Novel Parabolic Trough Collectors Driving a Small-Scale Organic Rankine Cycle System

2007 ◽  
Author(s):  
P. Kohlenbach ◽  
S. McEvoy ◽  
W. Stein ◽  
A. Burton ◽  
K. Wong ◽  
...  
Keyword(s):  
Steel Substrate ◽  
Low Cost ◽  
Sheet Steel ◽  
Organic Rankine Cycle ◽  
Glass Tube ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Small Scale ◽  
Inlet Temperature ◽  
Parabolic Trough

This paper presents component performance results of a new parabolic trough collector array driving an organic Rankine cycle (ORC) power generation system. The system has been installed in the National Solar Energy Centre at CSIRO Energy Technology in Newcastle, NSW, Australia. It consists of four rows of 18 parabolic mirrors each in a 2×2 matrix with a total aperture area of approximately 132m2. The absorber tube is a laterally aligned, 40mm copper tube coated with a semi-selective paint and enclosed in a 50mm non-evacuated glass tube to reduce convection losses. The mirror modules, which are light-weight and robust, are made from thin low iron back silvered glass bonded to a sheet steel substrate. They are supported by a box truss on semi circular hoops running on rollers for single axis tracking. The mirror design has been chosen to allow low-cost manufacturing as well as simple commissioning and operation. The ORC unit is a FP6 unit sourced from Freepower Ltd. with a net power output of 6kWel at 180°C inlet temperature and a total heat input of 70 kWth. It uses a two-stage expansion process with hydrofluoroether as the working fluid. A wet cooling tower is used to dissipate the reject heat from the ORC. The two key components of the envisioned system are the trough reflector/receiver and the ORC unit. The optical performance of the mirror elements was investigated with regard to the flux mapping onto the receiver tube. The ORC unit has been tested separately using an electrical oil heater as the heat source. This paper presents results for irradiation capture and intensity over the receiver width of a single trough mirror module. The complete system including trough collectors and ORC has not been in transient operation yet, thus experimental steady-state results of the ORC unit are presented.

1-D Model Analysis of Tesla Turbine for Small Scale Organic Rankine Cycle (ORC) System

2017 ◽  
Author(s):  
Jian Song ◽  
Chun-wei Gu
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Organic Rankine Cycle ◽  
Axial Flow ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Working Fluid ◽  
Small Scale ◽  
Low Grade ◽  
D Model

Energy shortage and environmental deterioration are two crucial issues that the developing world has to face. In order to solve these problems, conversion of low grade energy is attracting broad attention. Among all of the existing technologies, Organic Rankine Cycle (ORC) has been proven to be one of the most effective methods for the utilization of low grade heat sources. Turbine is a key component in ORC system and it plays an important role in system performance. Traditional turbine expanders, the axial flow turbine and the radial inflow turbine are typically selected in large scale ORC systems. However, in small and micro scale systems, traditional turbine expanders are not suitable due to large flow loss and high rotation speed. In this case, Tesla turbine allows a low-cost and reliable design for the organic expander that could be an attractive option for small scale ORC systems. A 1-D model of Tesla turbine is presented in this paper, which mainly focuses on the flow characteristics and the momentum transfer. This study improves the 1-D model, taking the nozzle limit expansion ratio into consideration, which is related to the installation angle of the nozzle and the specific heat ratio of the working fluid. The improved model is used to analyze Tesla turbine performance and predict turbine efficiency. Thermodynamic analysis is conducted for a small scale ORC system. The simulation results reveal that the ORC system can generate a considerable net power output. Therefore, Tesla turbine can be regarded as a potential choice to be applied in small scale ORC systems.

Moment Analysis of a Scroll Expander Used in an Organic Rankine Cycle

2014 ◽  
Author(s):  
Amrita Sengupta ◽  
Prashant Kumar ◽  
Pardeep Garg ◽  
Nirmal Hui ◽  
Matthew S. Orosz ◽  
...  
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Moment Analysis ◽  
Superior Performance ◽  
Working Fluid ◽  
Small Scale ◽  
Inlet Temperature ◽  
Positive Displacement ◽  
Scroll Expander

Recent studies on small-scale power generation with the organic Rankine cycle suggest superior performance of positive displacement type of expanders compared to turbines. Scroll expanders in particular achieve high isentropic efficiencies due to lower leakage and frictional losses. Performance of scroll machines may be enhanced by the use of non-circular involute curves in place of the circular involutes resulting non-uniform wall thickness. In this paper, a detailed moment analysis is performed for such an expander having volumetric expansion ratio of 5 using thermodynamic models proposed earlier by one of the present authors. The working fluid considered in the power cycle is R-245fa with scroll inlet temperature of 125 °C for a gross power output of ∼3.5 kW. The model developed in this paper is verified with an air scroll compressor available in the literature and then applied to an expander. Prediction of small variation of moment with scroll motion recommends use of scroll expander without a flywheel over other positive displacement type of expanders, e.g. reciprocating, where a flywheel is an essential component.

