There are several industries, such as paper Mills, textile Mills, chemical factories, drying plants, rubber
manufacturing plants, sugar factories, metal extraction, pharmaceutical, fertilizer, hotels, hospitals, and
commercial buildings etc, where a continuous demand for both heat and power exists. Saturated steam at
desired temperature is required for heating, drying etc. Apart from process heat, the factory also needs
electric power to drive various machines, for lighting, and for other purposes.
Formerly it was practice to generate steam for power purposes at a moderate/high pressure and to generate
saturated steam separately for process work (heating/drying) at a pressure, which gave the desired heating
temperature. Having two separate units for process heat & power is wasteful. Because approximately 60-
65 % of total heat input supplied to conventional condensing steam power plant will be carried away by the
cooling water in the condenser & flu gases. The major portion of this rejected heat can be utilised for
industrial process heating and district heating / cooling purpose on cogeneration principle.
Combined Heat and Power or Cogeneration is the simultaneous generation of
usable heat and power (usually electricity) in a single process. In other words, it utilises the heat rejected in
electricity generation rather than releasing it wastefully into the atmosphere through cooling tower. CHP is
sometimes referred to as co-generation in short “Cogen” or as ‘total energy’
By modifying the initial steam pressure and exhaust pressure, it is possible to generate the required power
and make available the required quantity of exhaust steam at desired temperature from the turbine for
process heating. In this case the process heater replaces the condenser of the ordinary Rankin cycle. For
constant temperature heating (or drying), steam is a very good medium, since isothermal condition can be
maintained by allowing saturated steam to condense at that temperature and utilising the latent heat
released for heating purpose.
manufacturing plants, sugar factories, metal extraction, pharmaceutical, fertilizer, hotels, hospitals, and
commercial buildings etc, where a continuous demand for both heat and power exists. Saturated steam at
desired temperature is required for heating, drying etc. Apart from process heat, the factory also needs
electric power to drive various machines, for lighting, and for other purposes.
Formerly it was practice to generate steam for power purposes at a moderate/high pressure and to generate
saturated steam separately for process work (heating/drying) at a pressure, which gave the desired heating
temperature. Having two separate units for process heat & power is wasteful. Because approximately 60-
65 % of total heat input supplied to conventional condensing steam power plant will be carried away by the
cooling water in the condenser & flu gases. The major portion of this rejected heat can be utilised for
industrial process heating and district heating / cooling purpose on cogeneration principle.
Combined Heat and Power or Cogeneration is the simultaneous generation of
usable heat and power (usually electricity) in a single process. In other words, it utilises the heat rejected in
electricity generation rather than releasing it wastefully into the atmosphere through cooling tower. CHP is
sometimes referred to as co-generation in short “Cogen” or as ‘total energy’
By modifying the initial steam pressure and exhaust pressure, it is possible to generate the required power
and make available the required quantity of exhaust steam at desired temperature from the turbine for
process heating. In this case the process heater replaces the condenser of the ordinary Rankin cycle. For
constant temperature heating (or drying), steam is a very good medium, since isothermal condition can be
maintained by allowing saturated steam to condense at that temperature and utilising the latent heat
released for heating purpose.