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Organic Rankine Cycle for Energy Recovery System

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Nguyễn Gia Hào

Academic year: 2023

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The analysis focused on how the estimated net effect of zeotropic mixtures compared to pure fluids is affected by the method used to specify the performance of the heat exchangers. 27] evaluated three methods to compare the performance of pure fluids and mixtures in heat pump applications.

Methods

The location of the minimum temperature difference of the compression point in the primary heat exchanger is assumed to be at the inlet, outlet, or liquid saturated point. A shell-and-tube heat exchanger model was used to estimate the heat transfer surface of the condenser.

Figure 1. A sketch of the organic Rankine cycle system.
Figure 1. A sketch of the organic Rankine cycle system.

Results and Discussion

In the equation based on minimum bottleneck temperature difference, 19 out of 30 fluids were zeotropic. Easily defined, reasonable minimum bottleneck temperature difference values ​​independent of ORC unit capacity.

Figure 4. T, s-diagrams for the four ORC units using propane, i-butane, propane/i-butane (0.2/0.8), and propane/i-butane (0.8/0.2) with ΔT pp,cond = 5 ◦ C.
Figure 4. T, s-diagrams for the four ORC units using propane, i-butane, propane/i-butane (0.2/0.8), and propane/i-butane (0.8/0.2) with ΔT pp,cond = 5 ◦ C.

Conclusions

Selection and optimization of pure and blended working fluids for low-grade heat utilization using organic Rankine cycles.Energy. Thermoeconomic comparison between pure and blended working fluids of organic Rankine cycles (ORCs) for low temperature waste heat recovery.

Table A1 displays the variation in net power output, condenser mean temperature difference, condenser ¯ U A values, and condenser areas as functions of the condenser pinch point temperature difference for the working fluids propane, i-butane, propane/i-buta
Table A1 displays the variation in net power output, condenser mean temperature difference, condenser ¯ U A values, and condenser areas as functions of the condenser pinch point temperature difference for the working fluids propane, i-butane, propane/i-buta

Off-Design Performances of an Organic Rankine Cycle for Waste Heat Recovery from Gas Turbines

Introduction

The authors have identified a limit for optimizing the cycle: the geothermal fluid injection temperature should not be less than 70◦C. Finally, Quoilin [32] demonstrated that better performance can be achieved for evaporation temperatures significantly lower than that of the heat source, while for higher values ​​(which ensure higher pressures and densities) the economic optimum is achieved due to the smaller size of the heat exchanger.

Materials and Methods 1. Working Fluid

The hot exhaust gas mass flow (first cycle) heats the diathermic oil (second cycle, points A to F) in the heat recovery boiler (HRB), the hot oil then passes through the heat recovery steam generator (points B-E), composed of economizer (ECO), evaporator (EV) and superheater (SH). In off-design analysis, the heat transfer coefficient is a function of the mass flow rate and fluid properties.

Figure 1. Saturation temperature vs. pressure for each organic fluid.
Figure 1. Saturation temperature vs. pressure for each organic fluid.

Results

The power absorbed from the organic liquid pump (Figure 10) presents exactly the same trend of organic liquid mass flow rate (Figure 9). Three-dimensional off-design numerical analysis of an organic turbine with radial inflow Rankine cycle. Appl.

Figure 4. ORC electrical output power varying ambient temperature.
Figure 4. ORC electrical output power varying ambient temperature.

Energy and Exergy Analysis of Different Exhaust Waste Heat Recovery Systems for Natural Gas Engine

Methodology

In SORC, the high-pressure organic working fluid (1 ORC) is expanded at the ORC turbine (T 1) to the lowest SORC pressure (2 ORC) before being cooled and condensed (ITC 3). In the ORC system, the high-pressure working fluid (stream 6 ORC) enters the first turbine stage (T 2), where it expands to medium system pressure and mixes with the fluid (stream 2 ORC), leaving the medium-pressure evaporator unit.

Table 2. Fuel composition and supply conditions for the Jenbacher JMS 2 GS-N. L engine.
Table 2. Fuel composition and supply conditions for the Jenbacher JMS 2 GS-N. L engine.

Thermodynamic Modeling

Pressure drops in heat exchangers are calculated as a function of equipment geometry and hydraulic flow characteristics. In addition, the input-output structure for the components of the proposed WHR-ORC systems is shown as in Table 6 , since the exergy losses must be distinguished from the exergy destroyed in each configuration [ 37 ].

Table 3. Parameters considered for internal combustion engines (ICE) simulation.
Table 3. Parameters considered for internal combustion engines (ICE) simulation.

Results and Discussions

The maximum net power output in the toluene-SORC combination represents 8.31% of the engine idle generating power at rated speed. As the operating load increases, the evaporation temperature of the organic liquid increases.

Table 11. Exergy analysis results for each component of the heat recovery system with RORC.
Table 11. Exergy analysis results for each component of the heat recovery system with RORC.

