Specifications

30 Catalog WSC/WDC-4

• True System Efficiency (KW/ton or COP); deals with the total annual power consumption of a

chiller system including auxiliaries such as pumps, purge units, Pre-Vac heaters and fans-of

great importance in determining facility energy cost and power plant CO

emissions.

• Toxicity and Flammability Rating

; per 1997 ASHRAE Fundamentals Handbook

• R-134a  A-1 R-123  B-1

Where A=Toxicity not identified

B=Evidence of toxicity identified

1=No flame propagation in air at 65°F, 50% rh and one atmosphere pressure

A certain future for R-134a:

The Clean Air Act of November 1990 allows the EPA to accelerate the phase-out schedule of

Class I (CFC) and Class II (HCFC) refrigerants if it deems it necessary. This leaves the future

of HCFCs (which includes R-22 and R-123) uncertain. R-134a will not be regulated or

phased out by the Clean Air Act or the Montreal Protocol. The commercial air conditioning,

home appliance, and automotive industries are just a few of the many markets that are using

R-134a now and for years into the future. This large market demand for R-134a translates to a

readily available and competitively priced product.

Compact Design

Small Footprint Cuts Installation Costs

At comparable cooling capacities, R-134a requires less than 3.2 cfm (1.5 l/sec) per ton of

refrigeration to be circulated by the compressor. R-123 requires over 18.0 cfm (8.5 l/sec) per ton.

The substantial increase in refrigerant volume requires significantly larger suction piping and

compressor components in negative pressure designs to maintain reasonable gas velocity, noise

levels and refrigerant pressure losses. Conversely, the small physical size of McQuay centrifugal

chillers will:

• Permit design of smaller equipment rooms.

• Cost less to rig and install.

• Lower joint surface area for lower likelihood of leaks.

• In smaller capacities, allow transit through standard equipment room doors, permitting

building construction to proceed on schedule before receipt of the chiller equipment.

Heat Exchangers

McQuay packaged centrifugal chillers are equipped with new high performance heat exchangers.

The unique design greatly increases heat transfer and reduces unit footprint and refrigerant charge

compared to previous designs. In many cases vessel length has been reduced by 40 percent.

Chillers are designed, constructed and tested in accordance with ASME Section VIII, ASHRAE

Standard 15 requirements and TEMA recommendations.

The replaceable water tubes are internally rifled and externally enhanced copper and are

mechanically bonded to steel tube sheets. Standard tubes are 0.025-inch wall thickness. Optional

tubes include 0.028 inch and 0.035-inch wall thickness on either vessels and 90/10 cupro-nickel,

304 stainless steel or titanium material. Clad tube sheets and epoxy-coated heads can be provided.

Vessels are available for 1, 2 or 3-pass water flow. A ¾-inch or 1½-inch thick, flexible foam

evaporator insulation is a factory installed optional. With either of these options, all seams are

glued to form an effective vapor barrier and the entire chiller barrel, including non-connection

heads and tube sheets, are insulated. Detailed information on the insulation can be found in the

“Physical Data” section of this catalog.