Fluid Selection Research Articles

Multi-Objective Optimization and Fluid Selection of Different Cogeneration of Heat and Power Systems Based on Organic Rankine Cycle

Cogeneration of heat and power systems based on the organic Rankine cycle (ORC-CHP) has been proven to be an effective way to utilize waste heat at medium and low temperatures. In this work, three ORC-CHP (combined heat and power based on organic Rankine cycle) systems are simulated and compared, including the SS (serial system), the CS (the condensation system), and the SS/CS. The multi-objective genetic algorithm (MOGA) is used to optimize the three systems respectively to achieve higher exergy efficiency and profit ratio of investment (PRI). The optimal thermal-economic performance is obtained. Twelve organic fluids are adopted to evaluate their performance as working fluids. The calculation results show that SS has the highest exergy efficiency, while SS/CS has the best economic performance. Compared with the highest exergy efficiency of SS and the best economic performance of SS/CS, CS will be the optimal solution considering these two objective functions. Under the optimal working conditions, SS has the highest thermal efficiency because it has the highest net power output. The components with the largest proportion of exergy destruction are the heat exchangers, which also has the highest cost.

Multi-variant hybrid techniques coupled with Taguchi in multi-response parameter optimisation for better machinability of turning alloy steel

ABSTRACT Despite having poor cooling property, minimum quantity lubrication (MQL) is very commonly utilised in machining processes because of its superb lubrication, cleanliness, fewer costs and ease of handling. However, the optimum process parameters and the cutting fluid selection are very important for efficient machining. Moreover, an easy technique for optimisation is required so that the technicians can easily find their optimum parameter combinations for any manufacturing process. Considering multiple objectives synchronously for selecting optimum conditions helps to enhance the overall machinability. In this work, optimisation of cooling/lubrication environment, speed and feed were accomplished for minimum cutting temperature, roughness, cutting force along with maximum MRR and chip thickness ratio in turning 42CrMo4 alloy steel. Three powerful multi-variant hybrid techniques, such as Taguchi-based PCA-GRA, PCA-MOORA and DEAR, were implemented for multi-response optimisation, which provided identical results. The optimal process parameters were: MQL with cutting oil with the speed of 352 m/min and feed of 0.10 mm/rev. But among these methods, compared to the complex PCA-GRA, the DEAR is the computationally simplest because it did not require weight calculation before optimisation and then PCA-MOORA. However, the limitation of the DEAR method is that it can work for the problem having conflicting objectives.

Energy and exergy analysis of a combined system: cascade organic Rankine cycle and cascade refrigeration cycle

In this paper, a new combined system is proposed for recovering thermal energy at medium temperature using a cascade organic Rankine cycle to feed a cascade refrigeration cycle. Energy and exergy analysis is applied to the combined system to determine its performance using different working fluids under the same operating conditions taking into account the effect of some operating parameters and the selection of organic fluids on cycle performance. The pair of organic fluid (Toluene/R245fa) used for the cascade organic Rankine cycle and the pairs (R717/R744, R717/R23, R134a/R23) used for the cascade refrigeration cycles. The results show that the combined system function with the couple (R717/R23) for cascade refrigeration cycle gives better exergy efficiency 50.03% compared to other couples, 49.57% for the couple (R717/R744), and 48.01% for the couple (R134a/R23). The thermodynamic evaluation shows that the operating temperatures, such as the cascade organic Rankine cycle evaporation temperature and the cascade refrigeration cycle evaporation temperature influence the performance of the combined system.

A hybrid adaptive neuro-fuzzy inference system integrated with equilibrium optimizer algorithm for predicting the energetic performance of solar dish collector

Solar energy exploitation has a vital role to fulfill sustainability and decrease the usage of non-renewable energy resources. Solar parabolic dish collector (SPDC) is an effective alternative to fossil fuels due to its high efficiency. Nevertheless, performance prediction, optimization, and working fluid selection of SPDCs are highly complex problems and need complicated calculations and/or costly time-consuming experiments. Artificial intelligence-based algorithms have been proven to be beneficial in modeling different solar systems. Therefore, this study proposes an improved method to predict the thermal performance parameters of SPDC with a cylindrical cavity receiver using a modified algorithm of the adaptive neuro-fuzzy inference system (ANFIS) integrated with equilibrium optimizer (EO). In the developed algorithm, EO is employed as a new metaheuristic approach to enhance the prediction accuracy of ANFIS via determining the optimal values of ANFIS parameters. To evaluate the performance of the developed method, ANFIS-EO is compared with ANFIS and the conventional artificial neural network. The three models were applied to compare and predict the temperature difference of working fluid, heat gain, and energy efficiency of cylindrical receiver for SPDC operating with two different solar working fluids, namely, multi-wall carbon nanotubes/thermal oil nanofluid and pure thermal oil. Moreover, five statistical criteria are utilized to evaluate the performance of the investigated algorithms. The statistical performance results showed that the ANFIS-EO technique had the best prediction accuracy among the three models, and can be regarded as a powerful optimization tool for predicting the energetic performance of SPDC. The predicted results obtained by the ANFIS-EO have an excellent determination coefficient of 0.99999 for all predicted responses.

