Exhaust Heat Utilization Research Articles

Investigation of Engine Exhaust Heat Recovery Systems Utilizing Thermal Battery Technology

Over 50% of an engine’s energy dissipates via the exhaust and cooling systems, leading to considerable energy loss. Effectively harnessing the waste heat generated by the engine is a critical avenue for enhancing energy efficiency. Traditional exhaust heat recovery systems are limited to real-time recovery of exhaust heat primarily for engine warm-up and fail to fully optimize exhaust heat utilization. This paper introduces a novel exhaust heat recovery system leveraging thermal battery technology, which utilizes phase change materials for both heat storage and reutilization. This innovation significantly minimizes the engine’s cold start duration and provides necessary heating for the cabin during start-up. Dynamic models and thermal management system models were constructed. Parameter optimization and calculations for essential components were conducted, and the fidelity of the simulation model was confirmed through experiments conducted under idle warm-up conditions. Four distinct operational modes for engine warm-up are proposed, and strategies for transitioning between these heating modes are established. A simulation analysis was performed across four varying operational scenarios: WLTC, NEDC, 40 km/h, and 80 km/h. The results indicated that the thermal battery-based exhaust heat recovery system notably reduces warm-up time and fuel consumption. In comparison to the cold start mode, the constant speed condition at 40 km/h showcased the most significant reduction in warm-up time, achieving an impressive 22.52% saving; the highest cumulative fuel consumption reduction was observed at a constant speed of 80 km/h, totaling 24.7%. This study offers theoretical foundations for further exploration of thermal management systems in new energy vehicles that incorporate heat storage and reutilization strategies utilizing thermal batteries.

Potential for Electrical Energy Savings in AC Systems by Utilizing Exhaust Heat from Outdoor Unit

This study explores the potential of utilizing waste heat from air conditioning systems, one of the largest consumers of electrical energy. Currently, most of the waste heat generated by outdoor units is typically released into the environment without being utilized, leading to missed energy-saving opportunities. This study analyzes the potential for improving electrical energy efficiency in air conditioning (AC) systems by harnessing this waste heat. Two primary approaches are evaluated: the first is the use of waste heat for domestic water heating, and the second is the conversion of heat into electrical energy using thermoelectric generators (TEG). The results of this research indicate that both methods have the potential to improve overall energy efficiency significantly. However, challenges related to conversion efficiency and integration of these technologies with AC systems require further, more specific studies. These findings are expected to contribute to more efficient and environmentally friendly cooling systems by optimizing technology and overcoming barriers to wider implementation.

Optimization of methane partial oxidation for hydrogen production with local free space addition: An efficient combination of porous media reactor and thermoelectric conversion system

Thermoelectric technology plays a pivotal role in the efficient conversion and utilization of exhaust heat. Abundant waste heat resources are present in the tail gas of hydrogen production, significantly influenced by combustion characteristics. To investigate the impact of combustion performance on hydrogen yield and power output, an efficient porous media reactor was designed and integrated with a thermoelectric conversion system. The combustion characteristics of a thermoelectric system incorporating unsteady porous media were examined. Furthermore, the effects of the porous media’s structural parameters on temperature distribution, gas concentration, and power generation were analyzed under various operating conditions. The results revealed that radial free space structures exhibited higher hydrogen and methane conversion efficiencies compared to axial free space structures at verge and toroidal positions. However, the height of the radial free space exerted a more substantial influence on temperature distribution and gas production than the size of the free space itself. At a height of 39 mm, hydrogen concentration and yield reached their peak values of 14.5 % and 53 %, respectively. Combustion was found to significantly impact power generation, with a downward shift of the flame resulting in decreased power output. The inlet velocity was observed to affect the thermoelectric generator power, with a maximum steady-state power of 3.95 W achieved at a velocity of 16 cm/s. These findings provide practical guidance for the efficient utilization of industrial waste heat.

