Combined Generation System Research Articles

Solar integrated combined cooling-power generation systems for waste heat recovery using different energy efficient materials

The prominent issues of energy crisis and environment toxicity are disused in these days globally. The CO2 concentration in atmosphere and depletion of conventional fuels can be control by the implementation of eco-friendly and energy efficient material-based cooling systems for heat recovery. The uncovered heat in terms of waste heat from different industrial process of power generation plant, iron industry, refineries, etc., is capable of producing combine generation of power-heating and cooling. This paper conducts the theoretical analysis of solar thermal energy operated vapour adsorption and steam jet cooling system for heat recovery of different capacity of power generation system. The result of present work summarise the efficient cooling effect with minimum high grade energy consumption. The integration of solar parabolic trough collector-based water heating unit helps to increase the desorber temperature and further improvement in refrigerator performance with the utilisation of alternative refrigerant material and achieve the de-carbonise infrastructure for massive industry.

Dynamic feasibility assessment and 3E analysis of a smart building energy system integrated with hybrid photovoltaic-thermal panels and energy storage

Using combined district generation systems provides many advantages to the buildings, mainly residential, because of its flexibility and higher energy efficiency and also from the emission point of view. In this paper, the demands of a building are modeled in Tehran, Iran, using transient simulation software. A combined heating, cooling, and power generation system based on solar loop (consisting of photovoltaic thermal panels, heat storage system and pumps), power block (consisting of a micro gas turbine), and heating and cooling loop (consisting of a chiller, heat exchangers and radiators) is proposed and studied in a dynamic method. The system is modeled in an exact and smart manner, which includes many controllers in the way of flow to direct the steam following the environmental temperature. Comprehensive modeling is conducted in the TRNSYS package based on energy, exergy, and environmental viewpoints. Results demonstrate that the proposed smart system provides all the buildings’ heating, cooling, and power demands in one year. Also, the temperature and radiation illustrations show a high potential of the solar system to be used in the city of the study. The energy system exchanges power with the network and can run the auxiliary equipment’s in the CCHP system and provides all the building’s power demand. Moreover, the additional annual power of 715.32 kWh can be sold to the grid to compensate for the building’s energy costs. Also, the maximum emission and efficiency of 0.12 ton/MWh and 34% are achieved in January and July, respectively. Moreover, the cooling capacity of 4906 kWh demonstrates the enormous potential of double effect chiller in recovering the waste heat.

Анализ стратегий управления гибридным энергокомплексом на базе возобновляемых источников энергии

One of the priority objectives faced by the Russian electric power industry is supplying power to decentralized areas. These areas include the regions of the Far North and the Far East, which are characterized by remoteness from the unified energy system, low population density in vast territories, weak transport links, and undeveloped industry. In view of these features, it can be concluded that it is economically unprofitable to connect such consumers to the unified energy system. The use of renewable energy sources is the most promising solution to this problem. This, in particular, was noted by the President of Russia V.V. Putin during the “Russian Energy Week”: ‘Wind power, of course holds promise as a method for solving the problem of supplying electricity to the population, but it would be more correct to talk about the integrated use of alternative energy sources....’ Recently, the idea of using hybrid energy generation systems has become a priority issue in considering the electrification of isolated regions. Calculations have shown that such systems are more reliable and economically profitable in comparison with the generation of energy from only one of the sources. The use of combined energy generation systems is dictated by several factors, the main of which is that individual sources of renewable energy are variable in nature, which entails difficulties in ensuring uninterrupted power supply. Such problems do not arise in the case of using hybrid systems. The possibility of using a load distribution control strategy for a hybrid system consisting of photovoltaic panels, a diesel generator, and storage batteries, and operating according to a specified load schedule with the known battery charge/discharge cycles is considered. It is pointed out that the HOMER software package is a suitable tool for carrying out an optimization analysis regarding the technical, economic, and environmental factors of the proposed systems, taking into account the load variation pattern, battery charge/discharge cycles and distributed load. By using this software, it is possible to select the most optimal control strategy for combined power supply systems that allows, along with improving their reliability, better efficiency and longer service life to be obtained.

