Heat Low Pressure Research Articles

Compositing of rGO to TiO2 by Low-Temperature Treatment and Their Photocatalytic Properties

Reduced graphene oxide (rGO)/TiO2 nanocomposites were prepared by low-temperature and low-pressure heat treatment. The structure and photocatalysis performance of the composites were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and UV-visible diffuse reflectance spectrum (UV-Vis DRS). The photocatalytic degradation performance of methyl orange (MO) by composites with different raw material ratios was studied under simulated solar-irradiation conditions. Results indicated that graphene oxide (GO) was reduced to graphene during heat treatment and bonded well with TiO2. Compared with TiO2, GO addition greatly improved its photocatalytic efficiency. Under simulated sunlight irradiation, the samples exhibited good photocatalysis performance. Within 50[Formula: see text]min, MO can be rapidly degraded by TiO2/40% rGO composite.

Thermo-economic investigation and comparative multi-objective optimization of dual-pressure evaporation ORC using binary zeotropic mixtures as working fluids for geothermal energy application

This contribution performs an energy, exergy, and exergoeconomic (3E) analysis of a dual-pressure evaporation organic Rankine cycle system employing twenty different binary zeotropic mixtures as working fluids for power production from a geothermal field. To this end, the designed system is modeled, invoking the mass and energy conservation laws and the exergy and cost balance analyses. Specific Exergy Costing (SPECO) procedure is utilized to provide practical insights into the exergoeconomic aspect of the system. Comparative optimization based on the multi-objective genetic algorithm is accomplished for each mixture in order to simultaneously maximize the exergy efficiency and minimize the total cost rate using the design variables of pressure factor in low-pressure and high-pressure stages, mixture fraction, pinch point temperature differences in low-pressure and high-pressure heat exchangers, and degree of superheat in the high-pressure heat exchanger. In this regard, the Pareto frontiers are drawn for the system with all twenty different binary zeotropic mixtures. The optimal point for each mixture is obtained via the decision-making technique of LINMAP. Subsequently, the LINMAP is re-utilized to find the preferred mixture. The optimization results suggest the R123/C2Butene (96.89/3.11) mixture for this system as the optimum working fluid, considering a trade-off between a low-cost rate of $88.0651 per hr and a high exergy efficiency of 64.07 %. Finally, the exergy flow diagram is plotted to provide the exergy flow rate and the amount of exergy destruction in each segment of the system considering the optimal working fluid. In the proposed system, exergy destruction chiefly occurs within the low-pressure preheater with a value of 1061 kW, followed by the low-pressure turbine and condenser with magnitudes of about 669 kW and 266 kW, respectively.

High power target for the High Brilliance Neutron Source

The High Brilliance Neutron Source (HBS) is a High-Current Accelerator-driven Neutron Source (HiCANS) under development at Jülich Centre for Neutron Science - Forschungszentrum Jülich. The unique specifications of the HBS require a neutron target with a high neutron emission able to operate in vacuum with a 70MeV proton beam with 90mA peak current and 1.6% duty cycle leading to an average thermal load of 100kW. A tantalum target of 100cm2 irradiated area with an internal cooling structure which removes the heat quite homogeneously, provides a good compromise between low pressure and high heat transfer and ensures an homogeneous protons energy loss was designed and optimized by means of MCNP, CFD and FEM simulations. Such a target was successfully manufactured and its operational capability was demonstrated by operating it under a heat load of 1kWcm−2 from an electron gun.

A Reduced-Order Model of a Nuclear Power Plant with Thermal Power Dispatch

This paper presents reduced-order modeling of thermal power dispatch (TPD) from a pressurized water reactor (PWR) for providing heat to nearby heat consuming industrial processes that seek to take advantage of nuclear heat to reduce carbon emissions. The reactor model includes the neutronics of the reactor core, thermal–hydraulics of the primary coolant cycle, and a three-lump model of the steam generator (SG). The secondary coolant cycle is represented with quasi-steady state mass and energy balance equations. The secondary cycle consists of a steam extraction system, high-pressure and low-pressure turbines, moisture separator and reheater, high-pressure and low-pressure feedwater heaters, deaerator, feedwater and condensate pumps, and a condenser. The steam produced by the SG is distributed between the turbines and the extraction steam line (XSL) that delivers steam to nearby industrial processes, such as production of clean hydrogen. The reduced-order simulator is verified by comparing predictions with results from separate validated steady-state and transient full-scope PWR simulators for TPD levels between 0% and 70% of the rated reactor power. All simulators indicate that the flow rate of steam in the main steam line and turbine systems decrease with increasing TPD, which causes a reduction in PWR electric power generation. The results are analyzed to assess the impact of TPD on system efficiency and feedwater flow control. Due to the simplicity of the proposed reduced-order model, it can be scaled to represent a PWR of any size with a few parametric changes. In the future, the proposed reduced-order model will be integrated into a power system model in a digital real-time simulator (DRTS) and physical hardware-in-the-loop simulations.

