Hybrid Energy System Based on Variable Steam Heat Source Stabilization and Control Method Thereof

Abstract

According to the hybrid energy system based on the stabilization of a fluctuating steam heat source of the present invention, the system comprises: a steam inlet that introduces fluctuating steam supplied from an incinerator waste heat boiler into a heat exchanger; a heat exchanger that heats pressurized hot water using the latent heat of condensation of fluctuating steam and the sensible heat of condensate; a pressurized hot water buffer tank that stores the pressurized hot water heated in the heat exchanger; a buffer bypass path that passes through the pressurized hot water buffer tank; a buffer bypass path that bypasses the pressurized hot water buffer tank; a flow control unit that controls the flow rate ratio of the buffer bypass path and the buffer bypass path; a closed pressurized circulation loop that supplies pressurized hot water to one or more of a heat pump module and an organic Rankine cycle module and returns the pressurized hot water that has released heat to the heat exchanger; a first sensor unit that measures the pressure of fluctuating steam; and a control unit that calculates a variability index using the pressure measured by the first sensor unit and controls the flow control unit according to the variability index.

Description

Technology Field

[0001] The present invention relates to a hybrid energy system based on the stabilization of a fluctuating steam heat source and a method for controlling the same. Background Technology

[0003] Since the waste fed into the waste incinerator does not have a constant calorific value, moisture content, size, or composition, the amount of heat generated during the combustion process can vary over time. Accordingly, the pressure, temperature, and flow rate of the steam generated in the incinerator's waste heat boiler can also vary by the second or minute.

[0005] When fluctuating steam is supplied directly to a heat pump, changes in steam pressure, temperature, or flow rate can be directly transferred to the heat source conditions of the evaporator. Consequently, the evaporation pressure changes, and the compressor's operating point may deviate from the design operating range, potentially leading to compressor surging or a decrease in the coefficient of performance.

[0007] Furthermore, directly supplying fluctuating steam to an organic Rankine cycle power generation system can cause the evaporator heat load and the evaporation state of the organic working fluid to change repeatedly. Consequently, the expander inlet conditions may deviate from the design point, leading to repeated partial-load operation and a decrease in power generation efficiency. Repeated abrupt changes in heat source conditions can also cause thermal stress to accumulate in heat exchangers, piping, and energy conversion equipment.

[0009] Conventionally, a technology for mitigating steam pressure fluctuations using a steam accumulator that stores steam inside a pressure vessel is known. While steam accumulators can buffer heat source fluctuations, they require pressure vessel conditions corresponding to the steam pressure because they store energy in the steam state, and it is difficult to additionally recover sensible heat remaining in the condensate.

[0011] Technology is also known for recovering waste heat generated during the combustion or gasification of waste into a heat transfer fluid and supplying the fluid to an organic Rankine cycle power generation device. While this technology can generate electricity using waste heat, it does not provide a structure for sequentially recovering the latent heat of condensation of fluctuating steam and the sensible heat of condensate, nor a structure for distributing heat between a heat pump and an organic Rankine cycle.

[0013] In addition, a technology is known for producing hot water for supply or cleaning water by heat-exchanging steam and hot water. While this technology can recover heat from steam as hot water, it is a unidirectional system where the produced hot water is consumed at an external point of consumption; therefore, it is difficult to form a closed-pressurized circulation loop that repeatedly circulates hot water as a heat medium.

[0015] In addition, although a technology for selecting operating equipment by comparing the operating costs of heat pumps and other heating equipment is known, there is a problem in that it is difficult to calculate a variability index from the pressure of fluctuating steam and simultaneously control the amount of heat supplied to the heat pump and the organic Rankine cycle power generation device while adjusting the flow rate of the pressurized hot water buffer tank according to the variability index. Prior art literature

[0018] Republic of Korea Registered Patent 10-2174013 US Registered Patent US 9,447,705 B2 US Registered Patent US 8,600,563 B2 US Registered Patent US 1,328,593 A The problem to be solved

[0019] The objective of the present invention is to provide a hybrid energy system based on fluctuating steam heat source stabilization and a control method thereof, which can sequentially recover the latent heat of condensation of fluctuating steam and the sensible heat of condensate, and mitigate temperature fluctuations of pressurized hot water supplied to a downstream module.

[0020] In addition, the objective of the present invention is to provide a hybrid energy system based on fluctuating steam heat source stabilization and a control method thereof, which can calculate a variability index from the pressure of fluctuating steam and adjust the flow rate ratio of pressurized hot water passing through or bypassing a pressurized hot water buffer tank according to the variability index.

[0021] In addition, the objective of the present invention is to provide a hybrid energy system based on stabilization of a fluctuating steam heat source and a control method thereof, which supplies stabilized pressurized hot water to one or more of a heat pump module and an organic Rankine cycle module, and can adjust the distribution ratio and circulation path of the pressurized hot water according to operating conditions. means of solving the problem

[0023] According to the hybrid energy system based on the stabilization of a fluctuating steam heat source of the present invention, the system comprises: a steam inlet that introduces fluctuating steam supplied from an incinerator waste heat boiler into a heat exchanger; a heat exchanger that heats pressurized hot water using the latent heat of condensation of fluctuating steam and the sensible heat of condensate; a pressurized hot water buffer tank that stores the pressurized hot water heated in the heat exchanger; a buffer bypass path that passes through the pressurized hot water buffer tank; a buffer bypass path that bypasses the pressurized hot water buffer tank; a flow control unit that controls the flow rate ratio of the buffer bypass path and the buffer bypass path; a closed pressurized circulation loop that supplies pressurized hot water to one or more of a heat pump module and an organic Rankine cycle module and returns the pressurized hot water that has released heat to the heat exchanger; a first sensor unit that measures the pressure of fluctuating steam; and a control unit that calculates a variability index using the pressure measured by the first sensor unit and controls the flow control unit according to the variability index.

[0024] In addition, the variability index is the standard deviation of the pressure of the fluctuating steam measured within the travel time window, and the control unit increases the flow rate ratio of the buffer via channel and decreases the flow rate ratio of the buffer bypass channel when the variability index exceeds the first threshold, and increases the flow rate ratio of the buffer bypass channel and decreases the flow rate ratio of the buffer via channel when the variability index is maintained below the second threshold for a set maintenance time.

[0025] In addition, the effective amount of the pressurized hot water buffer tank is determined to satisfy Equation 1 in order to limit the change in the supply temperature of the pressurized hot water to within the allowable temperature deviation in correspondence with the average recovered heat amount recovered in the heat exchanger during the representative fluctuation cycle of the fluctuating steam.

[0026] [Mathematical Formula 1]

[0027] V_eff ≥ Q_avg × τ ÷ (ρ × cp × ΔT_allow)

[0028] Here, V_eff is the effective volume of the pressurized hot water buffer tank, Q_avg is the average amount of heat recovered from the heat exchanger during a representative fluctuation cycle, τ is the representative fluctuation cycle, ρ is the density of the pressurized hot water, cp is the specific heat of the pressurized hot water, and ΔT_allow is the allowable temperature deviation.

[0029] In addition, it includes a second sensor unit for measuring the outlet temperature of the condensate discharged from the supercooling heat exchanger and the supply temperature and return temperature of the pressurized hot water, a pressurized hot water circulation pump for circulating the pressurized hot water in a closed pressurized circulation loop, and a closed expansion tank that absorbs volume expansion of the closed pressurized circulation loop and maintains pressure, wherein the pressurized hot water exchanges heat in a counterflow while sequentially passing through the supercooling heat exchanger and the condensation heat exchanger, and the control unit controls the flow control unit or the pressurized hot water circulation pump so that the difference between the outlet temperature of the condensate and the return temperature of the pressurized hot water and the difference between the supply temperature and the return temperature of the pressurized hot water are each maintained within a set range.

[0030] In addition, it includes a parallel circulation path that branches and supplies pressurized hot water to a heat pump module and an organic Rankine cycle module, respectively; a series circulation path that supplies pressurized hot water to the organic Rankine cycle module and then supplies the pressurized hot water, from which heat has been released by the organic Rankine cycle module, to the heat pump module; and a path switching unit that switches the flow of pressurized hot water between the parallel circulation path and the series circulation path. The control unit determines a distribution ratio to increase net energy benefit using real-time power unit price, on-site heat demand, ambient temperature, variability index, power consumption of the heat pump module, and power generation of the organic Rankine cycle module, and selects the parallel circulation path or the series circulation path.

[0031] In addition, it includes a plurality of automatic control valves that respectively regulate the flow rate of pressurized hot water supplied to the heat pump module and the organic Rankine cycle module, and a bypass path that circulates pressurized hot water by bypassing the heat pump module and the organic Rankine cycle module between the distribution header and the return header. When a stop signal is input to either the heat pump module or the organic Rankine cycle module, the control unit cuts off the pressurized hot water supplied to the module to which the stop signal was input, and supplies pressurized hot water to the bypass path or the remaining operable module to maintain the circulation of the closed pressurized circulation loop.

[0032] In addition, the steam inlet includes a pressure reducing valve, and the first sensor unit is connected to the upstream side of the pressure reducing valve so that pressure fluctuations of fluctuating steam generated in the incinerator waste heat boiler are measured in a state before being mitigated by the pressure reducing valve.

