scholarly journals Domestic Organic Rankine Cycle-Based Cogeneration Systems as a Way to Reduce Dust Emissions in Municipal Heating

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3983
Author(s):  
Piotr Kolasiński

Environmental issues are nowadays of great importance. In particular air and water quality should be kept at as high levels as possible. Energy conversion systems and devices which are applied for converting the chemical energy contained in different fuels into heat, electricity and cold in the industry and housing are sources of different gases and solid particle emissions. Medical data show PM2.5 dust in particular is highly dangerous for human health. Therefore, limiting the number of low-quality fuel combustion processes is a key issue of modern energy policy. Statistical data show that domestic heating systems account for a large share of the total emissions of PM2.5 and PM10 dust. For example in Poland in 2017, the share of households in the total annual emissions of PM2.5 dust was equal to ca. 35.8%, while the share of PM2.5 emission in industry (i.e., power generating plants, industrial power plants and technologies) was equal to only 23.6%. A possible way of solving this problem is by the successful replacement of old domestic furnaces by combined heat and power (CHP) or multigeneration boilers which can be used for heating the rooms and sanitary water and generating electricity and cold. Such systems can possibly contribute in the future to significant reductions of dust emissions and air pollution in urban and rural areas by limiting the number of low-quality fuel combustion processes. This article presents design considerations and experimental results related to a domestic micro-CHP unit which is based on organic Rankine cycle (ORC) technology. The main aim of the design works and experiments was therefore the analysis of the possibility of integrating the ORC system with a standard domestic central heating gas-fired boiler. The specially designed micro-ORC system was implemented in the laboratory and experiments were performed using this test stand. The main design aims of the test-stand were: low operating pressure, small working fluid flow, low price and compact dimensions. To meet these aims, volumetric machines were chosen as the expander and working fluid pump. The experimental results were positive and show that it is possible to integrate an ORC system with a standard domestic central heating gas boiler. For different heat source temperatures, the obtained expander power ranged from 109 W to 241 W and the thermodynamic cycle efficiency ranged from 4.3% to 8.8%. These positive research results were achieved partly thanks to the positive features of the different system subassemblies.

Author(s):  
Zbigniew Gnutek ◽  
Piotr Kolasiński

Small (10–100 kW) and micro (0.5–10 kW) Organic Rankine Cycle (ORC) power systems are nowadays considered for local and domestic power generation. Especially interesting are micropower applications for heat recovery from dispersed low potential (85–150 °C) waste and renewable heat sources. Designing and implementing an ORC system dedicated to energy recovery from such a source is difficult. A proper working fluid must be selected together with a suitable expander. Volumetric machines can be adopted as a turbine alternative in small-capacity applications under development, like, e.g., domestic cogeneration. Scroll and screw expanders are a common choice. However, scroll and screw expanders are complicated and expensive. Vane expanders are mechanically simple, commercially available and cheap. This paper documents a study providing the preliminary analysis of the possibility of employing vane-expanders in mini-ORC systems. The main objective of this research was therefore a comprehensive analysis of the use of a vane expander for continuous operation with a low-boiling working fluid. A test-stand was designed and set up starting from system models based on thermodynamic analysis. Then, a series of experiments was performed using the test-stand. Results of these experiments are presented here, together with a model of multivane expanders and a thermodynamic-based method to select the working fluid. The analysis presented in this paper indicates that multivane expanders are a cheap and mechanically simple alternative to other expansion devices proposed for small-capacity ORC systems.


Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4140 ◽  
Author(s):  
Costante M. Invernizzi ◽  
Abubakr Ayub ◽  
Gioele Di Marcoberardino ◽  
Paolo Iora

This study investigates the use of pure and hydrocarbons binary mixtures as potential alternatives working fluids in a usual biomass powered organic Rankine cycle (ORC). A typical biomass combined heat and power plant installed in Cremona (Italy) is considered as the benchmark. Eight pure hydrocarbons (linear and cyclic) and four binary mixtures of linear hydrocarbons were selected. The critical points of the binary mixtures at different composition were calculated using an in-house code developed in MATLAB© (R2018b) environment. Based on the critical point of a working fluid, supercritical and subcritical cycle configurations of ORC were analysed. A detailed thermodynamic comparison with benchmark cycle was carried out in view of cycle efficiency, maximum operating pressure, size of the turbine and heat exchangers. The supercritical cycles showed 0.02 to 0.03 points lower efficiency, whereas, subcritical cycles showed comparable efficiencies than that of the benchmark cycle. The cycles operating with hydrocarbons (pure and mixtures) exhibited considerably lower volume flow ratios in turbine which indicates lower turbine size. Also, size parameter of regenerator is comparatively lower due to the lower molecular complexity of the hydrocarbons. A noticeable increase in turbine power output was observed with change in composition of the iso-octane/n-octane binary mixture at the same thermodynamic efficiency.


2014 ◽  
Vol 659 ◽  
pp. 440-445 ◽  
Author(s):  
Tudor Prisecaru ◽  
Alexandru Dobrovicescu ◽  
Cristian Petcu ◽  
Valentin Apostol ◽  
Mălina Prisecaru ◽  
...  

