
SYSTEM ENGINEERING
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61
HEA
T PUMP
CONDENSING UNIT ENGINEERING MANUAL
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LATS MULTI V PIPE SYSTEM DESIGN TOOL
LATS Multi V
The proper design and installation of the refrigerant piping system
is a critical element of the Multi V system. Multi V Mini requires two
pipes between system components—a liquid line and a vapor line.
A properly designed refrigerant piping system ensures that refriger-
ant is delivered to the evaporator coil’s electronic expansion valve
(EEV) in a pure liquid state free of gas bubbles. A proper design
also ensures a sufficient refrigerant gas flow rate in the vapor line
that eliminates the possibility of refrigeration oil from collecting in the
vapor line. The piping system can be engineered manually using the
procedure outlined in the "Pipe Layout Procedure" on page 63;
however, the preferred method is to design the system using LG’s
LATS Multi V software.
LATS Multi V is a Windows-based application that assists the
engineer in the design of the refrigeration distribution pipe system,
verifies the design complies with most pipe design limitations, ap-
plies selected capacity correction factors, and calculates the system
refrigerant charge.
Adjusting LATS Multi V Output for Altitude
When a system is installed at elevations significantly above sea
level, the designer must also consider the impact air density has on
the capacity of the indoor and outdoor units. An altitude correction
factor must be manually applied to the indoor and outdoor unit data
provided in the LATS report or tree diagram. Refer to the "Select the
Outdoor Unit" procedure on page 52 for more information.
Design Choices
LATS Multi V is flexible, offering the HVAC system engineer a choice
of two design methods:
1. Using the CAD mode, the refrigerant pipe design and layout
work is performed concurrently. Simply import a copy of a plan
view drawing (.dwg format) for each floor of the structure into
LATS Multi V. Select and place system components on the floor
plan drawing(s), and draft interconnecting pipe between system
components and riser pipe segments between floors. Once the
layout is complete, use the export feature to create a file (.dxf for-
mat) that can subsequently be imported into the building design
drawings.
Note:
On multiple story buildings, all floor drawings must
have the same reference point relative to each other.
2. Using the TREE mode, the engineer can quickly create a one-line
schematic drawing of the Multi V system and create an export file
of the tree diagram in .dxf format. Integration of the engineered
pipe system layout into the building drawings is done at a later
date by the drafts person using standard drafting software tools.
In either case, LATS Multi V generates a report file (.xls format)
containing project design parameters, cooling and heating design
day system component performance, and capacity data. The report
calculates the system CR, calculates the system refrigerant charge,
and provides detailed bill of material information including a list of
Multi V outdoor units, indoor units, control devices, accessories,
and refrigerant pipe sizes segregated by building, by system, by
pipe size, and by pipe segments.
CAD mode
• Imports the building’s architectural CAD drawing (.dwg format)
• Imports building loads from an external file (.xls format)
• Lays out refrigerant piping directly onto an overlay of the building
drawing
• Assigns room loads to indoor units
• Automatically calculates pipe segment lengths based on drawing
layout
• Creates an export image file for import to the building drawing set
(.dxf format)
• Generates a system engineering report (.xls format)
Tree mode
• Imports building loads from an external file (.xls format)
• Selects system component using an easy drag and drop process
• Automatically analyzes and checks the design complies with
most piping design limitations
• Assigns room loads to indoor units
• Sizes refrigerant piping
• Generates a system engineering report (.xls format)
• Generates a picture of the piping tree diagram (.dxf format)
Figure 33: Screenshot of LATS Pipe System Design Tool Displaying
a Tree Mode Piping Diagram
Содержание Multi V mini
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