Conclusions

The potential of exhaust heat recovery (WHR) from marine diesel engines via organic rankine cycle.Energy. Simulation and thermodynamic analysis of an Organic Rankine Cycle (ORC) of a diesel engine (DE).Energy. A Novel Cascade Organic Rankine Cycle System (ORC) for Recovery of Waste Heat from Truck Diesel Engines.Energy Convers.

Comparison between regenerative organic Rankine cycle (RORC) and basic organic Rankine cycle (BORC) based on thermoeconomic multi-objective optimization considering exergy efficiency and levelized energy cost (LEC).Energy Convers.

Table A1. Energy balances for the components of each configuration.
Table A1. Energy balances for the components of each configuration.

Optimum Organic Rankine Cycle Design for the Application in a CHP Unit Feeding a District

Cogeneration Power Plant Description

The problem was solved by considering the heat demand profile (Figure 2) and the ICE and boiler performance maps (Figure 3). The results of the optimal load distribution procedure are reported in Figure 4, which shows the load of the three ICE units (Figure 4a), the total electricity production of the CHP unit (Figure 4b) and the boiler load (Figure 4c) as a function of the heating demand. Finally, in Figure 4d, total natural gas consumption (due to ICE units and boilers) was plotted against heating demand.

In addition to 13,800 kW, all ICEs worked at full load, but the power generated was not enough to meet the heating demand; therefore the backup boilers were also activated.

Figure 2. Heat demand yearly profile.
Figure 2. Heat demand yearly profile.

Integrating the Organic Rankine Cycle

Therefore, the heat demand for the DH would determine the temperature of the gas feeding the ORC. In the second architecture (Case B), the position of the heat recovery heat exchanger was reversed, with the ORC placed before the DH heat exchanger. To perform a realistic evaluation of ORC performance, thermodynamic design and off-design analyzes were performed.

Flow resistance coefficients, initialized at the design-point stage, were used to model the pressure drops across each side of the heat exchanger in the off-design.

Figure 5. Schematic of the organic Rankine cycle (ORC) architecture.
Figure 5. Schematic of the organic Rankine cycle (ORC) architecture.

Results and Discussion

The ICE-ORC solution was compared with the original arrangement in terms of economic performance using the differential present value index. Figure 13 shows the results of the economic assessment in terms of selling price of electrical energy for return on investment in a given payback period. A sensitivity analysis of organic liquid and key cycle parameters was performed to identify, for each proposed arrangement, the optimal design of the ORC.

The inclusion of the ORC resulted in significant savings in primary energy consumption, enabling the production of electricity with an efficiency close to 52%, higher than the efficiency of the mix of electrical products.

Figure 9. Sensitivity analysis results on organic fluid and IHTF design temperature: Case B and Case C layout.
Figure 9. Sensitivity analysis results on organic fluid and IHTF design temperature: Case B and Case C layout.

Pressure Pulsation and Cavitation Phenomena in a Micro-ORC System

Materials and Methods

Figure 3 shows four consecutive moments related to the rotation and engagement of the gear pump wheels. The suction and delivery ports of the gear pump are connected via sliding interfaces to the rotating domain. Dealing with dynamic analysis, the boundary conditions for the present study are average values ​​according to the rotation of the gear pump.

These phenomena, related to the thermodynamic state of the liquid phase at the pump inlet (close to the saturated state), and pressure losses introduced by the pipes and fittings (pipes, valves, CFM and bends), make the cavitation phenomenon one of the main problems of the current application (gear pump in a micro-ORC system).

Figure 2. The unstructured Cartesian grid on stationary components: the outlet section of the regenerator and the CFM inlet section.
Figure 2. The unstructured Cartesian grid on stationary components: the outlet section of the regenerator and the CFM inlet section.

Results: Pump Operation

Therefore, these leaks reduce the net flow handled by the pump as measured at the outlet, as a small portion of the fluid already handled by the wheels returns from the outlet to the suction port. At the outlet (pOUT), the pulsations are mainly due to the delivery of the trapped volume between two consecutive teeth. The flow field is taken relative to the cross-sectional plane shown in the figure, which is located in the discharge part of the regenerator.

Pressure pulsation at the suction and discharge ports of the gear pumps (see reference position).

Figure 8. Mass flow rate trend according to the angular position of the wheel (see reference position).
Figure 8. Mass flow rate trend according to the angular position of the wheel (see reference position).

Results: Response of the Cycle 1. Dynamic E ff ects on Coriolis Flow Meter

Figure 12 shows the pressure trends by angular position of the monitored wheel upstream (pIN,CFM) and downstream (pOUT,CFM) of the mass flow meter. The force magnitude (FCFM) is lower than 3 N but is variable according to the angular position of the wheel. For this reason, a proper design of gear pump capacity can reduce cavitation problems.

The mass flow rate processed by the pump in relation to the angular position of the gear is shown in Figure 16.

