Waste Thermal Energy Research Articles

Bidirectional circulating preheating method harnessing engine and battery waste heat reuse in hybrid electric vehicles

In hybrid electric vehicles (HEVs), both the engine and power batteries experience reduced performance at low temperatures, necessitating the consumption of significant energy for preheating. The bidirectional preheating system method, which for the first time applies waste thermal energy to preheat both the engine and power battery in HEVs, utilizes the engine’s residual thermal energy to preheat the power battery and the thermal energy from the power battery to preheat the engine. To implement this method, a numerical model of the engine radiator and power battery waste heat is first established, and the temperature rise characteristics and temperature distribution of the waste heat system are simulated and analyzed. This analysis reveals the heat transfer law of the engine radiator and power battery waste heat. An automatic bidirectional thermal control device based on waste heat reuse is designed. The device utilizes a multi-stage series thermal energy transfer system with phase change materials (PCM) as the medium. A low-temperature experiment is conducted to assess the integration of heating and cooling between the engine and power battery. The results indicate that this method effectively utilizes the engine’s waste heat for both heating and cooling purposes. Specifically, a heat exchanger is used to preheat the power battery using the engine’s cooling residual heat, maintaining the internal battery temperature at 30 °C. Simultaneously, the residual heat from the power battery’s cooling system is circulated back to the engine body, preheating the engine coolant to 42 °C. Compared with existing HEVs, it can save more than 90% of the preheating energy consumption of the engine and power battery. This method can reduce power battery and engine warm-up time by more than 50%, while reducing emissions by more than 40% during engine cold start. This approach effectively addresses the challenge of low-temperature preheating for both power batteries and engines by utilizing cooling residual heat bidirectionally, thereby maximizing energy utilization efficiency in HEV systems and optimizing both battery and engine performance.

Development of composite ultrafiltration membrane from fly ash microspheres and alumina nanofibers for efficient dye removal from aqueous solutions

In this work, a novel type of ultrafiltration ceramic membranes with the support based on fine fly ash microspheres and selective layer based on the alumina nanofibers with an aluminosilicate binder is proposed. The average pore sizes of the support and selective layer are 0.46 μm and 29 nm, respectively. The membrane is characterized by the compressive strength of 96 MPa and water permeability of 207 L m−2 h−1 bar−1. It is shown that the binder provides structural stability of selective layer and adhesion to the support. With increasing the binder content, the water permeability increases, reaches maximum, and then slightly decreases. The developed membranes are used for ultrafiltration of Blue Dextran dyes aqueous solutions with molecular weights of 70 kDa and 500 kDa and concentrations of 50 and 100 mg/L. The dyes rejection varies in the range 97–99 %, while the permeate flux is 100–140 L m−2 h−1 at the transmembrane pressure of 4 bars. The dye retention occurs via adsorption at the initial stage, which leads to the narrowing of pore size. Further, the dye filtration proceeds mainly due to size effects. The proposed membranes can be employed for dye removal from wastewater, and also allow chemical modification by carbon coating to be employed in electrochemically assisted ultrafiltration. The developed methodology promotes the recycling of thermal energy waste and introduces novel approaches to combine waste and synthesized raw materials in the production of low-cost ceramic membranes.

Utilization of waste hot air of medical oxygen plant in solar desalination unit employing jet impingement air heater for water production

ABSTRACT Many oxygen plants have been established specially during COVID-19 period and they are still serving for medical needs. The objective of the present work is to utilize solar and waste thermal energy of medical oxygen plants for water production. Humidification–dehumidification desalination (HDD) has been found suitable for this objective due to low temperature energy need during the process. The layout of an HDD unit has been presented to utilize waste heat, specially when solar energy is not much effective or absent. The system has been configured with a jet impingement solar air heater and a packed bed humidifier. A mathematical model has been developed and validated with the results of experiments. A comparative study of the proposed unit (HDD-O2) and a conventional unit has been performed in terms of yield and gained output ratio (GOR). The optimum flow rates of working fluids found in the range 0.03–0.04 kg/s and the temperature of air and water resulted in a continuous gain in yield. The average yield and GOR of the HDD-O2 unit were found to be 8.5 kg/d and 1.1 that could reach up to 11 kg/d and 1.4, respectively. The HDD-O2 unit provided yield at the cost of 0.04 $/kg with a payback period of 1.73 years. The findings of the present work indicated the suitability of the HDD-O2 plant for water production.