Hybrid Energy Storage System (HESS) optimization enabling very short-term wind power generation scheduling based on output feature extraction

Incorporating Energy Storage System (ESS) with wind farm to establish Wind-Storage Combined Generation System is a promising solution to improve the dependability of integrated wind power. Hybrid Energy Storage System (HESS) is designed based on wind power fluctuation and ESS features. The optimization of system sizing and very short-term generation scheduling are the key points affecting system effectiveness and reliability of wind power. This paper proposes a novel real-time model prediction control (MPC) -multi objective cross entropy (MOCE) based energy management algorithm (MMEMA) to coordinate an HESS based on power output feature extraction. The proposed algorithm includes the SOC regulation strategies considering practical issues including charge/discharge power. Firstly, based on Wavelet Package Decomposition (WPD) and Hilbert Huang Transform (HHT) respectively, the fluctuation feature of real-time wind power output is studied to propose a HESS model aiming to obtain the economic capacity as well as maximum charging/discharging power in every generation scheduling period (10 min). Thus, according to case study, the sizing approach can reduce invest cost by 25.7–47.0%. Then, HESS data is taken as parameters and constraints for the proposed model prediction control (MPC) –multi objective cross entropy (MOCE) algorithm to minimize the deviation between generation scheduling plan and real-time integrated power. The optimization results from case wind farm show that the proposed MMEMA algorithm performs better in smoothing out the fluctuation and managing the SOC of HESS than Non-dominated Sorting Genetic Algorithm II based method (NEMA) by means of evaluating the indexes PD, HSOC and MSE.

Experimental and theoretical study of thermoelectric generator waste heat recovery model for an ultra-low temperature PEM fuel cell powered vehicle

An energy recovery method for ultra-low waste heat temperature Proton Exchange Membrane (PEM) fuel cell is presented utilizing a combined thermoelectric generator (TEG), heat pipe and heat sink system. The aim is to analyze the fundamental characteristics through experimental works and obtain a steady-state model of the system under the scenario of a mini hydrogen fuel cell vehicle. A test bench was developed consisting of a 2 kW open-cathode PEM fuel cell and a single TEG. A thermal resistance network model was also developed and validated. The main variables were the TEG cooling modes and orientation of the TEG towards the heat flow. At 37 °C waste heat temperature, the highest voltage and power output of 25.7 mV and 218 mW respectively were obtained via forced convection cooling and normal flow orientation. The results obtained are unique as it positively showed that the combined use of TEG, heat pipe and heat sink on a vehicle would offset the ultra-low waste heat temperature from a PEM fuel cell. Successful characterization of this system and validation of the model would also allow the system to be further developed for higher performance and contribute to sustainability of PEM fuel cell systems.

A year-round dynamic simulation of a solar combined, ejector cooling, heating and power generation system

In this study, a year-round dynamic simulation of a Combined Cooling, Heating and Power generation (CCHP) system has been performed. The proposed system is composed of an ejector cooling system, an Organic Rankine Cycle (ORC), a solar collector field, heat exchangers and hot and cold storage tanks. It is considered that, a portion of the system input energy is provided by a solar collector field and an auxiliary heater supplies the extra required energy. The dynamic simulation of the introduced CCHP system is performed. The developed model is used to evaluate a year-round performance of the system for a residential building located in Tehran. The obtained results indicated that the proposed CCHP system can satisfy the building energy demand. Furthermore, it is shown that the ejector cooling system can provide the required cooling load during the hot season. The obtained results indicated that increasing the hot storage tank size does not improve the system performance, but, it can shift the system peak load. Also, by increasing the turbine inlet pressure from 1500 kPa to 2500 kPa, the overall system efficiency and solar fraction have decreased by 14.2% and 23.5%, respectively. Moreover, by decreasing the turbine inlet temperature from 110 °C to 90 °C, the system overall efficiency has decreased about 26%, but the solar fraction has enhanced about 11%. Furthermore, by increasing the solar collector filed area from 200 m2 to 400 m2 and 800 m2, the solar fraction has increased about 93% and 226%, respectively.

