April 7, 2010

In quest to harness energy, we must consider the environment more than ever, says professor

From the first controlled use of fire in the Early Stone Age to the invention of the steam engine in 1769, humans have often had little regard for their environmental footprint in their quest to harness and efficiently use energy, said mechanical engineer K. Max Zhang at a seminar April 1 to launch this month's celebration of the second annual Cornell Sustainability Month.

An assistant professor in Cornell's Sibley School of Mechanical and Aerospace Engineering, Zhang told the audience of primarily engineering students in Olin Hall how important it is that engineers, consumers and governments consider the environmental impacts of the sources of energy they use. While in the past, he said, the selection of energy sources was primarily affected by the free market, "the free market without regulation does not always help the public good."

He said that while energy and the environment are both essential to sustainable development, environmental constraints don't have to stifle energy innovations. "In fact, history has shown the opposite to be true," he said.

He explained, however, how innovations in energy development can often negatively impact the environment, using the example of chlorofluorocarbons (CFCs) as refrigerants, aerosol propellants in the mid 1900s and the subsequent depletion of the ozone layer.

However, within three years of the publication of a major study attributing the degradation of the ozone layer to CFCs in 1974, the S.C. Johnson corporation initiated a voluntary phase-out of CFCs in aerosol products. The following year, the U.S. government banned CFCs in all aerosol products. But such swift action is not always the case -- it took the government more than 50 years to address the environmental and health consequences of contamination of roadsides with lead from leaded gasoline; the eventual removal of lead from gasoline was motivated by engineering, not environmental protection, he said.

Zhang also pointed out that many Cornell mechanical engineering alumni have played prominent roles in energy development throughout history. Willis Carrier, Class of 1901, for example, invented the modern air conditioner by adding control of temperature and relative humidity. Thirty years later, Thomas Midgley Jr., Class of 1911, discovered that CFCs were a better alternative to the toxic and flammable sulfur dioxide and methyl chloride-based refrigerants in air conditioning systems.

Zhang's seminar, "Energy and the Environment: What Have We Learned from Recent History?" was part of the Energy Engineering seminar series, which will be held every Thursday in April.

Graduate student Kate Neafsey is a writer intern for the Cornell Chronicle.