The paper presents the work developed in the first stage of Research Grant called "Hybrid micro-cogeneration group of high efficiency equipped with an electronically assisted ORC" (acronym GRUCOHYB). The Research Grant is in progress at the Thermal Research Centre, Faculty of Mechanical and Mechatronics Engineering from University Politehnica of Bucharest having as research partner the Rokura Company. The hybrid micro-cogeneration group involves the use of an electric generator based on a 40 kW overcharged Diesel engine and an Organic Rankine Cycle (ORC). The aim of the research is to recover the waste heat available in the exhaust gas and cooling water and transfer it to the ORC in order to convert it into electricity. A description of the experimental setup is given according to the current stage of development. Also the paper presents the experimental results obtained and which show the amount of waste heat available for recovery for different engine operation loads. Based on these experimental results the proper ORC configuration and working fluid can be determined. Several possible ORC configurations suitable for this application are highlighted. Future work and development perspectives are also discussed.


2020 ◽  
Vol 92 (1) ◽  
pp. 10906
Author(s):  
Jeroen Schoenmaker ◽  
Pâmella Gonçalves Martins ◽  
Guilherme Corsi Miranda da Silva ◽  
Julio Carlos Teixeira

Organic Rankine Cycle (ORC) systems are increasingly gaining relevance in the renewable and sustainable energy scenario. Recently our research group published a manuscript identifying a new type of thermodynamic cycle entitled Buoyancy Organic Rankine Cycle (BORC) [J. Schoenmaker, J.F.Q. Rey, K.R. Pirota, Renew. Energy 36, 999 (2011)]. In this work we present two main contributions. First, we propose a refined thermodynamic model for BORC systems accounting for the specific heat of the working fluid. Considering the refined model, the efficiencies for Pentane and Dichloromethane at temperatures up to 100 °C were estimated to be 17.2%. Second, we show a proof of concept BORC system using a 3 m tall, 0.062 m diameter polycarbonate tube as a column-fluid reservoir. We used water as a column fluid. The thermal stability and uniformity throughout the tube has been carefully simulated and verified experimentally. After the thermal parameters of the water column have been fully characterized, we developed a test body to allow an adequate assessment of the BORC-system's efficiency. We obtained 0.84% efficiency for 43.8 °C working temperature. This corresponds to 35% of the Carnot efficiency calculated for the same temperature difference. Limitations of the model and the apparatus are put into perspective, pointing directions for further developments of BORC systems.


2021 ◽  
Vol 11 (5) ◽  
pp. 1984
Author(s):  
Ramin Moradi ◽  
Emanuele Habib ◽  
Enrico Bocci ◽  
Luca Cioccolanti

Organic Rankine cycle (ORC) systems are some of the most suitable technologies to produce electricity from low-temperature waste heat. In this study, a non-regenerative, micro-scale ORC system was tested in off-design conditions using R134a as the working fluid. The experimental data were then used to tune the semi-empirical models of the main components of the system. Eventually, the models were used in a component-oriented system solver to map the system electric performance at varying operating conditions. The analysis highlighted the non-negligible impact of the plunger pump on the system performance Indeed, the experimental results showed that the low pump efficiency in the investigated operating range can lead to negative net electric power in some working conditions. For most data points, the expander and the pump isentropic efficiencies are found in the approximate ranges of 35% to 55% and 17% to 34%, respectively. Furthermore, the maximum net electric power was about 200 W with a net electric efficiency of about 1.2%, thus also stressing the importance of a proper selection of the pump for waste heat recovery applications.


2021 ◽  
pp. 1-21
Author(s):  
G.E. Pateropoulos ◽  
T.G. Efstathiadis ◽  
A.I. Kalfas

ABSTRACT The potential to recover waste heat from the exhaust gases of a turboprop engine and produce useful work through an Organic Rankine Cycle (ORC) is investigated. A thermodynamic analysis of the engine’s Brayton cycle is derived to determine the heat source available for exploitation. The aim is to use the aircraft engine fuel as the working fluid of the organic Rankine cycle in order to reduce the extra weight of the waste heat recovery system and keep the thrust-to-weight ratio as high as possible. A surrogate fuel with thermophysical properties similar to aviation gas turbine fuel is used for the ORC simulation. The evaporator design as well as the weight minimisation and safety of the suggested application are the most crucial aspects determining the feasibility of the proposed concept. The results show that there is potential in the exhaust gases to produce up to 50kW of power, corresponding to a 10.1% improvement of the overall thermal efficiency of the engine.


Author(s):  
W Gu ◽  
Y Weng ◽  
Y Wang ◽  
B Zheng

This article describes and evaluates an organic Rankine cycle (ORC) for a waste heat recovery system by both theoretical and experimental studies. Theoretical analysis of several working fluids shows that cycle efficiency is very sensitive to evaporating pressure, but insensitive to expander inlet temperature. Second law analysis was carried out using R600a as a working fluid and a flow of hot air as a heat source, which is not isothermal, along the evaporator. The result discloses that the evaporator's internal and external entropy generation is the main source of total entropy generation. The effect of the heat source temperature, evaporating pressure, and evaporator size on the entropy generation rate is also presented. The obtained useful power is directly linked to the total entropy generation rate according to the Gouy—Stodola theorem. The ORC testing system was established and operated using R600a as a working fluid and hot water as a heat source. The maximum cycle efficiency of the testing system is 5.2 per cent, and the testing result also proves that cycle efficiency is insensitive to heat source temperature, but sensitive to evaporating pressure. The entropy result also shows that internal and external entropy of the evaporator is the main source of total entropy generation.


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