Approach to Designing a Solar Concentrator for Small Scale Remote Power Application

2010 ◽  
Author(s):  
Khaled Metwally ◽  
Lamyaa A. El-Gabry ◽  
Ahmed Makhlouf
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Small Scale ◽  
Concentrated Solar Power ◽  
Parabolic Trough ◽  
Capstone Project ◽  
Power Application

A small-scale concentrated solar power unit was designed to provide electricity and hot water using an organic Rankine cycle for Egypt as part of an undergraduate capstone project. The system was designed for a target power output of 3 KW. It uses parabolic troughs to heat ethylene glycol used as the heat transfer fluid which absorbs heat in the trough collector and transfers it to the working fluid through a heat exchanger. The system consists of 9 parabolic troughs and a total aperture area of 67 square meters, providing the required 3 KW of energy to the ORC. One parabolic trough was manufactured to test its thermal efficiency according to ASHRAE standard 93-2003 and compare it to its calculated value. A simple microcontroller-based system was used to track the sun.

scholarly journals Investigation of a Novel CO2 Transcritical Organic Rankine Cycle Driven by Parabolic Trough Solar Collectors

2021 ◽  
Vol 4 (3) ◽  
pp. 53
Author(s):  
Evangelos Bellos ◽  
Christos Tzivanidis
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Solar Irradiation ◽  
Electricity Production ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Present System ◽  
Secondary Circuit ◽  
Parabolic Trough ◽  
Turbine Inlet

The objective of the present study is the detailed investigation and optimization of a transcritical organic Rankine cycle operating with CO2. The novelty of the present system is that the CO2 is warmed up inside a solar parabolic trough collector and there is not a secondary circuit between the solar collector and the CO2. Therefore, the examined configuration presents increased performance due to the higher operating temperatures of the working fluid in the turbine inlet. The system is studied parametrically and it is optimized by investigating different pressure and temperature level in the turbine inlet. The simulation is performed with a validated mathematical model that has been developed in Engineering Equation Solver software. According to the results, the optimum turbine inlet temperature is ranged from 713 up to 847 K, while the higher pressure in the turbine inlet enhances electricity production. In the default scenario (turbine inlet at 800 K and turbine pressure at 200 bar), the system efficiency is found 24.27% with solar irradiation at 800 W/m2. A dynamic investigation of the system for Athens (Greece) climate proved that the yearly efficiency of the unit is 19.80%, the simple payback period of the investment is 7.88 years, and the yearly CO2 emissions avoidance is 48.7 tones.

Biomass combined cycles based on externally fired gas turbines and organic Rankine expanders

2011 ◽  
Vol 225 (8) ◽  
pp. 1066-1075 ◽  
Author(s):  
C M Invernizzi ◽  
P Iora ◽  
R Sandrini
Keyword(s):  
Gas Turbines ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Economic Feasibility ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Inlet Temperature ◽  
System A ◽  
Combined Cycles

This article investigates the possibility to enhance the performance of a biomass organic Rankine cycle (ORC) plant by adding an externally fired gas turbine (EFGT), yielding a combined EFGT + ORC system. A typical ORC configuration is first modelled and validated on data available from an existing unit 1.5 MW reference plant. Then, different working fluids belonging to the methyl-substituted benzene series and linear methylpolysiloxanes have been evaluated for the ORC section on the basis of both thermodynamics considerations and design issues of the regenerator and the turbine. Results of the simulations of the combined cycle (CC) referred to a furnace size of about unit 9 MW, assuming a maximum GT inlet temperature of 800 °C, show a maximum efficiency of 23 per cent, obtained in the case where toluene is adopted as a working fluid for the bottoming section. This value is about 4 points per cent higher than the efficiency of the corresponding simple ORC. Finally, to conclude, some preliminary considerations are given regarding the techno-economic feasibility of the combined configuration, suggesting the need of a further investigation on the possible technological solution for the furnace which represents the main uncertainty in the resulting costs of the CC.