Experimental investigation of two-stage NH3–H2O resorption heat storage system with solution concentration difference

Widespread application of solar energy is severely restricted to its instability in time and space. Heat storage system is considered to be one of the most effective pathways to achieve long-term heat supply. Among all the heat storage technologies, solution concentration difference storage technologies stand out for low heat loss and high energy density. By substituting condenser and evaporator in conventional absorption cycle with a high-pressure absorber and low-pressure generator, a resorption cycle could be established. Compared with absorption heat storage cycle, working pressure of resorption heat cycle is lower, making it possible to utilize low-pressure heat source. Two-stage heat source cycle is further proposed to lower working pressure and upgrading supply water temperature. Resorption energy storage cycle with solution concentration difference is established and studied. A prototype based on two-stage ammonia-water resorption heat storage cycle was set up and tested. The result shows that the constraint relation between ambient temperature and heat source temperature of the proposed system. In single-stage mode, the lowest working ambient temperature is 5 °C when heat source temperature is 90 °C. The lowest working ambient temperature could be declined to 0 °C when heat source temperature rises to 120 °C. In two-stage mode, the lowest working ambient temperature is 0 °C when heat source temperature is only 110 °C, which proves the adaptability of two-stage cycle. The highest ESCOP appears in the 15 °C–120 °C single-stage mode, which is 0.742. The highest COP is 1.324 under the same condition. The highest energy density occurs in two-stage mode, which is 467.07 kJ/kg when ambient and heat source is set as 15 °C, 120 °C. The advantage that two-stage mode could enlarge solution concentration difference is verified.

Improvement of plastic deformation property and current carrying capacity of Bi2212 wires through low oxygen partial pressure post-annealing of precursor

The performance of superconducting magnets is greatly dependent on the size and uniformity of the superconducting filaments within the wire. However, in the fabrication of Bi2Sr2CaCu2Ox (Bi2212) wires using ceramic oxide as the superconducting filaments, we face multiple challenges including filament fragility, poor uniformity, and non-smooth Ag/superconductor interfaces. These challenges primarily stem from the significantly lower plastic deformation capability of ceramic oxide powder filaments compared to metal matrices. To address these challenges, this study focuses on the modification of ceramic oxide precursor powders. Through the utilization of low-temperature, low oxygen partial pressure (pO2) heat treatment, we have observed significant changes in the Cu chemical states and lattice parameters within the Bi2212 grains. These alterations have proven to be highly effective in reducing the energy required for grain sliding and, in turn, enhancing the plastic deformation properties of the Bi2212 oxide filament. Furthermore, post-annealing the oxide powder under low pO2 conditions narrows the gap in plastic deformability between the Ag sheath and the oxide filaments, resulting in improved filament uniformity and a smoother Ag/oxide interface in Bi2212 wires. Notably, the Bi2212 grains exhibit an orderly arrangement within the wires. As a result of these improvements, the critical current density (Jc) of the final wires increases by an impressive 70 %. The outcomes of this study are not only crucial for producing Bi2212 magnets with higher magnetic field strength, improved magnetic field uniformity, and enhanced operational stability, but also offer fresh insights and methodologies for advancing the field of superconducting materials.

The failure causes analysis of low-pressure heater pipes based on the porous medium model and local model

Low-pressure heaters are critical heat exchange equipment in thermal and nuclear power generation. The high-speed steam flow in the low-pressure heaters induces pipe vibration, causing pipe failure. The large size and complex flow make it hard to calculate directly. This paper employs a combined method of the porous medium and local models by substituting the boundary to calculate and prove steam flow trajectory and velocity are consistent with the actual situation. The analysis of the turbulent kinetic energy exhibits that the primary causes of pipe vibration are the periodic vortex shedding and the impact of the impingement plate on the pipes. The stress analysis indicates that the loosening of the pipes leads to a 368 times amplification of the shear stress by 0.1 MPa. The most crucial step in solving such a problem is to strengthen the fixation of the pipes, especially near the shell region.

