CoGeneration

For the past decade Harbec Plastics, Inc. in Ontario, NY, has been researching and developing a plan that would help the company become more efficient and more ecologically correct. One part of the solution the company has adopted is called cogeneration, a highly efficient means of generating heat and electric power simultaneously from the same energy source. In other words, the exhaust heat from generating electricity replaces fossil fuel (oil, coal, or natural gas) combustion. This is heat that would normally be discharged into lakes and rivers or the atmosphere in the current process of traditional utility power generation. Also referred to as combined heat and power (CHP), Cogen offers the potential to reach efficiencies that triple, or even quadruple, conventional power generation. Although it has been a possibility for nearly a century, in the mid-1980's relatively low natural gas prices made it a widely attractive alternative for new power generation. To understand cogeneration, it is necessary to know that most conventional power generation is based on burning a fuel to produce steam. It is the pressure of the steam that actually turns the turbines and generates power, in an inherently inefficient process. Cogeneration, in contrast, makes use of the excess heat, usually in the form of relatively low-temperature steam exhausted from the power generation turbines. Such steam is suitable for a wide range of heating applications and effectively displaces the combustion of carbon-based fuels, with all their negative environmental implications. The heat potential can also be used to air condition with the help of absorptive chiller technology. The environmental implications of cogeneration stem not just from its inherent efficiency, but also from its decentralized character. Because it is impractical to transport heat over any distance, cogeneration equipment must be located physically close to its heat user. A number of environmentally positive consequences flow from this fact. Power tends to be generated close to the power consumer, significantly reducing transmission losses, stray current, and the need for distribution equipment. In recent years new methods of using this Cogen/CHP potential have been developing. HARBEC Plastics' application uses Compressed Natural Gas (CNG) to run Capstone micro turbine generators, which produce electricity used to operate their molding company. The hot exhaust from these micro turbines is directed to a heat exchanger, which is able to transfer the heat to water. The hot water is then used to heat the building through radiant in-floor heating systems and through pre-existing forced air systems. During the summer, the hot water is sent to an absorptive chiller, which uses heat to create cold water for air-conditioning.