[0033] In addition, the steam inlet includes an automatic steam control valve that regulates the flow rate of fluctuating steam flowing into the heat exchanger, and the control unit limits the rate of change in the opening of the automatic steam control valve and increases the flow rate ratio of the buffer flow path when the variability index exceeds the first threshold value, thereby mitigating the rapid transmission of changes in the pressure or flow rate of the fluctuating steam to the heat exchanger and allowing the heat quantity fluctuation to be buffered by the heat storage or heat dissipation of the pressurized hot water buffer tank.

[0034] According to the control method of a hybrid energy system based on the stabilization of a fluctuating steam heat source of the present invention, the method comprises the steps of: introducing fluctuating steam supplied from an incinerator waste heat boiler into a heat exchanger through a steam inlet; condensing the fluctuating steam in a condensing heat exchanger of the heat exchanger to recover latent heat, cooling the condensate discharged from the condensing heat exchanger in a subcooling heat exchanger to recover sensible heat, and heating pressurized hot water using the latent heat recovered from the condensing heat exchanger and the sensible heat recovered from the subcooling heat exchanger; measuring the pressure of the fluctuating steam using a first sensor unit and calculating a variability index using the measured pressure; adjusting the flow rate ratio of pressurized hot water flowing through a buffer bypass path passing through a pressurized hot water buffer tank and a buffer bypass path bypassing the pressurized hot water buffer tank according to the variability index; and supplying the heated pressurized hot water to one or more of a heat pump module and an organic Rankine cycle module. and a step of returning pressurized hot water that has released heat from one or more of the heat pump module and the organic Rankine cycle module to the heat exchanger. Effects of the invention

[0036] The effect of the present invention is that the amount of recoverable heat can be increased by sequentially recovering the latent heat of condensation of fluctuating steam and the sensible heat of condensate to heat pressurized hot water.

[0037] In addition, the effect of the present invention is to mitigate temperature fluctuations of pressurized hot water supplied to the downstream module by adjusting the flow rate ratio of the buffer transit path and the buffer bypass path according to the variability index.

[0038] In addition, the effect of the present invention is that it can respond to on-site heat demand and power conditions by adjusting the distribution ratio and circulation path of pressurized hot water supplied to the heat pump module and the organic Rankine cycle module. Brief explanation of the drawing

[0040] Figure 1 shows the overall flow in which fluctuating steam supplied from an incinerator waste heat boiler flows into a heat exchanger, and pressurized hot water heated in the heat exchanger is distributed by a flow control unit into a buffer bypass path passing through a pressurized hot water buffer tank and a buffer bypass path bypassing the pressurized hot water buffer tank, then merges, is supplied to one or more of a heat pump module and an organic Rankine cycle module through a distribution header, and returns to the heat exchanger through a return header. Figure 2 shows the series heat exchange relationship between the condensing heat exchanger and the subcooling heat exchanger, and the relationship in which pressurized hot water exchanges heat with the condensing water in a counterflow in the subcooling heat exchanger, and then exchanges heat with the fluctuating steam in a counterflow in the condensing heat exchanger. Figure 3 shows a process flow for calculating a variability index from the pressure of fluctuating steam and switching the operating mode according to the calculated variability index. Figure 4 shows the parallel operation, series operation, standalone operation, and bypass operation of the heat pump module and the organic Rankine cycle module, and the corresponding valve state. Figure 5 shows the processing relationship for determining the distribution ratio using real-time power unit price, on-site heat demand, ambient temperature, variability index, and operating characteristics of each module. Specific details for implementing the invention

[0041] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0042] Hereinafter, a hybrid energy system based on fluctuating steam heat source stabilization and a control method thereof will be described with reference to FIGS. 1 to 5.

[0043] Since the calorific value, moisture content, size, and composition of the waste fed into the waste incinerator can vary over time, the pressure, temperature, and flow rate of the steam generated from the incinerator's waste heat boiler can also vary by the second or minute.

[0044] If fluctuating steam is supplied directly to the heat pump module (71) or the organic Rankine cycle module (72), the heat source inlet conditions of each module may deviate from the design point, causing partial load operation to be repeated, and the coefficient of performance of the heat pump module (71) and the power generation efficiency of the organic Rankine cycle module (72) may decrease.

[0045] Specifically, if fluctuating steam is supplied directly to the heat pump module (71), changes in the pressure, temperature, or flow rate of the fluctuating steam can be directly transmitted to the evaporator of the heat pump module (71). Accordingly, the evaporation pressure of the heat pump module (71) changes, the operating point of the compressor may deviate from the design operating range, and surging of the compressor or a decrease in the coefficient of performance may occur.

[0046] Additionally, if fluctuating steam is supplied directly to the organic Rankine cycle module (72), the heat load of the evaporator of the organic Rankine cycle module (72) changes, and the evaporation state of the organic working fluid and the expansion inlet conditions may change repeatedly. Accordingly, the organic Rankine cycle module (72) may be operated in a partial load state deviating from the design point, and the power generation efficiency may decrease.

[0047] In addition, since repeated abrupt changes in heat source conditions can lead to the accumulation of thermal stress in the heat exchanger, piping, and downstream module, it is necessary to buffer the heat source conditions between the fluctuating steam and the downstream module.

[0048] The present invention can recover the latent heat of the fluctuating steam and the sensible heat of the condensate into pressurized hot water instead of storing the fluctuating steam in a steam state, and can stabilize the heat source conditions supplied to the downstream energy conversion facility by using a pressurized hot water buffer tank (30) and a closed pressurized circulation loop (70).

[0049] Since a steam thermal storage device stores energy in the steam state, pressure vessel conditions corresponding to the steam pressure may be required. On the other hand, the present invention condenses fluctuating steam to convert it into pressurized hot water and stores or releases heat in a pressurized hot water buffer tank (30), so it can provide a thermal buffering function at a relatively lower pressure condition than when storing energy in the steam state.

[0050] In addition, the present invention can recover not only the latent heat of condensation of fluctuating steam but also the sensible heat remaining in the condensate in a supercooling heat exchanger, thereby increasing the amount of heat that can be recovered compared to the case where only the latent heat of steam is used.

[0051] Since the pressurized hot water is not hot water supplied once to an external consumption point but a heat medium that circulates repeatedly in a closed pressurized circulation loop (70), the residual heat of the return water that has released heat from the downstream module can be recovered.

[0053] The hybrid energy system based on the stabilization of a fluctuating steam heat source according to the present invention may include a steam inlet (10), a heat exchanger (20), a pressurized hot water buffer tank (30), a buffer flow path (41), a buffer bypass flow path (42), a flow rate control unit (40), a sealed pressurized circulation loop (70), a first sensor unit (50), and a control unit (60).

[0054] First, the steam inlet (10) is described.

[0055] The steam inlet (10) can introduce fluctuating steam supplied from the incinerator waste heat boiler into the heat exchanger (20).

[0056] The steam inlet (10) may include a steam flow path connecting the steam outlet of the incinerator waste heat boiler and the steam inlet of the heat exchanger (20).

[0057] The steam inlet (10) may include one or more of a pressure reducing valve, an automatic steam control valve, a safety valve, and a drain trap to control the inflow of fluctuating steam.

[0058] The pressure reducing valve can limit the transmission of excessive pressure to the heat exchanger (20) by first adjusting the pressure of fluctuating steam supplied from the incinerator waste heat boiler to below the design pressure of the heat exchanger (20).

[0059] The automatic steam control valve can control the flow rate of fluctuating steam flowing into the heat exchanger (20), and the opening degree can be changed according to a control signal transmitted from the control unit (60).

[0060] The control unit (60) can control the automatic steam control valve so that fluctuating steam is supplied within the allowable operating range of the heat exchange unit (20) by using the pressure of the fluctuating steam measured by the first sensor unit (50) and optionally the temperature or flow rate measured.

[0061] The control unit (60) can reduce the opening of the automatic steam control valve or block the inflow of fluctuating steam when the pressure of the fluctuating steam exceeds the set upper limit or when a stop signal from the heat exchanger (20) is input.

[0062] The control unit (60) can increase the opening of the automatic steam control valve when the pressure and flow rate of the fluctuating steam are within the allowable range while the amount of heat supplied to the heat exchange unit (20) is insufficient.

[0063] The control unit (60) can limit the rate of change in the opening of the automatic steam control valve when the variability index exceeds the first threshold value, thereby mitigating the rapid transmission of pressure or flow rate changes of the fluctuating steam to the heat exchange unit (20).

[0064] The control that limits the rate of change in the opening of the automatic steam control valve primarily mitigates extreme changes in the fluctuating steam itself, and the heat storage or heat dissipation of the pressurized hot water buffer tank (30) described later can secondarily buffer the heat quantity fluctuations remaining after passing through the heat exchanger (20).

[0065] Accordingly, the steam control of the steam inlet (10) and the control of the buffer via-path (41) and buffer bypass-path (42) on the pressurized hot water side are interconnected to mitigate fluctuations in the supply temperature of the pressurized hot water supplied to the rear module.