Dynamic Simulation and Optimization of an Experimental Micro-CSP Power Plant

2015 ◽  
Author(s):  
Matthias Mitterhofer ◽  
Matthew Orosz
Keyword(s):  
Control Strategy ◽  
Low Cost ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Economic Benefits ◽  
Solar Thermal ◽  
Small Scale ◽  
Pinch Point ◽  
Simulation And Optimization ◽  
Dynamic Representation

Small scale solar thermal systems are increasingly investigated in the context of decentralized energy supply, due to favorable costs of thermal energy storage (TES) in comparison with battery storage for otherwise economical PV generation. The present study provides the computational framework and results of a one year simulation of a low-cost pilot 3kWel micro-Concentrated Solar Power (micro-CSP) plant with TES. The modeling approach is based on a dynamic representation of the solar thermal loop and a steady state model of the Organic Rankine Cycle (ORC), and is validated to experimental data from a test site (Eckerd College, St. Petersburg, Florida). The simulation results predict an annual net electricity generation of 4.08 MWh/a. Based on the simulation, optimization studies focusing on the Organic Rankine Cycle (ORC) converter of the system are presented, including a control strategy allowing for a variable pinch point in the condenser that offers an annual improvement of 14.0% in comparison to a constant condensation pinch point. Absolute electricity output is increased to 4.65 MWh/a. Improvements are due to better matching to expander performance and lower condenser fan power because of higher pinch points. A method, incorporating this control strategy, is developed to economically optimize the ORC components. The process allows for optimization of the ORC subsystem in an arbitrary environment, e.g. as part of a micro-grid to minimize Levelized electricity costs (LEC). The air-cooled condenser is identified as the driving component for the ORC optimization as its influence on overall costs and performance is of major significance. Application of the optimization process to various locations in Africa illustrates economic benefits of the system in comparison to diesel generation.

Performance Evaluation of a Small Scale High Efficiency Cogeneration System

2006 ◽  
Author(s):  
Mauro Reini
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
Organic Rankine Cycle ◽  
Thermodynamic Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Small Scale ◽  
Performance Parameters ◽  
Cogeneration System

In recent years, a big effort has been made to improve microturbines thermal efficiency, in order to approach 40%. Two main options may be considered: i) a wide usage of advanced materials for hot ends components, like impeller and recuperator; ii) implementing more complicated thermodynamic cycle, like combined cycle. In the frame of the second option, the paper deals with the hypothesis of bottoming a low pressure ratio, recuperated gas cycle, typically realized in actual microturbines, with an Organic Rankine Cycle (ORC). The object is to evaluate the expected nominal performance parameters of the integrated-combined cycle cogeneration system, taking account of different options for working fluid, vapor pressure and component’s performance parameters. Both options of recuperated and not recuperated bottom cycles are discussed, in relation with ORC working fluid nature and possible stack temperature for microturbine exhaust gases. Finally, some preliminary consideration about the arrangement of the combined cycle unit, and the effects of possible future progress of gas cycle microturbines are presented.

scholarly journals Integrated Vapor Compression Chiller with Bottoming Organic Rankine Cycle and Onsite Low-Grade Renewable Energy

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6401
Author(s):  
Muhammad Tauseef Nasir ◽  
Michael Chukwuemeka Ekwonu ◽  
Javad Abolfazali Esfahani ◽  
Kyung Chun Kim
Keyword(s):  
Renewable Energy ◽  
Heat Source ◽  
Energy Input ◽  
Cooling Water ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Sensitivity Analyses ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Low Grade

The present study offers a scheme to improve the performance of existing large-scale chillers. The system involves raising the temperature of the chiller’s cooling water stream using renewable energy sources by incorporating an organic Rankine cycle (ORC). The thermal analysis was conducted by raising the temperature of one-third of the approximately 200 ton chiller’s cooling water. The investigation was considered for ORC evaporator inlet temperature of 90~120 °C by the step of 10 °C. Various working fluids for the different ORC evaporator inlet temperatures were examined. Sensitivity analyses conducted on the degree of superheating, degree of subcooling, condenser saturation temperature, pinch point temperature differences of the ORC evaporator and condenser, and the mass flowrates of the heating and cooling streams were also reported. Genetic algorithm was employed to carry out the optimization. The best options for the ORC working fluid at the heating source ORC evaporator inlet temperatures of 90 °C was found to be DME, presenting an improvement of 48.72% in comparison with the rated coefficient of performance (COP) value of the VCC, with a renewable energy input requirement of 710 kW. At the heat source temperatures of 100 °C and 110 °C, butene, which presented an improvement in the COP equal to 48.76% and 68.85%, respectively, with the corresponding renewable energy requirements of 789.6 kW and 852 kW, was found to be the ideal candidate. Meanwhile, at the heat source inlet temperature of 120 °C, R1233zd (E), representing an improvement of 140.88% with the renewable energy input of around 1061 kW, was determined to be the most favorable ORC working fluid candidate.

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