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Re: [EnergyPlus_Support] Coldrooms
1-If central cooling is typically used for these rooms, use a furnace or
unitary system. You would most likely schedule the heating coil off. Be
careful to avoid frost build up on the coil (check the supply air
temperature). These models were intended to simulate air conditioners
for "occupied" zones and have not been tested at low temperatures. You
can probably simulate conditions down to about 15C but I'm not sure of
the lower limits.
2-The refrigerated case model is based on an empirical model by Howell.
This model varies case performance based on room relative humidity or
dew point. Interactions of the case with the zone is modeled through
case credits. This model is probably not the best choice for simulating
a cold room. And this refrigerated case would have to be connected to a
refrigeration compressor rack, which is typically not used for walk-in
coolers or "cold" rooms found in a super market. The model intent is to
simulate various display cases in a super market, other uses would be
crude approximations. The refrigerated case model could only be used to
"approximate" energy use for isolated and well-insulated walk-in type
coolers or freezers. The height input in the refrigerated case object is
only for anti-sweat heater calculations (heat balance method). Case
performance is based on lineal footage to simulate various case lengths.
See the Engineering documentation for equations used and references to
papers describing the model.
3-DB should answer this question.
The super market (SuperMarket*.idf) example files distributed with
Energy+ may also be useful. There is an example of a walk-in freezer,
but is only intended to be an example and shows how flexible the
refrigerated case model inputs were designed. You must carefully use
manufacturers data to get close to the actual energy use for this type
of equipment.
Ricardo Miranda wrote:
>
> Hello,
>
> I´m simulating a supermarket that have some coldrooms. This coldrooms are
> supplied by a central cooling and has a different height ( shorter) of the
> rest of the building. I have some questions:
>
> 1- what type of system should we use to refrigerate such rooms?
> 2-Can the coldrooms be modeled as a refrigereted case, and if so, how
> can we
> account for it´s height, since energy plus only account for the linear
> lenght and doesn´t have the height option?
> 3-If it cannot be modeled as a refrigereted case, using the interface tool
> Design builder, how can we model these rooms with a different height
> of the
> rest of the building?
>
> Regards,
> Ricardo Miranda
>
> [Non-text portions of this message have been removed]
>
>
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
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