[0066] The safety valve can protect the steam inlet (10) and the heat exchanger (20) by discharging steam when the pressure of the steam flow path exceeds the allowable pressure, independently of the electrical control of the control unit (60).

[0067] The drain trap can discharge condensate generated in the steam path to limit the rapid inflow of condensate into the heat exchanger (20) along with the steam.

[0068] The steam inlet (10) may further include a manual shut-off valve to block the steam flow for inspection or maintenance.

[0069] The control unit (60) may include a programmable logic controller or a monitoring control system and can communicate with the control system of the incinerator waste heat boiler to check the steam supply status, operating status and stop status.

[0070] In one embodiment, a Modbus communication method may be applied between the control unit (60) and the control system of the incinerator waste heat boiler, but is not limited thereto.

[0072] Next, the heat exchanger (20) will be described.

[0073] The heat exchanger (20) may include a condensing heat exchanger that recovers latent heat by condensing fluctuating steam, and a supercooling heat exchanger that recovers sensible heat by cooling the condensate discharged from the condensing heat exchanger.

[0074] The heat exchanger (20) can heat pressurized hot water using latent heat recovered from the condensation heat exchanger and sensible heat recovered from the supercooling heat exchanger.

[0075] A condensation heat exchanger can transfer the latent heat of condensation released while converting fluctuating steam into liquid condensate to pressurized hot water.

[0076] The supercooling heat exchanger can transfer the sensible heat contained in the condensate to the pressurized hot water while further cooling the high-temperature condensate discharged from the condensation heat exchanger.

[0077] Condensing heat exchangers and subcooling heat exchangers can transfer only heat while separating the steam-side flow path through which steam and condensate flow and the pressurized hot water-side flow path through which pressurized hot water flows.

[0078] Accordingly, the mixing of fluctuating steam and condensate into the pressurized hot water is restricted, and the pressurized hot water can be used repeatedly in a closed pressurized circulation loop (70).

[0079] The heat exchanger (20) may include a shell-and-tube type heat exchanger or a plate type heat exchanger, and the condensation heat exchanger and the supercooling heat exchanger may be formed as separate heat exchange sections within a single body or as separate heat exchangers connected to each other.

[0080] When the condensing heat exchanger and the subcooling heat exchanger are formed as separate devices, the condensate outlet of the condensing heat exchanger can be connected to the condensate inlet of the subcooling heat exchanger, and the pressurized hot water outlet of the subcooling heat exchanger can be connected to the pressurized hot water inlet of the condensing heat exchanger.

[0081] Since the steam or condensate generated from the incinerator waste heat boiler may contain chlorine or sulfur components, parts in contact with the steam and condensate may be made of stainless steel or corrosion-resistant materials.

[0082] For example, parts in contact with steam and condensate may include stainless steel of SUS316L or higher or a material treated with a corrosion-resistant coating, but are not limited thereto.

[0084] Referring to Fig. 2, pressurized hot water can be heat exchanged in a counterflow with condensate and fluctuating steam as it passes sequentially through a supercooling heat exchanger and a condensation heat exchanger.

[0085] The return water of pressurized hot water that has released heat from the heat pump module (71) or organic Rankine cycle module (72) first flows into a supercooling heat exchanger to recover the sensible heat of the condensate, and then moves to a condensation heat exchanger to recover the latent heat of the fluctuating steam.

[0086] Conversely, fluctuating steam can be condensed in a condensing heat exchanger and then transferred to a supercooling heat exchanger in the form of condensate.

[0087] The return water of the pressurized hot water, which has a relatively low temperature, first exchanges heat with the condensate whose temperature has been lowered at the condensate outlet side of the subcooling heat exchanger, and the pressurized hot water preheated in the subcooling heat exchanger can exchange heat with the fluctuating steam undergoing an isothermal phase change in the condensing heat exchanger.

[0088] In a condensing heat exchanger, fluctuating steam condenses while maintaining the saturation temperature, so the steam-side temperature can be kept constant, and in a subcooling heat exchanger, the temperature can drop as the condensate releases heat.

[0089] Such counterflow heat exchange maintains the temperature difference required for heat exchange along the heat exchange path, thereby enabling the sensible heat of the condensate and the latent heat of the fluctuating steam to be sequentially transferred to the pressurized hot water.

[0090] As the outlet temperature of the condensate approaches the return temperature of the pressurized hot water, the amount of sensible heat recovered from the condensate may increase, but the heat exchange temperature difference of the supercooling heat exchanger may decrease. Therefore, if the outlet temperature of the condensate discharged from the supercooling heat exchanger is maintained in a range 5°C or higher and 10°C or lower higher than the return temperature of the pressurized hot water, the sensible heat of the condensate can be transferred to the pressurized hot water while maintaining the heat exchange temperature difference of the supercooling heat exchanger.

[0091] The intermediate temperature of the pressurized hot water at the outlet side of the supercooled heat exchanger shown in Fig. 2 may vary depending on the state of fluctuating steam, the sensible heat of the condensate, the circulation flow rate of the pressurized hot water, and the heat exchange area.

[0092] Under the conditions of the embodiments described below, pressurized hot water can be preheated from about 85°C to about 88°C in a supercooling heat exchanger and then heated to about 110°C in a condensing heat exchanger.

[0093] Condensate discharged from the supercooling heat exchanger can be recovered into the feedwater system of the incinerator waste heat boiler or transferred to other hot water usage sites.

[0095] Next, the pressurized hot water buffer tank (30) will be described.

[0096] The pressurized hot water buffer tank (30) can store pressurized hot water heated in the heat exchanger (20).

[0097] The pressurized hot water buffer tank (30) can provide a thermal buffering function that absorbs temporal fluctuations in the amount of heat recovered from fluctuating steam or supplements insufficient heat, along with the function of temporarily storing the amount of pressurized hot water.

[0098] If the temperature of the pressurized hot water flowing in from the heat exchanger (20) is higher than the temperature inside the pressurized hot water buffer tank (30), the pressurized hot water buffer tank (30) can store the heat of the incoming pressurized hot water.

[0099] Conversely, if the temperature of the pressurized hot water flowing in from the heat exchanger (20) decreases or the heat demand of the downstream module increases instantaneously, the pressurized hot water buffer tank (30) can transfer the stored heat amount to the pressurized hot water.

[0100] The pressurized hot water buffer tank (30) may be an insulated pressurized tank capable of withstanding volume changes due to temperature changes of the pressurized hot water and the operating pressure of the sealed pressurized circulation loop (70).

[0101] The outer side of the pressurized hot water buffer tank (30) may include an insulating layer to reduce heat loss and a temperature sensor to measure the internal temperature.

[0102] In one embodiment, the pressurized hot water buffer tank (30) may be designed to store pressurized hot water at a temperature of 90°C or higher and 140°C or lower, and the sealed pressurized circulation loop (70) may be designed to handle pressurized hot water at a temperature of 70°C or higher and 140°C or lower, including the return temperature.

[0103] The design pressure of the pressurized hot water buffer tank (30) can be set to be greater than or equal to the saturation pressure corresponding to the supply temperature of the pressurized hot water, for example, a value that satisfies the boiling prevention margin and the allowable pressure of each device among candidate ranges of 2 bar (g) or more and 5 bar (g) or less, but is not limited thereto.

[0104] The effective amount of the pressurized hot water buffer tank (30) can be determined to satisfy the following mathematical formula 1 so as to limit the change in the supply temperature of the pressurized hot water to within the allowable temperature deviation in correspondence with the average recovered heat amount recovered from the heat exchanger (20) during the representative fluctuation cycle of the fluctuating steam.

[0105]

[0106] Here, V_eff is the effective amount of the pressurized hot water buffer tank (30), Q_avg is the average amount of heat recovered from the heat exchanger (20) during a representative fluctuation cycle, τ is the representative fluctuation cycle, ρ is the density of the pressurized hot water, cp is the specific heat of the pressurized hot water, and ΔT_allow is the allowable temperature deviation.

[0107] The product of the average recovered heat amount and the representative fluctuation cycle may represent the amount of heat that the pressurized hot water buffer tank (30) will absorb or release during the representative fluctuation cycle.

[0108] The product of the density, specific heat, and allowable temperature deviation of pressurized hot water can represent the amount of heat that a unit volume of pressurized hot water can store or release within the allowable temperature range.

[0109] Therefore, Equation 1 can represent the standard for the effective amount of water to prevent heat fluctuations occurring during a representative fluctuation cycle from being directly transferred to changes in the supply temperature of the pressurized hot water.

[0110] The total capacity of the actual pressurized hot water buffer tank (30) can be determined by reflecting the distribution of fluctuation amplitude, temperature stratification inside the tank, heat loss, and design safety factor in the effective water quantity calculated by Equation 1.

[0111] The representative fluctuation period and allowable temperature deviation can be determined by verifying the actual pressure, temperature, flow rate, fluctuation range, and fluctuation period of the incinerator waste heat boiler, as well as the allowable heat source temperature range of the downstream module.

[0112] Next, the buffer via-flow path (41), buffer bypass path (42), and flow control section (40) will be described.