Application of thermal energy optimization based on improved neural network algorithm in green innovation capability evaluation of manufacturing enterprises

As the global focus on sustainable development continues to increase, manufacturing companies face the dual challenges of energy efficiency and environmental impact in the process of enhancing green innovation capabilities. The purpose of this study is to explore the application of improved neural network algorithm in thermal energy optimization, so as to improve the green innovation ability of manufacturing enterprises and promote their sustainable development. By constructing an improved neural network model and using big data analysis technology, this paper conducts in-depth analysis of thermal energy use in manufacturing enterprises, so as to identify and optimize energy consumption patterns. The study considered a variety of influencing factors, including equipment efficiency, production process and environmental policy, and evaluated the optimization effect through model training and testing. The experimental results show that the improved neural network algorithm can effectively identify thermal energy waste points, and put forward the corresponding optimization measures. After optimization, the energy use efficiency of manufacturing enterprises has been improved, carbon emissions have been significantly reduced, and the comprehensive evaluation score of green innovation ability has been improved, providing effective technical support for promoting the sustainable development of enterprises.

Comprehensive analysis of waste heat recovery and thermal energy storage integration in air conditioning systems

The proposed work aims to address the challenge of effectively recovering and storing wasted heat in air conditioning (AC) systems, which is crucial for improving energy efficiency and system stability. This study focuses on the comprehensive analysis of a Waste Heat Recovery (WHR) system integrated with Thermal Energy Storage (TES) tanks. A lumped-dynamic thermal model was developed and validated against literature data to accurately simulate the system’s performance. Through a detailed parametric study, the research explores how factors like WHR effectiveness, TES type, PCM type, and TES volume influence the system. The results demonstrate that recovering and storing wasted heat from AC systems significantly enhances operational stability and performance. Notably, increasing WHR effectiveness from 0.55 to 0.85 extends the duration of constant thermal power recovery and also results in higher recovered water temperatures with reduced water pump energy consumption. Furthermore, latent heat storage (PCM tank) extends the duration of stable thermal power recovery by over 61 % compared to sensible storage. Using PCM RT 44HC is more effective for WHR in AC units compared to RT 50 and RT 54HC. Finally, it was shown that increasing PCM tank volume from 2 to 4 m3 improves the duration of constant thermal power recovery by up to 52 % while stabilizing the recovered water temperature.

2D‐Pyroelectric Materials for Waste Thermal Energy Harvesting and Beyond

AbstractPolar 2D materials hold the emerging functionalities such as ferro‐, piezo‐, and pyro‐electric properties. On account of infrared‐active low bandgap and polar nature at reduced dimensionality, they served as an ideal choice of pyroelectric material. It can cover up a diverse range of applications, such as waste thermal energy harvesting, IR imaging, photodetector, temperature sensors, and several catalytic processes due to the abundance of dynamic thermal fluxes. Recently, 2D pyroelectric materials have manifested a substantial role in thermal energy harvesting. Consequently, it is realized that there are plenty of scopes available to diversify its applicability. Thus, the challenges are spotlighted in this perspective to envision the desired 2D pyroelectric materials to achieve the effective thermal energy harvesting, sensing, and catalytic efficacy. Particularly, the emphasis is given to elucidate the role of spontaneous polarization in 2D materials to ascertain the giant pyroelectricity.

