Civil Engineering Reference
In-Depth Information
basic information that are required to be fed to the different software is basically
similar. Since almost all of software can generate some sort of output based on any
type of input, it is important that only people who have suffi cient degree of knowl-
edge about the building, its systems and the logic of the software perform the
energy modeling. Otherwise the reported results might be completely unreal and
even useless.
Some software are designed only to be used for load calculations such as HCCV,
and some are designed to be only used for energy modeling such as e-Quest. Some
specifi c software such as Trane Trace 700 can be used for both purposes of load
calculations and energy modeling. In the following paragraphs, I will describe the
common required structure of any typical software that can be used for both goals
of load calculations and energy modeling.
All these software generally have designated input spaces available for including
the name and other general information about the project with some useful descrip-
tions. These places can be used to describe the name and address of the project,
name and address of the engineering fi rm that performs the load calculations or
energy modeling, and any other general information that can be used for better iden-
tifi cation of the project.
The next group of input information which should be entered to the software is
usually the geographical location and the associated weather data for the specifi c
project location. Most of the software is designed with a relatively large bank of
weather data for many specifi c locations already built in it. In some cases simple
tools for generating or entering the weather data for some specifi c locations that are
not part of the general data storage of the software have been provided. Designer
can either generate or simply import the proper weather data to the software where
it is applicable. This weather data later will be used to calculate the cooling and
heating capacity for the system to offset the effects of the outdoor environment on
the inside of the building.
The next step usually is generating models for describing the different occupant
densities, types of occupant functions (in order to create people sensible and latent
loads), different lighting densities, and appliance densities. This type information
helps the software to calculate what in general is called the internal load for each
space within the building envelope. For example the inputs for a typical offi ce build-
ing can be in the following format: (type of function: offi ce area; occupant density:
70 square foot per person; people sensible load: 250 Btu per hour; people latent
load: 200 Btu per hour; type of lighting: recessed fl uorescent with a heat gain of
1.1 W per square foot; and type and density of appliances: 10 computers at 120 W
each). Software always provides provisions for specifying the daily schedules for
how each of these internal loads must be mapped in the calculations. For example
the designer can specify the occupancy of the space in the following manner. From
midnight to 7:00 A.M. 0 %, from 7:00 A.M. to 5:00 P.M. 100 %, and from 5:00 P.M.
to Midnight 30 % of designated occupant density shall be considered for the people
generated load in the calculations.
The next step generally is to set up the required outdoor airfl ow, thermostat,
humidistat, and CO 2 level settings for each specifi c space. Relevant standards such as
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