Method and apparatus for utilization of hot water plant waste heat recovery by incorporated high temperature water source heat pump

Abstract

The invention relates to a method and apparatus for low temperature waste heat utilization. In the scope of the hot water plant (HWP) there are few low temperature sources, which cannot be used by heat consumer (HC) directly. The method and apparatus for hot water power plant (HWP) waste heat recovery comprises at least one, preferably condensing type heat exchanger (HE), which collects the waste heat for water source high temperature heat pump (HP) employment, wherein a low temperature heat is upgraded to a high temperature heat, hence heat pump (HP) hot water outlet is fed to the boiler in a return line or in a supply line of hot water plant (HWP), wherein the thermal energy balance adjustment of generated heat is executed by adapting the power of said heat pump (HP) and/or by adapting the power of said furnace and/or by adapting the mass flow of the primary heat transfer medium in at least one open loop heating network and/or in at least one closed loop heating circuit in the scope of heat distribution network.

1 . A method of using a heat generation apparatus for heating at least one heat consumer (HC) in a heat distribution network by adopting the principle of a water source high temperature heat pump (HP) for waste heat source utilization, wherein said heat distribution network comprises at least one open loop heating network and/or at least one closed loop heating circuit, the method comprising:
 a fuel combustion process, wherein at least one furnace with incorporated boiler is used to provide a first heat releasing unit for heating at least one heat transfer medium in said heat distribution network, and wherein at least one waste heat source arise when said first heat releasing unit is turned on and operating by firing the fuel in the fuel combustion process;   a waste heat recovery process, wherein at least one waste heat recovery unit is used to collect at least a portion of the waste heat produced by said first heat releasing unit;   a liquid-vapor phase change thermodynamic cycle utilization process, wherein at least one water source high temperature heat pump (HP) is used to provide a second heat releasing unit for heating at least one heat transfer medium in said heat distribution network when said heat pump (HP) is turned on and operating, wherein the heat required for the liquid-vapor phase change cycle utilization is gained fully or in part by said waste heat recovery process, and wherein at least a portion of the heat collected in the waste heat recovery process is used for liquid-vapor phase change thermodynamic cycle process utilization; and   a heat distribution process, wherein the heat in said heat distribution network is preferably distributed by the stream of at least one heat transfer medium, characterized in that   at least a portion of the heat generated by said liquid-vapor phase change thermodynamic cycle utilization process is transferred to the heat transfer medium in said heat distribution network, wherein at least a portion of the heat generated by said heat pump (HP) is transferred to the boiler by stream of the heat transfer medium in said heat distribution network, hence at least a portion of the heat transfer medium in said heat distribution network is reheated in a return line of the closed loop heating circuit or at least a portion of said heat transfer medium is preheated in a supply line of the open loop heating network by water source high temperature heat pump (HP) principle utilization, at least when a design temperature of the heat distribution network is reached and said hot water plant (HWP) and heat pump (HP) are operating at full load.   
     
     
         2 . A method as in  claim 1  characterized in that
 the fuel combustion process is substantially a continuous process, wherein said furnace of hot water plant (HWP) operates in the range between its minimum and maximum rated operating power, preferably at normal rated power in continuous operation; 
 the liquid-vapor phase change thermodynamic cycle utilization process is substantially a continuous process, wherein said heat pump (HP) operates in the range between its minimum and maximum rated operating power, preferably at normal rated power in continuous operation; 
 the waste heat recovery process comprises a process of flue gas condensation, wherein the collected heat is used for heat pump (HP) principle utilization and wherein the temperature of the flue gas is reduced below 45° C., hence the flue gas in exhaust system is removed by ventilating the exhaust system by incorporated fan (FI); 
 the waste heat recovery process is used for cooling principle utilization, wherein the waste heat recovery process is used for cooling the lubrication oil of heat pump (HP) compressor unit; 
 the temperature of the heat transfer medium in the heat transfer network is determined, controlled and regulated by a group of automated regulation means comprising valves, pumps and sensors, wherein said regulation means are preferably adapted to be manipulated by at least one control unit. 
 
     
     
         3 . A method as in  claim 2  characterized in that
 the fuel combustion process is provided by plurality of furnaces with incorporated boiler units, wherein the heat generated by individual boiler unit is transferred to the heat distribution network in serial and/or in parallel connection in order to provide a first heat releasing unit; 
 the liquid-vapor phase change thermodynamic cycle utilization process is provided by plurality of heat pump (HP) units, wherein the heat generated by the individual unit is transferred to the heat distribution network in serial and/or parallel connection in order to provide the second heat releasing unit; 
 the heat distribution process in said heat distribution network is provided by plurality of heat distribution mediums, wherein the heat from waste heat recovery unit is transferred to the heat pump (HP) by circulation of the secondary heat transfer medium in at least one closed loop circuit. 
 