Thermodynamic performance assessment of the four-step copper-chlorine cycle in hydrogen production and compression

Rapidly increasing global energy demands requires sustainable alternatives to conventional fossil fuels. Hydrogen emerges as a promising energy carrier due to its high energy density and minimal environmental impact, mainly when produced via thermochemical cycles like the Copper Chlorine (CuCl), which makes use of low-grade waste thermal energy for hydrogen production in an environmentally friendly manner. This study integrates hydrogen production using the Cu-Cl cycle and hydrogen compression systems crucial for establishing robust hydrogen infrastructure. Following hydrogen generation, the study examines the thermodynamic analysis of compressing hydrogen to higher pressures. Parametric variations in compression, including inlet and outlet pressures and the number of stages, are analyzed to optimize energy efficiency and exergy performance. Energy efficiency of around 47.05% is obtained for the 4-step Cu-Cl cycle. The integrated step showed a notably high exergy efficiency of 98.48%. Other key findings include a 35% increase in energy efficiency with five compression stages for an inlet pressure increment from 15 to 30 bars, and a 12% efficiency decrease when varying outlet pressure from 500 to 800 bars. Exergy efficiency shows a 17% improvement with increased compression stages under constant inlet pressure but a 4% decline when varying outlet pressure with a five-stage configuration. These findings highlight the critical role of efficient compression systems in enhancing hydrogen storage and distribution for sustainable energy applications.

A Waste Heat Assessment of a Manufacturing Facility With Consideration for Demand Matching Through Thermal Energy Storage

Abstract A waste heat assessment of a manufacturing facility was conducted. A physical survey identified potential waste heat sources. For these sources, the temporal fluctuations in temperature and flowrate, and the frequency of occurrence of the waste heat, were determined from measurements, calculations, and company records. The energy and exergy of the waste heat were calculated. The total annual waste heat is 36.5 TJ of energy, which represents 0.84 TJ of exergy. The boiler, plant vacuums, and chiller comprise 96% of the energy rejected and are the major contributors to the rejected exergy. Using the waste heat for space heating is evaluated. Based on fuel consumption in the boiler, the annual energy for space heating is estimated at 8.5 TJ. Theoretically, waste heat from the boiler flue, polypropylene dryers, and plant vacuums could meet up to 39% of this energy without storage. Simply allowing the vacuum exhausts to cool in the building could theoretically meet up to 27%. Models are developed to investigate using waste heat recovery and thermal energy storage (TES) to provide space heating for a prototype warehouse building, and estimates for the initial costs of the recovery system are developed. Modeling indicates that TES is highly beneficial for matching short-term demand fluctuations and for smoothing the temporal oscillations in the waste heat. A nine-month heating season is simulated to determine the fraction of the load met by the recovery system. A small amount of thermal storage, e.g., 12.5–25% of daily waste heat, improved the fraction of demand that could be met. Larger sizes had diminishing returns and significantly increased the initial cost and payback period. To reduce initial cost, a refined recovery system design that uses a TES as an intermediate and for storage is proposed. The study highlights the need to consider fluctuations in the waste heat supply and sink demand, for thermal storage, and to identify relatively simple modifications to recover waste heat.

Cryogenic energy assisted power generation utilizing low flammability refrigerants

Cryogenic carbon-neutral fuels are potential alternatives as future marine fuels, releasing waste cryogenic energy during regasification and waste thermal energy during combustion. Organic Rankine Cycles (ORCs), using flammable hydrocarbon working fluids, are the preferred waste energy reutilization technology, prioritized over Brayton and Kaline cycles due to their compact system configuration. However, hydrocarbon flammability and explosiveness poses a huge safety risk. Therein lies the novelty of this study which presents an advanced dynamic model of a cryogenic enhanced ORC utilizing low flammability hydrofluorocarbons as working fluids for simultaneous reutilization of waste thermal and cryogenic energy from carbon-neutral cryogenic fuels. The evaporation temperature exhibits a direct correlation with energy and an inverse correlation with the exergy performance. System overcharging leads to a drastic performance decline, while undercharging can be tolerated to a certain liquid-to-volume ratio until critical failure. Marine classification societies’ recommendations-based scenarios were employed to gauge the emission reduction potential of low flammability working fluids for cryogenic ORCs, pitted against traditional combustion technologies. A maximum specific net-work, thermal efficiency, exergy efficiency, and cryogenic energy efficiency of 45.64 kJ/kg, 10.43 %, 12.75 %, and 11.8 % was achieved, respectively, with 85 % reduction in GHG emissions, using R452B as the working fluid.