Magnetically assembled flexible phase change composites with vertically aligned structures for thermal management and electromagnetic interference shielding

Phase change material (PCM) is promising in achieving zero-energy thermal management because of its prominent thermal storage capacity and steady phase-change temperature. However, low intrinsic thermal conductivity (TC), liquid leak, and solid rigidity are long-standing bottlenecks for heat-related applications. Here, we report an innovative dual-encapsulation strategy to develop multifunctional phase change composite (FMP) with vertically aligned NdFeB@Ag arrays and styrene-ethylene-propylene-styrene (SEPS) crosslinked network in paraffin (PA). The NdFeB@Ag arrays induced by magnetic-field driven procedure can offer the consecutive/oriented highways for efficient heat-transfer, and an electric/magnetic heterostructure for electromagnetic interference shielding efficiency (EMI SE). The flexible SEPS block copolymer not only ensures the high flexibility of PCM, but also combines with oriented NdFeB@Ag arrays for dual encapsulating PA. This multifunctional FMP can achieve high TC of 2.59 W m−1 K−1, attractive EMI SE of 35.42 dB, prominent enthalpy density of 120 J g−1, and impressive Joule heating performance, together with leakage-proof, dynamic assembly, and salient charging/discharging durability. Furthermore, the FMP-supported device is demonstrated for thermal energy harvesting and utilization. This dual-encapsulation design opens a new avenue for exploiting multifunctional PCMs for thermal management, anti-EM radiation, and low-grade exhaust heat utilization.

Performance improvement of the automotive thermoelectric generator by extending the hot side area of the heat exchanger through heat pipes

In pursuit of enhancing the utilization of exhaust heat in the automotive thermoelectric generator (ATEG), this study introduces a novel heat exchanger with integrated heat pipes to extend the effective hot-side surface area. Meanwhile, a numerical model containing multiphysical fields is developed, and the quantity and arrangement of heat pipes are optimized based on this model. Results suggest that (i) The incorporation of heat pipes markedly enhances the recovery of heat energy from the ATEG, leading to a substantial increase in its output power; (ii) With an increasing heat pipe quantity, the ATEG’s output power exhibits a continuous upward trend before eventually reaching stability; (iii) The arrangement of heat pipes also influences system performance, and through optimizations, the optimal quantity of heat pipes is determined to be N = 11 and toleration to be d = 1 mm. At an exhaust temperature of 550 K and a mass flow rate of 60 g/s, the ATEG achieves an output power of 213.19 W and a heat absorption of 4318.02 W, which increased by 42.95 % and 55.6 % respectively, compared with the traditional structure without heat pipes. This structural optimization concept for the heat exchanger provides a new approach to performance improvements of ATEGs. This study provides a design basis and guidance for optimizing the design of ATEG systems with integrated heat pipes.

Research on the thermal behavior of medium-temperature phase change materials and factors influencing the thermal performance based on a vertical shell-and-tube latent heat storage system

Medium-and-high temperature latent heat storage systems have been developed to address challenges related to exhaust heat utilization and energy peak regulation in the field of energy engineering. However, there is still a lack of understanding regarding the thermal behavior of medium-and-high temperature phase change materials within heat exchangers and the factors influencing the system's thermal characteristics. Therefore, this study designed and constructed a new medium-temperature (300 °C) latent heat storage system with spiral-finned heat exchanger tubes. It uses 260 kg of medium-temperature phase change material for 68.3 MJ energy storage over 2 h. The system's response to variations in the inlet temperature and flow rate of the heat transfer fluid is investigated using thermocouples and visualization windows and provides recommendations for operating parameters. Results show natural convection as the primary heat transfer mechanism in the charging process, leading to temperature stratification in the tank (the upper has a higher temperature than the lower part). In contrast, heat conduction dominates heat transfer during discharging, resulting in a more uniform temperature distribution in vertical latent heat storage systems. Besides, inlet parameters significantly influence the system. Increasing storage temperature by 20 °C or flow rate by 20 L/min reduces storage time by 33.5 % and 54.0 %, respectively. In contrast, during the exothermic stage, heat conduction dominates with a more uniform temperature distribution. Optimal conditions are found at 280–150 °C, 15 L/min, achieving an input of 84 MJ and output of 50.25 MJ over 200 min, with a cycle efficiency of approximately 59.82 %.

Uji Performa Alat Pengering Tray Dryer Untuk Komoditas Hasil Pertanian Yang Memanfaatkan Kalor Buangan Kondensor Mesin Pengkondisian Udara (Air Conditioning) Domestik

