Cogeneration

A method of conserving energy by establishing one day cycles of thermal storage in operation of a cogeneration plant at a site wherein electricity is locally generated for supplementing the power generated in a central station electric service and rejected heat is productively locally used at the site to satisfy a modified design day thermal load at the site comprising the steps of supplying combustible fuel, providing a heat activated electric power generating means, connecting the generating means to the electric power distribution grid of the central station electric service, burning the combustible fuel to operate the electric generating means, providing a heat storage unit in thermal communication with the heat activated electric generating means and with the thermal load, the heat storage capacity of the storage unit being generally limited in size to that of the modified design day thermal load at the site, the electric power generating means being sized to reject a quantity of heat generally equal to the modified design day thermal load at the site during a regular daily period of operation, and normally assigning priority of operation of the generating means to the condition where the expected following 24-hour heat demand is greater than the quantity of heat contained in the heat storage unit and operating the generating means ordinarily exclusively during the peak rate period of the central station electric service.

A cogeneration plant at a local site operating under the priority of supplying substantially all of a modified design day thermal load requirement at such site, the plant including a source of oxidizable fuel, electric power generating means for oxidizing the fuel to produce electrical power and a substantial quantity of rejected heat, means interconnecting the electrical power generating means to an electrical utility grid, the utility grid experiencing a load that regularly varies significantly in magnitude throughout a 24-hour period and is characterized by a peak demand period which is substantially less than 24 hours, a heat storage unit having a capacity sized in accordance with the modified design day thermal load requirement, first means thermally connecting the electric power generating means to the heat storage unit for conducting heat energy rejected by the electric power generating means to the storage unit, second means thermally connecting the heat storage unit to the thermal load, control means for energization of the electric power generating means ordinarily exclusively during the peak rate period of the utility, and sensing means monitoring the heat value stored in the storage unit and arranged to normally override said control means when said storage unit contains a desired capacity of heat to discontinue operation of said generating means, said sensing means and control means being mutually arranged to normally assign priority of operation of said electric power generating means ordinarily exclusively to the condition where, during the peak demand period, the expected following 24-hour modified design day thermal load requirement is greater than the quantity of heat contained in the heat storage unit.

A method of conserving energy by establishing one day cycles of thermal storage operation of a cogeneration plant at a site wherein electricity is locally generated for supplementing the power generated in a central station electric service and rejected heat is productively locally used at the site to satisfy a modified design day thermal load at the site comprising the steps of supplying oxidizable fuel, providing electric power generating means that operates in a manner which produces substantial rejected heat, connecting the generating means to the electric power distribution grid of the central station electric service, oxidizing the fuel to operate the electric generating means, providing a heat storage unit in thermal communication with the electric generating means and with the thermal load, the heat storage capacity of the storage unit being limited in size to that of the modified design day thermal load at the site, the electric power generating means being sized to reject a quantity of heat generally equal to the modified design day thermal load at the site during a regular daily period of operation, and normally assigning priority of operation of the generating means to the condition where the expected following 24-hour heat demand is greater than the quantity of heat contained in the heat storage unit and operating the generating means ordinarily exclusively during the peak rate period of the central station electric service.