Numerical study of an energy storage unit based on zeolite-water adsorption for mobilized thermal energy storage

Mobile energy storage heating trucks present a promising solution to address current challenges associated with low energy utilization and reliance on a singular heat supply method. This technology seamlessly integrates waste heat recovery and thermal energy utilization, offering potential advantages such as streamlining construction cycles and providing timely energy supply in scenarios with diverse energy demands. To enhance the energy delivery efficiency of mobile heating, this paper employs computational fluid dynamics (CFD) simulation to thoroughly examine the heat accumulator at the core of an adsorption-based mobilized thermal energy storage. Furthermore, the paper conducts simulations and analyses of heat and mass transfer within a zeolite-water accumulator, closely scrutinizing variations in temperature, vapor content, and water content within the zeolite field. The results indicate that, during the heat storage process in the 3 m/s to 5 m/s system, the zeolite sensible heat storage capacity increases by 6.48 %, accompanied by a reduction in latent heat. Specifically, when the inlet steam velocity is 5 m/s compared to 3 m/s, the equilibrium heat transfer time shortens by 24.6 %. Furthermore, for an inlet steam temperature ranging from 180 °C to 220 °C, the average temperature can be elevated by 28.8 °C, resulting in a 10.6 % increase in sensible heat storage capacity. However, the heat storage time experiences a 3.4 % increase. In the exothermic process, with an inlet air velocity of 5 m/s compared to 3 m/s, there is a 22.2 % reduction in latent heat exothermic and a 16.7 % reduction in exothermic time. The inlet air temperature during the exothermic process is 8.9 °C lower than the final temperature of 20 °C, leading to a 3.2 % increase in exothermic quantity and a 20 % improvement in exothermic efficiency.

Glass-Blowing-Inspired Upcycling of Thermosetting Polymer to Neuron-Like Hierarchical Carbon for Microwave Absorption and Conversion.

Upgrading thermosetting polymer waste and harvesting unwanted electromagnetic energy are of great significance in solving environmental pollution and energy shortage problems. Herein, inspired by the glass-blowing art, a spontaneous, controllable, and scalable strategy is proposed to prepare hollow carbon materials by inner blowing and outside blocking. Specifically, hierarchically neuron-like hollow carbon materials (HCMSs) with various sizes are fabricated from melamine-formaldehyde sponge (MS) waste. Benefiting from the synergistic of the hollow "cell body" and the connected "protrusions" networks, HCMSs reveal superior electromagnetic absorption performance with a strong reflection loss of -54.9dB, electromagnetic-heat conversion ability with a high conversion efficiency of 34.4%, and efficient energy storage performance in supercapacitor. Furthermore, a multifunctional device integrating electromagnetic-heat-electrical energy conversion is designed, and its feasibility is proved by experiments and theoretical calculations. The integrated device reveals an output voltage of 34.5mV and a maximum output power of 0.89 µW with electromagnetic radiation for 60s. This work provides a novel solution to recycle polymer waste, electromagnetic energy, and unwanted thermal energy.