The drying methods currently used by farmers still rely heavily on direct solar power, so that the continuity of drying to reduce water content cannot be controlled properly, which has a direct impact on the low quantity and quality of drying results, as well as poor product hygiene. Utilization of condenser waste heat from cooling machines is one of the development applications for heat pump systems. The advantages of heat pumps for the drying process include their ability to control the temperature and humidity in the drying chamber, so that they can be adjusted for various drying conditions and the drying process is more efficient and environmentally friendly. This research aims to determine the performance of drying machines for agricultural commodities (cocoa beans) using the method of developing a domestic air conditioning machine, by adding a condenser arranged in series with the main condenser to function as a drying chamber. The results of the modification of this tool consist of five main parts, namely the compressor, tray dryer room (additional condenser), main condenser, expansion valve, and evaporator. Testing of this dryer was carried out with two types of experiments, namely experiments without load and experiments with load. The test was carried out at the maximum working time of the condenser by setting the lowest working evaporator, namely 16°C. The lower the working temperature of the evaporator, the higher the working temperature of condenser 1. This is done to get maximum work from this modified dryer. Based on tests for temperature and relative humidity (RH) under load and no-load conditions, the values are not too different. After approximately 2 hours of operation or when the machine was working in steady state, the highest temperature was obtained at 87°C while the highest average RH was obtained at 78% in the drying rack space. The performance of this agricultural commodity drying machine has functioned well, especially for cocoa beans which have been dried to a standard moisture content of 7.5% in accordance with SNI 2322-2008 for an operating time of 130 minutes. The dryer system by utilizing exhaust heat from the condenser in this domestic air conditioning machine can work well without reducing its main function as indicated by the maximum temperature value of 20oC around the evaporator.Â

A review on ammonia-hydrogen fueled internal combustion engines

In the face of the electrification trend in transportation, the internal combustion engine (ICE) is expected to continue playing a vital role in generating electricity for power systems or directly propelling vehicles in certain sectors. However, ICEs are also under significant pressure to achieve carbon neutrality, with the key lying in carbon-free fuels. Ammonia, compared to hydrogen, offers advantages in terms of hydrogen-carrying capacity, storage and transportation convenience, and safety, making it a promising carbon-free fuel for large-scale use in ICEs. Nonetheless, ammonia's combustion inertness poses challenges for its application, requiring efforts to enhance its combustion. Hydrogen, as a carbon-free and highly reactive fuel, serves as a powerful combustion promoter, maximizing the carbon-free effect of ammonia. Furthermore, on-board ammonia decomposition can produce hydrogen, ensuring a stable hydrogen supply and enabling ammonia-hydrogen synergy combustion while carrying only ammonia. This ammonia-hydrogen synergy combustion, based on on-board hydrogen production, presents a highly promising development direction for ammonia engines. When combined with hybridization, it further enhances the overall energy efficiency of ammonia. The objective of this paper is to review recent advancements in ammonia-hydrogen engines, covering topics such as ignition methods and combustion strategies, fuel supply, pollutants, and after-treatment. Based on this review, a conceptual ammonia-hydrogen engine for hybrid power systems is proposed. This engine ignites the ammonia-hydrogen mixture in the main chamber using hydrogen active jet ignition, achieving spark-assisted compression ignition. Technical measures for efficient engine combustion, synergistic utilization of exhaust heat for hydrogen production, and effective after-treatment of NOx, unburned NH3, and N2O are discussed. At last, some perspectives on the development of ammonia-hydrogen engines are also presented.

A two-stage sodium converter coupled to a two-stage TEG: Parametric optimization

The aim of this study is to deeply study and analysis of energetic performance of the novel coupled system composed of a two-stage sodium thermal electrochemical converter and a two-stage thermoelectric generator. The main methods are to establish the model of the coupling system by considering the main irreversibilities, and obtain the analytical expressions of the power outputs and efficiencies of two subsystems and coupling system. The main novelties are to obtain the optimum ranges of critical parameters of the coupled system and give the reasonably matching conditions between the subsystems. The main contents of this study include that the influences of the intermediate and condenser temperatures of the sodium thermal electrochemical converter and current density of the first stage sodium thermal electrochemical converter as well as the electric current of the two-stage thermoelectric generator on the efficiency and power output density are discussed and the maximum power output density and efficiency of the system are calculated and compared with those of the single two-stage sodium thermal electrochemical converter and the existing coupling models. Results show that the maximum efficiency and maximum power output density of the coupled system attain 0.413 and 68.7×103 W m−2 and exhibit an improvement of about 14.1% and 66.7% than those of the standalone two-stage sodium thermal electrochemical converter respectively, and the maximum efficiency of the whole system increase 37.7% compared with that of the existing coupling system. The results obtained indicate that the performance of the proposed system is greatly improved by efficient the exhaust heat utilization. In addition, the multi-objective and multi-parametric optimization analyses are adopted to search for the global optimization profile and validate the obtained findings.

