A World Overview of the Organic Rankine Cycle Market

The Organic Rankine Cycle (ORC) technology is a reliable way to convert heat into electricity, either for renewable energy applications (biomass, geothermal, solar), or industrial energy efficiency. ORC systems range from micro-scale (a few kW) for domestic cogeneration to large multi-megawatt geothermal power plants. After a slow initial start, the technology has experienced a much stronger development since the 1970s, mainly because of economic incentives and surging energy prices. However, the large range of applications, manufacturers, and countries make it hard to track the evolution of the technology over the world. Information about more than 700 projects has been collected, cross-validating 27 manufacturers' data with publications and testimonies, allowing to build the first reliable and exhaustive database of ORC plants. As a result, this work analyses the evolution of the ORC market over the years, with today 2.7 GW of cumulated installed capacity. After introducing the ORC technology with a focus on its history, working principle and main applications, the current state and the new trends of the ORC market are presented with a detailed analysis of each application. The evolution of each market is discussed considering the present installed capacity, historical data and macro-economic trends. Finally, future perspectives and growth potential of the ORC market are evaluated, with a special focus on Waste Heat Recovery applications

Techno-Economic Optimization Of A Stand-Alone Hybrid Microgrid For The Rural Electrification In Sub Saharan Africa

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.This paper is focused on the design of a stand-alone micro-grid for rural electrification. The aim of this work is to define the best mix of energy sources and the optimal size of the energy storage for a small isolated village on the Ghana seaside. We obtain the optimal solution by simulating one year of operation for several different combinations of prime movers and battery sizes and comparing the economic performance in terms of levelized cost of electricity. We adopt a rolling-horizon strategy to simulate the micro-grid operation, which optimizes generators and loads schedule over a 12 hours time horizon. We solve a Mixed Integer Linear Programming problem for each time step, exploiting weather forecast for predicting the energy available from sun and wind and taking into account a realistic operation of each component like energy losses and costs during start-up of dispatchable generators and ageing cost for the battery. The optimal configuration found includes a 30 kWel wind turbine, a 60 kWel photovoltaic array, a 30 kWel biomass fired ORC and a 50 kWel diesel. The limited use of the diesel engine in the optimal solution demonstrates that energy access in a sustainable and economic way is possible even in rural contexts. Finally, two sensitivity analyses are presented varying the cost of the biomass and the error of wind speed forecast.cf201

Selection Maps for ORC and CO2Systems for Low-Medium Temperature Heat Sources

Low-medium temperature heat sources in the range 5 - 50 MWthare made available by many industrial fields but they may also be of interest for biomass and solar energy applications. ORC has been proposed in the last 20 years as a reliable solution for the exploitation of these energy sources since the alternative represented by steam cycles leads to an inefficient conversion of such small available thermal powers. However, the use of organic fluids involves a number of safety and environmental issues, either related to fluid flammability (for hydrocarbons) or to their high-Global Warming Potential (for halogenated fluids), and of limitations to the achievable cycle maximum temperature, due to fluids thermal decomposition. To overcome these limitations, CO2-based transcritical and supercritical cycles have been proposed, in recent years, as a viable option for waste heat recovery applications. The present work aims to present a fair comparison between CO2and ORC power plants for waste heat recovery applications

Preliminary Assessment of sCO2Power Cycles for Application to CSP Solar Tower Plants

This work presents a preliminary thermodynamic assessment of three different supercritical CO2(sCO2) power cycles integrated in a high temperature solar tower system, working up to 800°C. An indirect cycle configuration is considered with KCl-MgCl2molten salt as heat transfer fluid (HTF) in the solar receiver and a two tanks thermal energy storage (TES) system. The most promising cycle configuration is selected, optimizing the cycle turbine inlet temperature to achieve the best compromise between cycle and receiver efficiency. An estimate of the yearly energy yield of the proposed power plant is finally performed, indicating the possibility of reaching solar-to-electric efficiency of about 17.5%

Techno-economic Optimization of Low Temperature CSP Systems Based on ORC with Screw Expanders

AbstractSmall Organic Rankine Cycles (ORC) coupled with low temperature parabolic collectors can be an affordable solution for the rural electrification of many remote areas worldwide. The aim of this work is to investigate the feasibility of this concept investigating the capabilities of different plant layouts and the use of volumetric screw devices as expander. Thirty working fluids are considered as possible candidates and all the solutions are optimized from a techno-economic point of view minimizing the specific cost of the plant. Finally a sensitivity analysis is carried out varying solar field specific cost and solar collector pressure drops

Improved flexibility and economics of Calcium Looping power plants by thermochemical energy storage

Abstract In this work, a Calcium looping (CaL) system including high temperature sorbent storage is presented, allowing to reduce the size of the calciner and the associated capital-intensive equipment (ASU and CPU). Reduction of the capital costs is particularly important for power plants with low capacity factors, which is becoming increasingly frequent for fossil fuel power plants in electric energy mixes with increasing share of intermittent renewables. The process assessment is performed by: (i) defining pulverized coal power plant (PCPP) with CaL capture system with and without sorbent storage and their mass and energy balances at nominal load; (ii) defining a simple method to predict the performance of the plant at part-load; (iii) defining the economic model, including functions for the estimation of the plant equipment cost; (iv) performing yearly simulations of the systems to calculate yearly electricity production, CO2 emissions and levelized cost of electricity for different sizes of the calcination line and the storage system and (v) performing sensitivity analysis with different power production plans and carbon taxes. With this process, optimal size of the calciner and of the storage system minimizing the cost of electricity have been found. The optimal plant design was found to correspond to a solids storage system sized to manage the weekly cycling and a calciner line sized on the average weekly load. However, to avoid excessively large solids storage system, sizing the calciner on the average daily load and the storage system to manage the daily cycling appears more feasible from the logistic viewpoint and leads to minor economic penalty compared with the optimal plant design. For the selected case sized on the daily cycling, reduction of the cost of CO2 avoided between 16% and 26% have been obtained compared to the reference CaL plant without solids storage, for representative medium and low capacity factor scenarios respectively

Field Performance Evaluation of ORC Geothermal Power Plants Using Radial Outflow Turbines

This paper, after a brief description of the radial outflow turbine and of its main features, discloses the field performances evaluation of two operating geothermal ORC (Organic Rankine Cycle) plants installed by Exergy Spa in Turkey. The work describes the test procedure, the measurements and calculation methods used to obtain the turbine efficiency as well as overall power cycle performance from the set of available experimental data