Generation Scheduling Optimization of Wind-Energy Storage Generation System Based on Feature Extraction and MPC

Abstract Incorporating Battery Battery Energy Storage System (BESS) with wind farm to build up Wind-Storage Combined Generation System is a promising solution to improve the dependability of wind power. BESS sizing and generation scheduling optimization are the key points of this process to improve the economy and efficiency of the integrated combined system. In this paper, based on Quantization Index (QI) clustering, the fluctuation feature of real-time wind power output is studied to obtain the most economic capacity as well as maximum charging/discharging power of BESS in every scheduling circle (15min). Thus, this size of BESS is taken as parameters and constraints for MPC simulation process to minimize the deviation between generation scheduling plan and actual integrated power of Combined Generation System. The optimization results of case study shows that both economic size and ordinary size performs well for generation scheduling optimization, while the proposed BESS sizing method can reduce invest cost to a large extent.

Capacity optimization of concentrated solar power-photovoltaicwind power combined generation system

Due to the fluctuation and randomness of renewable resources, such as solar irradiation resource and wind resource, independent renewable power plants are not easy to generate stable and reliable power. However, multi-energy complementary power generation with energy storage can improve the power quality of renewable energy generation and meet the requirements of grid-connected, so it will be the mainstream of renewable energy generation in the future. Capacity optimization of multi-energy complementary system is the basis and key to improve the power quality and reduce cost of renewable power generation. This paper describes the capacity optimization model of concentrated solar power-photovoltaic-wind (CSP-PV-Wind) combined power generation system. The optimization objectives are as follows: (1) the power is as close to the load as possible; (2) the low overall investment of the combined power supply; (3) the high annual total power generation revenue. The improved particle swarm optimization algorithm is used to optimize the capacity configuration of CSP-PV-Wind combined power generation system, and obtain the optimal dispatch strategy. The results show that, power quality of CSP-PV-Wind combined power generation system is obviously better than that of PV-wind combined power generation system, while Surplus of Power Supply Probability (SPSP) and Loss of Power Supply Probability (LPSP) are all below 15%. However the power generation cost is still a little higher. Therefore, the strategy of reducing the area of collector and increasing the storage tank capacity will be used to decrease the generation cost in the future.

A review to refrigeration with thermoelectric energy based on the Peltier effect

Currently, energy demand and environmental pollution have boosted the evolution of different environment friendly technologies for the development of clean and renewable energies. That is why scientific research allows us to demonstrate the use of solid state based devices implementing temperature changes by electric induction. Given the above, a combined thermic generation system is taken into consideration, consisting in an environmentally friendly thermoelectric generator and refrigerator, wich is fueled and controlled by an electric fluid. Therefore, this study gives an approch and mathematic demonstrations to the concepts of greater relevance about the thermoelectric device and the effects of greater incidence, responsible for giving advantageous characteristics to the implementation of Peltier cells as a basic device in a cooling system for smaller applications, maintaining an ecological system, clean and without detrimental effects to the ozone layer, since there is no C02 emissions into the atmosphere.

Review on Target Tracking of Wind Power and Energy Storage Combined Generation System

The utilization of large-scale renewable energy resources can effectively alleviate the shortage of traditional fossil fuel energy resources and the problem of environmental pollution. In order to realize the grid-friendly access of renewable energy power generation represented by wind power, it is necessary to involve energy storage, of which the battery energy storage is the most widely used type, and build a relatively controllable combined power generation system. Target tracking is one of the demand that wind power and energy storage combined generation system is supposed to meet. According to the discrepancies in tracking target, this paper firstly categorizes the target tracking issue into three parts, namely tracking wind power forecasting curve, tracking generation plan and tracking dynamic power generation index. Then based on the categories and considering their own research focuses, relevant literatures are summarized and compared. Conclusions and future research points are provided in the end. It is found that the issue of tracking dynamic power generation index worth more attention attributed to its novelty and complexity, where future work may be conducted from two aspects, the mathematical model dynamic power generation index and control strategy with overall management ability.