Review of Closed SCO2 and Semi-Closed Oxy–Fuel Combustion Power Cycles for Multi-Scale Power Generation in Terms of Energy, Ecology and Economic Efficiency

Today, with the increases in organic fuel prices and growing legislative restrictions aimed at increasing environmental safety and reducing our carbon footprint, the task of increasing thermal power plant efficiency is becoming more and more topical. Transforming combusting fuel thermal energy into electric power more efficiently will allow the reduction of the fuel cost fraction in the cost structure and decrease harmful emissions, especially greenhouse gases, as less fuel will be consumed. There are traditional ways of improving thermal power plant energy efficiency: increasing turbine inlet temperature and utilizing exhaust heat. An alternative way to improve energy efficiency is the use of supercritical CO2 power cycles, which have a number of advantages over traditional ones due to carbon dioxide’s thermophysical properties. In particular, the use of carbon dioxide allows increasing efficiency by reducing compression and friction losses in the wheel spaces of the turbines; in addition, it is known that CO2 turbomachinery has smaller dimensions compared to traditional steam and gas turbines of similar capacity. Furthermore, semi-closed oxy–fuel combustion power cycles can reduce greenhouse gases emissions by many times; at the same time, they have characteristics of efficiency and specific capital costs comparable with traditional cycles. Given the high volatility of fuel prices, as well as the rising prices of carbon dioxide emission allowances, changes in efficiency, capital costs and specific greenhouse gas emissions can lead to a change in the cost of electricity generation. In this paper, key closed and semi-closed supercritical CO2 combustion power cycles and their promising modifications are considered from the point of view of energy, economic and environmental efficiency; the cycles that are optimal in terms of technical and economic characteristics are identified among those considered.

УДОСКОНАЛЕННЯ МЕТОДІВ ТЕХНІКО-ЕКОНОМІЧНОГО ОБҐРУНТУВАННЯ СИСТЕМ УТИЛІЗАЦІЇ ТЕПЛА ВИТЯЖНОГО ПОВІТРЯ ВИРОБНИЧИХ ПРИМІЩЕНЬ

Due to the constant growth of energy costs, the management of enterprises is forced to find ways to reduce energy consumption and the first step in this process is to conduct an energy audit. One of the significant consumers of thermal and electrical energy in industry is the ventilation and air conditioning systems. The main way to reduce the energy consumption of these systems is to implement the utilization of exhaust air heat, and the main problem is the complicated design of heat recovery devices and economic assessment of the feasibility of their implementation. Despite the obvious need for implementation of systems for the utilization of exhaust air heat, the high cost of their implementation raises questions about the feasibility of implementation and cost recovery of these energy-saving measures. 
 One of the proven areas of heat recovery in exhaust systems is the use of exhaust gas recuperators. These devices allow to carry out utilization of the heat of the exhaust air and transfer the heat to the heating of the supply air in the systems located at certain distances from each other. Installation of heat-retaining and heating heat exchangers in existing systems allows to slightly increase the load on the fan and do without its replacement.
 According to the results of the actually performed energy audit at one of the industrial enterprises of Ukraine, the task in the technical and economical arrangement of the given method of energy-saving was set. 
 The article considers approaches to the construction of a system of hydrochloric acid heat utilization of the exhaust air heat from the warehouse premises. The calculation and selection of heat exchangers were carried out, and the economical feasibility of the implementation of this energy utilization system was determined. The results of the research are implemented in the thermodernization of a real industrial facility. In the example of this object economical indicators of the implementation of systems of hydrocarbon, and recycling were determined. 
 The use of systems for utilization of exhaust heat allows to significantly increase the energy efficiency of ventilation systems, reduce heating costs, reduce the cost of production and increase the profitability of the enterprise.

Integrated design and optimization research of LNG cold energy and main engine exhaust heat utilization for LNG powered ships

This paper aims at the high-efficiency utilization of LNG cold energy and main engine exhaust heat of ten-thousand-box LNG-powered container ship, and takes the 9200TEU LNG powered ship as the target ship. The two-level parallel Rankine cycle system is used to replace the original exhaust heat boiler utilization system, and the LNG horizontal three-level nested Rankine cycle is added on the basis of the two-level parallel Rankine cycle, realizing the efficient integrated utilization of the LNG vaporization cold energy and the exhaust heat of the main engine. Aspen HYSYS is used to simulate the scheme, and the genetic algorithm is further used to optimize the parameter matching of the system. Finally, the economic analysis of the cost saved by the optimization scheme and the initial investment cost is carried out. The results show that the system exergy efficiency in summer conditions reaches 58.20%, and the system exergy efficiency in spring, autumn and winter conditions reaches 58.73%; the initial system equipment cost is US$34.41 million, the power production cost of the system is 0.129 US$/kWh, and the payback period PBP is 7.37 years.

