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Random Number Generation – Normal Distribution
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This component generates a random number based on a random normal distribution. Outputs from this model can be used for a variety of purposes
including the ability to generate realistic forcing function profiles based on 1 “average” profile and this scaling factor. For example, set the
daily DHW draw based on the anuual average DHW draw and a randomly generated number drawn from the normal distribution.
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Random Number Generation – Uniform Distribution
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This component generates a random number based on a random uniform distribution. Outputs from this model can be used for a variety of purposes
including the ability to generate realistic forcing function profiles. For example, this component could be used to set the number of occupants in
a conference room where the occupancy changes randomly from day to day.
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Ground Temperature Model
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This component models the temperature of the earth as a function of depth and time of year. The model is based on the Kusuda correlation and is
used in geothermal heat pump applications and basement loss calculations.
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Occupancy Loads
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This component calculates the latent and sensible loads to a conditioned space due to the occupancy and activity of the people located inside
the conditioned space. The correlation is based on a method published by the American Society of Heating, Refrigerating and Air Conditioning
Engineers.
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Equipment Fouling with Scheduled Cleanings
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This component was written for the fouling and scheduled cleanings of solar collectors, but may be used for any component whose performance
degrades linearly with time. At user-defined intervals, the equipment is perfectly cleaned and the performance restored to its rated value. This
model also allows for unscheduled cleanings (rain washing a collector for example) at a user-defined cleaning rate.
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Infiltration Forcing Function
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This forcing function sets the infiltration for a building to a user-defined repeating daily schedule. This model is a modified version of
the standard TRNSYS type 14 forcing function.
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Heating Season Forcing Function
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This forcing function is used in simulations where the heating equipment is not allowed to operate for certain periods of the year. An
example of where this component is used is to not allow heating during cool summer nights when the room temperature falls below the heating set-point
temperature. This model is a modified version of the standard TRNSYS type 14 forcing function.
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Cooling Season Forcing Function
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This forcing function is used in simulations where the cooling equipment is not allowed to operate for certain periods of the year. An
example of where this component is used is to not allow cooling during warm sunny winter days when the room temperature rises above the cooling
set-point temperature. This model is a modified version of the standard TRNSYS type 14 forcing function.
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Night Setback/Setup Forcing Function
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This forcing function is used in simulations where a room thermostat allows for night setback/setup. The outputs from this component are used as
control signal inputs to the room thermostat models. This model is a modified version of the standard TRNSYS type 14 forcing function.
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Infiltration Model
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This component models the infiltration to a conditioned space as a function of the temperature difference between the ambient and conditioned
space and as a function of the wind speed. The correlation is based on a method published by the American Society of Heating, Refrigerating and Air
Conditioning Engineers.
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Parametric Table Results Printer
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This component prints the results of at the very end of a simulation to a specified data file. The results are appended to the data file such
that the results from a parametric table analysis can be quickly viewed and compared. A time and date stamp is also appended to each results so
that the user knows exactly when the results were generated and from which input file the results were generated.
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Sky Temperature Model
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This component models the temperature of the sky and is based on the Berdahl correlation. This model is used as input to any component that
calculates radiative losses to the environment.
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Average Day Creator
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This output-producing component creates "average-day" hourly profiles for each month of the year for two different inputs. This component is
most commonly used in applications where the comparison of two alternatives is desired. The output file is in a special format that allows it to be
easily imported into the TRNSYS spreadsheet program for immediate graphical analysis. A sample output file graphed in the TRNSYS spreadsheet
software is included at the end of this document.
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2-D Bin Sorter
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This new output-producing component sorts two unique inputs into a 2-dimensional output array. This component is used to answer questions like "How
many hours of the year is the ambient temperature between 80 and 90 F with a relative humidity greater than 50%?" . The output file is in a
special format that allows it to be easily imported into the TRNSYS spreadsheet program for immediate graphical analysis. A sample output file
graphed in the TRNSYS spreadsheet software is included at the end of this brochure.
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Ashrae Occupancy Loads
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The ASHRAE Handbook of Fundamentals lists typical latent and sensible loads for occupancy based on the activity level of the occupants. This
component takes, as parameters, the number of different people types and their associated activity level, and as inputs the number of people at
each of these activity levels. The outputs from this component are the latent and sensible loads for the building (totals and per
activity).
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Nested Forcing Function
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The nested forcing function eliminates the multiple TYPE 14 forcing functions and numerous equations needed to set the schedule for an input that
changes throughout the year. This forcing function allows the user to “tier” the forcing functions such that the schedule of the tertiary function
depends on the value of the secondary and primary forcing functions.
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Multi Dimensional Data Interpolation
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A generalized adaptation of Type42, this component can be used to model the performance of generic equipment or as a device to interpolate data in
up to a four dimensions.
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Life Cycle Cost Analysis
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One of the most common measures of engineering economics is the life cycle cost of a system and one method of calculating the life cycle cost is
referred to as the P1 P2 method. The idea of the method is that the life cycle cost of a purchase option or alternative is calculated based on two
economic indicators. The first (P1) is the ratio of the life cycle fuel cost to the first year fuel cost. A low value of P1 indicates that
immediate fuel costs are high and that consequently, potential immediate fuel savings are important. The second indicator (P2) is the ratio of
life cycle expenditures incurred as a result of the investment to the investment amount. A high value of P2 indicates that the investment has a low
first cost but higher costs over the life of the equipment. This component operates in one of two modes. It can either calculate P1 and P2 based on
a set of simple economic indicators, or it can accept values of P1 and P2 directly. In both modes, the component calculates the life cycle cost
for up to ten system alternatives. More alternatives may be added by modifying a single parameter in the Fortran code and recompiling. The model
then compares each alternative to a user designated comparison system.
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Out Of Set Point Watcher
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When operating in temperature level control, it is a fairly common occurrence for the temperature of a zone to exceed the cooling set point
temperature or to be below the heating set point temperature. Type584 watches temperature conditions, records and (if desired) prints information
on the time, duration and extent to which the set points were exceeded. While most often, this component is used in building applications, there
is nothing inherent to it about buildings. Type584 may equally well be used in other situations in which a watched variable (mass flow rate,
relative humidity, power, etc.) is intended to be maintained within an allowable range but may at times exceed that range.
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