There are a wide variety of construction types for green roofs, so you'll have to create a custom construction (probably using custom materials) for the roof as-designed. The problem is that the roof's thermal properties are not constant; e.g. the soil/growing medium's conductivity depends on moisture content, among other things. eQUEST does not handle variable material properties, so you'll have to be comfortable with the inaccuracy. Also, if the resulting construction is too thick, roughly three feet or more, eQUEST will give you an error message.
Something to model which may improve the modeled performance of this
roof: You might want to create a series of building shades
immediately/shortly above and parallel to your roof surface(s) to
roughly match the coverage of the actual garden plants and assign them a
shade schedule (transmittance through the year) to match their foliage
patterns.
If this garden provides shading in the summer and allow direct sun loads
in the winter, it may help your heating/cooling loads in a good way both
seasons.
That said, coming up with a way to account for the variable thermal
properties of moist/dry soil as Dakota brought up is something I'd be
more concerned about. I'd like to hear what others may have done to
address that issue. A good place to start might be to create your
custom construction layers/materials based on "damp" (not dry or
saturated - a happy medium) soil conditions.
John,
Sorry to be relatively unavailable, Look on the eQ website at the bottom of
page Volume 3 probably has this info.
Or send me your # off line.
Carol
There are a wide variety of construction types for green roofs, so you'll have to create a custom construction (probably using custom materials) for the roof as-designed. The problem is that the roof's thermal properties are not constant; e.g. the soil/growing medium's conductivity depends on moisture content, among other things. eQUEST does not handle variable material properties, so you'll have to be comfortable with the inaccuracy. Also, if the resulting construction is too thick, roughly three feet or more, eQUEST will give you an error message.
Dakota Kelley
Does anyone have an .INP example for me to use. LOAD-RESET? is EASY. OA-RESET is not.
Thanks.
Additional food-for-thought...
Something to model which may improve the modeled performance of this
roof: You might want to create a series of building shades
immediately/shortly above and parallel to your roof surface(s) to
roughly match the coverage of the actual garden plants and assign them a
shade schedule (transmittance through the year) to match their foliage
patterns.
If this garden provides shading in the summer and allow direct sun loads
in the winter, it may help your heating/cooling loads in a good way both
seasons.
That said, coming up with a way to account for the variable thermal
properties of moist/dry soil as Dakota brought up is something I'd be
more concerned about. I'd like to hear what others may have done to
address that issue. A good place to start might be to create your
custom construction layers/materials based on "damp" (not dry or
saturated - a happy medium) soil conditions.
NICK CATON, E.I.T.
John,
Sorry to be relatively unavailable, Look on the eQ website at the bottom of
page Volume 3 probably has this info.
Or send me your # off line.
Carol