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Specification of Thermal Behavior of CRAC Units
TileFlow 4.0 allows you to specify the thermal behavior of CRAC units, which
determines how the supply air temperature of a CRAC unit is calculated. The available options are:
- The supply temperature is set equal to a common “cooling air temperature.” (This practice was used in TileFlow 3.7 and earlier versions.)
- The supply temperature for each CRAC unit is specified by the user. This allows you to simulate CRAC unit control systems that maintain a
set supply temperature. Also, if you have measured values of the supply temperature for the CRAC units, you can enter them in this option.
- The supply temperature depends on the return temperature (according to the thermal characteristics of the CRAC unit). This option can be
used with or without thermostatic control, for which you can specify the set-point temperature for the return air. If the conditions are such that the return temperature is higher than the set-point
temperature, TileFlow will calculate the supply temperature using the thermal characteristics. Otherwise, TileFlow will automatically adjust the supply temperature that will lead to the specified set-point
temperature as the return temperature.
The above options are available in the dialog for CRAC unit properties. The Edit CRAC Style dialog has been modified to specify
the thermal characteristics.
Cooling Produced by CRAC Units
With the above treatment, the cooling produced by each CRAC unit will reflect the supply and return temperatures (as possibly affected by the
thermostatic control). The amount of cooling produced is reported by the Inspect Tool. Also, “AF Results at a Glance” provides a button “CRAC Cooling Behavior”; it activates a table that gives the return and
supply temperatures for each CRAC unit and the corresponding cooling produced.
Calculation of Temperatures Under the Raised Floor
The supply temperature of a CRAC unit is dictated by its thermal behavior,
and for a general situation, there will be a variation of temperature under the raised floor. TileFlow 4.0 calculates this temperature variation, which is then used in the calculation of temperatures above the
raised floor.
Display of Under-Floor Temperature Field
There is now a new command to display the under-floor temperature field. This
is normally plotted using the same color scale as the one used for the above-floor temperatures. However, a check box on the color-scale dialog allows you to stretch the scale from the minimum to maximum
temperature in the under-floor region only. This produces a more colorful plot. A temperature gage is provided for reading the local temperature and horizontal velocity.
The under-floor temperature field can also be used to visualize the “zone of influence” of each CRAC unit. If different CRAC
units have different supply temperatures, the plot clearly shows the region over which the influence of a CRAC unit extends.
For each perforated tile, the Inspect Tool now shows the temperature of the air emerging from it.
Metric Units
You can now choose either English units or Metric units for displaying the input and output quantities. Under English units, distances are shown in feet or
inches, flow rates in CFM (cubic feet per minute), pressures in inches of water, and temperatures in degrees Fahrenheit. Under the Metric units, the corresponding units are meters/millimeters, CMH (cubic
meters per hour) or liters per second, Pascals, and degrees Celsius, respectively.
You can switch between the English and Metric units by using the Use English Units and Use Metric Units commands from the Edit
menu. For each document, the current choice of units is stored and it can be changed at anytime.
In addition, the units used in the databases (for CRAC units, perforated tiles, and server racks) can be specified (and changed)
independently.
Specification of Tile Size
You can now specify the tile size (side dimension). (The tile must still be square.) For your convenience, tile sizes of 2 ft and 600 mm are
readily made available. Also, a list of other commonly used sizes is provided. Finally, there is a Custom option, in which you can specify any tile size.
To get a desired tile size, use the command: File > New With Tile Size choice. You can select a tile size while creating a new
document. It cannot be changed later on.
Convert Commands
Two convert commands have been provided for converting layouts with tile size of 2 ft to those with tile size of 600 mm and vice versa. These will
be especially useful for the users outside the USA, who have used earlier versions of TileFlow (with 2-ft tile size) for actual layouts of 600-mm tiles. These commands would normally lead to adjustment of the
floor size. You must carefully examine the converted layout.
Specification of CoolBlue Parameters
You can now specify the water flow rate and inlet temperature for the CoolBlue rear-door heat exchanger. These parameters can be varied
from rack to rack. For a rack with a CoolBlue heat exchanger, the Inspect Tool now shows the cooling produced by CoolBlue and the AF Results at a Glance dialog reports the total cooling produced by all
CoolBlue heat exchangers.
Display of Rack Heat Load Distribution
You can now paint the tops of racks and hot boxes according to the their heat load. You can use an overall color scale going from 0–20 kW
or stretch the color scale between the minimum and maximum heat loads in your layout.
Customization of Temperature Range for Color Scale
In earlier versions of TileFlow, the default color scale for temperature used
the cooling-air temperature (specified in Floor Design > Operating Conditions) as the minimum temperature. The maximum temperature was 40 F higher than the minimum temperature. A separate command was
provided to use 55 F as the minimum temperature and 95 F as the maximum.
In TileFlow 4.0, the default color scale for temperature uses 55 F (12.8 C) as the minimum temperature and 95 F (35 C) as the
maximum. A new command (Specify Tmin and Tmax for Color Scale), under Preferences menu, allows you to specify the values of minimum and maximum temperatures for the color scale. Once these values are set, they
will affect all subsequent displays until the next re-setting of these values.
The ability to set the temperature range can be used to create Tmin and Tmax values that are specific to a given simulation or to
provide a common basis for displaying the results of many simulations.
Calculation of Heat Load Density
The Object dialog box (Floor Design menu) now reports the heat load density for the data center. This parameter is reported as W/sq ft
for English units and as W/sq m for Metric units.
Fit to Window Command
The Fit to Window command from the View menu allows you resize the view in the currently active window so that it fits the data center in the
available space in the window.
Velocimeter
Temperature billboards in TileFlow display the temperature and velocity arrows on a chosen plane. You can use the thermometer to read a local value of
temperature. Now a velocimeter has been added. It gives you the magnitudes of three velocity components and the total velocity component at a given point on a billboard.
Folder Tree Structure for Databases
A folder tree structure has been implemented to facilitate the management of the database styles. The built-in styles are arranged in
folders. You can create new folders and arrange them using Move Up and Move Down commands. New styles can be placed in the existing folder or in new folders, and can be moved from one folder to another. Within
a folder, the user-defined styles can be arranged in any desired manner, by using the Move Up/Down commands. The list of styles (within a given folder) can be sorted according to its sequence number, name, or
date modified.
Tab Dialogs for Styles
The dialogs for editing styles have been converted to tab dialogs. The information required for the definition of a style has been split into
subsections, and individual tabs have been devoted to each of these subsections.
Expanded Databases
The database of CRAC styles has been expanded to include the models from Liebert Hiross and Compu-Aire. The database of perforated tile styles
contains many new cutouts and missing tiles of different sizes. The database of server rack styles has been expanded to include new configurable racks and racks from Chatsworth Products Inc.
Import of Server Rack Data from Text File
A new command has been added to import the server rack data from a text file.
The text file contains complete information about the server rack dimensions, heat load, and position on the floor. It can be created manually or by writing scripts for database (inventory management) programs
like Aperture Vista.
When this command is given, the initial floor size can be arbitrary, and there may or may not be any server racks present. The
command will resize the floor if necessary and place the entire set of racks on the floor with a single click of the mouse.
If the imported racks overlap with any existing racks, an informative message will be given.
Click here to see the new features introduced in Version 3.7.
Click here to see the new features introduced in Version 3.5.
Click here to see the new features introduced in Version 3.2.
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