Mapping of the Temperature–Entropy Diagrams of van der Waals Fluids

Imre, Attila R.; Kustán, Réka; Groniewsky, Axel

doi:10.3390/en13061519

Cited by 6 publications

(3 citation statements)

References 23 publications

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“…Real refers to the fact that these classes have reverse S‐shaped saturated vapor lines; therefore, it is possible to have an isentropic “saturated vapor state to another saturated vapor state” transition with them, described in Section 3. Neither ACZM nor ACNZM fluids have been found so far 21,36 . Subjects of the current investigation are the “real” isentropic fluids when expansion is assumed to be reversible and adiabatic, but in later passages, wet fluids under real expansion conditions will also be studied.…”

Section: Design Of Tl–tu Diagrams For Extended Isentropic Expansion P...mentioning

confidence: 98%

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Simultaneous working fluid and expander selection method for reaching low‐threshold technology organic Rankine cycle (ORC) design

Groniewsky

Kustán

Imre

2023

Energy Science & Engineering

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Maximizing the utilization of an available source serves as the ideal approach, provided that only technical factors are considered. For sources with low heat flux, however, cost‐effective solutions are more suitable due to the minimal net power generated, regardless of the effectiveness of the energy conversion. In such cases, utilizing low‐threshold technology may be the most fitting solution, the layout of these cycles should be simple and inexpensive. In the case of organic Rankine cycles (ORCs)‐based power cycles, this means the omission of superheaters or recuperative heat exchangers and the use of simple expanders and small heat exchangers. Simplifying the design, however, requires additional considerations about the elementary steps of the cycle. This work presents a procedure to select favorable working fluids for ORC while considering the expander's internal efficiency. The criteria for favourability is to have a nonideal expansion process starting and ending in (or very near) saturated vapor states to avoid problems related to wetness/dryness between the given maximal and minimal expansion temperatures. It is demonstrated that the design can be simplified under the simultaneous working fluid and expander selection method presented in this study, regardless of the type and isentropic efficiency of the expander. The resulting methodology applies the novel classification of working fluids using the sequences of their characteristic points on temperature‐entropy space. The proposed approach is illustrated with a case study finding optimal working fluid for an ORC system fitted to industrial waste heat, a low‐temperature geothermal, and a cryogenic heat source.

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Section: Design Of Tl–tu Diagrams For Extended Isentropic Expansion P...mentioning

confidence: 98%

“…Neither ACZM nor ACNZM fluids have been found so far. 21,36 Subjects of the current investigation are the "real" isentropic fluids when expansion is assumed to be reversible and adiabatic, but in later passages, wet fluids under real expansion conditions will also be studied.…”

Section: Design Of T L -T U Diagrams For Extended Isentropic Expansio...mentioning

confidence: 99%

Simultaneous working fluid and expander selection method for reaching low‐threshold technology organic Rankine cycle (ORC) design

Groniewsky

Kustán

Imre

2023

Energy Science & Engineering

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“…A reservoir abandonment temperature of 120-140 • C was selected for the electricity generation analysis based on the operational binary cycle GPP of Kamchatka Peninsula (Russia; [60]). However, Organic Rankine Cycle using an optimized working fluid has helped to achieve favorable electricity generation from lower geothermal energy source of about 80 • C [61][62][63][64]135]. Although the efficiency of the GPP with such low heat source is lower than 10% [35], this can be advantageous for remote northern regions where deep drilling cost is high ($12 million USD for a 4-km-well; [37]).…”

Section: Deep Geothermal Energy As a Viable Solution To Reduce Fossil Fuels Dependency Of Remote Communitiesmentioning

confidence: 99%

Uncertainty and Risk Evaluation of Deep Geothermal Energy Source for Heat Production and Electricity Generation in Remote Northern Regions

2020

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The Canadian off-grid communities heavily rely on fossil fuels. This unsustainable energetic framework needs to change, and deep geothermal energy can play an important role. However, limited data availability is one of the challenges to face when evaluating such resources in remote areas. Thus, a first-order assessment of the geothermal energy source is, therefore, needed to trigger interest for further development in northern communities. This is the scope of the present work. Shallow subsurface data and outcrop samples treated as subsurface analogs were used to infer the deep geothermal potential beneath the community of Kuujjuaq (Nunavik, Canada). 2D heat conduction models with time-varying upper boundary condition reproducing climate events were used to simulate the subsurface temperature distribution. The available thermal energy was inferred with the volume method. Monte Carlo-based sensitivity analyses were carried out to determine the main geological and technical uncertainties on the deep geothermal potential and risk analysis to forecast future energy production. The results obtained, although speculative, suggest that the old Canadian Shield beneath Kuujjuaq host potential to fulfill the community’s annual average heating demand of 37 GWh. Hence, deep geothermal energy can be a promising solution to support the energy transition of remote northern communities.

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A rigorous approach for characterising the limiting optimal efficiency of working fluids in organic Rankine cycles

González

Llovell

Garrido

et al. 2022

Energy

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Mapping of the Temperature–Entropy Diagrams of van der Waals Fluids

Cited by 6 publications

References 23 publications

Simultaneous working fluid and expander selection method for reaching low‐threshold technology organic Rankine cycle (ORC) design

Simultaneous working fluid and expander selection method for reaching low‐threshold technology organic Rankine cycle (ORC) design

Uncertainty and Risk Evaluation of Deep Geothermal Energy Source for Heat Production and Electricity Generation in Remote Northern Regions

A rigorous approach for characterising the limiting optimal efficiency of working fluids in organic Rankine cycles

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