Integrated Design and Optimization Research of Lng Cold Energy and Main Engine Exhaust Heat Utilization for Lng Powered Ships

Integrated Design and Optimization Research of Lng Cold Energy and Main Engine Exhaust Heat Utilization for Lng Powered Ships

Operational Scenarios of a Gas Turbine Using Exhaust Gas Recirculation for Carbon Capture

Abstract Finding viable economic solutions to significantly reduce or eliminate greenhouse gas emissions from energy and transportation products in the near future is paramount for the long-term survival of fossil fuel-burning systems. One of which, the industrial gas turbine, has proven for decades to be a versatile energy system providing high efficiencies in combined heat and power (CHP) applications melding well within existing infrastructure. Applying appropriate technology, the industrial gas turbine could be augmented to both sequester carbon and improve efficiency leveraging the full heating value of the fuel. The paper considers a more detailed operational assessment of a gas turbine using exhaust gas recirculation (EGR) to enable cost-effective postcombustion carbon sequestration and utilization. In this study, the effect of using EGR will be assessed at part load and throughout the operational envelope quantifying component and overall performance, detailed combustion characteristics, and maximizing the utilization of exhaust heat and sequestered carbon in various applications. This study will also attempt to quantify true carbon footprint of gas turbine installations and endeavor to understand the relative change of replacing the gas turbine with an all-electric alternative. Fundamentally, we are looking to see if there is a future to sustain and adapt this significant natural gas (NG) energy infrastructure to a net-zero carbon emissive future by 2050.

Optimization research on the off-design characteristics of partial heating supercritical carbon dioxide power cycle in the landfill gas exhaust heat utilization system

• Off-design characteristics of partial heating supercritical CO 2 cycle are studied. • A novel calculation flow chart for the system off-design performance is proposed. • Separation control and inventory control are adopted for the thermal system. • A best control scheme relied on the net power maximization can be determined. Landfill gas waste heat power generation is an effective way to promote the efficiency and economics of power plants. However, the operating performance of the power generation system needs to be improved further. In this paper, a systematic optimization research on the off-design characteristics of the partial heating supercritical carbon dioxide power system for exhaust heat utilization from gas turbine cycle are conducted. Optimal operating conditions in thermodynamics and economics obtained by genetic algorithm are determined as design conditions. Gradient descent method is used to obtain the best operating point under a certain off-design working condition. With the goal of maximizing net power output, separation control and inventory control are applied to the system. The results exhibit that the best thermoeconomic performance can be gained when the pressure ratio is 2.28 with separation ratio of 0.35 at design stage. In the off-design stage, the maximum net power shows an approximately linear growth trend from 1581 kW to 2924 kW with increasing heat source temperature and mass flow rate under the inventory control, while growth rate of net power output gradually decreases under the separation control. Finally, the best control scheme mixed with inventory control and separation control is proposed and determined quantitatively.

Dealing with uncertainty in automated operational planning for residential fuel cell system: A comparative study of state-of-the-art approaches

Polymer electrolyte fuel cell cogeneration systems (PEFC-CGSs) provide hot water by utilizing exhaust heat produced in electricity generation process. The energy saving potential of PEFC-CGSs can be maximized by optimal operational plans, and most state-of-the-art approaches implement operational planning function (OPF) based on energy demand time-series prediction by using machine learning techniques. In general, prediction of demand time-series with small expected average errors is regarded as the most important point in obtaining appropriate operational plans; however, several recent studies have revealed that other complex factors such as the direction and timing of forecast errors greatly affect the quality of operational plans in some cases. Core ideas proposed in these previous studies are broadly classified into seven types. The purpose of this study is to characterize these OPFs from the two aspects: the output form of prediction model and prediction target variable, and to clarify “what kind of uncertainty should be focused on” and “how this uncertainty should be handled” in designing OPF. The seven kinds of OPFs were comprehensively evaluated via numerical simulations using real-world data. The results show the significance of OPF based on prediction of expected operational cost surface using multiple output prediction model.

