Waste Heat: An Overview

For millions of years before human activity, the extent of heat radiated away from the earth remained largely unchanged, thus ensuring global climate patterns remained stable. Lately, the effects of anthropogenic climate change have become increasingly obvious in the form of increased incidence of forest fires, icecap melting, and hurricanes. The drastic increase in the levels of greenhouse gases (GHGs) in the atmosphere due to the Industrial Revolution has reduced the level of heat radiated away, thereby retaining more heat within the global climate system. In addition to the reduction of heat loss from the earth’s surface, there is another less-discussed contribution to global warming: waste heat. Waste heat is simply all primary energy expended by human activities that is not stored as other forms of energy, such as mechanical, chemical, gravitational, etc.