Synthesis of C3N4/rGO Composites by Low Temperature and Low Pressure Heat Treatment and Their Photocatalytic Properties

Synthesis of C3N4/rGO Composites by Low Temperature and Low Pressure Heat Treatment and Their Photocatalytic Properties

Multiresonant Selective Emitter with Enhanced Thermal Management for Infrared Camouflage.

Tailoring the optical properties of metamaterials is crucial for improving the performance of infrared (IR) applications. Generally, IR camouflage materials are required to have low IR-emission properties for the detected bands (3-5 and 8-12 μm), in which IR detection is accomplished. However, the heat residue by suppressed thermal radiation degrades the thermal dissipation capacity and thermal stability of IR camouflage materials. Herein, a multilayer metal-dielectric-metal (MDM) selective emitter with high IR-emission performance in the undetected band for thermal management and low IR-emission performance in the detected band for IR camouflage is introduced. Compared to a conventional selective emitter and a low-emission material (Au film), the multiresonance selective emitter exhibited 125 and 2910% increases in heat dissipation within the undetected band, respectively. In addition, the proposed camouflage material exhibited a substantial reduction in emissive energy within the detected bands of 3-5 and 8-12 μm, with reductions of 72 and 83%, respectively, compared to that of a high-emission surface. The effectiveness of our IR camouflage was demonstrated by IR camera measurements. When the surface temperature was 360 K, the radiance temperatures of the multilayer multipeak selective emitter were 314 and 309 K for the 3-5 and 8-12 μm bands, respectively. Thermal management experiments demonstrated the enhanced thermal stability of the multiresonance selective emitter, especially in conditions of low pressure and high heat flux, when compared to that of the low-emissivity film. This work provides a practical strategy to enhance the thermal emission of a selective emitter, expanding its potential beyond IR camouflage to various energy applications.

The influence of the HIP process on the microstructure, critical temperature and critical current density of double-doped (with Dy2O3 + C, and Tb2O3 + C) MgB2 bulk compounds

ABSTRACT We present the results of the irreversibility field (B irr ), critical temperature (T c), and magnetic critical current density (J cm) for cylindrical samples encapsulated in carbon and doped with 1-3 at% dysprosium and terbium oxides. All samples were analyzed microstructurally by using a scanning electron microscope (SEM) and X-ray diffraction (XRD). The influence of annealing temperature and time and high isostatic pressure on J cm was investigated. Our results show that double-doped (C + Tb2O3 and C + Dy2O3) and low isostatic pressure heat treatment (0.1 MPa) decrease the T c by about 0.5 K compared to the undoped MgB2 (0.1 MPa). The magnetic measurements show that double-doped and heat treatment under high isostatic pressure (HIP - 1 GPa) leads to a decrease in T c of about 2.5 K compared to the undoped MgB2 sample after the HIP process. Our results show that the HIP process slightly increases J cm at 4.2 K and 20 K, and improves J cm at 30 K in undoped MgB2 samples. Furthermore, our results show that the HIP process and double-doped significantly increase J cm at 4.2K and decrease J cm at 30K. Our results indicate that the HIP process can produce high field and low-temperature pinning centers in doubly doped MgB2 materials.

Digital twin modeling and operation optimization of the steam turbine system of thermal power plants

The increasing deployment of renewable energy sources necessitates peak regulation services from thermal power plants, impacting their energy efficiency. Central to these plants, the steam turbine system significantly influences their operational efficiency. A digital twin model of this system was developed, integrating mechanism-driven and data-driven modeling methods. The neural network data-driven approach was specifically utilized for parameters such as feedwater pump speed and steam flow rate to the pump turbine. Other parameters were modeled with mechanism data hybrid driven modeling method. This model computes vital metrics such as low-pressure turbine exhaust steam enthalpy, work done and heat absorption per unit mass of steam, system efficiency, feedwater mass flow rate, and water-coal ratio—key for evaluating and enhancing the system's energy efficiency. An investigation into a reference case showed a decline in efficiency below design levels due to aging. By optimizing the live steam pressure and the cold-end system, relative improvements in energy efficiency of 0.35 % and 0.14 %, respectively, were achievable.

