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Pulp and paper production is a highly energy intensive process and improvement of energy efficiency in this process is considered as promising measures for reducing industrial greenhouse gases emissions (GHG). This study focuses the Pakistan's pulp and paper industry which consumes around 7% of the country's industrial energy and contributes to over 317,269 tonnes of CO 2 emissions. With rising demands for fuels and consequently as harp increase in CO 2 emissions due to the growth of the paper sector in Pakistan, this article aims to analyse the energy efficiency and carbon dioxide emissions reductions potential through the incorporation of cogeneration technologies. The cogeneration technologies studied are agas turbine, steam turbine and combined cycle and are evaluated from the energetic and economic point of view to propose a best suitable technology for each paper mill. The proposed cogeneration technologies are selected on the basis of high energy utilisation factor, as implepayback period of five years or less with least Annualised life cycle cost. The result shows that a theoretical energy saving potential equivalent to 16.9% of the actual thermal energy requirement of mills can be achieved through cogeneration which will lead to 14.3% reduction of the present carbon emissions levels in Pakistan's paper sector.

During the building operation phase, it is recognized that the performance of building envelope elements and energy supply systems drops with time. This performance degradation usually leads to lower energy efficiency and higher life cycle costs than predicted in the early design phase. This paper quantitatively reviews the impacts of this deterioration on the whole building performance. From the findings of the reviewed literature, it can be concluded that the whole building performance is very sensitive to several deterioration factors, particularly the performance degradation of the heating, ventilation and air conditioning (HVAC) system. The impact on the whole building performance mostly ranges from 20% to 30% over 20 years, according to the reviewed studies.

At the present time, reliability and stability of electric power have been very important when it comes to electrical systems in any plants, especially in terms of distribution. Phoenix Pulp & Paper PCL (PPPC) in Khon Kaen, Thailand, is currently generating electric power about 90% of its current needed by themselves and buys the rest from Provincial Electricity Authority (PEA). Nonetheless, the protection system should be installed to protect the electrical bus when electrical generating process trips or breakdown. Otherwise, it would cause the shutdown of electrical system and lose all manufacturing. To protect electrical system, PPPC therefore has to use load shedding system for cutting the connection of the machines from the system within few minutes. Power flow of electric power from 115 kV PEA to 11 kV via 2 transformers of 115 kV/11 kV and PPPC's 3 generators are studied in this research by setting the real electric power (P), reactive electric power (Q), current (I) and voltage (V) in the protection relay of load shedding system of 11 kV switchboards. In addition, motor control panel, simulated by SKM Power Tools program, is investigated in this research work. The simulation results: P, Q, I and V will be divided into 4 cases: the trips from TG-PUC, TG2, TG3 (in-house generation) and the one from PEA. In the case that there is a trip from PEA electrical distribution, P, only generated from the first three generators in house, will be insufficient to cover the plant's electric need and require around 6,512 kW more. As a result, the machines would have to be stopped running. However, if there is a trip from its in-house generation (TG-PUC, TG2 and TG3) instead, some P can be directly received from PEA. Thus, the load shedding scheme is important to protect the blackout system from electrical system's trip in distribution.

In the recent decades, Jojoba biodiesel is considered as one of the most potential renewable energy sources of many countries. Thus, an investigation was conducted for the enhancement of jojoba biodiesel-diesel blends with the addition of 10% n-butanol by volume which is generally acknowledged as an oxygenated additive. Engine performance was examined at variable loads, ranging from no load (0 N.m) to 13.5 N.m at a constant speed of 2000 rpm on a compression ignition engine. The cylinder pressure and the heat release rate analysis were explored for the tested fuels to examine the behavior of the combustion process. Engine emissions of NO x , CO, and UHC were also investigated. The combustion outcomes exhibited that the maximum cylinder pressure and the peak heat release rate were slightly reduced as compared to diesel oil. There was a significant reduction in the exhaust emissions where the NO x , CO, and UHC were reduced by 80%, 80%, and 65%, respectively. It can be concluded that the addition of n-butanol with jojoba biodiesel-diesel blends has a remarkable positive effect on the engine performance and emissions.

