The Scroll Compressor A Case Study in Reverse Engineering and Industrial Competitive Assessment Prof. Anthony Marchese Mechanical Engineering

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.

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 America’s “Sun Belt” to air conditioning.

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.

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.

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.

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!

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).

Scroll Compressors (Circa 1988) Reverse Engineering Scroll Compressors (Circa 1988) Hitachi Mitsubishi Copeland

First Generation Carrier Scroll Compressor (Circa 1990) 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.

First Generation Carrier Scroll Compressor (Circa 1990) 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 competitor’s 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 competitor’s product lines.

Competitive Assessment Activities 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 competitor’s compressors, was called Competitive Assessment. In addition to competitor’s 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.

Reverse Engineering Scroll Compressor 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.

Reverse Engineering Epilogue Scroll Compressor 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.