An Ejector and Flashbox-Integrated Approach to Flue Gas Waste Heat Recovery: A Novel Systematic Study

In this study, a comprehensive examination was conducted to explore the technology involved in the recovery of waste heat from flue gas emitted by a 1000 MW unit. Traditional methods are constrained in their ability to harness waste heat from flue gas solely for the purpose of generating medium-temperature water. The system being examined not only recovers waste heat but also utilizes it to generate steam, thereby greatly improving resource efficiency. The process entails utilizing the flue gas to heat water to a certain temperature, followed by subjecting it to flash evaporation. This process leads to the generation of low-pressure waste heat steam. Within the steam ejector, the waste heat steam combines with high-pressure motive steam extracted from the source, resulting in the formation of medium-pressure steam. Within the steam ejector, the waste heat steam blends with high-pressure motive steam drawn from the source, forming medium-pressure steam that eventually feeds into the A8 steam extraction pipe (low-pressure turbine pumping pipe). The present study examines the fluctuation patterns in motive steam flow, suction coefficient, waste heat steam volume, and outlet temperature of the flue water heat exchanger when different motive steam sources are used. Additionally, the research calculates the reduction in CO2 emissions, the coal consumption for power supply, and the cost savings in fuel for the retrofitted system. The findings indicate that maximizing energy utilization can be achieved by operating the retrofitted unit at the lowest feasible waste heat steam pressure. The implementation of the new system has resulted in a substantial decrease in coal consumption for power supply. When employing main steam as the extraction steam source, the consumption of coal for power generation decreases in proportion to the decrease in waste heat steam pressure while maintaining a constant unit load. When the waste heat steam pressure reaches 0.0312 MPa, the recorded coal consumption for power generation varies between 289.43 g/kWh at 100% turbine heat acceptance (THA) and 326.94 g/kWh at 30%THA. When comparing this performance with the initial thermal power plant (TPP) unit, it demonstrates reductions of 2.26 g/kWh and 1.52 g/kWh, respectively. After implementing modifications to this 1000 MW unit, it is projected that the annual CO2 emissions can be effectively reduced by 6333.97 tons, resulting in significant cost savings of approximately USD 0.23 million in fuel expenses. This system exhibits considerable potential in terms of emission reduction and provides valuable insights for thermal power plants aiming to decrease unit energy consumption.

The Preparation and Properties of Ni2Al3 Intermetallic Compound Coating

In this work, a Ni2Al3 intermetallic compound coating was prepared on 45 # steel by combining methods of low-pressure cold spray and heat treatment. Firstly, powders mixed with Ni powders, Al powders, and Al2O3 powders as a mass ratio of 20:6:4 were sprayed on surface of 45 # steel by low-pressure cold spraying technology to prepare a Ni-Al pre-coating. Subsequently, the pre-coating was annealed at 570 °C in an argon atmosphere for 12 h to obtain the Ni2Al3 intermetallic compound coating. The composite coating was characterized using TEM, SEM, and XRD. High temperature oxidation performance of the composite coating was analyzed by isothermal oxidation tests conducted at 600 °C in air atmosphere for 96 h. The results show that the composite coating is composed of Ni2Al3 phase. Under a high-temperature oxidation environment, a protective oxide film composed by Al2O3 and NiO was formed on the coating surface, which resulting in a superior high-temperature oxidation resistance compared to 15CrMo heat-resistant steel. The mechanism of the Ni2Al3 coating resistance to high-temperature oxidation is that an oxide film mainly composed of Al2O3 and NiO formed on the surface during the high-temperature oxidation process; this oxide film can effectively resist oxidation and protect the substrate material from oxidation at a high temperature of 600 °C.

Accelerated Degradation Test on Electric Scroll Compressor Using Controlled Continuous Liquid Slugging