Energy recovery from black liquor can be performed through gasification process at temperatures above the melting point of the inorganic chemicals. Complementing the experimental research, this study was conducted in Aspen Plus software to simulate thermodinamic modeling of detail process for gasification and combined cycle in an integrated system power plant. Mass and energy balances were examined to quantify process performance. The unrecoverable energy in a single process will be utilized in other processes. The combination of these technologies is expected minimizing the total exergy destruction the throughout system. Kraft black liquor was used as sample during process calculation. The proposed integrated-system shows a high energy efficiency. A significant positive energy harvesting from black liquor can be achieved for further development.

Economic evaluation of a reactive distillation for biodiesel production is performed. Palm fatty acid distillate (PFAD) consisting of a mixtures of triglycerides, moisture and free fatty acids is considered a feedstock. A simulation model of the biodiesel production process based on a reactive distillation is developed using Aspen Plus. Effect of key operating parameters, such as the number of reactive stages and liquid holdup, is investigated. The economic analysis considers total investment costs, operating costs and economic indicators, such as return on investment (ROI) and net present value (NPV). Performance of the reactive distillation processes is compared with a conventional process using two continuous reactors. The simulation results show that a single step acid – catalyzed process can be carried out in a reactive distillation for higher biodiesel productivity and purity. Although the conventional process has lower total production cost, the reactive distillation process is more economical process providing a higher ROI and NPV. The biodiesel production using a reactive distillation without recycling upstream is the most preferred configuration. Furthermore, the reactive distillation process can save the energy requirement of 51.2% compared with the conventional process.

IMO issued latest environmental regulations Tier Ⅲ has strengthened the emission standards, in which the NOx emission should be less than 3.4g/(kWh) for marine two-stroke engines (engine speed lower than 130r/min) in NOx ECAs. In order to meet the strengthened emission regulations, EGR and fuel injection strategies have been used in marine two-stroke engines to reduce emissions. In this paper, a full cycle computation fluid dynamics (CFD) simulation model has been established in GT-Power software to study the effects of EGR rate, post-injection and pilot-injection on emissions and overall performance of a low speed two-stroke marine engine. By changing the EGR rates and the degree and mass of the post-injection and pilot-injection, an optimal combination among different fuel injection strategies and EGR rates is proposed in this paper. The results indicate that the degree and mass of injection strategies with EGR play an important role in NOx and soot emissions. The trade-off relationship between NOx and soot is improved by changing the fuel injection strategies with different EGR rates.

The local wind environment and daylight conditions of buildings directly affect the safety and comfort (e.g. thermal environment and lighting environment) of the residents and staff, and influence the energy consumption and energy efficiency of building’s operation. However, in the view of a planning designer, it is likely to pay more attention to the building’s functional arrangement, appearance and space utilization, but the problems of area ventilation and daylight condition may be neglected. This paper takes a layout design of a commercial building group in Haidong, Qinghai Province as an example to demonstrate, for an urban planner, how to use the CFD and building lighting simulation technology to carry out the preliminary evaluation on an initial design scheme. Simulation results indicated under local meteorological conditions, the initial design scheme fully considered the cold air infiltration in winter and natural ventilation in summer, as well as safety issues in the human walking area, which formed a good local wind environment. However, the problem of poor daylight condition in some areas requires adjustments and modifications based on actual circumstance. From the examples presented in this paper, the numerical simulation techniques play an important role at the initial stages of planning and design to detect the design defects timely and provides a basis for subsequent adjustments later. Meanwhile, this paper also provides a reference for interdisciplinary cooperation between urban planners and HVAC engineers.

The temperature of exhaust gas can exceed 800K, which is much higher than surroundings. It’s easy to demonstrate IR and get bombed. Therefore, it’s necessary to lower the temperature of exhaust gas. In this paper, a kind of infrared suppressor which uses engine exhaust to eject cold air and water spray is designed. Water spray is produced by ultrasonic atomization. The mixing process of the ejector is revealed by CFD. CFD results are validated with the experimental values. After validation is satisfied, this paper analyzes the temperature field inside the ejector and compares the performances of ejectors with varying geometries. According to CFD results, a device is made. Test results show that a good performance is achieved: radiation energy is only 36% of the original.