[0113] The buffer transit route (41) allows the pressurized hot water discharged from the heat exchanger (20) to pass through the pressurized hot water buffer tank (30).

[0114] The buffer bypass channel (42) allows the pressurized hot water discharged from the heat exchanger (20) to bypass the pressurized hot water buffer tank (30) and move to the rear supply channel.

[0115] The flow rate control unit (40) can control the flow rate ratio of pressurized hot water flowing through the buffer via-flow path (41) and the buffer bypass flow path (42).

[0116] The mixing or bypass system illustrated in FIG. 1 can be used as a flow control unit (40) that changes the degree of flow in the pressurized hot water buffer tank (30) by controlling the flow rates of the buffer flow path (41) and the buffer bypass flow path (42).

[0117] The flow control unit (40) may include a single three-way flow control valve or a plurality of automatic control valves connected to the buffer via flow path (41) and the buffer bypass flow path (42), respectively.

[0118] The flow rate ratio of the buffer via-flow path (41) can be determined by the value obtained by dividing the flow rate of the buffer via-flow path (41) by the total flow rate of the buffer via-flow path (41) and the buffer bypass path (42).

[0119] The control unit (60) can increase the flow rate of the buffer via-flow path (41) and decrease the flow rate of the buffer bypass path (42) when the variability index exceeds the first threshold value.

[0120] Accordingly, a larger portion of the pressurized hot water passes through the pressurized hot water buffer tank (30), and fluctuations in the supply temperature of the pressurized hot water can be mitigated by the heat storage or heat dissipation of the pressurized hot water buffer tank (30).

[0121] The control unit (60) can increase the flow rate of the buffer bypass flow path (42) and decrease the flow rate of the buffer bypass flow path (41) if the variability index is maintained at a level lower than the first threshold value for a set maintenance period.

[0122] Accordingly, when the fluctuating steam is in a stable state, the flow rate of pressurized hot water passing through the pressurized hot water buffer tank (30) can be reduced, and the pressure loss and pump power of the circulation system can be reduced.

[0123] The first threshold can be set to be greater than the second threshold, and the difference between the two thresholds can limit the repeated switching between buffer-passing operation and buffer-bypassing operation at short intervals.

[0124] The set holding time can be used as a time condition to limit the immediate switching of the operating mode when the variability indicator temporarily drops below the second threshold, and to verify whether the fluctuating steam is in a stable state.

[0126] Next, the sealed pressurized circulation loop (70) will be described.

[0127] The closed pressurized circulation loop (70) supplies pressurized hot water heated in the heat exchanger (20) to one or more of the heat pump module (71) and organic Rankine cycle module (72), and can return the pressurized hot water that has released heat from each module to the heat exchanger (20).

[0128] Referring to FIG. 1, the closed pressurized circulation loop (70) can connect the pressurized hot water outlet of the heat exchanger (20), the pressurized hot water buffer tank (30) or buffer bypass path (42), the distribution header (80), the heat pump module (71) or organic Rankine cycle module (72), the return header (90), and the pressurized hot water inlet of the heat exchanger (20).

[0129] The distribution header (80) can branch the pressurized hot water to the heat pump module (71) and the organic Rankine cycle module (72), and the return header (90) can combine the pressurized hot water discharged from each module.

[0130] The pressurized hot water can be repeatedly circulated inside a closed pressurized circulation loop (70) without being consumed for external hot water supply or cleaning.

[0131] Accordingly, the residual heat of the return water that has released heat from the heat pump module (71) and the organic Rankine cycle module (72) is not discarded to the outside but can be recovered again in the supercooling heat exchanger and the condensation heat exchanger.

[0132] The pressurized hot water initially charged can be treated with deoxygenation or anti-corrosion, and since the continuous inflow of external replenishment water is restricted, scale and corrosion can be managed.

[0133] The sealed pressurized circulation loop (70) may include a pressurized hot water circulation pump (73) that circulates pressurized hot water and a sealed expansion tank (74) that absorbs volumetric expansion of the pressurized hot water.

[0134] pressurized hot water circulation pump (73) It may include a variable speed driving method by an inverter, and the circulation flow rate of pressurized hot water may be changed according to a rotation speed control signal transmitted from the control unit (60).

[0135] Sealed expansion tank (74) It can absorb volume expansion due to the temperature rise of the pressurized hot water and maintain the pressure of the closed pressurized circulation loop (70).

[0136] The pressure of the sealed pressurized circulation loop (70) can be maintained above the saturation pressure corresponding to the supply temperature of the pressurized hot water, and the actual operating pressure can be set to include a margin for preventing boiling.

[0137] In one embodiment, when the supply temperature of the pressurized hot water is about 110°C, the pressure of the closed pressurized circulation loop (70) can be set to about 3 bar (g), but the actual pressure can be determined by checking the maximum supply temperature, pipe pressure loss and the allowable pressure of each device.

[0138] The supply temperature of the pressurized hot water can be set within a range of 100°C or higher and 140°C or lower, and the return temperature can be set lower than the supply temperature by 20°C or higher and 30°C or lower, but is not limited thereto.

[0140] Next, the first sensor unit (50) and the variability indicator are described.

[0141] The first sensor unit (50) can measure the pressure of fluctuating steam supplied from the incinerator waste heat boiler to the heat exchange unit (20).

[0142] The first sensor unit (50) is connected to the upstream side of the pressure reducing valve so that the pressure fluctuation of fluctuating steam generated in the incinerator waste heat boiler can be measured in a state before being mitigated by the pressure reducing valve. The first sensor unit (50) can transmit a pressure signal corresponding to the measured pressure to the control unit (60).

[0143] In one embodiment, the first sensor unit (50) can additionally measure the temperature and flow rate of fluctuating steam, and the temperature and flow rate can be used to check the operating status of the steam inlet unit (10) and to calculate the amount of recovered heat.

[0144] The control unit (60) can calculate a variability index using the pressure measured by the first sensor unit (50).

[0145] The volatility indicator may be the moving standard deviation of the pressure of fluctuating steam measured within a moving time window.

[0146] The travel time window may be a data interval containing multiple pressure measurements collected during the most recent set time based on the current time, and may be updated whenever a new pressure measurement is entered.

[0147] In one embodiment, the travel time window may be 60 seconds or more and 300 seconds or less, but may vary depending on the representative fluctuation cycle and pressure measurement cycle of the incinerator waste heat boiler.

[0148] The control unit (60) can calculate the average of the pressure measurements included in the moving time window and calculate the moving standard deviation using the degree to which each pressure measurement deviates from the average.

[0149] A larger volatility indicator may indicate that the pressure of fluctuating steam has changed significantly in the recent moving time window, while a smaller volatility indicator may indicate that the pressure of fluctuating steam has become relatively stable.

[0150] The first threshold, the second threshold, and the set holding time can be initially set using the pressure change range and representative fluctuation cycle of the fluctuating steam measured during the commissioning process.

[0151] The control unit (60) can update the first threshold value, the second threshold value, or the set holding time by checking the pressure signal stored during the operation period and the change in the supply temperature of the pressurized hot water.

[0153] Next, we will explain the driving control based on the volatility indicator.

[0154] FIG. 3 can illustrate a process of calculating a variability index for the pressure of fluctuating steam and controlling the ratio of the pressurized hot water buffer tank (30) and the pressurized hot water circulation state according to the calculated variability index. The control unit (60) can repeat steps S1 to S4 of FIG. 3 for every set control cycle.

[0155] In step S1 of FIG. 3, the control unit (60) can measure the pressure of fluctuating steam supplied from the incinerator waste heat boiler using the first sensor unit (50). The first sensor unit (50) can further measure the temperature or flow rate of the fluctuating steam, and the measured temperature and flow rate can be used to check the operating status of the steam inlet unit (10) or to calculate the amount of heat recovered from the heat exchange unit (20).

[0156] The pressure, temperature, or flow rate measured by the first sensor unit (50) can be transmitted to the control unit (60) according to a set sampling period. In one embodiment, the sampling period may be set to 1 second or less, but is not limited thereto and may vary depending on the fluctuation period of the fluctuating steam and the response speed of the first sensor unit (50).

[0158] In step S2 of FIG. 3, the control unit (60) can calculate a variability index using the pressure of the fluctuating steam measured by the first sensor unit (50). The variability index may be the moving standard deviation of a plurality of pressure measurements included within a moving time window.

[0159] The travel time window may include pressure values ​​measured during the most recent set time based on the current time, and may be updated by excluding the oldest pressure value whenever a new pressure value is entered. In one embodiment, the travel time window may be set to 60 seconds or more and 300 seconds or less, but the actual travel time window may vary depending on the representative fluctuation cycle of fluctuating steam generated in the incinerator waste heat boiler.

[0160] The control unit (60) can compare the variability index calculated in step S2 with a first threshold and a second threshold. The first threshold can be set to be greater than the second threshold.

[0161] When the volatility index exceeds the first threshold, the control unit (60) can apply the M1 buffer priority mode of FIG. 3.

[0162] In M1 buffer priority mode, the control unit (60) can increase the flow rate ratio of the buffer bypass channel (41) and decrease the flow rate ratio of the buffer bypass channel (42) so that a larger portion of the pressurized hot water discharged from the heat exchange unit (20) passes through the pressurized hot water buffer tank (30).