Optimal design of organic Rankine cycle system for multi-source waste heat recovery involving multi-period operation

This paper addresses a three-step method to design the optimal ORC waste heat recovery system (WHRS) that adapts to the multi-period and multi-source heat recovery requirements. In the proposed method, the candidate working fluids and the corresponding cycles of WHRS are preliminarily selected based on analysis of the heat source load curve and the quantitative relationship of temperatures between the heat sources and working fluids. In this step, the quantitative relationship for working fluid selection in single-source system is generalized to the multi-source WHRS, and a series of principles for the combination and classification of inflection points on heat source load curve are presented to simplify the design process and avoid the structure redundancy at the same time. Then, based on these selections, a multi-source and multi-cycle WHRS model is established and solved to determine the optimal configuration of multi-source WHRS, which consists of an ORC thermodynamic model and a waste heat recovery network (WHRN) model. The number of cycles, the working fluids, the WHRN structure, and the design and operating parameters are thus determined for multi-source and multi-cycle WHRS. At the last step, the time-sharing model is extended and solved to finalize the design of multi-source WHRS, so that the multi-period operation requirements can be easily met through the combination and sharing of operating units. The application and effectiveness of the proposed method are verified via an industrial case study and the results are expected to provide guidance for the design of the multi-period and multi-source waste heat recovery process in practice.

Optimal hydrocarbon based working fluid selection for a simple supercritical Organic Rankine Cycle

In this paper, several hydrocarbons' performance as a working fluid for a supercritical Organic Rankine Cycle are studied. Energy, exergy, and exergoeconomic analysis are conducted for the cycle operating with a low-grade waste heat source. Initially, fifteen different working fluids, primarily hydrocarbons, were considered based on their environmental characteristics, global warming potential, ozone depletion potential, flammability, and toxicity. The cycle efficiency for each working fluid was analyzed for different cycle operating pressures and different inlet heat source temperatures from 400 K to 500 K for a constant turbine work output. Three different trends of cycle performance characteristics were observed for various working fluids with the cycle operating at different evaporator pressures and source inlet temperatures. The working fluids that exhibited similar characteristic trends were then categorized into families for further analysis. Three hydrocarbons, i.e., Dimethyl Ether, R1234yf, and Diethyl Ether, were each selected as the representative of their respective family, along with Isobutane as the reference working fluid for comparison. After detailed energy and exergy analyses, Dimethyl Ether and Isobutane were found to be promising working fluids for the range of pressure and source inlet temperatures considered. Finally, the exergoeconomic analysis showed Dimethyl Ether to be the optimal working fluid based on the unit cost of net work produced and the total cost of exergy destruction, which were calculated to be (59.18 ± 0.49) $/MWh and (8.92 ± 0.48) $/h, respectively, when operating at 450 K.

A novel working fluid selection and waste heat recovery by an exergoeconomic approach for a geothermally sourced ORC system

A novel working fluid selection methodology is proposed for organic Rankine cycles (ORCs) coupled with low-grade geothermal sources by employing an existing dataset of an operating binary geothermal plant that works with n-pentane. Thermodynamic and thermoeconomic aspects of power production are combined to evaluate 29 different single-component working fluid candidates from different chemical branches in four-step elimination methodology. In terms of working fluid classification from physical point of view, results indicate that there is a direct relationship between vapor expansion ratio (VER) and net work output for dry working fluids. On the other hand, it is shown that isentropic fluids behave differently from dry fluids. Based on the proposed methodology, R113 is selected as a new working fluid for the existing plant instead of n-pentane. Results indicate that by applying the proposed methodology, it is possible to increase first and second law efficiencies of plant 0.59% and 3.18%, respectively, while reducing the levelized electrical cost (LEC) around 11% in comparison to base plant outputs with n-pentane. Furthermore, a case study is presented in addition the plant level analysis by implementing a hypothetical waste heat recovery cycle, configurated with proposed methodology, in order to reduce exergy losses originating from brine re-injection. It is shown that it may be possible to further reduce the LEC around 1% and increase the overall efficiencies 0.1% for the first law and 0.26% for the second law. However, it is necessary to be deliberate about these final results since they also demonstrate the sensitivity of LEC to the increases in second law efficiency rather than levelized capital investments.