To deal with climate change, clean energy is a necessity in the present world. Energy requirement is growing faster each decade. Over the long term some of the traditional sources (coal, gas and oil) have become inadequate to meet up the increasing demand. The current consumption rate of fossil fuel will make them extinct by the year 2050 to 2100. Based on these facts nuclear power plant is a strategic choice to develop a clean energy. This paper is an outcome of the review - Nuclear power as foundation of a clean energy future. Though nuclear energy can’t be called as ‘Carbon neutral’ but it gives rise to much less emission of carbon dioxide than fossil fuels. Comparing with other energy structures, nuclear electricity chain emits a limited amount of greenhouse gas. Despite the uncertainty of building nuclear power plants in the future, this paper will further discuss climate changing issues have larger impact than the policies which are against the nuclear electricity production. The safety issue which is a public concern is also discussed here in short.

A novel air source heat pump powered bed-based space radiation heating (ASHP-BBSH) system is reported in this paper. This novel system combines the merits from a Chinese Kang, or a heated bed, widely used in northern rural China and a standard ASHP system, which can provide localized space heating via both convection and radiation to maintain a comfortable indoor thermal environment, at reduced energy use. In this novel bed-based system, a bed is heated and thus used as a radiator for providing space heating at both daytime and nighttime. In this paper, firstly, there is an introduction to the novel ASHP-BBSH system. Secondly, based on the experiment setup dimensions, a numerical model is built with a real size thermal manikin. Thirdly, the thermal environment generated by the ASHP-BBSH system is analysed by Fluent. The numerical results show that the ASHP system can achieve a uniform thermal environment and energy saving potential.

In recent years, with the rapid expansion of urban power grids, the automatic voltage control (AVC) system develops some new characteristics. Based on the technology of big data analysis and mining, this paper expounds an AVC system for urban power network with high load density based on the integrated dispatch and operation mode. This paper introduces several different application modes, and shows the operation characteristics of the multi-point distribution mode and the integrated control mode. The big data mining technology is used to discovering the hidden troubles and defects in AVC system. This paper also presents some other AVC key technologies such as security check of remote control, self-adaption analysis method and so on.

Due to the increasing penetration level of tidal power in power system, the tidal turbines can provide less frequency support than conventional generators due to their small rotor mass. This makes the power system with low inertia and cause frequency problem. This paper presents a simulation model of a tidal power farm based on a MW-level variable speed tidal turbine with doubly-fed induction generator (DFIG) developed in the simulation tool of Matlab/Simulink. According to the reserve capacity required for primary frequency control, a de-loading control method is proposed in this paper to resolve the issue of primary frequency control via tidal power plant. Based on the analysis method of the frequency control characteristics of DFIGs, it is proposed by improved variable pitch control method. The control strategy, which is based on pitch control system of tidal turbine, is proposed in order to participate into primary frequency regulation of power system. Simulation results show that the proposed control strategy is effective means the tidal turbines with DFIG generators could providing frequency support for power system when they are working under the de-loading condition in this paper.

Distillation is a common separation process since its emergence in the early 20th century due to its capability for mass production without compromising the product(s) quality. However, the energy efficiency is still become the challenge for the industry players. Since then, they put so much effort in ensuring the energy efficiency of the process. It is not only for economic purpose but also to address the environmental issue whereby the legislation become stringent over the years. Therefore, this paper aims to investigate the energy efficiency of distillation column sequence by using the pinch analysis method. Rigorous simulation of the distillation for component n-butane, n-hexane, n-heptane and n-nonane has been carried-out for 5 different sequences namely direct, indirect, driving force sequence (indirect-direct), direct-indirect and split for energy analysis. Aspen HYSYS V9 has been used for the simulation while the data was extracted for pinch analysis including the construction of problem table algorithm to obtain the minimum cooling and heating load for each sequence. The results that were analyzed and compared including total heat load, heating load and cooling load. Then the grid diagrams for the best sequence was constructed. From the results of energy analysis, all distillation sequences except for direct-indirect sequence recorded further energy saving compared to the base case whereby the highest saving is driving force sequence at 6.31% total energy saving. It also recorded the highest percentage of heating and cooling load at 4.85% and 9.05% respectively. This paper also strengthens the advantage of driving force method in determining the best sequence since it was proved to produce lower energy consumption compared to others. Then, the energy can be further reduced by using the pinch analysis. Therefore, for this case study, it can be concluded that the heat integration via pinch analysis is a promising method for further saving for any distillation column sequence.

