Prof. Anthony Marchese

1
The Scroll Compressor
A Case Study in Reverse Engineering and
Industrial Competitive Assessment
Rowan University Freshman Engineering Clinic
II January 27, 2003
Prof. Anthony Marchese Mechanical Engineering
2
History
In 1902, Willis Carrier invented the air
conditioner to control the heat and humidity for
a printing process in Brooklyn, NY printing
company. After designing similar systems for a
series of manufacturers, Carrier raised 32,600
to form Carrier Engineering Company in 1915.
In 1924, Carrier built the first comfort
cooling system for J.L. Hudson Department Store
in Detroit, MI.
By 1930, comfort cooling systems were installed
in 300 movie theaters nation wide.
3
History
In 1928, Carrier developed the first residential
air conditioning system, but the Great Depression
and WW II put home air conditioning on hold for
about 20 years.
In 1955, William Levitt predicted that air
conditioning would be a basic feature in all new
homes. In 1985, 70 of all new homes had air
conditioning.
Sociologists credit the dramatic growth of
Americas Sun Belt to air conditioning.
4
Vapor Compression Refrigeration
The majority of refrigeration and air
conditioning systems in place today employ the
simple vapor compression refrigeration cycle.
These systems include a compressor, a condenser,
an expansion valve and an evaporator.
5
The Refrigeration Compressor
Like the engine of an automobile, the compressor
is the heart of he refrigeration system. It is
the most complicated and costly component and is
responsible for over 90 of the power consumption.
In the 1980s, the old standard reciprocating
(piston) compressors were being phased out by
efficient, quiet, and reliable new compressors
such as the rotary, scroll and screw
compressor. Although these new compressors were
required for the bulk of their residential
products, Carrier somehow found themselves
without the ability to manufacture these
compressors this is like a GM or Ford without
the ability to manufacture engines.
6
The Rotary Compressor
In the mid 1980s, Carrier embarked on a program
to gain back their ability to manufacture their
own compressors. In most typically sized room
air conditioners (5,000 to 15,000 BTU/hr) the
rotary compressor is used.They decided to design
their own rotary compressor by reverse
engineering.
7
Rotary Compressor
The plan was a complete success. Using the mid
80s fleet of rotary compressors as a guideline, a
small group of Carrier engineers designed and
developed a new rotary compressor. The Carrier
rotary compressor was the most efficient
compressor on the market!
8
The Scroll Compressor
In the late 1980s, given the success of the
rotary compressor project, Carrier engineers
embarked on a similar project to reverse engineer
the scroll compressor. Scroll compressors were
quickly gaining the market share in typical
residential central air conditioning applications
(25,000 to 40,000 BTU/hr).
9
Scroll Compressor Reverse Engineering
Scroll Compressors (Circa 1988)
Hitachi
Mitsubishi
Copeland
10
Scroll Compressor Reverse Engineering
First Generation Carrier Scroll Compressor (Circa
1990)
Although the same approach was used in reverse
engineering the scroll compressor...
after 3 years, and untold spent, the Carrier
scroll compressor was noisy, in-efficient and
unreliable.
11
Scroll Compressor Reverse Engineering
First Generation Carrier Scroll Compressor (Circa
1990)
What went wrong?
The scroll compressor is a much more complicated
device than the rotary compressor. Reverse
engineering is more than just taking apart
competitors products and re-designing based on
appearance, materials and manufacturing
processes. To develop a viable new design using
existing products as a guideline, engineers must
understand why these products are designed the
way they are. In other words, as engineers, we
need to know, not only the what and the how of
the design, but also the why of the design. One
way to understand the why of design is through
detailed testing of competitors product lines.
12
Scroll Compressor Reverse Engineering
Competitive Assessment Activities
To perform the required testing, Carrier
contracted UTRC, the central research
organization of their parent company, United
Technologies Corporation.
The project, which entailed acquiring,
dissecting, evaluating, instrumenting, and
testing competitors compressors, was called
Competitive Assessment. In addition to
competitors products, Carrier products were
tested under the same controlled operating
conditions.
Above, a Carrier Scroll Compressor is shown
instrumented with 4 eddy current proximity
probes, 11 pressure transducers, 6 heat flux
gages, 37 thermocouples and an acoustic emission
sensor.
13
Scroll Compressor Reverse Engineering
Ethical Implications
The competitive assessment activities resulted in
some ethical issues for management and engineers.
Carrier was under contract to purchase hundreds
of thousands of scroll compressors per year from
Copeland Corporation.
Acquiring larger compressors, like the 170,000
BTU/hr compressor manufactured by Trane proved to
be difficult.
14
Scroll Compressor Reverse Engineering
Epilogue
As a consequence of these activities, the Carrier
Scroll compressor was completely re-designed. In
1993, Carrier entered an agreement with Bristol
Compressor Co. to form a joint venture called
Scroll Technologies in Arkadelphia, Arkansas.
Scroll Tech manufactures hundreds of thousands of
scroll compressors per year. They are still not
as quiet or efficient as Copeland.