Experimental investigation of an ORC system for a micro-solar power plant (original) (raw)
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E3S Web of Conferences, 2021
Suitability to off-design operation, applicability to combined thermal and electrical generation in a wide range of low temperatures and pressures and compliance with safety and environmental limitations qualify small-scale Organic Rankine Cycle plants as a viable option for combined heat and power generation in the residential sector. As the plants scale down, the electric and thermal output maximization has to account for issues, spanning from high pump power absorption, compared to the electric output of the plant, to intrinsically low plant permeability induced by the expander, to the intermittent availability of thermal power, affected by the heat demand for domestic hot water (DHW) production. The present paper accounts for a flat-plate solar thermal collector array, bottomed by an ORC unit featuring a sliding vane expander and pump and flat-plate heat exchangers. A high-temperature buffer vessel stores artificially heated water – electric heaters, simulating the solar collect...
Analysis of a solar assisted micro-cogeneration ORC system
International Journal of Low-Carbon Technologies, 2008
In this work, three solar assisted thermodynamic cycles for a micro-cogeneration system with a power output of 5 kW are studied. The thermodynamic cycles are based on the Organic Rankine Cycle (ORC) and the operating temperatures of solar thermal collectors are 80°C, 100°C-150°C and 200°-250°C, for cycles 1, 2 and 3, respectively. The main work objective was to model the selected cycles for optimisation according to the temperature range. The performance of several fluids was evaluated from a thermal and an economical point of view. The integration of the micro-cogeneration system with solar thermal collectors was evaluated and solar fractions were calculated for the climatic conditions of Almeria (Spain), Tunis (Tunis) and Cairo (Egypt).
Design of Organic Rankine Cycle (ORC) Power Plant Systems by Using Flat-Plate Solar Collector
International Journal of Marine Engineering Innovation and Research, 2019
⎯ electrical energy is the most used energy today in daily activities and industry is increasing. In rural areas that do not have electricity still exists in Indonesia. In this study, it can be used as an alternative power plant that can be used by the countryside. The system used in this study is the new types of power plants, namely the Organic Rankine Cycle (ORC) system. In connection with the problems stated above, through this research, an effort will be made to design an ORC power generation system. The ORC power plant system that will be designed utilizes solar energy sources and working fluids. Solar power is used to heat the heating fluid in the form of water. This heating water is used to vaporize the working fluid which can evaporate at low temperatures and high pressures. So that the working fluid gas can be used to rotate the turbine shaft and produce electrical energy through a generator. Simulation is done using energy system software. In addition to simulations, examples of manual calculations are also needed for validation. The simulation results of the ORC generating system design on the two working fluids produce the greatest power at the pump outlet pressure of 6 bar with Ẇnet of 13.61 kW and the smallest power is generated by the pump outlet pressure of 5.03kW. While the design simulation of the ORC generating system produces power close to 10 kW at the pump outlet pressure of 5 bars with 11.38 kW. The flat collector solar-plate system gets the energy that is useful for collectors of 191.92 W and an efficiency of 9.8%.
2014
Solar thermoelectric, even for small sizes, is continuing to garner more attention, by virtue of maturation of small size organic Rankine cycle generators, and of small size absorption chiller even if cost and reliability are still not optimal. Indeed, solar thermal power technology improvement would consent to stimulate an ambit already present in Europe and Italy with a well-known tradition and established leadership and efforts focused on a single solar technology would bring to positive effects concerning controllable electric and thermal energy uses. In this context, the present work tries to summarize the possible cycles and fluids that can be applied in a small solar thermal power plant. Despite a plethora of simulated and experimental cycles and fluids, the simplest cycle using near isentropic fluids seems to be the best choice for a small ORC-based CHP system, even if particular attention has to be done to all the sizing parameters (electricity, heating and cooling demand; area and type of solar collector; flow and temperature of the thermal carrier; flow, temperature and pressure of the working fluid; storage volumes; etc.). Indeed, efficiency and reliability of the reported systems are very different, but, it seems that global efficiency of even more than 10% and global cost of even less than 10,000 €/kW can be obtained even at size of few kW if adequate systems are constructed and managed.
SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019, 2019
The aim of this work is to present a dynamic model of an innovative small-scale trigeneration system implemented by means of TRNSYS. The modelled system is composed of a solar field, a low-temperature micro-Organic Rankine Cycle plant (ORC) and an adsorption chiller (AC). In particular, the main innovation of the model is the utilization of a micro-ORC machine and adsorption chiller implemented on TRNSYS by user-defined types that use experimental performance data obtained by a full characterization of ORC and AC prototypes, implemented at University of Bologna and at CNR-ITAE respectively. The considered micro-ORC system is driven by a reciprocating piston expander prototype, made of three radial cylinders with total displacement of 230 cm 3. The other components are two brazed plate heat exchangers as evaporator and recuperator, a prototypal gear pump and a shell-and-tube condenser. The adopted working fluid is HFC-134a, suitable for heat source temperature up to 100 °C and characterized by a global warming potential (GWP) equal to 1430. The adsorption chiller prototype is characterized by an innovative architecture, employing 3 adsorbers connected to a single evaporator and condenser and by the use of hybrid adsorbers, realized embedding microporous Silica Gel loose grains into aluminium flat tube heat exchangers, previously coated with the Mitsubishi AQSOA FAM Z02 sorbent. The cooling machine has a nominal capacity of 4.4 kWc. Both the AC and ORC prototypes can be driven by low grade thermal energy (<90°C) from waste heat, industrial processes or renewable energy sources. The model realized is easily adaptable to any other plant by redefining the different subsystems of the desired technology and, in conclusion, this study has highlighted the promising characteristics of ORC and AC technologies in tri-generative configuration, with a 63% of global efficiency.