Recent studies have shown that energy-efficient smart LED lighting systems provide a better visual comfort-working environment at a reduced energy consumption compared to existing lighting systems. Present daylighting systems are able to regulate the light intensities via communication technologies utilizing smart sensors. This paper presents implementation of a smart LED lighting system utilizing different energy-efficient techniques without compromising the visual comfort of occupants. The proposed lighting system uses ZigBee and Wi-Fi communication protocols to control the lights of commercial/residential buildings according to natural daylight, occupancy or as per the requirements of the inhabitants of the building. The lighting system can be operated in three different modes: Manual, Auto, and Hybrid to account for various applications. A wireless sensor and actuator network (WSAN) is used to collect available data, regarding the usage of personalised smart LED lights by occupants in the building. A complete design and implementation of the smart lighting system are presented in the paper. The paper also presents the detailed test-bed implementation of the proposed smart lighting technique and data management system to illustrate the impact of the proposed lighting system on energy consumption and occupants’ visual satisfaction. The proposed lighting system aims to reduce energy consumption by 60-70% compared to the existing lighting system while satisfying the visual comfort of the occupants. The proposed work also suggests the guidelines to incorporate intelligence into the system such that it can automatically predict the occupant preferences in a decentralized framework for better visual comfort and improved energy utilization in existing buildings.

The world is facing critical energy concern, in view of depleting fossil fuel reserves and increasing environment pollution. Biodiesel can potentially substitute fossil fuel, and is produced through the transesterification of vegetable oils. This paper will emphasize on the transition from first generation derived from waste cooking oil, to second generation biodiesel derived from calophyllum inophyllum, which is a non-edible plant. The objective of this paper is to optimize the performance of biodiesel blends with diesel in a 30 kW microturbine. The characterization of chemical fuel properties of distillate and biodiesel blends will be conducted to determine if it meets international standards for power generation. Temperature profiles, pressure, and flame imaging will be closely monitored to detect possible problems in operability of the combustor caused by the differences in fuel characteristics. The findings may provide useful information towards optimization of microturbine performance, considering the wide range of biodiesel feedstock that exist. The paper outcome will show the potential of non-edible biodiesel blends to be used as alternative fuel in microturbines for power generation.

This paper evaluates simple metamodels to predict local electricity demand and grid restrictions, in residential neighborhoods with heat pumps and photovoltaics. The procedure and challenges of developing such models are described. Modeling is based on results obtained from detailed simulation of buildings and the grid. Linear and logistic regression models are developed for electricity demand and minimum voltage respectively, as a function of neighborhood characteristics, related to both building and electrical network properties. The paper shows that linear regression can be used for a first evaluation of electricity demand. For voltage violations, logistic regression gives acceptable results, however more complex models are needed to approximate voltage levels. ispartof: pages:550-560 ispartof: NSB 2017: 11th Nordic Symposium on Building Physics vol:132 pages:550-560 ispartof: Nordic Symposium on Building Physics location:Trondheim date:11 Jun - 14 Jun 2017 status: published

This paper presents a research activity aimed at exploiting combined cycles (gas turbine plants coupled with steam cycles) for small-scale energy generation from carbon-neutral biomass. Such a goal has never been achieved before, since combined cycles are generally suited only for large-scale applications and for clean fuels. In order to adapt combined cycles to small-scale energy generation using dirty fuels, the implementation of cost-effective and commercially available components is studied, such as the use of a turbocharger and a power turbine taken from the automotive industry. The ongoing realization of the first prototype of small-scale combined cycle is presented in this paper, providing a detailed description of both the plant architecture and the main components chosen. In addition, a commercially available tool (Cycle Tempo) is used to demonstrate the high feasibility and potential of the plant in terms of efficiency. To that end, different plant configurations are studied and the effects of losses on the plant performance are investigated in detail.