A two-step procedure for the selection of innovative high temperature heat transfer fluids in solar tower power plants

This work compares with a two-step procedure the performance of different Heat Transfer Fluids (HTF) for high temperature receiver applications (up to 715 °C) in advanced Solar Tower (ST) plants. The most promising molten salts and liquid metals are initially selected and ranked according to their performance, estimated with different Figures of Merit (FoM) available in literature or newly defined. For the best performing fluids, different hydraulic configurations and tube diameters at fixed receiver size are tested. The optimized external tubular receiver configuration for each HTF is then implemented in a ST plant and its performance is assessed through a detailed techno-economic analysis, considering the use of a direct thermal energy storage system and of a sCO2 based power cycle. As a second step, the yearly electricity yield and the LCOE are evaluated for two different sites. Results show NaCl–MgCl2 as the best option for the considered type of plant with a LCOE of 151 $/MWh, which is anyhow 10% higher than the reference Solar Salts case.

Pursuit of the ideal antiseptic irrigation solution in the management of periprosthetic joint infections.

Irrigation and debridement in the treatment of periprosthetic joint infection (PJI) serve an integral role in the eradication of bacterial burden and subsequent re-infection rates. Identifying the optimal irrigation agent, however, remains challenging, as there is limited data on superiority. Direct comparison of different irrigation solutions remains difficult because of variability in treatment protocols. While basic science studies assist in the selection of irrigation fluids, in vitro results do not directly translate into clinical significance once implemented in vivo. Dilute povidone iodine, hydrogen peroxide, chlorhexidine gluconate, acetic acid, sodium hypochlorite, hypochlorous acid, and preformed combination solutions all have potential against a broad spectrum of PJI pathogens with their own unique advantages and disadvantages. Future clinical studies are needed to identify ideal irrigation solutions with optimal bactericidal properties and low cytotoxicity for PJI treatment.

Thermodynamic analysis of a hydrogen fuel cell waste heat recovery system based on a zeotropic organic Rankine cycle

In this study, a thermodynamic model of a hybrid system consisting of a proton-exchange membrane fuel cell (PEMFC) system and an organic Rankine cycle (ORC) system is established using Aspen Plus software. The optimal working fluid is selected by comparing the performance of pure working fluids and zeotropic mixtures of working fluids in an ORC system. The zeotropic working fluid consisting of R245fa/R123 with a mixing ratio of 0.6/0.4 shows the best performance. The effects of some key parameters, including the current density and operating temperature, on the performance of the PEMFC–ORC system with zeotropic mixing fluids are discussed. The results indicate that the power and efficiency of the PEMFC–ORC system with the zeotropic mixing fluid increase with increasing operating temperature. When the R245fa/R123 zeotropic working fluid with a mixing ratio of 0.6/0.4 is used, the net power and efficiency of the hybrid system reach optimum values under the studied boundaries, with improvements of 12.87% and 4.84%, respectively. The influence of the maximum allowable evaporation pressure and stack operating temperature on the selection of optimum working fluid for the hybrid system is discussed in addition.

Fluid Therapy and the Microcirculation in Health and Critical Illness.

Fluid selection and administration during shock is typically guided by consideration of macrovascular abnormalities and resuscitative targets (perfusion parameters, heart rate, blood pressure, cardiac output). However, the microcirculatory unit (comprised of arterioles, true capillaries, and venules) is vital for the effective delivery of oxygen and nutrients to cells and removal of waste products from the tissue beds. Given that the microcirculation is subject to both systemic and local control, there is potential for functional changes and impacts on tissue perfusion that are not reflected by macrocirculatory parameters. This chapter will present an overview of the structure, function and regulation of the microcirculation and endothelial surface layer in health and shock states such as trauma, hemorrhage and sepsis. This will set the stage for consideration of how these microcirculatory characteristics, and the potential disconnect between micro- and macrovascular perfusion, may affect decisions related to acute fluid therapy (fluid type, amount, and rate) and monitoring of resuscitative efforts. Available evidence for the impact of various fluids and resuscitative strategies on the microcirculation will also be reviewed.