[0163] If the instantaneous temperature of the pressurized hot water is higher than the temperature inside the pressurized hot water buffer tank (30), the pressurized hot water buffer tank (30) can store excess heat, and if the instantaneous temperature of the pressurized hot water is lower than the temperature inside the pressurized hot water buffer tank (30), the pressurized hot water buffer tank (30) can transfer the stored heat to the pressurized hot water. Accordingly, the increase or decrease in heat of the fluctuating steam can be mitigated from being directly transferred to the heat pump module (71) and the organic Rankine cycle module (72).

[0164] The control unit (60) can limit the rate of change in the opening of the automatic steam control valve included in the steam inlet unit (10) in M1 buffer priority mode. By limiting the rate of change in the opening of the automatic steam control valve, the fluctuation in heat quantity can be absorbed by utilizing the heat storage or heat dissipation of the pressurized hot water buffer tank (30) while mitigating the rapid change in the pressure or flow rate of the fluctuating steam.

[0165] If the volatility index is above the second threshold and below the first threshold, the control unit (60) can apply the M2 standard mode of FIG. 3.

[0166] In M2 standard mode, the control unit (60) can control the flow rate control unit (40) and the pressurized hot water circulation pump (73) to maintain the current flow rate ratio of the buffer via-flow path (41) and the buffer bypass-flow path (42), or to maintain the difference between the supply temperature and return temperature of the pressurized hot water within a set range.

[0167] In the M2 standard mode, cascade proportional-integral-derivative control or model predictive control may be applied. In one embodiment, the control unit (60) may control the flow rate control unit (40) or the pressurized hot water circulation pump (73) so that the supply temperature of the pressurized hot water is maintained within a range of ±3℃ based on approximately 110℃, but the temperature corresponds to one design example.

[0168] If the volatility indicator is maintained below the second threshold for a set maintenance period, the control unit (60) can apply the M3 direct supply parallel mode of FIG. 3.

[0169] In the M3 direct supply parallel mode, the control unit (60) can increase the flow rate ratio of the buffer bypass channel (42) and decrease the flow rate ratio of the buffer bypass channel (41), thereby reducing the flow rate of pressurized hot water passing through the pressurized hot water buffer tank (30).

[0170] When the flow rate ratio of the buffer bypass channel (42) increases, pressurized hot water can be supplied to the downstream module by bypassing the pressurized hot water buffer tank (30) while the fluctuation is relatively small, so the pressure loss of the channel connected to the pressurized hot water buffer tank (30) and the power consumption of the circulation pump can be reduced.

[0171] The set holding time may be a time condition to restrict the immediate switching to the M3 direct supply parallel mode when the volatility indicator temporarily drops below the second threshold, and to verify whether the fluctuating steam is maintained in a stable state.

[0172] The first threshold, the second threshold, and the set holding time can be determined using pressure fluctuation data of fluctuating steam measured during the commissioning process. The control unit (60) can update the first threshold, the second threshold, or the set holding time by checking the pressure signal stored during the operation period and the change in the supply temperature of the pressurized hot water.

[0173] The control unit (60) can proceed to step S3 of FIG. 3 after selecting any one of M1 buffer priority mode, M2 standard mode and M3 direct supply parallel mode.

[0175] In step S3 of FIG. 3, the control unit (60) can calculate the difference between the supply temperature and the return temperature using the supply temperature and the return temperature of the pressurized hot water measured by the second sensor unit (51).

[0176] The control unit (60) can control the rotational speed of the pressurized hot water circulation pump (73) so that the difference between the supply temperature and the return temperature of the pressurized hot water is maintained at 20°C or higher and 30°C or lower. In one embodiment, the pressurized hot water circulation pump (73) can be controlled so that the difference between the supply temperature and the return temperature is maintained at approximately 25°C.

[0177] If the difference between the supply temperature and the return temperature of the pressurized hot water is greater than the set range, the control unit (60) can increase the rotational speed of the pressurized hot water circulation pump (73) to increase the circulation flow rate of the pressurized hot water. Conversely, if the difference between the supply temperature and the return temperature is smaller than the set range, the control unit (60) can decrease the rotational speed of the pressurized hot water circulation pump (73) to decrease the circulation flow rate of the pressurized hot water.

[0178] The control unit (60) can proceed to step S4 of Fig. 3 after proceeding to step S3.

[0180] In step S4 of FIG. 3, the control unit (60) can update the distribution ratio between the heat pump module (71) and the organic Rankine cycle module (72).

[0181] The control unit (60) can determine the distribution ratio using one or more of the real-time power unit price, on-site heat demand, ambient temperature, variability index, power consumption of the heat pump module (71), and power generation of the organic Rankine cycle module (72).

[0182] In one embodiment, the distribution ratio can be updated at a cycle of 5 minutes or more and 15 minutes or less. When the variability index is large, the amount of change in the distribution ratio can be limited so that the operating flow path and heat load do not change abruptly, and when the variability index is small, the distribution ratio can be updated according to changes in the power unit price or on-site heat demand.

[0183] After completing step S4, the control unit (60) can return to step S1 of the next control cycle to repeat the measurement of the pressure of the fluctuating steam, calculation of the variability index, selection of the operating mode, temperature difference control, and updating of the distribution ratio.

[0185] Next, the second sensor unit (51) and the temperature and circulation control of the pressurized hot water will be described.

[0186] 2nd sensor unit (51) It can measure the outlet temperature of the condensate discharged from the supercooling heat exchanger, as well as the supply temperature and return temperature of the pressurized hot water.

[0187] The outlet temperature of the condensate can be measured at the outlet side of the condensate of the supercooling heat exchanger. The supply temperature of the pressurized hot water can be measured at the location where the pressurized hot water heated in the condensing heat exchanger is supplied to the flow control unit (40), and the return temperature of the pressurized hot water can be measured before the pressurized hot water that has released heat from the heat pump module (71) or the organic Rankine cycle module (72) flows into the supercooling heat exchanger.

[0188] The control unit (60) can control the rotational speed of the pressurized hot water circulation pump (73) using the temperature measured by the second sensor unit (51) so that the outlet temperature of the condensate discharged from the supercooling heat exchanger is maintained at a temperature 5°C or higher and 10°C or lower than the return temperature of the pressurized hot water.

[0189] Additionally, the control unit (60) can assistly control the flow rate control unit (40) to mitigate temperature changes of the pressurized hot water returning to the heat exchange unit (20).

[0190] If the difference between the outlet temperature of the condensate and the return temperature of the pressurized hot water is maintained at 5°C or more and 10°C or less, the temperature difference required for supercooling heat exchange can be secured while recovering the sensible heat remaining in the condensate.

[0191] In addition, by limiting abrupt changes in condensate outlet conditions even when the fluctuating steam flow rate changes, it is possible to mitigate abrupt changes in the condensation state and condensation pressure in the condensation heat exchanger.

[0192] pressurized hot water circulation pump (73)The rotational speed can be adjusted within a range greater than the minimum flow rate required for the heat exchanger (20), heat pump module (71), and organic Rankine cycle module (72), and less than the maximum allowable flow rate of the piping and each device.

[0193] Sealed expansion tank (74) It can absorb volume expansion due to temperature changes of the pressurized hot water and maintain the pressure of the closed pressurized circulation loop (70). The pressure of the closed pressurized circulation loop (70) can be maintained above the saturation pressure corresponding to the supply temperature of the pressurized hot water, and the actual operating pressure can be set to include a pressure margin to prevent boiling of the pressurized hot water.

[0195] Next, the heat pump module (71) and the organic Rankine cycle module (72) will be described.

[0196] The heat pump module (71) can receive heat from pressurized hot water supplied through a closed pressurized circulation loop (70) as an evaporator heat source and produce hot water or low-pressure steam at a temperature higher than that of the pressurized hot water.

[0197] The heat pump module (71) may include a refrigerant circulation system including a compressor, a condenser, an expansion means, and an evaporator, and the pressurized hot water may move to a return header (90) after transferring heat to the refrigerant in the evaporator.

[0198] The organic Rankine cycle module (72) can evaporate the organic working fluid using the heat of pressurized hot water supplied through the closed pressurized circulation loop (70), and drive the expander with the evaporated organic working fluid to produce electricity.

[0199] The organic Rankine cycle module (72) may include an evaporator, an expander, a condenser, and a working fluid pump, and the pressurized hot water may transfer heat from the evaporator to the organic working fluid and then move to the return header (90).

[0200] In one embodiment, the organic Rankine cycle module (72) may include a screw-type expander, and the screw-type expander may secure an operating range in a partial load condition where the heat source flow rate changes, but is not limited thereto.

[0201] Since the heat exchanger (20) and the pressurized hot water buffer tank (30) mitigate the heat fluctuation of the fluctuating steam, pressurized hot water with a more stable temperature and flow rate can be supplied to the heat pump module (71) and the organic Rankine cycle module (72) than when fluctuating steam is supplied directly.

[0203] Next, parallel circulation paths, series circulation paths (76), and bypass operation will be described.

