original Message -----
From: <ajitk@iitk.ac.in>
To: <trnsys@relay.doit.wisc.edu>
Sent: Monday, April 01, 2002 9:40
Subject: Re: Simulating a GrassRoof


> Dear Anil Mishra,
> Namaskar,
> I do not understand you problem, as with your solution method because i am
not
> using trnsys software. I am working on conditioning the building space
using
> ammonia referegeration cycle having indirect cooling beside solar
appication
> like cooker and flat plate heater. For building cooling we are cutting of
solar
> roof gain by providing polythene cover (net) which cut off direct radaiton
by
> 90 %. because of this roof top temperature is reduced from 90 deg C to
45-50
> deg C. This reduces the thermal gain. I would like know your experience in
this
> with comparison of using grass cover roof.
> Ajit Kumar N Shukla
> Research Phd Student
> Refergeration and Air conditioning Lab
> Indian Institute of Technology
> Kanpur (INDIA)
>
>
>