[TRNSYS-users] Modelling a Greenhouse in TRNSYS (Vegetation)

[Knut Erik Enerstvedt]

Hello,

You are on the right track concerning modelling greenhouse vegetation. As
you suggest, you can create a Type for the vegetation and use outputs of
heat transfer rate (kJ/hr) and water vapor flow rate (kg/hr) as inputs to a
Gain in Type 56. Model equations can be found for example in this PhD
thesis:

Hendrik Feije de Zwart, 1996: "Analyzing energy-saving potensials in a
greenhouse cultivation using a simulation model". PhD. Dissertation,
Landbouwuniversiteit, Wageningen.

Hope this helps.

Kind regards,

Knut Erik Enerstvedt


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From: Tammo Bruinsma <tammo.bruinsma at me.queensu.ca>
To: "trnsys-users at cae.wisc.edu" <trnsys-users at cae.wisc.edu>
Cc:
Date: Wed, 21 May 2014 15:52:44 +0000
Subject: [TRNSYS-users] Modelling a Greenhouse in TRNSYS (Vegetation)
 Hello,

 I am currently working on a model of a greenhouse in TRNSYS. I have gotten
as far as crating the 3D model in Google Sketchup and importing it into
TRNBuild Type 56. The temperature and humidity control for the greenhouse
will be handled by an external liquid desiccant unit that I am still in the
process of creating.

 I am more concerned about the internal characteristics of the greenhouse.
I have created a structure with mostly windows and although I have not yet
been able to apply a double polyethylene type to them this shouldn't pose
too much of a problem. I read somewhere that the Type 56 does not account
for radiation that crosses through parallel windows and back out of the
greenhouse, has anyone found a solution for this?

 Another puzzling process is the transpiration and respiration of the plant
vegetation. I am aware of the equations that model these factors but do not
know how to apply them to the system. One possibility might be to create an
external type for the vegetation and use the necessary outputs as input
variables into the Type 56 Building. Or possibly adding a "Gain" in
TRNBuild that might account for the added humidification and CO2 levels,
although I am not sure how this would work.

 I was hoping someone might be able to shed some light on these issues and
if there are any working models around I would very much appreciate taking
a look at one.

 Sincerely,

 Tammo Bruinsma
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