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LATS Multi V Piping Design Software
The proper design and installation of the refrigerant piping system is
a critical element of the Multi V system. Multi V Water Mini requires
two pipes between system components – a liquid line and a vapor
line. A properly designed refrigerant piping system ensures that
refrigerant is delivered to the evaporator coil's electronic expan-
sion 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 lines.
Refrigerant Piping Quality Assurance
LG's LATS Multi V software makes designing the refrigerant system
easy. LATS Multi V is a Windows
engineer in the design of the refrigeration distribution pipe system, verifies the design complies with pipe design limitations, applies capac-
ity correction factors, and calculates the system refrigerant charge. The piping system can be entered manually into LATS from a one-line
pipe diagram. To ensure that the refrigerant piping design meets LG's quality standards, a LATS refrigerant piping design must be
provided with every Multi V Water Mini 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 limits may be converted into a conditional application by field changes to pipe equivalent
lengths. User should 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," which 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.
Note:
Any field changes, such as re-routing, 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 profitable installation, reduce the potential for rework, and will reduce the potential for multiple visits
to the job site to complete the system commissioning.
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 water source units. LATS does not de-rate indoor unit capacity for high altitude applications. Locally accepted
altitude correction factors must be applied to indoor unit capacities.
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 a VRF system. Therefore,
variable refrigerant flow systems have to be designed to 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 present, fitting installation orientation, and end use device
elevation differences.
Note:
It is imperative the designer avoids creating excessive pressure drop. When liquid refrigerant is subjected to excessive pressure drop, liquid
refrigerant will change state and "flash" to vapor. Vapor present in a stream of liquid refrigerant before reaching the electronic expansion
valve (EEV) results in a loss of system control and causes damage to the valve. The pipe system must be designed in a manner that avoids
the creation of unwanted vapor.
REFRIGERANT PIPING DESIGN
-based application that assists the
®
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 11: LATS Pipe System Design Tool in Tree Mode.
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