Refrigerant-based electric scroll compressors are known for their reliability, efficiency, and quiet operation. They are often used in heat pump systems due to their ability to efficiently handle varying levels of load conditions, both for heating and cooling modes of operation. As electric compressors are considered the heart of the heat pump system, being able to determine degradation of compressors prior to failure is of paramount importance for the health of this system. Typical failures for electric scroll compressors range from electrical faults, refrigerant leaks, to mechanical failures and overheating. Specifically, one of the primary failure modes for an electric scroll compressor is mechanical damage due to the high stress effects of refrigerant liquid slugging. These stresses are due to excessively high internal pressures exhibited on the compressor scrolls, which are generated by compressing liquid refrigerant at the suction side of the compressor. This paper provides a new testing methodology that introduces liquid slugging at various degrees of refrigerant quality to degrade a compressor to near the end of useful life. Furthermore, this test aims to determine specific operating conditions and signals that can indicate early compressor degradation. This fault injection configuration consists of a modified heat pump system with the addition of two low pressure heat exchangers added in parallel (with respective electronically controlled expansion valve for each heat exchanger) used to control the refrigerant quality during compressor operations. For a given refrigerant quality, the heat pump system was operated at a fixed compressor performance conditions to sustain liquid slugging for a fixed duration. Afterwards, refrigerant was controlled to be pure vapor at the compressor suction side and the compressor was controlled at several different performance conditions (i.e., fixed compressor suction superheat temperature and compressor pressure ratios, at various compressor speeds), so as to duplicate conditions known to us from the compressor component data sheet for an ideal electric scroll compressor. Through these tests, the results show that the severity of scroll failures depend heavily on the refrigerant quality and the amount of liquid slugging exposure time. Furthermore, symptoms of compressor degradation are detected using the following signals: i) temperature and pressure at the compressor suction side, ii) temperature and pressure at the compressor discharge side, and iii) electric compressor speed and power consumption. To further aid in determining the compressor degradation ground truth, complete compressor teardown was performed to identify sections within the compressor that exhibited significant amounts of wear as compared to a stock compressor.

A LOW-PRESSURE STEAM ELECTRIC HEATER AS THE BASIS OF A NEW GENERATION AUTONOMOUS HEATING SYSTEM

The article is dealing with studying an electric vacuum heater and a low-pressure steam electric heater developed on its basis. A low-pressure steam electric heater can be the basis of a new generation autonomous heating system. Prototypes of a low-pressure steam electric heater with an automatic control system for its operation modes have been developed. The prototype power is 600, 800, 1000 W. Reliability of the electric vacuum heater has been tested empirically. A low-pressure steam electric heater combines the efficiency of an electric coil and the comfort of heat from a traditional central heating radiator without the drawbacks of oil-filled electric radiators and is a reliable, fireproof electric heater.

Fenton and photo-assisted advanced oxidative degradation of ionic liquids: a review.

Ionic liquids (ILs) are the class of materials which are purely ionic in nature and liquid at room temperature. Their remarkable properties like very low vapour pressure, non-inflammable and high heat resistance are responsible for their use as a very appealing solvent in a variety of industrial applications in place of regular organic solvents. Because ILs are water soluble to a certain extent, the industrial wastewater effluents are found to contaminate with their traces. The non-biodegradability of ILs attracts the attention of the researchers for their removal or degradation from wastewater. Numbers of methods are available for the treatment of wastewater. However, it is very crucial to use the most efficient method for the degradation of ILs. Advanced oxidation process (AOP) is one of the most important techniques for the treatment of ILs in wastewater which have been investigated during last decades. This review paper covers the cost-effective Fenton, photochemical and photocatalytic AOPs and their combination that could be applied for the degradation of ILs from the wastewater. Theoretical explanations of these AOPs along with experimental conditions and kinetics of degradation or removal of ILs from water and wastewater have been reported and compared. Finally, future perspectives of IL degradation are presented.

Experimental study on low pressure heat transfer properties of water evaporator with screen separation element

Water evaporator is often used in spacecraft thermal management as heat sink. In a water evaporator, heat is transferred from the microchannels of cooled glycol liquid to the external water, which causes the phase transition of water near external fins. Due to the severe weight requirements of hypersonic vehicles, it is very important to study the heat transfer performance and water utilization of water evaporator. The present study experimentally investigated the boiling heat transfer of water evaporator on external rectangular fins (RF) at low pressure, and the heat transfer of cooled glycol liquid in microchannels with offset strip fins (OSF). At the same time, the experiment explored the effects of three types of screen devices on the heat transfer performance and water utilization efficiency of water evaporators. The heat transfer experiments of water evaporator were conducted at the pressure of 11 kPa. The inlet temperature of hot glycol liquid was controlled 85 °C, and the mass flow rate were at 1500 kg/h and 2500 kg/h, respectively. The experimental results show that when the mass flow rate of ethylene glycol is the same, the water consumption of the water evaporator significantly decreases and the water utilization efficiency increase with the increase of screen density, but it can weaken the boiling heat transfer performance. In addition, the empirical correlation of boiling in low-pressure is modified, and the maximum deviation is within ±10%. The screen separator element and the new modified correlation provide a reference for the design of water evaporator.

