scholarly journals Design and Analysis of Domestic Micro-Cogeneration Potential for an ORC System Adapted to a Solar Domestic Hot Water System

Author(s):  
Daniel Leal-Chavez ◽  
Ricardo Beltran-Chacon ◽  
Paola Cardenas-Terrazas ◽  
Saul Islas ◽  
Nicolas Velazquez

This paper proposes the configuration of an Organic Rankine Cycle (ORC) coupled to a solar domestic hot water system (SDHWS), with the purpose of analyzing the cogeneration capacity of the system. A simulation of the SDHWS was conducted at different temperatures, observing its performance to determine the amounts of useable heat generated by the solar collector; thus, from an energy balance, the amount of heat that may be used by the ORC could be determined. The working fluid that would be suitable for the temperatures and pressures given in the system were selected. The best fluid for the given conditions of superheated vapor at 120 °C and 604 kPa and a condensation temperature of 60 °C and 115 kPa was acetone. The main parameters for the expander thermodynamic design that may be used in such ORC were obtained with the possibility of generating 443 kWh of annual electric energy, with 6.65 % global efficiency of solar to electric power, or an overall efficiency of the cogeneration system of 56.35 % with a solar collector of 2.84 m2.

Entropy ◽  
2019 ◽  
Vol 21 (9) ◽  
pp. 911 ◽  
Author(s):  
Daniel Leal-Chavez ◽  
Ricardo Beltran-Chacon ◽  
Paola Cardenas-Terrazas ◽  
Saúl Islas ◽  
Nicolás Velázquez

This paper proposes the configuration of an Organic Rankine Cycle (ORC) coupled to a solar domestic hot water system (SDHWS) with the purpose of analyzing the cogeneration capacity of the system. A simulation of the SDHWS was conducted at different temperatures, observing its performance to determine the amounts of useable heat generated by the solar collector; thus, from an energy balance point of view, the amount of heat that may be used by the ORC could be determined. The working fluid that would be suitable for the temperatures and pressures in the system was selected. The best fluid for the given conditions of superheated vapor at 120 °C and 604 kPa and a condensation temperature of 60 °C and 115 kPa was acetone. The main parameters for the expander thermodynamic design that may be used by the ORC were obtained, with the possibility of generating 443 kWh of annual electric energy with 6.65% global efficiency of solar to electric power, or an overall efficiency of the cogeneration system of 56.35% with a solar collector of 2.84 m2.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 500
Author(s):  
David Vera ◽  
Francisco Jurado ◽  
Bárbara de Mena ◽  
Jesús C. Hernández

This paper presents the theoretical model and the simulation of a cutting edge hybrid power system composed of an externally-fired gas turbine (EFGT) coupled with an organic Rankine cycle (ORC) as a bottoming unit for the maximization of electrical power. The power plant is fed with different biomass sources from olive industry wastes (pruning, dry pomace, stones, leaves and twigs), providing more than 550 kW of electric power and a net electrical efficiency of 26.0%. These wastes were burnt directly at atmospheric pressure in an EFGT, producing 400 kW of electric power and exhaust gases at 300 °C. Ten suitable ORC working fluids have been studied to maximize the electric power generation: cyclohexane, isohexane, pentane, isopentane, neopentane, R113, R245fa, R365mfc, R1233zd and methanol. The best fluid was R1233zd, reaching 152.4 kW and 22.1% of ORC thermal efficiency; as drawback, however, R1233zd was not suitable for Combined Heat and Power CHP applications due its lower condensation temperature. Thus, despite R113 gave minor electricity production (137.5 kW) this allowed to generate additional thermal power (506.8 kW) in the way of hot water at 45 °C.