Performance characteristics and working fluid selection for high-temperature organic Rankine cycle driven by solar parabolic trough collector

Abstract In present paper, thermodynamic analysis and techno-economic assessment of an organic Rankine cycle (ORC) coupled with solar parabolic trough collector (PTC) are investigated. The thermodynamic and economic models, based on the principles of thermodynamics and heat transfer, as well as dynamic economic analysis, are developed for the components of the combined system. By performing a parametric study, the effects of outlet temperature (TPTC,out) and temperature difference between inlet and outlet of PTC (ΔT) and pinch point temperature difference of heat exchangers on the thermo-economic performance are evaluated. Moreover, under reasonable thermodynamic boundary conditions, the optimal operational parameters are obtained via a Pareto frontier solution. It is indicated that the improving TPTC,out is beneficial to the thermo-economic performance. Among the fluid candidates, toluene yields the best energy, exergetic and economic performance. There exists an optimal ΔT at which the thermal and exergy efficiency achieve the maximum. The optimal ΔT is 19–26°C for the screened working fluids. The pinch point temperature difference of evaporator has different impact on the system performance compared with that of condenser. The evaporator pinch point temperature difference has slight influence on the economic performance when it is larger than 10°C. While there is optimized condenser pinch point temperature difference (7–8°C), the economic performance is the optimal. The PTC and heat exchanger are the main source of total investment cost, account for more than 75%. The Pareto frontier solutions can provide a design guide for the decision maker.

Sensitivity Analysis of F Reservoir in M Area

The sensitivity analysis of F reservoir in M area is carried out by core laboratory experiment. The experimental results show that F reservoir in this area belongs to medium weak-strong water sensitivity, strong acid sensitivity and medium strong alkali sensitivity, and its speed sensitivity is very weak, and its sensitivity is basically weak-no speed sensitivity. Through laboratory experimental analysis, it provides a basis for rational selection of injection fluid for F reservoir in this area.

Thermodynamic comparison of modified Rankine cycle configurations for LNG cold energy recovery under different working conditions

In this study, we present the evaluation of two modified single-stage Rankine cycles (RC) and two two-stage RCs to provide a guidance for configuration selection under different working conditions. Moreover, a regenerative-reheat RC, which is the combination of the modified single-stage RCs, is proposed to utilize the cold energy of liquefied natural gas (LNG) and the thermal energy of low grade heat. The key parameters of these five configurations using eight working fluids are optimized with exergy efficiency as the optimization objective. The results show that the modified single-stage RCs are usually better than the two-stage RCs since they have simpler configurations with similar or higher efficiencies. The regenerative-reheat RC performs even better under most working conditions and it achieves the maximum efficiency of 24.57% by using ethane as the working fluid under the heat source temperature of 180 °C and the pipeline pressure of 3 MPa. The addition of direct expansion cycle can improve the exergy efficiencies of most fluids and configurations under lower pipeline pressures. However, the improvements decrease greatly for fluids with low normal boiling point temperatures (NBPTs) and especially under higher pipeline pressures. As to the fluid selection, high critical temperature and low NBPT are both important for reheat RC and parallel two-stage RC. NBPT weights more than critical temperature for regenerative RC and regenerative-reheat RC. Besides, wet working fluids are more suitable for reheat RC while dry and isentropic fluids are more suitable for regenerative RC and regenerative-reheat RC. The optimal regenerative ratio and reheat pressure ratio vary with different working fluids and working conditions. Lower reheat pressure ratio usually leads to higher regenerative ratio.

A new hybrid decision-making strategy of cutting fluid selection for manufacturing environment

A new hybrid decision-making strategy of cutting fluid selection for manufacturing environment

Evaluation and selection of dry and isentropic working fluids based on their pump performance in small-scale organic Rankine cycle

• A trapezoid model used to represent the power consumption of pump is established. • The perfection of Organic Rankine Cycle relative to the Carnot cycle is analyzed. • The deviation between the real and ideal gas behavior is obtained. • The optimal condensation temperature of each working fluids is determined. • Their suitable pump types are determined. The circulation pump is an important element limiting the development of small-scale Organic Rankine Cycle system which may have a negative efficiency when the power consumption of the pump is considered and if a suitable pump that corresponds to the working fluid is not properly selected. Based on the consideration mentioned above, in this paper, a trapezoid used to represent the power consumption of the pump and a triangle used to represent the degree of subcooling of the working fluid are defined. Using these two models, the perfection of Organic Rankine Cycle at the optimal condensation temperature relative to the Carnot cycle within the same temperature limitation is analyzed when 69 dry and isentropic working fluids are used in Organic Rankine Cycle. The deviation between the real and ideal gas behavior of each working fluid is also obtained. On this basis, the optimal condensation temperature of each dry and isentropic working fluid is determined. Moreover, the applicability of each organic working fluid in Organic Rankine Cycle is discussed from the viewpoint of pump performance. 36 working fluids are suitable and 33 ones not suitable for the application in small-scale Organic Rankine Cycle system. Suitable pump types corresponding to applicable organic working fluids are also analyzed and determined. The graphic method proposed in this paper and the findings about pump performance can provide reference for the operation of practical Organic Rankine Cycle.