Exergy Analysis of Thermal Power Plant for Three Different Loads

This paper presents the energy and exergy analysis of thermal power plant Tuzla in Tuzla, Bosnia and Herzegovina. The main aim of this paper is to analyze the components of a 200 MW steam power plant unit in order to identify and quantify the sites with the highest exergy losses and to calculate exergy efficiency values of all components when operating at nominal load. The influence of the change in ambient temperature and block load on the value of exergy losses and exergy efficiency was taken into analysis. The analysis further includes the impact of steam block operation without high-pressure and low-pressure heaters on the exergy efficiency of the steam block. The goal of the analysis is to determine the functional state of individual steam block components after a long period of exploitation and maintenance in order to take appropriate measures to improve their technical performance. Exergy losses during nominal operation of the steam power plant unit are the largest in boiler and amount to 313.42 MW, followed by a turbine with 205.60 MW, condenser 1 with 6.03 MW, condenser 2 with 5.75 MW, while other components of the steam power plant have exergy losses in the range of 0.03 to 2.15 MW. Operation of the unit at nominal load without HPH results in an exergy efficiency decrease from 5.60 to 9.80 %, while in case of operation without HPH and LPH it results in a decrease in exergy efficiency from 9.86 to 16.40 % depending on the pattern used to calculate. The conclusion after the analysis indicates that the biggest exergy losses are in the boiler and turbine and consequently these components have the lowest exergy efficiency values. The increase in ambient temperature has different effects on individual components of the thermal power plant, increasing exergy losses of the boiler while reducing the turbine exergy losses and condensers.

Advanced exergoeconomics of a steam power plant based on double-tier splitting of exergy destruction rates

The advanced exergy and exergoeconomic analysis methodologies excel over their conventional counterparts by quantifying endogenous/exogenous exergy destruction rates and related costs that reveal the interactions among system components. By quantifying avoidable/unavoidable losses, they also reveal the potentials for component improvements that are practically achievable. These data are imperative for improving the cost-effectiveness of thermal systems. This paper presents the performances of a complex gas-fired power plant obtained via an advanced exergoeconomic analysis. The study advances existing studies by undertaking second-tier splitting of exergy destruction cost rates and associated investment cost rates to determine avoidable endogenous, unavoidable endogenous, avoidable exogenous, and unavoidable exogenous cost rates of the plant’s components. Component exergy destruction cost rates were found to be predominantly unavoidable, while most of the component investment cost rates were avoidable. Except for the low pressure heater 3, exergy destruction cost rates are endogenous in all the plant components, contributing 84% of overall cost rates. The proportions of exergy destruction cost rates and investment cost rates of the plant that are avoidable endogenous were 21% and 28% respectively, while the respective portions that are avoidable exogenous were 4% and 27%. Furthermore, it was shown that as much as 96.3% improvements in overall plant cost-effectiveness were achievable by eliminating avoidable endogenous exergy destruction cost rates and investment cost rates for major components of the plant.

Design and Modelling of Heat-Coupled Storage System with High- and Low-Pressure Bypass: Electrothermal Characteristics and Peak Regulating Performance

To achieve a balance between supply and demand during cogeneration system operation, it is necessary to improve the peak regulation capacity and regulatory flexibility of the unit. Considering the excellent performance of energy storage systems, a heat-coupled storage system with high- and low-pressure bypass is proposed to increase peak regulation capacity. Employing a 300 MW heating unit as the research object, thermal system models of a traditional-pumping steam-heating system, a high- and low-pressure bypass heating system, and a coupled system were built using Aspen Plus software. The electric heating characteristics of the three systems, as well as the peak regulation capacity and peak regulation depth of the coupled system, were analysed under different storage and heat release loads. Results indicate that the high- and low-voltage bypass system and the coupled system both improve the peak capacity and control flexibility of the unit. Moreover, the coupled system has a greater influence on the maximum thermoelectric ratio and minimum charge rate than the high- and low-voltage bypass heating system, thereby extending the range of safe operation. The peak capacity and depth of heat storage are 65.55 MW and 21.85%, respectively, while the peak capacity and the depth of the heat-release process are 39.32 MW and 13.10%.