A water heater includes a water tank and a flow-through heating element. The water tank contains heated water. The flow-through heating element is located in the lower portion of the water tank and heats water as water is passed through an interior channel of the heating element. In another configuration, the water heater further includes a recirculation line and the heating element further includes an input end external of the water tank to receive water to be heated and an output end to output heated water into the water tank. The recirculation line transports water from the water tank to the input end of the heating element that is external of the water tank.

A steam generator for converting a fluid to steam includes a combustion chamber for receiving a combustion fuel into the combustion chamber. A steam chamber surrounds and is heated by the combustion chamber to a temperature exceeding a vaporization temperature of the fluid. A heat exchanging chamber surrounds and is heated by residual heat of the steam chamber. A preheating coil is disposed within the heat exchanging chamber and has a fluid inlet for receiving the fluid under pressure into the preheating coil for preheating the fluid within the heat exchanging chamber. An injector communicates with the preheating coil and the steam chamber for injecting a controlled flow of the preheated fluid under pressure into the steam chamber where it flashes to steam and is super-heated to the temperature of the steam chamber. A steam outlet conveys the super-heated steam externally of the steam generator.

A steam generator for converting a fluid to steam includes a combustion chamber for receiving a combustion fuel into the combustion chamber. A steam chamber surrounds and is heated by the combustion chamber to a temperature exceeding a vaporization temperature of the fluid. A heat exchanging chamber surrounds and is heated by residual heat of the steam chamber. A preheating coil is disposed within the heat exchanging chamber and has a fluid inlet for receiving the fluid under pressure into the preheating coil for preheating the fluid within the heat exchanging chamber. An injector communicates with the preheating coil and the steam chamber for injecting a controlled flow of the preheated fluid under pressure into the steam chamber where it flashes to steam and is super-heated to the temperature of the steam chamber. A steam outlet conveys the super-heated steam externally of the steam generator.

The steam boiler system comprises a steam boiler comprising a burner and a chimney for exhausting flue gases, a feedwater line for leading feedwater to said steam boiler for producing steam, a steam line leading from said steam boiler to at least one application heat exchanger for feeding steam to said application heat exchanger, said application heat exchanger for heating an application fluid, and a condensate line leading away from said application heat exchanger for recuperating condensate from said application heat exchanger. An economizer heat exchanger is provided in said chimney, wherein at least one of said condensate return line and said feedwater line circulates through said economizer heat exchanger for allowing at least one of said condensate and said feedwater to be in heat exchange relationship with the flue gases for simultaneously cooling the flue gases while heating at least one of the condensate and the feedwater.

The steam boiler system comprises a steam boiler comprising a burner and a chimney for exhausting flue gases, a feedwater line for leading feedwater to said steam boiler for producing steam, a steam line leading from said steam boiler to at least one application heat exchanger for feeding steam to said application heat exchanger, said application heat exchanger for heating an application fluid, and a condensate line leading away from said application heat exchanger for recuperating condensate from said application heat exchanger. An economizer heat exchanger is provided in said chimney, wherein at least one of said condensate return line and said feedwater line circulates through said economizer heat exchanger for allowing at least one of said condensate and said feedwater to be in heat exchange relationship with the flue gases for simultaneously cooling the flue gases while heating at least one of the condensate and the feedwater.

A coal fired Oxy boiler power plant having a combustion system configured to burn coal using an oxygen stream to produce a flue gas stream, a CO2 capture system connected to the flue gas stream and a steam cycle with serially arranged low pressure heaters forming part of a condensate system. The combustion system includes, an Air Separation Unit for removing N2 from air to produce the oxygen stream for the boiler. The Air Separation Unit includes an Air Separation Unit heat exchanger that is thermally and fluidly connected to the condensate system so as to be fluidly parallel to at least one serial low pressure heater and fluidly parallel to at least one less that the total number of serial low pressure heaters. The Flue Gas Heat Recovery System, Flue Gas Condenser and Gas Processing unit are thermally integrated into the condensate system.

A coal fired Oxy boiler power plant having a combustion system configured to burn coal using an oxygen stream to produce a flue gas stream, a CO2 capture system connected to the flue gas stream and a steam cycle with serially arranged low pressure heaters forming part of a condensate system. The combustion system includes, an Air Separation Unit for removing N2 from air to produce the oxygen stream for the boiler. The Air Separation Unit includes an Air Separation Unit heat exchanger that is thermally and fluidly connected to the condensate system so as to be fluidly parallel to at least one serial low pressure heater and fluidly parallel to at least one less that the total number of serial low pressure heaters. The Flue Gas Heat Recovery System, Flue Gas Condenser and Gas Processing unit are thermally integrated into the condensate system.

A thermal power plant has an exhaust gas system, a feed-water system, a high-pressure feed-water heater provided to the feed-water system, a main economizer, a catalytic NOx removal equipment, and a sub economizer. The main economizer is provided to the secondary side of the high-pressure feed-water heater of the feed-water system and increases the temperature of the feed-water by using the residual heat of the combustion gas from the boiler. The catalytic NOx removal equipment is provided to the secondary side of the main economizer of the exhaust gas system. The exhaust gas is supplied to the catalytic NOx removal equipment at a required temperature or higher. The sub economizer is provided between the high-pressure feed-water heater and the main economizer and increases the temperature of water by using the exhaust gas on the secondary side of the NOx removal equipment.

A thermal power plant has an exhaust gas system, a feed-water system, a high-pressure feed-water heater provided to the feed-water system, a main economizer, a catalytic NOx removal equipment, and a sub economizer. The main economizer is provided to the secondary side of the high-pressure feed-water heater of the feed-water system and increases the temperature of the feed-water by using the residual heat of the combustion gas from the boiler. The catalytic NOx removal equipment is provided to the secondary side of the main economizer of the exhaust gas system. The exhaust gas is supplied to the catalytic NOx removal equipment at a required temperature or higher. The sub economizer is provided between the high-pressure feed-water heater and the main economizer and increases the temperature of water by using the exhaust gas on the secondary side of the NOx removal equipment.

A boiler including one or more evaporators, an economizer, and a low-temperature heat exchanger. The economizer is located on a downstream side of the most downstream evaporator which is an evaporator at the most downstream side among the one or more evaporators. The low-temperature heat exchanger is located on the downstream side of the economizer, has an inlet for receiving water from the outside, and is configured to heat the water introduced from the inlet and sent to the economizer with the combustion gas.