Water weakening of soft and stiff outcrop chalk induced by electrical double layer disjoining pressure

In this work we assessed the strength and stiffness of high and low porosity outcrop chalk plugs saturated with three different fluids. Plugs were triaxially tested in a Hoek cell at varying confining stress to probe different parts of the failure envelope as described in the p-q’ space (brittle, transition and yield failure modes). Stiffness of the plugs was derived from bulk density and P and S-wave ultrasonic velocities measured throughout the mechanical test. Selection of the saturating fluids was aimed at testing the hypothesis that water weakening of chalk arises due to a physico-chemical process acting on the vicinity of the chalk grain contact, the electrical double layer (EDL) disjoining pressure. This pressure depends both on the salinity and ionic species dissolved in the saturating water. Fluids used were designed to exert varying levels of disjoining pressure between the chalk grains: calcium chloride brine (highest), calcite equilibrated water (moderate) and as reference Isopar-L or Ethylene glycol (no induced disjoining pressure). We found that both strength and stiffness parameters are affected by the level of the EDL disjoining pressure: The higher the pressure between grains induced by the saturating fluid, the weaker and softer were the core plugs. Water related reduction in strength and stiffness were more prevalent in the soft chalk samples and for the samples mechanically tested at low confining stress. We attribute this selectivity to the smaller cementation area between grains (assessed by Biot's coefficient) for the softer chalk.

Fracturing Fluids and Their Application in the Republic of Croatia

Hydraulic fracturing operations are performed to enhance well performance and to achieve economic success from improved production rates and the ultimate reserve recovery. To achieve these goals, fracturing fluid is pumped into the well at rates and pressures that result in the creation of a hydraulic fracture. Fracturing fluid selection presents the main requirement for the successful performance of hydraulic fracturing. The selected fracturing fluid should create a fracture with sufficient width and length for proppant placement and should carry the proppant from the surface to the created fracture. To accomplish all those demands, additives are added in fluids to adjust their properties. This paper describes the classification of fracturing fluids, additives for the adjustment of fluid properties and the requirements for fluid selection. Furthermore, laboratory tests of fracturing fluid, fracture stimulation design steps are presented in the paper, as well as a few examples of fracturing fluids used in Croatia with case studies and finally, hydraulic fracturing performance and post-frac well production results. The total gas production was increased by 43% and condensate production by 106% in selected wells including wellhead pressure, which allowed for a longer production well life.

An integrated approach for cutting fluid selection using multiple attribute decision making methods

The choice of most appropriate cutting liquid in any machining process should be performed to attain maximum benefit. Selection of cutting fluid needs more than one dimension. For this purpose, many criteria should be deemed in the selection process. In this study decision making methods such as AHP, TOPSIS and VIKOR are employed to select the suitable cutting fluid. AHP is used to compute the objective weights for the criteria.The three alternatives considered are Ahonol- 7, Blaser and YBI. A case study of cutting fluid selection for machining LM 25 Aluminium alloy which finds application in automobile industries is presented to explain the applicability and suitability of the anticipated method. Ranking of alternatives in the above methods suggests Ahonol – 7 as the best cutting fluid for CNC turning LM 25 aluminium alloy.

Concept design and numerical evaluation of a highly efficient rotary electrocaloric refrigeration device

Abstract Enabled by the discovery of giant electrocaloric effect (ECE) in inorganic ceramics and organic polymers, Electrocaloric (EC) cooling technology has attracted considerable attention from both academia and industrial. However, there remains many challenges in the refrigeration efficiency and/or capacity of the currently reported electrocaloric refrigeration devices. In this work, we propose a concept design of EC refrigeration device, in which the working bodies are rotating in a plane perpendicular to the direction of fluid flow. The rotary EC device adopting heat transfer fluid as an intermediate medium allows for improved heat exchange between EC materials and outside environment, and efficiently delivers cooling effects to where it’s needed. Simulations have been performed to investigate the system cooling performance under different operating strategies. Meanwhile, comparative researches on different heat transfer fluid are conducted and the corresponding cooling effects are studied. When using deionized water as heat transfer medium, the system can achieve a cooling power density of 9.89 W·cm−3 and COP of 10.48 over 10 K temperature span. In general, this work provides a highly-efficient rotary EC refrigeration device concept that employs fluid–solid conjugated heat transfer, and guides the optimization of operating strategy and selection of heat transfer fluid.