NPFC - OO-A-374
AIR CONDITIONERS WITH REMOTE CONDENSING UNITS OR REMOTE AIR-COOLED, AND WATER-COOLED CONDENSER UNITS, UNITARY
|Publication Date:||28 March 1995|
This specification covers factory-made air conditioners with remote condensing units or condensers. The separate assemblies should be designed to be used together with matched assemblies of the same manufacturer, and be rated and tested in accordance with Air-conditioning and Refrigeration Institute (ARI) Standards. When required, provisions for heating and humidification may be supplied.
This specification covers split-systems air conditioners designed for a large office space or space consisting of several rooms. A general guide to selection of types and classes are as... View More
This specification covers split-systems air conditioners designed for a large office space or space consisting of several rooms. A general guide to selection of types and classes are as follows.
Types I and III air conditioners are generally specified where condenser cooling water and drain facilities are not available.
Type II air conditioners can be used only in areas where there is a cooling tower or readily available water supply and drain facilities.
Type IV air conditioners can be used only in areas where cooling water and drain facilities are available. Generally they are used in lieu of Type II units in localities where water is in short supply and is restricted for cooling purposes. Type IV air conditioners are not readily available, as Type I or II units.
Type V air conditioners are generally specified for use with residential furnaces and must be matched with furnace. The make, model, air flow data (volume and static pressure), size of opening of plenum, whether upflow (style C) or down flow (style D) is required, and manufacturer should be specified.
Style A evaporator-blower unit should be specified where the conditioned air can be discharged directly into the conditioned space. To accomplish this, the air conditioner should be located either within the conditioned space or adjacent to the space.
Style B evaporator-blower unit should be specified where duct work is necessary to supply the cooled air to the conditioned space. The unit is usually located outside the conditioned space and duct work is required to deliver the cooled air to the conditioned space, or where the unit is located in a conditioned space and connected to other spaces by duct work.
Class 1 air conditioners should be specified when heating of the space to be conditioned is required. Where hot water, gas, electricity or light fuel oil is available for heating, the appropriate type of heating coil or heat exchanger should be specified. For steam and hot water coils, the following information should be supplied:
a. Velocity of air across coil face, ft/min (m/min) - standard air
b. Entering air dry-bulb temperature, °F (°C)
c. Water velocity range, ft/min (m/min) - hot water coil
d. Entering water temperature, °F (°C) - hot water coil
e. Steam pressure at coil inlet, psi (kPa) - steam coil
f. Maximum superheat in steam at coil inlet; °F (°C) - steam coil
Class 2 air conditioners should be specified when no heating is required.
Many applications of unitary air conditioners require ratings under conditions other than standard rating conditions of ARI 360 (see 3.6.5 and 6.10.e). The following information should be supplied by the procuring authority to the contractor as indicated by the "X" in the applicable blocks.
Indoor air conditioner components made of ferrous metals located in coastal areas should withstand 125 hours at 100 percent relative humidity per ASTM D 2247. Out door components made of ferrous and nonferrous metals located in coastal areas should withstand 125 hours and in severe coastal areas 500 hours of salt spray per ASTM B 117 (see 3.14.1 and 3.14.2). In coastal areas, condenser should be made of copper tube and copper fins and insulated for protection against galvanic corrosion from ferrous metal parts. For units 65,000 Btu/h (19,050 W) or less, condenser may be made of aluminum tubes and aluminum fins, and coated to resist corrosion, providing units pass the reference standards tests.
Filter-driers are furnished with remote condensing units less than 65,000 Btu/h (19,050 W), and are sized for 25 feet (7.62 m) of interconnecting tubing (see 3.10.9). On remote condensing units 65,000 Btu/h (19,050 W) and over, the drier should be furnished as a separate item, size of which should be determined by the piping and installation of the unit on location, and should be field installed by the contractor.
For all single phase, 230 volt air conditioning units 65,000 Btu/h (19,050 W) or less, the SEER applies and the minimum SEER should be 8.0 (see 3.13.3). Other air conditioning units should conform to the Energy Policy Act of 1992 (EPACT), as listed in the following:
Unitary Air-Conditioners and Heat Pumps
< 65,000 Btu/h (19,050 W), 3 phase, Split System
10.00 SEER & 6.8 HSPF
≥ 65,000 Btu/h (19,050 W), and ≤ 135,000 Btu/h (39,564 W)
8.9 EER & 3.0 COP (47°F)
Water-Cooled and Evaporatively-Cooled