A novel mathematical optimization method to obtain the maximum-power electrical configuration of thermoelectric generators for energy harvesting

Waste thermal energy recovery with thermoelectric generators has been widely studied as a method to make systems that produce hot exhaust gases, such as aircrafts, ground vehicles and factories, more sustainable. In this type of applications, the mismatch in hot and cold side temperatures of thermoelectric modules (TEMs) creates a mismatch in the electrical output. For each situation, there is a certain electrical interconnection between the modules that gives the maximum global power output. Three optimization models to find what is the best way of connecting the TEMs without a trial-and-error process, as usually done in previous literature, based on mathematical programming are proposed: single branch of series-connected TEMs, multiple parallel-connected branches of series-connected TEMs, and multiple groups of independent series-connected TEMs. The main novel contributions of this paper are: (i) a mathematical optimization approach that provides how to connect the thermoelectric modules one by one, (ii) the application of the above-mentioned method in a common case study: an automotive thermoelectric generator, (iii) information about how the optimal connection between modules changes if the heat source changes its operation (iv) a method for selecting a fixed optimal connection even when the heat source operation changes, e.g. different operation modes in a thermal engine, based on introducing weighting parameters in the optimization mathematical model. The optimization approach followed here is novel and has not been applied before to thermoelectric generators.

Performance optimization of an integrated solar combined cycle for the cogeneration of electricity and fresh water

Many Arabic countries suffer water scarcity while having an energy surplus. The present work investigates and optimizes a proposed plant for the cogeneration of electricity and fresh water. This plant comprises an Integrated Solar Combined Cycle (ISCC) power plant and a Multi Stage Flash (MSF) desalination unit. The steam condenser of the ISCC acts as a brine heater of the MSF desalination unit. Thus, the waste thermal energy from the ISCC is used to desalinate the seawater. The proposed cycle produces fresh water during its part load operating conditions. Simulation programs were developed and validated using real data from the ISCC power plant in Kuraymat-Egypt. The present results show that the proposed plant is very promising for the cogeneration of electricity and fresh water. An optimum top brine temperature (To) of 80 °C was estimated based on the amount of fuel required to desalinate the seawater. The proposed plant produces up to 1140 m3/h of fresh water under the typical operating conditions of Hurghada-Egypt, 50 % of the rated output power, and To = 80 °C. It saves up to 84.7 % of the fuel required for desalination compared to a standalone MSF desalination unit that operates under the same conditions.

Experimental investigation of axial finned tube evaporator thermal distillation system using for diesel engine waste heat recovery process

The study aims to improve the waste thermal energy retrieval from flue gas of an internal combustion engine (ICE). The recovered waste heat energy was used for distillation by using a thermal distillation system. The performance of the thermal distillation unit was investigated by varying the evaporator (boiler) type and engine load (25, 50, 75 %). Four different types of boilers were used including one smooth copper tube and other three were two, three and four axial finned copper tube evaporators. The impact of boiler type and engine load on the net retrieved energy and exergy, net energy and exergy efficiency, and distillate yield rate of thermal distillation unit was also examined. The results showed that the net extracted heat energy and exergy for axial finned tube evaporator was approximately 26.823 – 45.513 % and 7.614 – 25.203 W higher than that of smooth tubes evaporator at 25 and 75 % engine load, respectively. The distillation yield was found to be ~ 2.35 liter/ hour in the case of four axial finned tube boiler at 75 % engine load.

Harvesting Thermal Energy through Pyroelectric and Thermoelectric Nanomaterials for Catalytic Applications

The current scenario sees over 60% of primary energy being dissipated as waste heat directly into the environment, contributing significantly to energy loss and global warming. Therefore, low-grade waste heat harvesting has been long considered a critical issue. Pyroelectric (PE) materials utilize temperature oscillation to generate electricity, while thermoelectric (TE) materials convert temperature differences into electrical energy. Nanostructured PE and TE materials have recently gained prominence as promising catalysts for converting thermal energy directly into chemical energy in a green manner. This short review provides a summary and comparison of catalytic processes initiated by PE and TE effects driven by waste thermal energy. The discussion covers fundamental principles and reaction mechanisms, followed by the introduction of representative examples of PE and TE nanomaterials in various catalytic fields, including water splitting, organic synthesis, air purification, and biomedical applications. Finally, the review addresses challenges and outlines future prospects in this emerging field.