RANCANG BANGUN SISTEM PEMANFAATAN PANAS BUANG PADA KOMPOR PORTABEL MENGGUNAKAN THERMOELECTRIC GENERATOR

The world's population continues to grow, causing energy needs to increase rapidly.In fact, not all regions have a special supply of electrical energyareas that are located in remote and difficult to access places. Besides the depletion of reservesfossil fuels as the main source of electricity generation and effectsbad pollution also encourages the change of energy sources into new energyrenewable (EBT). The purpose of this research is to design a solution forovercome both of these by using the exhaust heat utilization system(waste-heat recovery) in domestic combustion, especially portable stoves.Thermoelectric generator (TEG) is the right choice because it has severaladvantages needed such as simple conversion process, reliabilityhigh, and ease of application. The research will discuss the design of the toolwaste-heat recovery on portable stoves mechanically and electrically. Designcarried out on 2 different types of TEG modules, namely TEP1-1264-3.4 and SP1848-27145. The proposed tool has an estimated output power of about 9.24 W for the moduleTEP1-1264-3.4 and 9.0048 W for SP1848-27145 module using 8a TEG module with an approximate temperature difference of 60 ? and a cooling systemwater based. Thus the TEP1-1264-3.4 module generates more powerhigher than SP1848-27145 module and the series configuration is rated better because of thishave no problem when experiencing voltage differences between modules. Designmechanical build that is made to have 2 separate frame parts for conveniencecircuit maintenance.

Characteristic of methanol steam reforming in fan-shaped channel reactor for efficient hydrogen production

ABSTRACT On-board methanol steam reforming fan-shaped channel micro-reactor heated by engine exhaust (simulated by hot wind) for hydrogen production was designed and analyzed in this study. Effects of the reactor material and structural parameters were investigated. The optimal size of reactor structure, using the stainless steel as the reactor material, are predicted to be 26 mm and 35 mm for the hot wind side radius and total radius, respectively. Additionally, the optimal angle of the fan shaped reactor unit is 10°, while the thickness of the intermediate between the hot wind and reaction sides as well as side and top walls are 1 mm. Under these structure parameters, the methanol conversion rate is 73.48%, the engine exhaust heat efficiency is 36.50%, and the hydrogen production rate of the whole reactor is 78439.30 mm3/s. These results can be utilized as reference for the comprehensive utilization of engine exhaust heat and engine hydrogen-mixed combustion.

Analysis and Evaluation of Multi-Energy Cascade Utilization System for Ultra-Supercritical Units

To address the large temperature difference in the air heater (AH) inlet of a traditional exhaust heat utilization system and energy grade mismatch problems during the heat and mass transfer processes, this study proposed a new multi-level waste heat cascade utilization system. Based on a principle of “temperature-to-port and cascade utilization”, this system uses the boiler side high-temperature flue gas and low-temperature air, and the turbine side high-temperature feed water and low-temperature condensate water, to conduct cross heat exchange according to the energy grade matching principle. Combined with a typical 1000 MW coal-fired unit, the heat transfer characteristics and energy-saving benefits of the new system were analyzed. The results showed that the new system has excellent performance: the heat rate decreased by 91 kJ/kWh, coal consumption decreased by 3.3 g/kWh, and power generation efficiency increased to 49.39%.

Designing Regenerators of Thermoacoustic Engines for Automotive Waste Heat Recovery

<div class="section abstract"><div class="htmlview paragraph">Extraction and utilization of automotive waste exhaust heat is an effective way to save fuel and protect the environment. One promising technology for this purpose is the thermoacoustic engine, where thermal energy is converted to mechanical energy in terms of high amplitude oscillations. The core component in a travelling-wave thermoacoustic engine is its regenerator where the process of energy conversion is mainly realized. This paper introduces a strategy for the design of the regenerator for applications in typical light- and heavy-duty vehicles. Starting from 1-D linear thermoacoustic theory, the nonlinear effects (given by the high amplitude oscillations) are modelled as acoustic resistances and introduced into the basic linear equations to estimate the nonlinear dissipations in the regenerator. Then, a few dimensionless parameters are derived by normalizing these thermoacoustic equations. This yields a good overview of how different design parameters such as the geometrical dimensions, operating temperature, and thermal boundary conditions influence the performance of the regenerator. For the application of automotive waste heat recovery, the thermal properties of the actual exhaust gas are accepted to be the boundary condition for the heat matching. The results obtained in the current work show that the optimum designs for the regenerators in travelling-wave thermoacoustic engines aimed at light- and heavy-duty applications widely differ due to the different thermal properties of their exhaust gas. Finally, two possible optimal designs of the regenerators in travelling-wave thermoacoustic engines for the typical light- and heavy-duty applications are presented. The designs are based on heat matching between the required heat by the regenerators and the available heat from the exhaust gases.</div></div>