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LATS Multi V Refrigerant Piping Design Software
Note:
LG Electronics U.S.A.,Inc., is not responsible for any piping calculations, refrigerant leaks, degradation of performance, or any other potential
problems or damages as a result of interconnecting piping, their joint connections, isolation valves, introduced debris inside the piping system, or
other problems caused by the interconnecting piping system.
Proper design and installation of the refrigerant piping
system is a critical element of the Multi V Water IV
system. A heat pump water source unit installation
requires two pipes (liquid line and vapor line) between
system components. A heat recovery water source
unit installation requires three pipes (liquid, low-
pressure vapor, and high-pressure vapor) between
system components A properly designed refrigerant
piping system ensures that refrigerant 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(s) that eliminates the possibility
of refrigeration oil collecting in the vapor line(s).
Piping Quality Assurance
LG Air Conditioning Technical Solution (LATS) Multi
V software makes designing the refrigerant system
easy. LATS Multi V is a Microsoft Windows
application that assists the engineer in refrigeration
distribution pipe system design, verifies the design complies with pipe design limitations, applies capacity correction factors, and calculates the
system refrigerant charge. The piping system design can be entered manually into LATS from a one-line pipe diagram. To ensure that the refrig-
erant piping design meets LG's quality standards, a LATS refrigerant piping design must be provided with every Multi V Water Source
Unit order. Following the installation, if any changes or variations to the design were necessary, a new "as-built" LATS piping design
software report must be created and provided to LG prior to system commissioning.
Systems that are close to the standard application piping limits may be converted into a conditional piping application by field changes to
pipe equivalent lengths. Always check the LATS report actual pipe layout versus pipe limits. The user may want to increase pipe lengths
when design conditions are approaching the Standard Application Piping Rule limits to force the LATS program to engineer the system using
the Conditional Application Pipe Rules. This will increase the diameter of the main and a few branch segments to minimize the possibility of
required pipe changes due to field installation variations.
Adjusting LATS Multi V Output for Altitude
When a system is installed at elevations significantly above sea level, consider the impact air density has on the capacity of the indoor and
water source units. LATS does not de-rate indoor unit capacity for high altitude applications. Be sure to apply locally accepted altitude
correction factors to calculate actual indoor unit capacities at that altitude.
Any field changes such as re-routing piping, shortening or lengthening a pipe segment, adding or eliminating elbows and/or fittings, re-sizing,
adding, or eliminating indoor units, changing the mounting height or moving the location of a device or fitting during installation should be done with
caution and ALWAYS VERIFIED in LATS MULTI V SOFTWARE BEFORE supplies are purchased or installed. Doing so may lead to a more profit-
able installation, reduce the potential for rework, and reduce the potential for multiple visits to the job site to complete system commissioning.
Creating a Balanced Piping System
Unlike designing duct-work or chilled and hot water pipe systems where balancing dampers, ball valves, orifices, circuit setters, or other flow
control devices can be installed to modify or balance the flow of cooling medium, these cannot be used in VRF systems. Therefore, VRF
system designs must be "self balanced." Balanced liquid refrigerant distribution is solely dependent on the designer choosing the correct
pipe size for each segment. Pipe sizing considerations include pipe length, pipe segment pressure drop relative to other pipe segments in
the system, type and quantity of elbows, bends, fitting installation orientation, and end use device elevation differences.
It is imperative to avoid creating excessive pressure drop. When liquid refrigerant is subjected to excessive pressure drop, liquid refrigerant will
change state and "flash" to vapor. The pipe system must be designed and installed in a manner that avoids the creation of unwanted vapor.
REFRIGERANT PIPING INSTALLATION
-based
®
Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
Computer-assisted Refrigerant Pipe Design
Figure 19: LATS Pipe System Design Tool in Tree Mode.
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