Thermodynamical model of an atmospheric steam engine

Bortolin, Vítor Augusto Andreghetto; Lemos, Bernardo Luiz Harry Diniz; Amaral, Ronaldo; Freire, Cesar Monzu; Meneghini, Júlio Romano

doi:10.1007/s40430-021-03209-9

Cited by 3 publications

(8 citation statements)

References 21 publications

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“…In turn, the pressure difference p act between chambers A and B of the cylinder will increase such that the pressure difference undergoes a net action force F ACT = F A – F B . Thus, as expected based on the background on the performance of useful mechanical work of vacuums starting with Savery's work, [ 2–11 ] the results of Table 1 and 2 agree with previously verified facts about steam engines. As every cycle is completed by two inactive time lags (one per motion stroke), two DACs are required to complete a continuous motion cycle.…”

Section: Proposed Disruptive Technology With a Closed Process‐based C...supporting

confidence: 87%

“…In summary, two heat-work converters characterized by the use of vacuums to obtain valuable work can be distinguished: 1) Open processes characterized by inherent changes of state, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] which suffer losses in open process transformations that include condensation, vaporization, and flow work losses.…”

Section: Technological Improvement Strategies Subject To the Criterio...mentioning

confidence: 99%

“…Although vacuums have been used experimentally and applied to industry for more than two centuries, [1][2][3][4][5][6][7][8][9][10][11] this technological proposal exhibits and uses the cutting-off or disruptive concept of vacuum achieved by closed process-based isochoric heat extraction, [12][13][14][15][16][17][18][19][20][21][22][23] which is assumed to be an absolutely disruptive technique.…”

Section: Proposed Disruptivementioning

confidence: 99%

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Study of the Disruptive Design of a Thermal Power Plant Implemented by Several Power Units Coupled in Cascade

García

2023

Energy Tech

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This work discusses a study of the disruptive design of a thermal power plant implemented by several power units coupled in cascade aiming at increase the heat utilizations factor. Thus, the study addresses the phases prior to the implementation of a prototype of a heat‐to‐work converter and analyzes the performance using a vacuum carried out by cooling. Vacuums have been used in steam engines according to open processes with changes of state for several centuries. In the case under study, a disruptive technique is proposed by which a vacuum is used in closed processes without a change of phase. Likewise, a plant structure based on the cascading coupling of three thermal cycles is designed to achieve a high heat utilization factor. Although the average thermal efficiency obtained in this study is 59.8 for air and 66.7 for helium as working fluids, the most relevant criterion deals with plant performance, for which the heat utilization factor surpasses 85% for air and 96% for helium as a working fluid. Despite the unprecedentedly high heat utilization factor, this study indicates some potential to further increase the heat utilization factor because the power plant can be implemented using heat regeneration strategies.

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Section: Proposed Disruptive Technology With a Closed Process‐based C...supporting

confidence: 87%

Section: Technological Improvement Strategies Subject To the Criterio...mentioning

confidence: 99%

Section: Proposed Disruptivementioning

confidence: 99%

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Study of the Disruptive Design of a Thermal Power Plant Implemented by Several Power Units Coupled in Cascade

García

2023

Energy Tech

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“…3 Recently, the theory of the CE was re-assessed and improved. 8 Experiments with a bench scale engine resulted in an efficiency of 5.5% for an expansion ratio of 1:4, 9 These efficiencies were however limited by high pressure losses in valves and comparatively high heat sink temperatures, so that there is still room for improvements. The comparative analysis of ORC and CE efficiencies 3 showed that for operating temperatures of 80-120°C the ORC systems have efficiencies of 4.2-6.8%.…”

Section: The Condensing Enginesmentioning

confidence: 99%

Assessment of the Newcomen engine’s development potential as heat engine for low temperature waste heat

Müller,

Mereš

2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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There is a large but mostly unused energy resource available from low temperature waste heat with temperatures of 80–150°C. The lack of a cost-effective technology prevents the generation of power from this potential. Recently, the Condensing Engine, which employs the condensation of steam and the arising vacuum as the driving force, had been developed to address this problem. Its simplicity and the use of water as working fluid promises cost-effectiveness. In the context of this work, it was decided to investigate the Newcomen Engine to assess its potential. This engine is usually neglected because of is low efficiency, thought to be caused by the continuous cooling and re-heating of the cylinder. A thermodynamic model of the engine was developed. Surprisingly, the model indicated that 78% of the heat losses are caused by the re-heating of the injection water and only 22% by the cooling and re-heating of the cylinder. This finding allowed to conceptualise a new engine, the Internal Condensation Engine, where plastic material for the cylinder and the forced ejection of the water minimise losses. The engine would have a similar or better efficiency than competitive technologies whilst being simpler, and therefore more cost-effective.

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“…According to parameters for calculation given by Table 2, the change of in-cylinder pressure and temperature during operation can be obtained, as shown in Fig11. It can be seen that in a working cycle O-A-B-C-D-E-F-O, the change of in-cylinder pressure has undergone six different processes, corresponding to the six thermodynamic processes of the engine working cycle 31 . When the output shaft angle is located in O-A, the in-cylinder pressure remains basically unchanged, same as the external pressure, which corresponds to the exhaust process; When the output shaft angle is located in A-B, the in-cylinder pressure begins to increase.…”

Section: Influence Of the Ports Position Anglementioning

confidence: 99%

Influence of gas distribution port parameters on in-cylinder working pressure of Annular Connecting Straight Cylinder Engine

Yang

Cai

et al. 2022

Preprint

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In this paper, a novel type of Annular Connecting Straight Cylinder Engine (ACSCE) is proposed, and an innovative dynamic position gas distribution system based on airway reuse is designed. Combined with the characteristics of the differential rotation of the rotor cylinder, the thermodynamic model of the air-powered working process for ACSCE is established. The mathematical structure model of the gas distribution system is also described, and the influence of different parameters of the gas distribution port, including the position angle, size and shape, on in-cylinder working pressure of ACSCE are analysed. The simulation and experimental results show that the position angle of the intake and exhaust ports of the Central Valve Shaft (CVS) has a greater impact on incylinder working pressure, while the port size of CVS has a relatively small effect, and the port size of the Rotary Valve (RV) also has a great impact on in-cylinder working pressure, while the port shape has less effect. When the intake port position angle φ z 0 = 78°, the exhaust port position angleφ z 0 ' = 30 o , the intake port size d 1 =10 mm , the exhaust port size d 1 ' =14 mm of CVS and the port size d 2 = 6 mm of RV, the ACSCE can be in correct gas distribution state and work stably.

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Thermodynamical model of an atmospheric steam engine

Cited by 3 publications

References 21 publications

Study of the Disruptive Design of a Thermal Power Plant Implemented by Several Power Units Coupled in Cascade

Study of the Disruptive Design of a Thermal Power Plant Implemented by Several Power Units Coupled in Cascade

Assessment of the Newcomen engine’s development potential as heat engine for low temperature waste heat

Influence of gas distribution port parameters on in-cylinder working pressure of Annular Connecting Straight Cylinder Engine

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