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

Author(s):  
Khaled Metwally ◽  
Lamyaa A. El-Gabry ◽  
Ahmed Makhlouf

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.

Author(s):  
P. Kohlenbach ◽  
S. McEvoy ◽  
W. Stein ◽  
A. Burton ◽  
K. Wong ◽  
...  

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.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1030
Author(s):  
Muhammad Tauseef Nasir ◽  
Michael Chukwuemeka Ekwonu ◽  
Yoonseong Park ◽  
Javad Abolfazli Esfahani ◽  
Kyung Chun Kim

This study presents a combined cooling, heating, and power system powered by biogas, suitable for small scale communities in remote locations. To run such a system, in order to obtain the daily life essentials of electricity, hot water, and cooling, municipal waste can be considered as an option. Furthermore, the organic Rankine cycle part of the organic Rankine cycle powered vapor compression chiller can be used in times of need for additional electric production. The system comprises a medium temperature organic Rankine cycle utilizing M-xylene as its working fluid, and the cooling was covered by an Isobutane vapor compression cycle powered by an R245fa employing organic Rankine cycle. The system analyzed was designated to provide 250 kW of electricity. The energetic and exergetic analysis was performed, considering several system design parameters. The impact of the design parameters in the prime mover has a much greater effect on the whole system. The system proposed can deliver cooling values at the rate between 9.19 and 22 kW and heating values ranging from 879 up to 1255 kW, depending on the design parameter. Furthermore, the second law efficiency of the system was found to be approximately 56% at the baseline conditions and can be increased to 64.5%.


Author(s):  
John McClintic ◽  
David A. Kistenmacher ◽  
Josh Anderson ◽  
Onur Demirer ◽  
Halil Berberoglu

A systems level analysis is presented for a solar organic Rankine cycle (S-ORC) for assessing the feasibility of the cycle to be used in small scale rural/residential power generation. A thermodynamic model was generated for a system composed of the collector, the heat transfer fluid, the pump, the expander, and the heat exchangers, using five different working fluids. Based on the collector efficiency and incident radiation, the thermodynamic efficiency of the system was evaluated. For flat panel solar collectors, the highest system efficiency was found to be 6.2% when using R-134a as a working fluid. R-134a also required the least boiler heat transfer area, although its operation required relatively higher pressures. The performance of the solar-ORC system is compared with that of photovoltaic systems and the practicality of these solar thermal systems are discussed in terms of system size and end use.


2013 ◽  
Vol 291-294 ◽  
pp. 1627-1630 ◽  
Author(s):  
Eunkoo Yun ◽  
Hyun Dong Kim ◽  
Sang Youl Yoon ◽  
Kyung Chun Kim

In order to determine the operating characteristics of a small-scale ORC (organic Rankine cycle) system for various low temperature heat sources, experiments were carried out. A small-scale ORC power generation system adopting R-245fa as a working fluid was designed and manufactured. Hot water was used for the heat source and the temperature was controlled by the 110 kW electric resistance heaters which provided up to 150 °C. Cooling temperature was controlled by a circulating water chiller to simulate various heat sink environments. An open-drive oil-free scroll expander directly connected to a high-speed synchronous generator was installed in the ORC unit. The efficiencies of the cycle and the expander, electric power of the developed ORC system with respect to the operating conditions were investigated by experiments. The factors which influence the performance of the oil-free scroll expander were analyzed and discussed.


Author(s):  
Mir Akbar Hessami

Geothermal power generation is achieved by feeding the harnessed geothermal heat into the boiler of an ORC (Organic Rankine Cycle) based engine which uses an organic working fluid characterised by its low boiling temperature. For the purpose of this study, such a system was designed, built and operated to verify the concept of small-scale power generation using heat from a low temperature source. This experimental facility used hot water as the source of heat, brazed plate heat exchangers as the boiler and the condenser, an automotive inline fuel pump for circulation and a Scroll compressor operated in reverse to act as the expander. The working fluid was R245fa with a boiling point of 80°C at a pressure of 790kPa (or 40°C at 250kPa). A Prony Brake was fitted on the shaft of the expander to determine its power output. Experimental investigations found that ∼600W of power could be produced under optimum conditions at a rotational speed of ∼2000RPM. The details of the experimental facility as well as the results of the experiments are provided in this paper.


Author(s):  
Jian Song ◽  
Chun-wei Gu

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.


2019 ◽  
Vol 9 (15) ◽  
pp. 3048
Author(s):  
Reyhaneh Loni ◽  
Gholamhassan Najafi ◽  
Ezzatollah Askari Asli-Ardeh ◽  
Barat Ghobadian ◽  
Willem G. Le Roux ◽  
...  

A parabolic solar dish concentrator, as the heat source of an organic Rankine cycle (ORC), can be used for power generation. Different types of tubular cavity receivers with different nanofluids can be considered for use in the solar dish collector to improve its efficiency. In the current research, an ORC with three different cavity receivers including hemispherical, cubical, and cylindrical are investigated using three nanofluids: Al2O3/oil, CuO/oil, and SiO2/oil. A numerical model is validated using experimental data. The ORC analysis is done for a constant evaporator pressure of 2.5 MPa, and condenser temperature of 38 °C. Methanol is employed as the ORC’s working fluid and a non-regenerative, ideal ORC system with different turbine inlet temperatures is considered. Furthermore, a fixed solar heat transfer fluid flow rate of 60 mL/s and dish diameter of 1.9 m is investigated. Results show that, compared to pure oil, the thermal efficiency of the cavity receivers increases slightly, and the pressure drop increases with the application of nanofluids. Furthermore, results show that the cubical cavity receiver, using oil/Al2O3 nanofluid, is the most efficient choice for application as the investigated solar ORC’s heat source.


Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 829 ◽  
Author(s):  
Ruiqi Wang ◽  
Long Jiang ◽  
Zhiwei Ma ◽  
Abigail Gonzalez-Diaz ◽  
Yaodong Wang ◽  
...  

Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper, which aims to explore the potential of power generation for domestic utilisation. A solar thermal collector was used as the heat source for a hot water storage tank. Thermal performance was then evaluated in terms of both the conventional ORC and an ORC using thermal driven pump (TDP). It is established that the solar ORC using TDP has a superior performance to the conventional ORC under most working conditions. Results demonstrate that power output of the ORC using TDP ranges from 72 W to 82 W with the increase of evaporating temperature, which shows an improvement of up to 3.3% at a 100 °C evaporating temperature when compared with the power output of the conventional ORC. Energy and exergy efficiencies of the ORC using TDP increase from 11.3% to 12.6% and from 45.8% to 51.3% when the evaporating temperature increases from 75 °C to 100 °C. The efficiency of the ORC using TDP is improved by up to 3.27%. Additionally, the exergy destruction using TDP can be reduced in the evaporator and condenser. The highest exergy efficiency in the evaporator is 96.9%, an improvement of 62% in comparison with that of the conventional ORC, i.e., 59.9%. Thus, the small-scale solar ORC system using TDP is more promising for household application.


Author(s):  
Mauro Reini

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.


Sign in / Sign up

Export Citation Format

Share Document