Emerson MINI-MATE2 user manual 3.5Free-Cooling

Optional Factory-Installed Features - Evaporator/Chilled Water Units

3.5Free-Cooling

Free-cooling option includes separate cooling coil, three-way slow-close valve and separate supply and return piping. Free-cooling is activated when the water temperature reaches a field-adjustable temperature, typically 45°F (7°C). The valve is rated for 300psi (2068kPa) working pressure.

Air-cooled condensing units can be matched with evaporators using free-cooling coils with chilled water sources to serve as backup cooling. When matched with a water/glycol condensing unit, a three-way water regulating valve is recommended for the condensing unit to simplify piping to the main supply pipes. The coil is designed for closed-loop applications using properly treated and circulated fluid. Not available with SCR reheat options.

Figure 7 Free-cooling arrangement

Free-cooling option: A second cooling coil allows the system to take advantage of colder outdoor temperatures and bypass compressor operation.

When the water temperature goes below 45°F (7°C), cooling switches over to free-cooling operation. A separate chilled water source can also be used with air-cooled systems.

Drycooler

Liebert Mini-Mate2

Free -

Cooling

Coil

Water Temperature

Sensor

Water/Glycol

Condenser

Field Piping

NOTE

If free-cooling is applied to an open water tower, an optional copper-nickel (CuNi) coil is required to prevent premature corrosion, or a heat exchanger must separate the tower water from the free-cooling loop. The copper-nickel coil requires an extended lead time.

3.6Optional Configurations—Prop Fan Condensing Units

Outdoor Prop Fan Condensing Units are also available in the following optional configurations:

•High ambient, top discharge models for catalog capacities at ambient temperatures up to 105°F (40°C).

•Quiet-Line models for low noise level conditions (below 56 dBA) and catalog capacities for ambient temperatures up to 95°F (35°C).

•Condenser coil(s) can be phenolic-coated for extended coil life in coastal areas.

3.7Optional Configurations—Water/Glycol Condensing Units

Indoor Water/Glycol Condensing Units are also available with the following piping options:

•Two-way water reg. valve with 350 psi (2413kPa) design pressure.

•Three-way water reg. valve with 150psi (1034kPa) design pressure.

•Three-way water reg. valve with 350psi (2413kPa) design pressure.

Liebert® Mini-Mate2™ 10