Research on Capacity Optimization of Wind-Storage System Based on Fuzzy Control Strategy

The wind storage combined power generation mode can effectively solve the technical bottlenecks of large-scale wind power grid connected operation and improve the grid's ability to accept wind power. However, due to the high cost of energy storage and the imperfection of the electricity price mechanism, it is necessary to study the capacity optimization of wind-storage combined generation system. Based on the fuzzy control strategy, this paper determined the charge and discharge model of the wind-storage system, and established the Monte Carlo reliability evaluation model and the economic evaluation model that aims at maximizing the annual economic benefits of the system. Then the optimal allocation of wind-storage capacity was obtained by analyzing the reliability index and economic index of the different wind storage capacity rate through the actual wind field test data. Finally, the State of Charge (SOC) at the optimal capacity allocation was analyzed. The result shows that the reasonable allocation of wind-storage capacity is conducive to the reliable and economic operation of the system.

Analysis and performance assessment of a combined geothermal power-based hydrogen production and liquefaction system

In this paper, the thermodynamic study of a combined geothermal power-based hydrogen generation and liquefaction system is investigated for performance assessment. Because hydrogen is the energy of future, the purpose of this study is to produce hydrogen in a clear way. The results of study can be helpful for decision makers in terms of the integrated system efficiency. The presented integrated hydrogen production and liquefaction system consists of a combined geothermal power system, a PEM electrolyzer, and a hydrogen liquefaction and storage system. The exergy destruction rates, exergy destruction ratios and exergetic performance values of presented integrated system and its subsystems are determined by using the balance equations for mass, energy, entropy, energy and exergy and evaluated their performances by means of energetic and exergetic efficiencies. In this regard, the impact of some design parameters and operating conditions on the hydrogen production and liquefaction and its exergy destruction rates and exergetic performances are investigated parametrically. According to these parametric analysis results, the most influential parameter affecting system exergy efficiency is found to be geothermal source temperature in such a way that as geothermal fluid temperature increases from 130 °C to 200 °C which results in an increase of exergy efficiency from 38% to 64%. Results also show that, PEM electrolyzer temperature is more effective than reference temperature. As PEM electrolyzer temperature increases from 60 °C to 85 °C, the hydrogen production efficiency increases from nearly 39% to 44%.

Study on Optimization of Control Parameters for Generator Operation with Multiple Units in a Combined Generator System

Study on Optimization of Control Parameters for Generator Operation with Multiple Units in a Combined Generator System

Renewable-integrated Traffic Energy

This work is a development of an indigenous technology combined Flap-motor power generator (FMPG) and PV system that harnesses the free renewable energies in rural area to generate electricity. FMPG and solar renewable energy power technologies are affordable, clean and sustainable and can replace or supplement power generator for road traffic signal light. Combined energy systems integrate these renewable energy technologies with flap base car passing power generators, PV and batteries to provide road signal power in remote areas not connected to a utility grid. Such an isolated grid will help to supply electricity for traffic signal to avoid road accident and maximum vehicle efficiency at intersections. This power generation device will provide constant power supply while no sunlight for long days. At the same time technology will represent instance power supply for rural area traffic light electrification system without grid connection.

Research on smart tracking strategy of wind power and energy storage combined generation system based on three‐stage rolling optimisation

Research on smart tracking strategy of wind power and energy storage combined generation system based on three‐stage rolling optimisation

Conception optimization and CFD structure study of Wind firm power generation based on OWC-WTGS combined generation system with battery storage system

In this paper, a deep study and optimization process for wind firm generation system based on full solar, wind and OWC chamber structure for wave energy harvesting and battery storage system, a combined WTGS (wind turbine generation system) with OWC (oscillating water column chamber) hybrid generation system has been involved for offshore generation firms for power lifting, an FEM (finite element modeling) structure study has been applied to a novel proposition using double orifice chamber structure with form optimization for the maximization of the harvested power, a CFD (Computational fluid dynamics) simulator software module was used for the study of the pneumatic power evolution through the structure. A novel wave generation method was applied to a 1:30 mechanical prototype that was built for this purpose to get an oscillated wave model through the RWMD method (Real Wave Model Simulator) instead of using an ordinary sin wave generator on the tank to make the waves the closest possible to the real sea waves. An experimental energy management system has been implemented for the battery storage energy control using two phase interleaved electronic system for the battery charging process between this latter and the full system. A DC-DC converter for the management of the global power system has been studied for this purpose.