[0204] Referring to FIG. 4 and Table 1, the closed pressurized circulation loop (70) supplies pressurized hot water supplied from the distribution header (80) to one or more of the heat pump module (71) and the organic Rankine cycle module (72), and can recover the pressurized hot water that has released heat from each module to the return header (90). In one embodiment, the distribution header (80) supplies pressurized hot water at approximately 110°C, and the return header (90) can return the pressurized hot water, which has been lowered to approximately 85°C by releasing heat from each module, to the heat exchanger (20).

[0205] A first automatic control valve (V1) for controlling the flow rate of pressurized hot water supplied to the heat pump module (71) may be connected between the distribution header (80) and the heat pump module (71). A second automatic control valve (V2) for controlling the flow rate of pressurized hot water supplied to the organic Rankine cycle module (72) may be connected between the distribution header (80) and the organic Rankine cycle module (72).

[0206] A first flow meter may be connected to the flow path supplying pressurized hot water to the heat pump module (71), and a second flow meter may be connected to the flow path supplying pressurized hot water to the organic Rankine cycle module (72).

[0207] The first flow meter and the second flow meter can measure the flow rate of pressurized hot water supplied to each module and transmit a flow rate signal corresponding to the measured flow rate to the control unit (60).

[0208] The control unit (60) can determine the ratio of the flow rate actually supplied to the heat pump module (71) and the organic Rankine cycle module (72) using the flow rates measured by the first flow meter and the second flow meter. In addition, the opening of the first automatic control valve (V1) and the second automatic control valve (V2) can be adjusted so that the determined ratio of the flow rate corresponds to the selected distribution ratio.

[0209] A series circulation path (76) may be connected between the pressurized hot water outlet of the organic Rankine cycle module (72) and the pressurized hot water inlet of the heat pump module (71), and a third automatic control valve (V3) that controls whether pressurized hot water passes through may be connected to the series circulation path (76). Additionally, a bypass path (77) that circulates pressurized hot water without passing through the heat pump module (71) and the organic Rankine cycle module (72) may be connected between the distribution header (80) and the return header (90), and a fourth automatic control valve (V4) may be connected to the bypass path (77).

[0210] The first automatic control valve (V1) to the third automatic control valve (V3) can be used as a flow path switching unit to switch the flow of pressurized hot water between the parallel circulation path and the series circulation path (76).

[0211] The control unit (60) can select one of parallel simultaneous operation, series operation, heat pump standalone operation, organic Rankine cycle standalone operation, and module stop / maintenance operation by controlling the opening, closing, or opening of the first automatic control valve (V1) to the fourth automatic control valve (V4).

[0212] In parallel simultaneous operation, the first automatic control valve (V1) and the second automatic control valve (V2) can be opened respectively, and the third automatic control valve (V3) and the fourth automatic control valve (V4) can be closed. Accordingly, the pressurized hot water supplied from the distribution header (80) can be branched and supplied to the heat pump module (71) and the organic Rankine cycle module (72), respectively.

[0213] In parallel simultaneous operation, the control unit (60) can adjust the opening of the first automatic control valve (V1) and the second automatic control valve (V2) according to the distribution ratio. For example, if the ratio of the amount of heat supplied to the heat pump module (71) is set as the distribution ratio α, the opening of the first automatic control valve (V1) can be adjusted to correspond to the distribution ratio α, and the opening of the second automatic control valve (V2) can be adjusted to correspond to 1-α. However, the actual valve opening can be determined by considering the pressure loss of each flow path, the flow rate characteristics of the valve, and the required flow rate of each module.

[0214] In series operation, the second automatic control valve (V2) and the third automatic control valve (V3) can be opened, and the first automatic control valve (V1) and the fourth automatic control valve (V4) can be closed. Accordingly, the pressurized hot water at a relatively high temperature supplied from the distribution header (80) can be supplied first to the organic Rankine cycle module (72). The pressurized hot water, whose temperature has been lowered by releasing some heat from the organic Rankine cycle module (72), can be supplied to the heat pump module (71) through the series circulation path (76), and after releasing heat again from the heat pump module (71), it can move to the return header (90).

[0215] In such series operation, heat in a relatively high temperature range is first used for power generation in the organic Rankine cycle module (72), and after heat is released from the organic Rankine cycle module (72), the remaining heat in the low temperature range is heated in the heat pump module (71) and reused, thereby increasing the range of use of thermal energy held by the pressurized hot water and the exergy utilization rate.

[0216] In heat pump standalone operation, the first automatic control valve (V1) can be opened and the second automatic control valve (V2) to the fourth automatic control valve (V4) can be closed. Accordingly, the pressurized hot water from the distribution header (80) can be supplied to the heat pump module (71) to provide high-temperature heat and then move to the return header (90).

[0217] In organic Rankine cycle standalone operation, the second automatic control valve (V2) can be opened and the first automatic control valve (V1), the third automatic control valve (V3), and the fourth automatic control valve (V4) can be closed. Accordingly, the pressurized hot water from the distribution header (80) can be supplied to the organic Rankine cycle module (72), used for power generation, and then moved to the return header (90).

[0218] When a stop signal or a maintenance signal is input to either the heat pump module (71) or the organic Rankine cycle module (72), the control unit (60) may close the automatic control valve corresponding to the module to be stopped or maintained and open the automatic control valve corresponding to the remaining module that can be operated. At this time, the third automatic control valve (V3) may be closed, and the fourth automatic control valve (V4) may be partially or fully opened to maintain the circulation flow rate required for the sealed pressurized circulation loop (70).

[0219] When the fourth automatic control valve (V4) is opened, some or all of the pressurized hot water can be moved from the distribution header (80) to the return header (90) through the bypass path (77). Accordingly, the minimum circulation flow rate of the pressurized hot water circulation pump (73) can be secured even during the shutdown or maintenance of the module, and the interruption of circulation in the sealed pressurized circulation loop (70) can be limited.

[0220] Driving mode V1 (HP) V2 (ORC) V3 (serial) V4 (bypass) note Parallel simultaneous operation ◐ (α) ◐ (1-α) ● ● Continuous distribution of heat and electricity with distribution ratio α Series (Cascade) ● ○ ○ ● ORC downstream low-temperature water as an HP heat source HP Exclusive ○ ● ● ● Heat demand concentration (winter) ORC standalone ● ○ ● ● Power peak season (summer) Module Stop / Maintenance ● / ○ ○ / ● ● ◐ Automatic stop line isolation, non-stop operation

[0222] In [Table 1], empty circles indicate the open state of the corresponding automatic control valve, filled circles indicate the closed state, and partially filled circles may indicate a state where the opening is adjusted according to the distribution ratio or the required circulation flow rate. The valve state shown in FIG. 4 is an example of each operating mode, and the actual opening and switching point may vary depending on the distribution ratio, the operating state of each module, the required heat amount, the amount of power generated, and the circulation flow rate of the sealed pressurized circulation loop (70).

[0224] Next, the determination of the distribution ratio is explained.

[0225] Referring to FIG. 5, the control unit (60) can determine the heat distribution ratio between the heat pump module (71) and the organic Rankine cycle module (72) using a plurality of operating information.

[0226] Specifically, the control unit (60) can use one or more of real-time power unit price, on-site heat demand, ambient temperature or weather forecast, variability indicator and module efficiency characteristics as input information.

[0227] Real-time power unit prices may include system marginal prices or time-of-use power rates, and on-site heat demand may include the demand for hot water or steam required by the process.

[0228] The ambient temperature or weather forecast can be used as information to predict future changes in heat demand. The variability index can be used as information indicating the stable state of the fluctuating steam heat source, and the module efficiency characteristics may include the power consumption of the heat pump module (71), the power generation of the organic Rankine cycle module (72), and the partial load efficiency characteristics of each module.

[0229] The control unit (60) can compare operating conditions according to multiple candidate distribution ratios using multiple input information.

[0230] For example, the control unit (60) can calculate the benefits from power production or power saving and the benefits from heat supply for each candidate distribution ratio, and compare the net energy benefits by considering the auxiliary power costs consumed by the pressurized hot water circulation pump (73) and the auxiliary equipment of each module.

[0231] The control unit (60) can select a distribution ratio that increases net energy benefits among a plurality of candidate distribution ratios.

[0232] The distribution ratio may be the value obtained by dividing the heat amount of pressurized hot water supplied to the heat pump module (71) by the total heat amount of pressurized hot water supplied to the heat pump module (71) and the organic Rankine cycle module (72).

[0233] If the distribution ratio increases, the proportion of heat energy of the pressurized hot water supplied to the heat pump module (71) may increase, and if the distribution ratio decreases, the proportion of heat energy of the pressurized hot water supplied to the organic Rankine cycle module (72) may increase.

[0234] The control unit (60) can apply the selected distribution ratio to the distribution header (80) to control the flow rate of pressurized hot water supplied to the heat pump module (71) and the organic Rankine cycle module (72), respectively.

[0235] The control unit (60) can select a parallel circulation path or a series circulation path (76) using the selected distribution ratio and the heat source inlet conditions and operating state of each module.