2016 ◽  
Vol 37 (3) ◽  
pp. 79-93 ◽  
Author(s):  
Jan Wajs ◽  
Dariusz Mikielewicz ◽  
Michał Bajor ◽  
Zbigniew Kneba

AbstractThe results of investigations conducted on the prototype of vapour driven micro-CHP unit integrated with a gas boiler are presented. The system enables cogeneration of heat and electric energy to cover the energy demand of a household. The idea of such system is to produce electricity for own demand or for selling it to the electric grid – in such situation the system user will became the prosumer. A typical commercial gas boiler, additionally equipped with an organic Rankine cycle (ORC) module based on environmentally acceptable working fluid can be regarded as future generation unit. In the paper the prototype of innovative domestic cogenerative ORC system, consisting of a conventional gas boiler and a small size axial vapour microturbines (in-house designed for ORC and the commercially available for Rankine cycle (RC)), evaporator and condenser were scrutinised. In the course of study the fluid working temperatures, rates of heat, electricity generation and efficiency of the whole system were obtained. The tested system could produce electricity in the amount of 1 kWe. Some preliminary tests were started with water as working fluid and the results for that case are also presented. The investigations showed that domestic gas boiler was able to provide the saturated/superheated ethanol vapour (in the ORC system) and steam (in the RC system) as working fluids.


Author(s):  
Wahiba Yaïci ◽  
Evgueniy Entchev ◽  
Pouyan Talebizadeh Sardari

Abstract Globally there are several viable sources of renewable, low-temperature heat (below 130°C) particularly solar energy, geothermal energy, and energy generated from industrial wastes. Increased exploitation of these low-temperature options has the definite potential of reducing fossil fuel consumption with its attendant very harmful greenhouse gas emissions. Researchers have universally identified the organic Rankine cycle (ORC) as a practicable and promising system to generate electrical power from renewable sources based on its beneficial use of volatile organic fluids as working fluids (WFs). In recent times, researchers have also shown a preference for/an inclination towards deployment of zeotropic mixtures as ORC WFs because of their capacity to improve thermodynamic performance of ORC systems, a feat enabled by better matches of the temperature profiles of the WF and the heat source/sink. This paper demonstrates both the technical feasibility and the notable advantages of using zeotropic mixtures as WFs through a simulation study of an ORC system. The study examines the thermodynamic performance of ORC systems using zeotropic WF mixtures to generate electricity driven by low-temperature solar heat source for building applications. A thermodynamic model is developed with an ORC system both with and excluding a regenerator. Five zeotropic mixtures with varying compositions of R245fa/propane, R245fa/hexane, R245fa/heptane, pentane/hexane and isopentane/hexane are evaluated and compared to identify the best combinations of WF mixtures that can yield high efficiency in their system cycles. The study also investigates the effects of the volumetric flow ratio, and evaporation and condensation temperature glides on the ORC’s thermodynamic performance. Following a detailed analysis of each mixture, R245fa/propane is selected for parametric study to examine the effects of operating parameters on the system’s efficiency and sustainability index. For zeotropic mixtures, results showed that there is an optimal composition range within which binary mixtures are inclined to perform more efficiently than the component pure fluids. In addition, a significant increase in cycle efficiency can be achieved with a regenerative ORC, with cycle efficiency ranging between 3.1–9.8% and 8.6–17.4% for ORC both without and with regeneration, respectively. Results also showed that exploiting zeotropic mixtures could enlarge the limitation experienced in selecting WFs for low-temperature solar organic Rankine cycles.


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.


Author(s):  
Musbaudeen O. Bamgbopa ◽  
Eray Uzgoren

This paper presents a solar Organic Rankine Cycle (ORC) for electricity generation; where a regression based approach is used for the working fluid. Models of the unit’s sub-components (pump, evaporator, expander and condenser) are also presented. Heat supplied by the solar field can heat the water up to 80–95 °C at mass flow rates of 2–12 kg/s and deliver energy to the ORC’s heat exchanger unit. Simulation results of steady state operation using the developed model shows a maximum power output of around 40 kWe. Both refrigerant and hot water mass flow rates in the system are identified as critical parameters to optimize the power production and the cycle efficiency.