The paper presents a novel control architecture developed with the aim to satisfy the requirements of the cooling system of an ICE, by means of an electric pump and of an ad-hoc developed control module. The developed controller is based on the Robust Model Predictive Control and is designed with the purpose to satisfy the input and output constraints and to reject the external disturbances, by adopting a lumped parameter model of the engine cooling system, which predicts the coolant temperature, the average wall temperature and the heat transfer regime including nucleate boiling. Given that the proposed methodology is valid for each condition, in the present paper the focus is on the engine operating under fully warmed conditions, with the aim to keep the wall temperature into the prescribed limits, with the lowest possible coolant flow rates. This goal is achieved by properly defining the controller parameters. Different control strategies are proposed and their effectiveness is evaluated in terms of engine wall temperature, coolant temperature, coolant flow rate and heat transfer regime in response to step-wise variations in fuel flow rate. The region of stability of the controller is also discussed. Results show that the control algorithm is robust in terms of disturbance rejections and ensures effective and safe cooling with much lower coolant flow rates if compared to the ones provided by the use of the standard crankshaft driven pump.

One of the main issues of nuclear reactor design is the accurate calculation of control rod worth. However, in the calculation results there exists uncertainty inevitably, which is propagated from uncertainty in input parameters, computing models and calculation methods. Therefore, carrying out control rod worth uncertainty quantification is urgent but full of challenges, especially for application of a feasible method for propagating input uncertainties to control rod worth. In this paper, a new uncertainty analysis method for quantifying uncertainty of control rod worth propagated from macroscopic cross sections has been proposed. The basic idea is to use efficient sampling method to propagate nuclear data uncertainties through the function between control rod worth and all macroscopic cross sections. This is done by applying perturbation theory. Numerical results indicate that the new method proposed in this paper is an effective way to quantify uncertainty of control rod worth propagated from nuclear data.

This paper reports a new approach for exposing materials, including solar cell structures, to atomic hydrogen. This method is dubbed Shielded Hydrogen Passivation (SHP) and has a number of unique features offering high levels of atomic hydrogen at low temperature whilst inducing no damage. SHP uses a thin metallic layer, in this work palladium, between a hydrogen generating plasma and the sample, which shields the silicon sample from damaging UV and energetic ions while releasing low energy, neutral, atomic hydrogen onto the sample. In this paper, the importance of the preparation of the metallic shield, either to remove a native oxide or to contaminate intentionally the surface, are shown to be potential methods for increasing the amount of atomic hydrogen released. Excellent, damage free, surface passivation of thin oxides is observed by combining SHP and corona discharge, obtaining minority carrier lifetimes of 2.2 ms and J0 values below 5.47 fA/cm2. This opens up a number of exciting opportunities for the passivation of advanced cell architectures such as passivated contacts and heterojunctions.

A pump is a necessary component of ORC units. Although it is simple in a principle and various pump types can be used, reality may easily bring many complications. When designing an ORC for very low power output applications (1-10 kW gross power production), problems such as leakages, mechanical and electrical losses are more significant. Using a tight and reliable pump, typically of a diaphragm type, results in extremely low efficiency, which negatively affects the overall cycle performance. We propose for micro ORC units a gear pump. Typical losses in a gear pump and their contributions with respect to issues that need to be overcome (hermetic seal requirement, reliability and overall efficiency) are described in general in the first part of this paper. The losses are volumetric, mechanical and also electrical of motor and variable frequency drive. In the second part of the paper we present the measured characteristics of the modified commercially available gear pump. The pump is intended for an ORC with a net power output of 1-10 kW. Characteristics are given for both a standalone pump and the pump coupled with an asynchronous motor. They show significantly higher efficiency than typically reported in the literature. Contribution of different losses is discussed. Mechanical losses influence operation of the pump at low pressures (lower hydraulic work but nearly constant power input) while volumetric losses at higher pressure have only small effect. The largest loss comes from electrical efficiencies of motor and variable frequency drive, especially for operation at low speed. Optimizing the operating conditions of the pump together with the motor is therefore the most important in terms of reducing pump power consumption.