Pumped thermal energy storage and bottoming system part A: Concept and model

This work introduces a new concept for a utility scale combined energy storage and generation system. The proposed design utilizes a pumped thermal energy storage (PTES) system, which also utilizes waste heat leaving a natural gas peaker plant. This system creates a low cost utility-scale energy storage system by leveraging this dual functionality. This Part A of a two-part paper presents a review of previous work in PTES as well as the details of the proposed integrated bottoming and energy storage system. A time-domain system model was developed in Mathworks R2016a Simscape and Simulink software to analyze this system. Validation of both the fluid state model and the thermal energy storage model are provided. The experimental results showed the average error in cumulative fluid energy between simulation and measurement was ±0.3% per hour. Comparison to a Finite Element Analysis (FEA) model showed <1% error for bottoming mode heat transfer. Part B of this two-part paper gives a detailed characterization of the integrated bottoming with energy storage system.

Analysis of combined solar photovoltaic-nanostructured thermoelectric generator system

ABSTRACTIn this paper, a combined solar photovoltaic (PV) and thermoelectric (TE) generator system is investigated. The TE generator converts the temperature gradient into electricity eventually improving the overall performance of the system. A nanostructured TE material is used in this investigation and its power generation performance is compared with the traditional TE material. Using the analytical solutions, different performance parameters (e.g. heat input, power output, efficiency) are calculated and expressed graphically as a function of solar radiation and convection heat transfer coefficient. In addition to this, different performance parameters were also compared between traditional and nanostructured TE materials. Moreover, the nanostructured TE material leads to improvement in performance of TE generator due to the reduction in thermal conductivity and improvement in electrical conductivity. The TE generators have a large impact on the overall efficiency of the combined system at higher radiation.

Development of an Active Power Reserve Management Method for DC Applied Wave-Wind Combined Generation Systems

A system that combines a wind turbine and a wave generator can share the off-shore platform and therefore mix the advantages of the transmission system construction and the power conversion system. The current hybrid generation system considers output limitation according to the instructions of the transmission system operator (TSO), and controls the profile using wind turbine pitch control. However, the integrated wave generation system utilizing a DC network does not adapt a power limitation scheme due to its mechanical constraints. In this paper, a control plan focusing on the electrical section of wave generators is formed in order to effectively manage the output profile of the hybrid generation system. The plan pays attention to power reserve flexibility for the utility grid using the analysis of the controllable elements. Comparison with the existing system is performed based on real offshore conditions. With the help of power system computer aided design (PSCAD) simulation, the ability of the novel technique is estimated by proposing the real power control based on the reference signal of TSO and the reactive power capacity it produces.

Energy and exergy analyses of an integrated underground coal gasification with SOFC fuel cell system for multigeneration including hydrogen production

A novel integrated system, including underground coal gasification (UCG), steam assisted gravity drainage (SAGD) based oil sands, syngas fueled Solid Oxide Fuel Cell (SOFC), integrated gasification combined cycle (IGCC) and an electrolyzer, for hydrogen production is proposed and analyzed for practical applications, especially for Alberta region in which there are huge capacity of oil sands and coal reserves. This combined multi generation system produces syngas from underground coal without mining, produced syngas is utilized for generating electricity from IGCC and SOFC. A part of generated electricity in the Rankine cycle is used for hydrogen production through an electrolyzer. The excess steam in IGCC is utilized for SAGD process in order to extract Bitumen from underground as in-situ extraction. Energy and exergy analyses are conducted to assess the performance of the cycle, and the effects of various system parameters on energy and exergy efficiencies of the overall system and its subsystems are studied comparatively. The overall energy and exergy efficiencies of the system are found as 29.2% and 26% respectively for 20 kg/s coal feed rate. Furthermore, the effects of varying ambient temperature and pressure, syngas temperature, coal and syngas lower heating value, air and steam injection rates on the system performance are investigated.