Author(s):  
Eunkoo Yoon ◽  
Hyun Jun Park ◽  
Hyun Dong Kim ◽  
Kyung Chun Kim ◽  
Sang Youl Yoon

This study aims to evaluate the performance of an organic Rankine cycle (ORC) power system adopting dual expanders in parallel by experiment. A dual-expander ORC system was designed to provide competitive advantages over a general single expander ORC system in typical applications with large thermal fluctuation of heat sources such as solar heat, marine waste heat, and etc. The ORC system consists of two scroll expanders installed in parallel, a hydraulic diaphragm type pump to feed and pressurize the working fluid, R-245fa, two plate heat exchangers for the evaporator and the condenser, and two generators with shaft power torque meters. The two scroll expanders were modified from two oil-free air scroll compressors, and were tested in the ORC loop with R245fa. The maximum isentropic efficiency of each expander was measured about 53%, and the shaft power was reached to about 2kW. The hot water was used as heat source, and the water temperature was controlled up to 150 °C by the 100 kW-class electric heater. A circulating air-cooled chiller was utilized for the control of the cooling water temperature. In order to determine the static performance of the system, efficiencies and shaft powers were measured with 130 °C heat source temperature. In addition, performance tests were conducted with various working fluid mass flow rates to control pressure ratios. The characteristics and total thermal efficiency of the dual parallel expander ORC system and optimal operating modes are addressed.


Clean Energy ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 476-491
Author(s):  
Yunis Khan ◽  
Radhey Shyam Mishra

Abstract In this study, a parametric analysis was performed of a supercritical organic Rankine cycle driven by solar parabolic trough collectors (PTCs) coupled with a vapour-compression refrigeration cycle simultaneously for cooling and power production. Thermal efficiency, exergy efficiency, exergy destruction and the coefficient of performance of the cogeneration system were considered to be performance parameters. A computer program was developed in engineering equation-solver software for analysis. Influences of the PTC design parameters (solar irradiation, solar-beam incidence angle and velocity of the heat-transfer fluid in the absorber tube), turbine inlet pressure, condenser and evaporator temperature on system performance were discussed. Furthermore, the performance of the cogeneration system was also compared with and without PTCs. It was concluded that it was necessary to design the PTCs carefully in order to achieve better cogeneration performance. The highest values of exergy efficiency, thermal efficiency and exergy destruction of the cogeneration system were 92.9%, 51.13% and 1437 kW, respectively, at 0.95 kW/m2 of solar irradiation based on working fluid R227ea, but the highest coefficient of performance was found to be 2.278 on the basis of working fluid R134a. It was also obtained from the results that PTCs accounted for 76.32% of the total exergy destruction of the overall system and the cogeneration system performed well without considering solar performance.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Suresh Baral

The current research study focuses on the feasibility of stand-alone hybrid solar-geothermal organic Rankine cycle (ORC) technology for power generation from hot springs of Bhurung Tatopani, Myagdi, Nepal. For the study, the temperature of the hot spring was measured on the particular site of the heat source of the hot spring. The measured temperature could be used for operating the ORC system. Temperature of hot spring can also further be increased by adopting the solar collector for rising the temperature. This hybrid type of the system can have a high-temperature heat source which could power more energy from ORC technology. There are various types of organic working fluids available on the market, but R134a and R245fa are environmentally friendly and have low global warming potential candidates. The thermodynamic models have been developed for predicting the performance analysis of the system. The input parameter for the model is the temperature which was measured experimentally. The maximum temperature of the hot spring was found to be 69.7°C. Expander power output, thermal efficiency, heat of evaporation, solar collector area, and hybrid solar ORC system power output and efficiency are the outputs from the developed model. From the simulation, it was found that 1 kg/s of working fluid could produce 17.5 kW and 22.5 kW power output for R134a and R245fa, respectively, when the geothermal source temperature was around 70°C. Later when the hot spring was heated with a solar collector, the power output produced were 25 kW and 30 kW for R134a and R245fa, respectively, when the heat source was 99°C. The study also further determines the cost of electricity generation for the system with working fluids R134a and R245fa to be $0.17/kWh and $0.14/kWh, respectively. The levelised cost of the electricity (LCOE) was $0.38/kWh in order to be highly feasible investment. The payback period for such hybrid system was found to have 7.5 years and 10.5 years for R245fa and R134a, respectively.


Sign in / Sign up

Export Citation Format

Share Document