Mechanical engineers invented the technologies of efficient air conditioning and refrigeration. Today, these systems not only keep people safe and comfortable, but also preserve food and medical supplies in refrigeration systems. Like other infrastructures, we typically do not recognize the value of air conditioning until it is gone. In a record European heat wave during the summer of J003, for instance, over 10,000 people—many elderly—died in France as a direct result of the scaring temperatures. Mechanical engineers apply the principles of heat transfer and energy conversion to design refrigeration systems that preserve and store food at its source, during transportation, and in the home. We regularly purchase food that was grown thousands of miles away, perhaps even in a different country, with confidence that it is fresh.
Although mechanical refrigeration systems had been available as early as the 1880s, their application was limited to commercial breweries, meat-packing houses, ice-making plants, and the dairy industry. Those early refrigeration systems required significant amounts of maintenance, and they were also prone to leaking hazardous or flammable chemicals, rendering them inappropriate for use in a home. The development of the refrigerant Freon in 1930 was a major turning point for the commercialization of safe residential refrigeration and air conditioning. Since that time, the use of Freon largely has been supplanted by compounds that do not contain chlorofluorocarbons, which are now- known to degrade the Earth's protective ozone layer.The next technology is computer-aided engineering. The term "computer-aided engineering" (CAE) refers to a wide range of automation technologies in mechanical engineering, and it encompasses the use of computers for performing calculations, preparing technical drawings, simulating performance, and controlling machine tools in a factor.
Over the past several decades, computing and information technologies have changed the manner in which mechanical engineering is practiced. Most mechanical engineers have access to advanced computer-aided design and analysis software, information databases, and computer-controlled prototyping equipment. In some industries, these CAE technologies have replaced traditional paper-based design and analysts methods. In large multinational corporations, design teams and technical information are distributed around the world, and computer networks are used to design products 24 hours a day. As an example, the Boeing 777 was the first commercial airliner to be developed through a paperless computer-aided design process. The 777's design began in the early 1990s, and a new computer infrastructure had to be created specifically for the design engineers. Conventional paper-and-pencil drafting services were nearly eliminated. Computer-aided design, analysis, and manufacturing activities were integrated across some 200 design teams that were spread over 17 time zones. Because the plane had over 3 million individual components, making everything lit together was a remarkable challenge. Through the extensive usage of CAE tools, designers were able to check part-to-part fits in a virtual, simulated environment before any hardware was produced. By constructing and testing fewer physical mock-ups and prototypes, the aircraft was brought to market more quickly and more economically than would have otherwise been possible. Current CAE tools are being developed for diverse computing platforms including leveraging mobile devices, cloud computing technologies, and virtual machines.