     
     
         4 . A method as in  claim 3  characterized in that
 the temperature of the primary heat transfer medium in the heat distribution network is maintained at predetermined set point value, wherein thermal energy balance adjustment is executed by adapting the power of said heat pump (HP) and/or by adapting the power of said hot water plant (HWP) and/or by adapting the mass flow of the primary heat transfer medium through the individual boiler unit and/or by adapting the mass flow of the primary heat transfer medium through the heat pump (HP) and/or by adapting the mass flow of the secondary heat transfer medium in said closed loop circuit for waste heat source utilization. 
 
     
     
         5 . A method as in  claim 4  characterized in that
 the mass flow of the primary heat transfer medium in said heat distribution network is adapted by changing the flow velocity in said heat distribution network and/or the mass flow of the secondary heat transfer medium in said closed loop circuit is adapted by changing the flow velocity in said closed loop circuit, wherein the velocity of heat transfer medium in heat distribution network is adapted by switching and/or by adjusting the power of at least one circulation pump. 
 
     
     
         6 . A method as in  claim 4  characterized in that
 the heat generated by the first heat releasing unit and second heat releasing unit is transferred to the heat consumer (HC) by stream of heat transfer medium in said heat distribution network, wherein said heat distribution network comprises at least one open loop heating network and/or at least one closed loop heating circuit. 
 
     
     
         7 . A method as in  claim 5  characterized in that
 the mass flow of the primary heat transfer medium in said heat distribution network is adapted by stream flow regulation, wherein at least a portion of the primary heat transfer medium stream in the return line of said closed loop heat distribution circuit is redirected to the return line of said heat distribution circuit to provide a heat pump (HP) bypass connection, and/or wherein at least a portion of the primary heat transfer medium stream from said heat pump (HP) is redirected to a forward line of the heat distribution network to provide a first heat releasing unit bypass connection; 
 the mass flow of the secondary heat transfer medium in said closed loop circuit for waste heat source utilization is adapted by stream flow regulation, wherein at least a portion of the secondary heat transfer medium stream is redirected in said closed loop circuit to provide a bypass connection for at least one waste heat recovery unit. 
 
     
     
         8 . A method as in  claim 2  characterized in that
 the mass flow regulation of the primary heat transfer medium and/or the mass flow regulation of the secondary heat transfer medium for thermal energy balance adjustment is determined, controlled and executed by said control unit, wherein the position and/or the state of the 
 automated regulation means is adjusted in respect to the heat demand in said heat distribution network. 
 
     
     
         9 . A method for controlling a hot water plant (HWP) and at least one adopted water source high temperature heat pump (HP) to enhance the heating power of the furnace with incorporated boiler by collecting the waste heat of at least one waste heat source and liquid-vapor phase change thermodynamic cycle utilization, the method comprising:
 a determination process, wherein at least one input from hot water plant (HWP) sensors and/or heat distribution network sensors is determined by at least one control unit for comparison process;   a comparison process, wherein at least one of the inputs from determination process is checked and processed, wherein the value of at least one input parameter is analyzed and compared to the limiting values, preferably defined in said control unit;   an execution process, wherein instructions, preferably stored in at least one control unit, generate appropriate output signal for control of hot water plant (HWP) and/or heat pump (HP) and/or heat distribution network automated regulation means adjustment, characterized in that,   at least one parameter to control the power of the hot water plant (HWP) and/or the power of the heat pump (HP) and/or the state and/or the position of automated regulation means in heat distribution network is determined for waste heat source utilization and thermal energy balance adjustment execution, wherein at least a portion of the heat required for heat pump (HP) principle utilization is gained fully or in part by waste heat recovery process, and wherein at least a portion of the heat generated by the heat pump (HP) is used for preheating the heat transfer medium in a supply line of an open loop heating network and/or at least a portion of the heat generated by the heat pump (HP) is used for reheating the heat transfer medium in at least one return line of a closed loop heating circuit to establish the set-point value of heat transfer medium temperature.   
     
     
         10 . A method as in  claim 9 , characterized in that
 the heat is distributed in the heat distribution network by stream of a heat transfer medium, wherein at least a portion of the heat generated by hot water plant (HWP) is transferred to at least one heat consumer (HC) through the heat distribution network, wherein the heat transfer medium in at least one supply line and/or in at least one return line of said heat distribution network is preheated and/or reheated by said heat pump (HP) with aim to reach and maintain the threshold value, wherein said threshold value is defined between the maximum value and the minimum value for set point equal value in order to provide a hysteresis for thermal energy balance adjustment;   the heat required for heat pump (HP) principle utilization is gained fully or in part by utilization of at least one from group of waste heat sources comprising a flue gas in exhaust system, and a lubrication oil in lubrication oil cooling system, wherein utilization of waste heat sources comprises at least two waste heat recovery units, wherein the collected heat is transferred to the heat pump (HP) by circulation of a secondary heat transfer medium in plurality of closed loop circuits in parallel and/or serial connection, wherein received heat is furthermore upgraded by the heat pump (HP) principle utilization and furthermore transferred to the primary heat transfer medium for preheating and/or reheating at least one heat distribution medium in said heat distribution network;   the mass flow of the primary heat transfer medium and/or the mass flow of the secondary heat transfer medium and/or the temperature of at least one heat transfer medium in said heat distribution network is determined and regulated by at least one control unit in cooperation with automated regulation means, preferably by motorized valves and pumps, wherein the heat generated by first heat releasing unit and the heat generated by second heat releasing unit and the state and/or the position of the automated regulation means is adjusted by said control unit in respect to the heat demand in said heat distribution network.   
     