Modeling Small Scale Solar Powered ORC Unit for Standalone Application
… Problems in Engineering, 2012
When the electricity from the grid is not available, the generation of electricity in remote areas is an essential challenge to satisfy important needs. In many developing countries the power generation from Diesel engines is the applied technical solution. However the cost and supply of fuel make a strong dependency of the communities on the external support. Alternatives to fuel combustion can be found in photovoltaic generators, and, with suitable conditions, small wind turbines or microhydroplants. The aim of the paper is to simulate the power generation of a generating unit using the Rankine Cycle and using refrigerant R245fa as a working fluid. The generation unit has thermal solar panels as heat source and photovoltaic modules for the needs of the auxiliary items pumps, electronics, etc. . The paper illustrates the modeling of the system using TRNSYS platform, highlighting standard and "ad hoc" developed components as well as the global system efficiency. In the future the results of the simulation will be compared with the data collected from the 3 kW prototype under construction in the
Energy, 2016
A detailed experimental investigation of a small-scale low-temperature organic Rankine cycle (ORC) with R-404A is presented. The tests are first conducted at laboratory conditions for detailed evaluation of the main components at both design and off-design conditions, for variable heat input up to 48 kW th and hot water temperature in the range of 65e100 C. A scroll compressor in reverse operation is used as expansion machine and a dedicated helical coil heat exchanger is installed, suitable for high-pressure and temperature operation. The ORC pump is a diaphragm pump coupled with an induction motor. The rotational speeds of both the expander and pump are regulated with frequency inverters, in order to have the full control of the engine operation. The ORC has been then connected with concentrating PV/ thermal collectors, which produce electricity and heat and provide it to the ORC. These field tests are also presented with the overall focus on the performance of the whole ORC unit and its power contribution to the solar field. The tests have revealed that such low-temperature ORC unit can have adequate efficiency and that its coupling with a solar field is feasible, increasing the power production of the whole system.
Solar Operated Organic Rankine Cycle Units For 0.2 to 10 MWe Systems
This paper presents the solar operated organic Rankine cycle (ORC) for 200 kWe to 10 MWe systems. The paper includes discussions of the technical and economical aspects of the solar ORC design. The nine SEGS power plants located at three sites in the Mojave Desert in California; currently produce about 90% of the world's solar thermal electric power and about 60% of all solar electricity ever generated worldwide. However, between 1991 and 2004 no new SEGS-type commercial systems were commissioned. Currently, ORMAT is supplying a 1 MWe on grid unit, scheduled for commissioning in early 2005, which is considered the first commercial solar thermal power plant since 1990. As a developer and manufacturer of ORC systems, ORMAT evaluates the technical combination of the solar trough technology and ORC power generation systems. Advantages such as unattended work, low maintenance cost and operation in a wide range of temperatures give this combination a lead over other thermal systems in the range of 200 kWe to 10 MWe. The combination of the well-proven ORMAT ® Energy Converter (OEC) organic cycle unit with a parabolic trough or other medium temperature collectors such as the linear Fresnel collector represent an attractive alternative to photovoltaic cells and to solar steam Rankine cycle plants. Hybridization is possible with this technology to improve solar to electricity overall conversion efficiency and provide base load power or peaking capacity. Future promising paths for this technology are combining the solar ORC with a biomass backup boiler, achieving an all renewable solar-biomass package or utilizing the excess heat to drive an absorption chiller.
Simulation of a solar assisted combined heat pump-Organic Rankine Cycle-system
ep.liu.se
In conventional collector systems for the supply of domestic hot water and space heating the collectors come to a standstill during summer whenever the maximum temperature in the storage tank is reached. The resulting excess heat can be harnessed by a combined heat pump-Organic Rankine Cycle-system. The aim of this work is to simulate such a system in order to determine the optimum operating conditions and impacts on power requirement and cost. For this purpose models for collector, storage tank, heat pump and geothermal heat exchanger are implemented. First results indicate that the isentropic efficiency of the scroll expander has the largest influence on the ORC-revenue. For a system consisting of 12 m² flat-plate collector area with an expansion efficiency of ,exp 0.7 s η = the power requirement for space heating and domestic hot water is reduced by 3.6%, whereas the costs decrease by 42 € or 12.3% respectively compared to a conventional system. The results suggest that an installation is more reasonable in larger dwelling units like hotels, senior citizens' homes and multiple family dwellings.