Experimental investigation of three fluid heat exchangers using roughness on the outer surface of a helical coil

AbstractThe aim of this study is to utilize waste thermal energy from industries into useful heat for water and air heating. In this paper, the thermal modeling and performance of three fluid heat exchangers (TFHE) have been experimentally investigated. The TFHE considered here is an enhanced version of the double‐pipe heat exchanger. A novel TFHE having fin (1 mm thin copper wire of 10 mm pitch) acts as a roughness element, which is wrapped on the helical coil's outer surface for increasing heat transfer (HT) rate and the turbulence effect for normal water, and this outer surface finned helical coil is inserted between two concentric straight tubes. The innermost tube carries atmospheric air, the finned helical coil tube carries waste hot fluid while normal water flows in the inner annulus of the outermost tube. The coiled‐side Reynolds number is varied in the range of 7000–30,000, while the curvature ratio of 0.1315, pitch‐to‐inside diameter ratio of 2.88 and wire‐to‐tube diameter of the helical tube is kept constant. A counterflow arrangement has been made for experimentation. Nusselt number is calculated using the traditional Wilson plot method that is compared and validated with results available in the literature. The overall HT coefficient is found to increase by increasing the volume flow rate of fluids, while effectiveness decreases or increases depending on residence time and capacity ratio. The percentage increment in the Nusselt number, maximum friction factor, overall HT coefficient between waste hot fluid to normal water, effectiveness is found to be 21.10%–23.88%, 90.91%, 3.40%–29.45%, 3.40%–25.33%, respectively, for the coil side. TFHE is thus proposed for heating water and space simultaneously.

Comprehensive analysis and optimization of a low-carbon multi-generation system driven by municipal solid waste and solar thermal energy integrated with a microbial fuel cell

Abstract In this article, a novel multi-generation plant is addressed and assessed from the energy, exergy, exergoenvironmental and exergoeconomic points of view. The multi-generation plant is composed of two main units: one unit for energy production and another unit for carbon capture and methanol synthesis. Biomass fuel, solar energy and seawater are the main nutrients in the plant. Steam, Brayton, organic Rankine and Kalina cycles have been employed to generate electricity. A linear Fresnel collector-driven solar farm is considered as an auxiliary heat source. In addition, an integrated desalination unit based on a multi-effect desalination unit, a microbial fuel cell and a reverse osmosis unit has been installed in the multi-generation plant. The proposed structure for the offered multi-generation plant is designed under a new configuration and layout that had not been reported in the publications. From the outcomes, the multi-generation plant can produce 69.6 MW of net electricity, 0.53 kg/s of methanol, 0.81 kg/s of oxygen gas, 73.8 kg/s of fresh water and ~0.015 kg/s of hydrogen gas. Under such performance, the offered multi-generation plant can be 51.72 and 27.5% efficient from the points of view of energy and exergy, respectively. Further, the total cost rate and environmental impact of the plant are ~3378 US$/h and 294.1 mPts/s, respectively. A comparative analysis is developed to exhibit the superiority of the planned multi-generation plant. A five-objective optimization is also developed to achieve the optimum design data and outcomes of the plant.

Advancements in Thermoelectric Generator Design: Exploring Heat Exchanger Efficiency and Material Properties

This paper presents a comprehensive study on the application and optimization of automotive thermoelectric generators (ATEGs), focusing on the crucial role of heat exchangers in enhancing energy conversion efficiency. Recognizing the substantial waste of thermal energy in internal combustion engines, our research delves into the potential of TEGs to convert engine waste heat into electrical energy, thereby improving fuel efficiency and reducing environmental impact. We meticulously analyze various heat exchanger designs, assessing their influence on the TEG’s output power under different exhaust gas flow rates and temperatures. Furthermore, we explore the impact of TEG material properties on the overall energy conversion effectiveness. Our findings reveal that specific heat exchanger designs significantly enhance the efficiency of waste gas heat exchange, leading to an improved performance of the TEG system. We also highlight the importance of thermal insulation in maximizing TEG output. This study not only contributes to the ongoing efforts to develop more sustainable and efficient vehicles but also provides valuable insights into the practical application of thermoelectric technology in automotive engineering. Through this research, we aim to pave the way for more environmentally friendly transportation solutions, aligning with global efforts to reduce fossil fuel dependence and mitigate environmental pollution.

