ASHRAE

Human Comfort. ASHRAE has extensively researched the effect of air conditioning on human comfort. The more practical results are summarized below reference 4 contains a complete discussion. 

Thermal comfort may be defined as "that condition of mind in which satisfaction is expressed with the thermal environment" (4). It is thus defined by a statistically vaUd sample of people under very specific and controlled conditions. No single environment is satisfactory for everybody, even if all wear identical clothing and perform the same activity. The comfort zone specified in ASHRAE Standard 55 (5) is based on 90% acceptance, or 10% dissatisfied. 

Eigure 3 shows the winter and summer comfort zones plotted on the coordinates of the ASHRAE psychrometric chart. These zones should provide acceptable conditions for room occupants wearing typical indoor clothing who are at or near sedentary activity. Eigure 3 appHes generally to altitudes from sea level to 2150 m and to the common case for indoor thermal environments where the temperature of the surfaces (/) approximately equals air temperature (/ and the air velocity is less than 0.25 m/s. A wide range of environmental appHcations is covered by ASHRAE Comfort Standard 55 (5). Offices, homes, schools, shops, theaters, and many other appHcations are covered by this specification. 

ASHRAE Standards, American Society of Heating, Refrigerating, and Air Conditioning Engineers, Inc., Publications Department, Atlanta, Ga. Standard 55, 1981. Standards are upgraded on a regular basis. 

D. G. Traver, in Fan Application - Testing and Selection Symposium Papers, San Francisco, Calif, Jan. 1970, ASHRAE, Atlanta, 1972. 

T. W. Rimmer and R. J. Anderson In-Duct Measurement of Centrfugal Fan Sound Power, ASHRAE, Sept. 1976. 

ASHRAE Handbook ofFundamentals, American Society of Heating Refrigerating, and Air-Conditioning Engineers, New York. 

Lower flammability limits (LFL) are expressed as vol % in dry ambient air. No entry means ASHRAE Safety Classification (2) (see Fig. 3). NR = not rated. 

Fig. 3. Refrigerant safety group classifications estabUshedby ANSI/ASHRAE 34-1992 (2). See text.

M. J. Kurylo, Proceedings ofHSHRAE 1989 CFC Technology Conference at the National Institute of Standards andTechnology, Gaithersburg Md, Sept. 27—28, 1989, ASHRAE Pubhcations Department, Atlanta, Ga., 1990, pp. 5—15. 

Most recent tabulations of ammonia properties are based upon the extensive tabulation to 5000 bar, 750 K of Haar, L. and J. S. Gallagher, y. Fhys. Chem. Ref Data, 7, 3 (1978) 635-792, which does, however, neglect dissociation. For tables to 70,000 psia, 920 F, see Stewart, R. B., R. T. Jacobsen, et al., Theimodynamic Fiopeiiies of Reft igei ants, ASHRAE, Atlanta, GA, 1986 (521 pp.). A chart in fps units corresponding witb these tables appears on page 17.34 of the ASHRAE 1989 Fundamentals Handbook. 

The 1993 ASHRAE Handbook—Fundamentals (SI ed.) gives material for integral degrees Celsius witb temperatures on the ITS 90 scale for saturation temperatures from —77.66 to 132.22 C. The same diagram reproduced here appears in that source. 

Saturation and superheat tables and a diagram to 300 bar, 580 K are given by Reynolds, W. C., Theimodynamic Propeities in S.I., Stanford Univ. pubL, 1979 (173 pp.). Saturation and superheat tables and a chart to 10,000 psia, 640 F appear in Stewart, R. B., R. T Jacobsen, et al., Theimodynamic Propeiiies of Refiigerants, ASHRAE, Atlanta, GA, 1986 (521 pp-)- For specific beat, thermal conductivity, and viscosity, see Theimophysical Propeiiies of Refiigerants, ASHRAE, 1993. The 1993 ASHRAE Handbook—Pundamentals (SI ed.) contains a thermodynamic diagram from 0.1 to 700 bar for temperatures to 600 K. 

Ruiter, J. P, Rev. Jnt. Fioid = Jnt. J. Refrig., 13 (1990) 223—236 gives subroutines for computer calculations. See also ASHRAE Handbook—Fundamentals. 

For specific heat, thermal conductivity, and viscosity, see Theimophysical Piopeities of Refiigeiants, ASHRAE, 1993. 

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