[bldg-sim] Hygrothermal analysis capability

[Jon Hand]

>    The concrete structure is expected to give off moisture for many years
> as part of its cure. I expect that it will also react to internal and
> external vapour pressure and act in a hygroscopic manner. Can this be
> modelled with ESP-r for example?
Hygroscopic is possible in ESP-r and is dependant on some difficult-to-find
material properties. Be aware the facility expects a high degree of
domain and tool expertise and occassionally dragons have been spotted.
>
>    Another interesting feature could be the inclusion of unfired clay for
> hygroscopic buffering.
Ditto the comments above. 
>
> 2. In order to model the thermal mass of waste within the store it was
> necessary to represent it as "internal partitions". Does esp-r (or any
> similar) have the capability to "fudge in" extra thermal mass into a room
> space along with any other parameters such as surface area, thermal
> transmittance, surface resistance, etc.
In esp-r internal mass can be explicitly modelled via surfaces floating
within a zone. Such surfaces take part in explicit longwave radiation
exchange with all other surfaces in the zone and take part in the usual
convective exchanges or can use user supplied hc coeff.  Radiation
viewfactors can be either explicitly calculated or based on area-weightings.

Such interior surfaces have mass and will act as thermal sponges. There are
a few rules to follow in defining layers in constructions, but folk have 
worked with mass of 1-1.5m thickness with little or no difficulty. Run times
are longer because of the extended start-up day requirements which
are associated with really massive construction.

Truly clever folk could include phase change properties, but that probably
is not an issue for this sort of constructoin. The limit the the degree of 
internal 'clutter' is largely a function of how many extra surfaces you 
include.

-Jon Hand

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