Photothermal catalytic hydrogen production coupled with thermoelectric waste heat utilization and thermal energy storage for continuous power generation

Photothermal catalytic water splitting is a potential way to produce renewable hydrogen. However, low-grade heat converted from solar energy in the photochemical process is inevitably dissipated to the environment and often wasted. Besides, the intermittency of solar energy causes the devices unable to work continuously. Here, a novel integrated solar to hydrogen-electricity and thermal storage system (STHET) is proposed to solve above problems. STHET consists of a photothermal catalytic system and a thermoelectric generator (TEG) system, which can realize hydrogen-electricity co-production and thermal self-storage. Photothermal effect in STHET is increased by recycling scattered light, leading to an enhancement of 22.7% in hydrogen production than the traditional system without TEG. Meanwhile, the maximum power of waste heat utilization by TEG is 193.53 μW. Furthermore, since strengthened heat exchange in STHET with forced cooling, the output power of TEG can improve to 1578.13 μW, and hydrogen production is reduced by only 1.4% than the traditional system without TEG. Additionally, STHET can continuously generate power using stored thermal by the liquid reaction system to achieve continuous working in the dark, in which 19% (maximum proportion) of the electrical energy output can be obtained at night. The heat exchange methods in STHET can be flexibly selected according to the requirement for hydrogen energy and electric power. As a conceptual model, STHET can also be promoted in other solid-liquid reaction systems.

Концептуальні аспекти та принципи формування конкурентних ринків теплоенергії

Thermal energy should be considered as a commodity that has its own competitive market, where equilibrium is established in the plane of «supply and demand», so it is necessary to separate commercial (production and supply) and non-commercial (transmission and distribution) functions of heat supply, ensuring the development of fair competition between producers of heat energy and minimization of its costs for consumers. It is proposed to develop competition in the heat energy markets according to the single buyer model. Such a market will be managed by an independent system operator. It consists of a market operator – a single buyer who manages the trading platform, as well as performs the functions of an administrator of settlements between producers and consumers, and a transmission system operator who is responsible for the transmission, distribution and dispatching of heating networks. The peculiarity of heat energy markets is the impossibility of separating the wholesale and retail levels, so there is no need to allocate the supply function. Conceptual provisions for the formation of competitive heat energy markets are based on: 1) zonal delimitation with flow market relations; 2) centralized dispatching; 3) the embodiment of the market infrastructure by an independent system operator; 4) organized over-the-counter trading in the form of a price dialogue for small settlements without backbone networks and exchange trading in the form of heat auctions for medium and large settlements with backbone networks; 5) derivatives (annual), spot (monthly), and balancing segments of the market; 6) the uniform non-discriminatory pricing for consumers and declared pricing on the basis of benchmarking for producers; 7) annual baseload contracts, monthly peak load contracts, and balancing time contracts. The principles of formation of competitive heat energy markets are: transparency, openness, economic efficiency, fair access, competitiveness of producers, fair competition, price compromise, balance and reliability, decarbonization. The expected results of the opening of competition in the heat energy markets are: transparency of heat purchase and sale transactions; minimization of heat purchase prices by consumers; optimization of the utilization of heat-generating capacities of the heat and power system; promoting the development of highly efficient and low-carbon district heating. The latter is especially important from the point of view of restoring Ukraine's energy system after russian aggression, as priority should be given to independent heat producers who use renewable energy sources, have excess or waste thermal energy.