PAPER TRACES HISTORY OF NIST REFRIGERANTS PROGRAM.

A new paper traces the history of NIST's research on the thermophysical properties of refrigerants. In 1909, when the agency was only 8 years old, the American Society of Refrigeration Engineers (now the American Society of Heating, Refrigerating and Air-Conditioning Engineers) asked the then-National Bureau of Standards (NBS) to determine the properties of calcium chloride brines. Four years later, it asked NBS to do research on ammonia; the tables resulting from this work, published in 1923, remained the accepted properties for this important fluid until superseded by another NBS formulation in 1978.

Other early work of interest to the refrigeration industry included determination of the specific and latent heats of ice and properties of steam. Some of these early data for ammonia and steam, most notably the heat capacity and heat of vaporization data, still are considered to be among the very best available.

In the 1950s, some of this work transferred to the new NBS laboratory in Boulder, CO. Its early work addressed the needs of the space program for thermophysical properties of hydrogen, oxygen, and other fuels and oxidizers. Later, the program focused on simple hydrocarbons and their mixtures, and other fluids of industrial interest.

The current program began in 1981 as a collaboration between NBS Boulder and NBS Gaithersburg groups to provide properties for refrigerant mixtures being investigated for use in heat pumps. The program increased dramatically in scope 6 years later when chlorofluorocarbon refrigerants were implicated in destruction of stratospheric ozone. Because of its long-standing research in fluid properties, NIST was in a unique position to respond to the urgent international need for data on new refrigerants. NIST transfers this data to industry in a variety of ways, including a computer database known REFPROP.