Figure 12 shows the pressure trends according to the wheel angular position monitored upstream (p IN,CFM ) and downstream (p OUT,CFM ) of the mass flow meter
Figure 12 shows the pressure trends according to the wheel angular position monitored upstream (p IN,CFM ) and downstream (p OUT,CFM ) of the mass flow meter

Structured Mesh Generation and Numerical Analysis of a Scroll Expander in an Open-Source Environment

Results 1. Mesh Results

The pressure pattern as the operation of the scroll develops with the conditions described in Section 2.3 is reported in Figure 5. As a general comment, the actual gas effects lower (Z tends to 1) as the liquid passes through the gaps and increases in the bulk of the chambers. This is in perfect agreement with what was found in the previous simulation and with the nameplate power of the machine (it is 1 kW, very close to 7 times the actual power).

In Proceedings of the 24th Purdue International Refrigeration and Air Conditioning Conference, West Lafayette, IN, USA, 9–12 July 2018.

Figure 5. Pressure pattern evolution during the operation of the expander: (a) 0 ◦ , (b) 90 ◦ , (c) 180 ◦ , and (d) 270 ◦ .
Figure 5. Pressure pattern evolution during the operation of the expander: (a) 0 ◦ , (b) 90 ◦ , (c) 180 ◦ , and (d) 270 ◦ .

Regression Models for the Evaluation of the Techno-Economic Potential of Organic Rankine

Discussion

Both the statistical significance and the expected accuracy of the proposed regression curves were analyzed. Analysis of the Effect of Organic Rankine Cycle (ORC) Evaporator Back Pressure on the Exhaust Line of a Heavy-Duty Turbine-Charged Diesel Generator for Marine Applications. Energy conversion. Multiple regression models for predicting the maximum achievable thermal efficiency of organic Rankine cycles. Energy 2013, 1–8.

A neural network approach for the combined multi-objective optimization of the thermodynamic cycle and the radial inflow turbine for organic Rankine cycle applications. Appl.

Life Cycle Assessment of a Commercially Available Organic Rankine Cycle Unit Coupled with

Case Study and Model Settings

A schematic view of the system and its main units is given in figure 1 and table 2. Inlet temperature of the heat transfer fluid (water) ◦C ≥160 Outlet temperature of the heat transfer fluid (water) ◦C 140. They include weights of pipes, valves, condensate tank, cooling tower, inverter, electrical cabinet and sliding shoes.

Regarding the end-of-life scenario, approximately 80% of the organic liquid is expected to be recycled at the end of plant life, while the remaining 20% ​​is considered to be released into the environment [53].

Table 1. Main features of the Organic Rankine Cycle (ORC) module at design conditions.
Table 1. Main features of the Organic Rankine Cycle (ORC) module at design conditions.

Materials and Methods

In Proceedings of the 29th International Conference on Efficiency, Costs, Optimization, Simulations and Environmental Impact of Energy Systems (ECOS 2016), Portoroz, Slovenia 19-26. June 2016. In the course of the 32nd International Conference on Efficiency, Energy Efficiency, Impact, Environmental Optimization219 (ECOS 201) ław, Poland, 23-28 June 2019. In conjunction with the 32nd International Conference on Efficiency, Costs, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 2019), Wrocław, Poland, 23-28 June 2019; pp.

In Proceedings of the 32nd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems (ECOS 2019), Wrocław, Poland, 23–28 June 2019;.

Table 4 summarises the impacts computed with the ReCiPe 2016 method for the operation at full electric load, while Figure 3 depicts the contribution of the different operations on the overall impact.
Table 4 summarises the impacts computed with the ReCiPe 2016 method for the operation at full electric load, while Figure 3 depicts the contribution of the different operations on the overall impact.

Thermodynamic, Exergy and Environmental Impact Assessment of S-CO 2 Brayton Cycle Coupled with

The Brayton cycle consists of the following components: a primary turbine (T1), a secondary turbine (T2), an axial compressor (C1), a reheater (RH) and a recuperator (HTR). Then, by means of the recuperator (HTR), the carbon dioxide (point 7) leaving the compressor (C1) is reheated, which is conveyed to the heater (RH) to obtain the thermodynamic state reported as (point 8). The net power of the Brayton cycle (W.net,Brayton S−CO2) is calculated based on equation (8), from the power of the main turbine (T1), the secondary turbine (T2) and the compressor (C1).

Therefore, they offer small irreversibilities and allow better use of the energy in the system.

Figure 1. Physical structure of the Brayton S-CO 2 integrated into an organic Rankine cycle (ORC) as a bottoming cycle.
Figure 1. Physical structure of the Brayton S-CO 2 integrated into an organic Rankine cycle (ORC) as a bottoming cycle.

Hình ảnh

Figure 4. T, s-diagrams for the four ORC units using propane, i-butane, propane/i-butane (0.2/0.8), and propane/i-butane (0.8/0.2) with ΔT pp,cond = 5 ◦ C.
Table 5. Fluid selection and optimization based on fixed values of ¯ U A tot = U A ¯ PrHE + U A ¯ cond = 3500 kW/ ◦ C.
Figure 2. Organic Rankine Cycle (ORC) power plant layout. Points 1–8: organic fluid cycle, points A–F:
Table 1. Main design and operation parameters of Jenbacher JMS 612 GS-N. L engine.
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