HISTORICAL DEVELOPMENT

HISTORICAL DEVELOPMENT

The historical development of air conditioning can be summarized briefly.

Central Air Conditioning Systems

As part of a heating system using fans and coils, the first rudimentary ice system in the United

States, designed by McKin, Mead, and White, was installed in New York City’s Madison Square

Garden in 1880. The system delivered air at openings under the seats. In the 1890s, a leading consulting

engineer in New York City, Alfred R. Wolf, used ice at the outside air intake of the heating

and ventilating system in Carnegie Hall. Another central ice system in the 1890s was installed in

the Auditorium Hotel in Chicago by Buffalo Forge Company of Buffalo, New York. Early central

heating and ventilating systems used steam-engine-driven fans. The mixture of outdoor air and return

air was discharged into a chamber. In the top part of the chamber, pipe coils heat the mixture

with steam. In the bottom part is a bypass passage with damper to mix conditioned air and bypass

air according to the requirements.

Air conditioning was first systematically developed by Willis H. Carrier, who is recognized as

the father of air conditioning. In 1902, Carrier discovered the relationship between temperature and

humidity and how to control them. In 1904, he developed the air washer, a chamber installed with

several banks of water sprays for air humidification and cleaning. His method of temperature and

humidity regulation, achieved by controlling the dew point of supply air, is still used in many industrial

applications, such as lithographic printing plants and textile mills.

Perhaps the first air-conditioned office was the Larkin Administration Building, designed by

Frank L. Wright and completed in 1906. Ducts handled air that was drawn in and exhausted at roof

level. Wright specified a refrigeration plant which distributed 10°C cooling water to air-cooling

coils in air-handling systems.

The U.S. Capitol was air-conditioned by 1929. Conditioned air was supplied from overhead

diffusers to maintain a temperature of 75°F (23.9°C) and a relative humidity of 40 percent during

summer, and 80°F (26.7°C) and 50 percent during winter. The volume of supply air was controlled

by a pressure regulator to prevent cold drafts in the occupied zone.

Perhaps the first fully air conditioned office building was the Milan Building in San Antonio,

Texas, which was designed by George Willis in 1928. This air conditioning system consisted of one

centralized plant to serve the lower floors and many small units to serve the top office floors.

In 1937, Carrier developed the conduit induction system for multiroom buildings, in which recirculation

of space air is induced through a heating/cooling coil by a high-velocity discharging

airstream. This system supplies only a limited amount of outdoor air for the occupants.

The variable-air-volume (VAV) systems reduce the volume flow rate of supply air at reduced loads

instead of varying the supply air temperature as in constant-volume systems. These systems were introduced

in the early 1950s and gained wide acceptance after the energy crisis of 1973 as a result of

their lower energy consumption in comparison with constant-volume systems. With many variations,

VAV systems are in common use for new high-rise office buildings in the United States today.

Because of the rapid development of space technology after the 1960s, air conditioning systems

for clean rooms were developed into sophisticated arrangements with extremely effective air

filters. Central air conditioning systems always will provide a more precisely controlled, healthy,

and safe indoor environment for high-rise buildings, large commercial complexes, and precisionmanufacturing

areas.

Unitary Packaged Systems

The first room cooler developed by Frigidaire was installed about in 1928 or 1929, and the “Atmospheric

Cabinet” developed by the Carrier Engineering Company was first installed in May 1931.

The first self-contained room air conditioner was developed by General Electric in 1930. It was a

console-type unit with a hermetically sealed motor-compressor (an arrangement in which the motor

and compressor are encased together to reduce the leakage of refrigerant) and water-cooled condenser,

using sulfur dioxide as the refrigerant. Thirty of this type of room air conditioner, were built

and sold in 1931.

Early room air conditioners were rather bulky and heavy. They also required a drainage connection

for the municipal water used for condensing. During the postwar period the air-cooled model

was developed. It used outdoor air to absorb condensing heat, and the size and weight were greatly

reduced. Annual sales of room air conditioners have exceeded 100,000 units since 1950.

Self-contained unitary packages for commercial applications, initially called store coolers, were

introduced by the Airtemp Division of Chrysler Corporation in 1936. The early models had a refrigeration

capacity of 3 to 5 tons and used a water-cooled condenser. Air-cooled unitary packages

gained wide acceptance in the 1950s, and many were split systems incorporating an indoor air handler

and an outdoor condensing unit.

Packaged units have been developed since the 1950s, from indoor to rooftops, from constantvolume

to variable-air-volume, and from few to many functions. Currently, packaged units enjoy

better performance and efficiency with better control of capacity to match the space load. Computerized

direct digital control, one of the important reasons for this improvement, places unitary packaged

systems in a better position to compete with central hydronic systems.

Refrigeration Systems

In 1844, Dr. John Gorrie designed the first commercial reciprocating refrigerating machine in the

United States. The hermetically sealed motor-compressor was first developed by General Electric

Company for domestic refrigerators and sold in 1924.

Carrier invented the first open-type gear-driven factory-assembled, packaged centrifugal chiller

in 1922 in which the compressor was manufactured in Germany; and the hermetic centrifugal

chiller, with a hermetically sealed motor-compressor assembly, in 1934. The direct-driven hermetic

centrifugal chiller was introduced in 1938 by The Trane Company. Up to 1937, the capacity of centrifugal

chillers had increased to 700 tons.

During the 1930s, one of the outstanding developments in refrigeration was the discovery by

Midgely and Hene of the nontoxic, nonflammable, fluorinated hydrocarbon refrigerant family

called Freon in 1931. Refrigerant-11 and refrigerant-12, the chlorofluorocarbons (CFCs), became

widely adopted commercial products in reciprocating and centrifugal compressors. Now, new refrigerants

have been developed by chemical manufacturers such as DuPont to replace CFCs, so as

to prevent the depletion of the ozone layer.

The first aqueous-ammonia absorption refrigeration system was invented in 1815 in Europe. In

1940, Servel introduced a unit using water as refrigerant and lithium bromide as the absorbing solution.

The capacities of these units ranged from 15 to 35 tons (52 to 123 kW). Not until 1945 did

Carrier introduce the first large commercial lithium bromide absorption chillers. These units were

developed with 100 to 700 tons (352 to 2460 kW) of capacity, using low-pressure steam as the heat

source.

Positive-displacement screw compressors have been developed in the United States since the

1950s and scroll compressors since the 1970s because of their higher efficiency and smoother rotary

motion than reciprocating compressors. Now, the scroll compressors gradually replace the reciprocating

compressors in small and medium-size refrigeration systems. Another trend is the development of

more energy-efficient centrifugal and absorption chillers for energy conservation. The energy consumption

per ton of refrigeration of a new centrifugal chiller dropped from 0.80 kW/ton (4.4 COPref)

in the late 1970s to 0.50 kW/ton (7.0 COPref) in the 1990s. A series of rotary motion refrigeration