[0236] When a parallel circulation path is selected, pressurized hot water can be supplied by branching from the distribution header (80) to the heat pump module (71) and the organic Rankine cycle module (72), respectively.

[0237] When the serial circulation path (76) is selected, pressurized hot water is first supplied to the organic Rankine cycle module (72), and the pressurized hot water, which has released some heat from the organic Rankine cycle module (72), can be supplied to the heat pump module (71).

[0238] As shown in the seasonal application example in Fig. 5, when the real-time power unit price rises during the peak power hours of summer and the on-site heat demand is relatively low, the control unit (60) can reduce the distribution ratio to increase the proportion of heat of the pressurized hot water supplied to the organic Rankine cycle module (72).

[0239] Accordingly, the power generation of the organic Rankine cycle module (72) can be increased to respond to the summer power peak.

[0240] Conversely, if the on-site heat demand for process hot water or steam increases during the winter season, the control unit (60) can increase the distribution ratio to increase the proportion of heat of the pressurized hot water supplied to the heat pump module (71).

[0241] Accordingly, the production volume of high-temperature hot water or low-pressure steam using the heat pump module (71) can be increased.

[0242] However, the control unit (60) may determine the distribution ratio by using real-time power unit price, on-site heat demand, ambient temperature or weather forecast, variability indicator and the operating characteristics of each module together, rather than uniformly determining the distribution ratio based only on the season.

[0243] For example, even during the summer, if the on-site heat demand increases or the power generation efficiency of the organic Rankine cycle module (72) is low, the proportion of heat supplied to the heat pump module (71) can be increased.

[0244] Even during the winter season, if the real-time power unit price is high and the on-site heat demand is low, the proportion of heat supplied to the organic Rankine cycle module (72) can be increased.

[0245] The distribution ratio can be periodically updated according to changes in operating conditions.

[0246] In one embodiment, the distribution ratio may be updated at a cycle of 5 minutes or more and 15 minutes or less, but the actual update cycle may vary depending on the update cycle of real-time power unit price, on-site heat demand, ambient temperature, and variability indicator.

[0247] In cases where the variability indicator is large, the amount of change in the distribution ratio can be limited to prevent abrupt changes in the operating flow path and the heat load of each module.

[0248] When the variability indicator is small, the distribution ratio can be updated according to changes in real-time power unit prices, on-site heat demand, or ambient temperature.

[0249] In one embodiment, the control unit (60) may apply rule-based control that determines the distribution ratio according to preset conditions.

[0250] In another embodiment, the control unit (60) may apply model prediction control to determine the distribution ratio using heat demand within the prediction clock, real-time power unit price, or weather forecast, but is not limited thereto.

[0252] Next, the calculation of the heat balance and device capacity according to one embodiment will be described.

[0253] In this embodiment, fluctuating steam with a saturation temperature of about 150°C and a rated flow rate of about 1.5 t / h is used as a heat source, and the pressurized hot water supply temperature of the closed pressurized circulation loop (70) is set to about 110°C and the return temperature to about 85°C.

[0254] The saturation pressure corresponding to a saturation temperature of about 150°C is about 4.8 bar(a), and the mass flow rate of fluctuating steam is converted to about 0.417 kg / s.

[0255] The latent heat of vaporization of saturated steam at approximately 150°C was applied as approximately 2,114 kJ / kg, and accordingly, the latent heat recovered in the condensation heat exchanger is calculated to be approximately 881 kW.

[0256] As a result of cooling the condensate discharged from the condensation heat exchanger from about 150°C to about 90°C and applying the specific heat of the condensate as about 4.29 kJ / kg·K, the sensible heat recovered in the supercooling heat exchanger is calculated to be about 107 kW.

[0257] The total amount of heat recovered from the condensing heat exchanger and the subcooling heat exchanger is calculated to be approximately 988 kW, and the sensible heat recovered accounts for about 11% of the total recovered heat. Compared to the case where only latent heat is recovered, this corresponds to an additional recovery of about 12%.

[0258] If the difference between the supply temperature and the return temperature of the pressurized hot water is set to about 25°C and the specific heat of the pressurized hot water is applied as about 4.23 kJ / kg·K, the pressurized hot water circulation flow rate to transport about 988 kW of heat is calculated to be about 9.34 kg / s, which corresponds to about 34 t / h or about 35 m³ / h.

[0259] The pressurized hot water recovers about 107 kW of sensible heat in the supercooling heat exchanger, so it rises by about 2.7°C, and the return water at about 85°C is preheated to about 88°C. The preheated pressurized hot water recovers latent heat in the condensing heat exchanger and is heated to about 110°C.

[0260] The pressure of the sealed pressurized circulation loop (70) in this embodiment is set to about 3 bar (g), which is a pressure higher than the saturation pressure corresponding to a pressurized hot water supply temperature of about 110°C.

[0261] The supply temperature stability of the pressurized hot water is targeted at approximately 110℃±3℃ and can be maintained by switching the operating mode according to the variability index and by thermal buffering of the pressurized hot water buffer tank (30).

[0262] When mathematical formula 1 is calculated by setting the representative fluctuation cycle to approximately 300 seconds and the allowable temperature deviation to approximately 5℃, the effective water volume of the pressurized hot water buffer tank (30) is calculated to be approximately 15 m³. When the representative fluctuation cycle is set to approximately 900 seconds, the effective water volume of the pressurized hot water buffer tank (30) is calculated to be approximately 44 m³. If the representative fluctuation cycle increases threefold, the required effective water volume also increases by approximately threefold.

[0263] When the entire amount of recovered heat is supplied to the organic Rankine cycle module (72), a screw-type expander is applied at a heat source temperature of about 110°C, and the heat-to-electricity conversion efficiency is assumed to be about 8% or more and 10% or less, the total output of the generator can be expected to be about 80 kW or more and 100 kW or less. The actual net power generation can be calculated by excluding the power consumed by the working fluid pump, the pressurized hot water circulation pump (73), the cooling water pump, the cooling tower or the fan and control device of the dry cooler.

[0264] The numerical values ​​of this embodiment are calculated according to design formulas and defined operating conditions, and are not limited to specific steam temperature, steam flow rate, pressurized hot water temperature, buffer tank capacity, or power generation output.

[0266] Next, modularization and installation are described. The steam inlet (10), heat exchanger (20), pressurized hot water buffer tank (30), distribution header (80), and control unit (60) can be included in a single core skid.

[0267] The heat pump module (71) and the organic Rankine cycle module (72) can each be manufactured in the form of an independent skid or container.

[0268] The fluid interface between the core skid and each module can be formed with standard flange specifications, and the control interface can be connected using a standard communication method.

[0269] Accordingly, the system can be installed on-site by connecting piping, electricity, and communications, and the scope of modification for existing incineration facilities can be reduced.

[0270] If the on-site heat demand or power generation capacity increases, multiple heat pump modules (71) or multiple organic Rankine cycle modules (72) can be added in parallel.

[0271] Finally, the control method is explained.

[0272] The control method according to the present invention may include the step of introducing fluctuating steam supplied from an incinerator waste heat boiler into a heat exchanger (20) through a steam inlet (10).

[0273] In the stage of fluctuating steam inflow through the steam inlet (10), the pressure of the fluctuating steam can be controlled to below the design pressure of the heat exchanger (20) using a pressure reducing valve, and the flow rate of the fluctuating steam supplied to the heat exchanger (20) can be controlled using an automatic steam control valve.

[0274] The control method may include the step of recovering latent heat by condensing fluctuating steam in a condensing heat exchanger, recovering sensible heat by cooling the condensate in a subcooling heat exchanger, and heating pressurized hot water using the recovered latent heat and sensible heat.

[0275] The control method may include the step of measuring the pressure of the fluctuating steam using the first sensor unit (50) and calculating a variability index corresponding to the standard deviation of movement within the movement time window using the measured pressure.

[0276] The control method may include the step of limiting the rate of change of opening of the automatic steam control valve and increasing the flow rate of the buffer flow path (41) when the variability index exceeds the first threshold.

[0277] The control method may include the step of increasing the flow rate of the buffer bypass channel (42) when the variability indicator is maintained below a second threshold for a set maintenance time.

[0278] The control method may include the step of using the temperature measured by the second sensor unit (51) to check the difference between the outlet temperature of the condensate and the return temperature of the pressurized hot water and the difference between the supply temperature and the return temperature of the pressurized hot water, and controlling the flow rate control unit (40) or the pressurized hot water circulation pump (73).

[0279] The control method may include the step of supplying heated pressurized hot water to one or more of the heat pump module (71) and the organic Rankine cycle module (72).

[0280] The control method may include the step of determining a distribution ratio using one or more of the real-time power unit price, on-site heat demand, ambient temperature, variability index, power consumption of the heat pump module (71), and power generation of the organic Rankine cycle module (72), and selecting a parallel circulation path or a series circulation path (76).

[0281] The control method may include the step of blocking the pressurized hot water supplied to the corresponding module when a stop signal is input to either the heat pump module (71) or the organic Rankine cycle module (72), and supplying the pressurized hot water to the bypass path (77) or the remaining operable module.