     
         11 . An apparatus assembly for hot water plant (HWP) waste heat source utilization comprising:
 a first heat releasing unit comprising at least one furnace and boiler for heating at least one heat transfer medium in a heat distribution network, wherein said furnace further comprises an exhaust system, and wherein said boiler further comprises at least one inflow aperture and at least one outflow aperture;   a second heat releasing unit comprising at least one water source high temperature heat pump (HP), wherein said heat pump (HP) further comprises a lubrication oil cooling system (CS), an evaporator unit and a condenser unit, and wherein said evaporator unit and said condenser unit further comprises an inlet aperture and an outlet aperture;   and at least one waste heat recovery unit, preferably a heat exchanger (HE) adapted to be associated with said evaporator unit in a closed loop circuit characterized in that   said waste heat recovery unit is adapted to be associated with at least one from group of waste heat sources comprising an exhaust system and a lubrication oil cooling system (CS) for collecting the heat of said waste heat source;   said evaporator unit is adapted to be associated with said waste heat recovery unit in a closed loop circuit for transferring the collected heat from said waste heat recovery unit to said evaporator unit by a secondary heat transfer medium in said closed loop circuit;   said outlet of the condenser unit is adapted to be associated with said boiler inflow aperture for transferring the heat of condenser unit to the boiler by a primary heat transfer medium in said heat distribution network;   said inlet of the condenser unit and said outflow of the boiler are adapted to be associated with said heat distribution network, wherein said heat distribution network further comprises at least one thermal energy receiving unit, preferably a heat consumer (HC).   
     
     
         12 . The apparatus assembly for hot water plant (HWP) waste heat source utilization as in  claim 11  characterized in that
 said heat distribution network comprises at least one forward line to transfer the heat generated by said first heat releasing to said heat consumer (HC), and furthermore, said heat distribution network further comprises at least one supply line of an open loop heating network and/or at least one return line of a closed loop heating network, wherein said primary heat transfer medium circulate in said heat distribution network to transfer the heat of heat source to the heat consumer (HC); 
 said outflow of the boiler is operably coupled to the forward line of said heat distribution network; 
 said inlet of the condenser unit is operably coupled to at least one supply line and/or at least one return line of said heat distribution network; 
 said outlet of the condenser unit is operably coupled to the inflow of said boiler wherein said heat distribution network comprises a primary heat transfer medium; and 
 said heat exchanger (HE) is incorporated to said exhaust system to receive at least a portion of the heat of flue gas, wherein said heat exchanger (HE) is operably coupled to said evaporator unit in the closed loop circuit comprising a secondary heat transfer medium, wherein the heat collected in heat exchanger (HE) is transferred to the evaporator unit by secondary heat transfer medium circulation in said closed loop circuit, and furthermore, the heat of said condenser unit is transferred to the boiler by primary heat transfer medium circulation in said head distribution network at least when the first heat releasing unit and second heat releasing unit are turned on and powered at operating conditions; 
 said closed loop further comprises a heat exchanger in form of a lubrication oil cooling system (CS) for collecting the heat of said waste heat source, wherein said lubrication oil cooling system (CS) is adapted to be associated with a compressor of said heat pump (HP). 
 
     
     
         13 . The apparatus assembly for hot water plant (HWP) waste heat source utilization as in  claim 12  characterized in that
 said heat distribution circuit comprises a plurality of the heat consumers (HC) in parallel connection and/or in serial connection; 
 said heat distribution circuit comprises a plurality of the heat pumps (HP) in parallel connection and/or in serial connection, wherein closed loop circuit of said evaporator unit comprises a plurality of heat exchangers (HE) in parallel connection and/or in serial connection, and wherein at least one of the condenser unit outlet aperture is operably coupled to the inflow of said boiler. 
 
     
     
         14 . The apparatus assembly for hot water plant (HWP) waste heat source utilization as in  claim 13  characterized in that
 said hot water plant is designed as a furnace which runs on a gas fuel selected from group comprising a natural gas, liquefied petroleum gas, landfill gas, wood gas or biogas; 
 the primary heat transfer medium in preferential embodiment is water; 
 the secondary heat transfer medium in preferential embodiment is mix of water and glycol; 
 said waste heat recovery unit is designed as a condensing heat exchanger (HE), wherein the temperature of flue gas is reduced under 45° C., hence the exhaust system further comprises at least one fan (FI) for flue gas extraction. 
 
     
     
         15 . The apparatus assembly for hot water plant (HWP) waste heat source utilization as in  claim 12  characterized in that
 said compressor of the heat pump (HP) is adopted to be driven by electric machine, powered by electricity from grid or generator and/or said compressor adopted to be coupled with and driven by additional internal combustion engine.