[0282] The control method may include the step of returning pressurized hot water, which has released heat from one or more of the heat pump module (71) and organic Rankine cycle module (72), to the heat exchanger (20) through the return header (90).

[0283] Each step can be repeated at set control cycles, and the control cycle may vary depending on the state of fluctuating steam and the operating state of the downstream module.

[0285] A person skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and their equivalents should be interpreted as being included within the scope of the present invention. Furthermore, the order of operation of the configurations described in the above process does not necessarily need to be performed in a chronological order, and it is understood that even if the order of execution of each configuration and step is changed, such a process may fall within the scope of the present invention as long as it satisfies the essence of the present invention. Explanation of the symbols

[0287] 10: Steam inlet 20: Heat exchanger 30: Pressurized hot water buffer tank 40: Flow control unit 41: Buffer route 42: Buffer bypass route 50: 1st sensor unit 51: 2nd sensor unit 60: Control unit 70: Closed pressurized circulation loop 71: Heat pump module 72: Organic Rankine cycle module 73: Pressurized hot water circulation pump 74: Sealed expansion tank 76: Series circulation path 77: Bypass Euro 80: Distribution Header 90: Return header V1: First automatic control valve V2: Second automatic control valve V3: Third automatic control valve V4: 4th automatic control valve

Claims

Claim 1 A steam inlet that introduces fluctuating steam supplied from an incinerator waste heat boiler into a heat exchanger; a heat exchanger comprising a condensing heat exchanger that condenses the fluctuating steam to recover latent heat and a subcooling heat exchanger that cools the condensate discharged from the condensing heat exchanger to recover sensible heat, and which heats pressurized hot water using the latent heat recovered from the condensing heat exchanger and the sensible heat recovered from the subcooling heat exchanger; a pressurized hot water buffer tank that stores the pressurized hot water heated in the heat exchanger; a buffer bypass path through which pressurized hot water discharged from the heat exchanger passes through the pressurized hot water buffer tank; a buffer bypass path through which pressurized hot water discharged from the heat exchanger bypasses the pressurized hot water buffer tank; a flow control unit that regulates the flow rate ratio of pressurized hot water flowing through the buffer bypass path and the buffer bypass path; and a closed pressurized circulation that supplies pressurized hot water to one or more of a heat pump module and an organic Rankine cycle module, and returns the pressurized hot water that has released heat from one or more of the heat pump module and the organic Rankine cycle module to the heat exchanger. A hybrid energy system based on fluctuating steam heat source stabilization, comprising: a loop; a first sensor unit for measuring the pressure of fluctuating steam; and a control unit for calculating a variability index using the pressure measured by the first sensor unit and controlling a flow rate control unit according to the variability index. Claim 2 A hybrid energy system based on stabilizing a fluctuating steam heat source, wherein, in claim 1, the variability index is a moving standard deviation of the pressure of the fluctuating steam measured within a moving time window, and the control unit increases the flow rate ratio of the buffer bypass path and decreases the flow rate ratio of the buffer bypass path when the variability index exceeds a first threshold, thereby mitigating the supply temperature fluctuation of the pressurized hot water by heat storage or heat dissipation of the pressurized hot water buffer tank, and when the variability index is maintained below a second threshold that is smaller than the first threshold for a set maintenance time, the control unit increases the flow rate ratio of the buffer bypass path and decreases the flow rate ratio of the buffer bypass path, thereby reducing the flow rate of the pressurized hot water passing through the pressurized hot water buffer tank. Claim 3 A hybrid energy system based on fluctuating steam heat source stabilization according to claim 2, wherein the effective amount of the pressurized hot water buffer tank is determined to satisfy the following Equation 1 so as to limit the change in the supply temperature of the pressurized hot water to within an allowable temperature deviation, corresponding to the average recovered heat amount recovered in the heat exchanger during the representative fluctuation cycle of the fluctuating steam. [Equation 1] V_eff ≥ Q_avg × τ ÷ (ρ × cp × ΔT_allow) where V_eff is the effective amount of the pressurized hot water buffer tank, Q_avg is the average recovered heat amount recovered in the heat exchanger during the representative fluctuation cycle, τ is the representative fluctuation cycle, ρ is the density of the pressurized hot water, cp is the specific heat of the pressurized hot water, and ΔT_allow is the allowable temperature deviation. Claim 4 A hybrid energy system based on stabilizing a fluctuating steam heat source according to claim 2, further comprising: a second sensor unit for measuring the outlet temperature of condensate discharged from a supercooling heat exchanger, and the supply temperature and return temperature of pressurized hot water; a pressurized hot water circulation pump for circulating pressurized hot water in a closed pressurized circulation loop; and a closed expansion tank for absorbing volumetric expansion of the closed pressurized circulation loop and maintaining pressure; wherein the pressurized hot water sequentially passes through the supercooling heat exchanger and the condensation heat exchanger and undergoes heat exchange in a counterflow with fluctuating steam and condensate, and the control unit controls the flow rate control unit or the pressurized hot water circulation pump using the temperature measured by the second sensor unit so that the outlet temperature of the condensate is maintained at a level 5°C or higher and 10°C or lower than the return temperature of the pressurized hot water, and the difference between the supply temperature of the pressurized hot water and the return temperature of the pressurized hot water is maintained at a level 20°C or higher and 30°C or lower, and the closed expansion tank maintains the pressure of the closed pressurized circulation loop at a level higher than the saturation pressure corresponding to the supply temperature of the pressurized hot water. Claim 5 In claim 1, a parallel circulation path that branches and supplies pressurized hot water to a heat pump module and an organic Rankine cycle module, respectively; and a series circulation path that supplies pressurized hot water to the organic Rankine cycle module and then supplies the pressurized hot water, from which heat has been released in the organic Rankine cycle module, to the heat pump module; A hybrid energy system based on the stabilization of a fluctuating steam heat source, comprising: a flow switching unit that switches the flow of pressurized hot water between the parallel circulation channel and the series circulation channel; wherein the control unit sets the value obtained by dividing the heat amount of pressurized hot water supplied to the heat pump module by the total heat amount of pressurized hot water supplied to the heat pump module and the organic Rankine cycle module as the distribution ratio, and determines the distribution ratio using real-time power unit price, on-site heat demand, ambient temperature, the variability index, the power consumption of the heat pump module, and the power generation amount of the organic Rankine cycle module so as to increase the net energy benefit, which is the sum of the benefits from power production or reduction and the benefits from heat supply, excluding auxiliary power costs, and selects the parallel circulation channel or the series circulation channel according to the determined distribution ratio. Claim 6 A hybrid energy system based on the stabilization of a fluctuating steam heat source, wherein, in claim 5, a plurality of automatic control valves each controlling the flow rate of pressurized hot water supplied to the heat pump module and the organic Rankine cycle module; and a bypass path between the distribution header and the return header for circulating pressurized hot water without passing through the heat pump module and the organic Rankine cycle module; wherein the control unit, when a stop signal is input to either the heat pump module or the organic Rankine cycle module, cuts off the pressurized hot water supplied to the module to which the stop signal was input, and supplies the cut-off pressurized hot water to the corresponding bypass path or the remaining operable module so as to maintain the circulation of pressurized hot water in a closed pressurized circulation loop. Claim 7 A hybrid energy system based on fluctuating steam heat source stabilization according to claim 1, wherein the steam inlet includes a pressure reducing valve, and the first sensor unit is connected to the upstream side of the pressure reducing valve so that the pressure fluctuation of fluctuating steam generated in the incinerator waste heat boiler is measured in a state before being mitigated by the pressure reducing valve. Claim 8 A hybrid energy system based on the stabilization of a fluctuating steam heat source, wherein, in paragraph 2, the steam inlet includes an automatic steam control valve that controls the flow rate of fluctuating steam flowing into the heat exchanger, and the control unit limits the rate of change in opening of the automatic steam control valve and increases the flow rate ratio of the buffer flow path when the variability index exceeds the first threshold value, thereby mitigating the rapid transmission of pressure or flow rate changes of the fluctuating steam to the heat exchanger while buffering the heat quantity fluctuation by heat storage or heat dissipation of the pressurized hot water buffer tank. Claim 9 A step of introducing fluctuating steam supplied from an incinerator waste heat boiler into a heat exchanger through a steam inlet; a step of condensing the fluctuating steam in a condensing heat exchanger of the heat exchanger to recover latent heat, cooling the condensate discharged from the condensing heat exchanger in a subcooling heat exchanger to recover sensible heat, and heating pressurized hot water using the latent heat recovered from the condensing heat exchanger and the sensible heat recovered from the subcooling heat exchanger; a step of measuring the pressure of the fluctuating steam using a first sensor unit and calculating a variability index using the measured pressure; a step of adjusting the flow rate ratio of pressurized hot water flowing through a buffer bypass path passing through a pressurized hot water buffer tank and a buffer bypass path bypassing the pressurized hot water buffer tank according to the variability index; and a step of supplying the heated pressurized hot water to one or more of a heat pump module and an organic Rankine cycle module. A control method for a fluctuating steam heat source stabilization-based hybrid energy system comprising: a step of returning pressurized hot water, which has released heat from one or more of the heat pump module and the organic Rankine cycle module, to the heat exchanger.

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