The article presents the results of study on the reasonability of using radial-outflow turbines in ORC. Peculiarities of radial-outflow turbine design utilizing modern design technologies and application to ORC was considered in the first part of the paper. The second part of the paper describes the selection process of the best turbine type for a 3 MW WHR ORC power unit for an internal combustion engine. The selection was performed among different turbine types, like radial-inflow, axial and radial-outflow turbines which were designed with given boundary conditions. The advantages and disadvantages of their application were shown. Eventually, the recommendations regarding application of different turbine types for a 3 MW WHR Organic Rankine Cycle were given. For this particular cycle design, turbines of radial-outflow type were chosen. Their application enables the increase of mechanical output power by 11 % compared to original radial-inflow turbines.

Addition of a CO2 capture system to an existing power station has some impact on water consumption. CO2 capture systems require additional water for cooling and process make-up. During the past decade, a number of relevant studies have been published that estimate the increase in water use when a capture system is added to Pulverized Coal (PC), Natural Gas Combined Cycle (NGCC) and Integrated Gasifier Combined Cycle (IGCC) power generation facilities. This paper provides a comprehensive analysis of these estimates available for post-, oxy- and pre-combustion CO2 capture systems, making it possible to compare different technologies, and to better understand how adding a CO2 capture system on a power plant impacts the volume of water withdrawn and consumed. The results of this study serve to dispel myths about the use of water in CCS systems. Specifically, they challenge the generic statement that CCS systems will double water consumption, which is often reported in papers and articles. Water use estimates cannot be generalized and are very dependent on the power plant type, the CO2 capture technology and the cooling system used. The estimates indicate that for power plants served by wet-recirculating systems, the increase in actual water consumed varies approximately from 20 to 60 per cent, depending on the capture technology. For once through cooling systems the increase can be negligible, or even be negative when water recovery options are implemented.

In this paper a distributed two-stage photovoltaic system using three levels inverter for stand-alone application is treated. The maximum power point tracking based on the “perturb & observe” (P&O) approach as a control strategy of the two boost DC-DC converters is applied. In order to get the best AC voltage waveform, the space vector pulse width modulation technique is used in this paper. To maintain the two capacitors voltages of DC bus equal, a new algorithm using the load, capacitors and boost converters currents is introduced to control loop. Without introduced any system to regulate the fluctuation of the DC bus and to get a stable output inverter voltage, authors in this paper propose a proportional regulator of inverter modulation index. A theoretical analysis with a complete simulation of the system with different profiles of irradiance for each DC/DC converter is presented to prove the excellent performance of the proposed technique.

This paper presents a control scheme for variable speed wind energy conversion system (WECS) using permanent magnet synchronous generator (PMSG). The control scheme extracts maximum power from wind using maximum power point tracking (MPPT) technique. In this paper, the proposed control scheme is achieved using two back-to-back voltage source converters (VSC) with the DC-link whose voltage is to be maintained. The control scheme discussed in this paper is zero direct-axis current (ZDC) control where the d-axis stator current is kept zero. Performance evaluation of the system is carried out and detail simulation results are demonstrated using MATLAB/SIMULINK environment. The simulation results proves the effectiveness of application of the ZDC control for variable speed WECS.

The disturbances occurring in a power system induce electromechanical oscillations of the electrical generators. These oscillations, also called power swings, must be effectively damped to maintain the system's stability. The aim is to mitigate power oscillations in power systems. There is currently interest in using Thyristor controlled series capacitors (TCSC) in transmission lines for the dual purpose of altering the steady-state power flow and enhancing system stability. Thyristor controlled series capacitors (TCSC) is one of the typical FACTS device which is used to improve the voltage profile and transient stability in power system by damping the frequency oscillation in it. This paper describes an adaptive method for control of a TCSC device for power oscillation damping. In this paper, a self-tuning PI controller for Thyristor Controlled Series Capacitor (TCSC) is proposed. Simulation results illustrate the effectiveness of the proposed self-tuning controller in simultaneously damping local-mode and inter-area oscillations. Results are compared with the fixed gain PI controller and Self-tuning PI controllers.

In recent years, light emitting diode (LED) has changed the scenario of residential and commercial lighting. Day lighting applications has huge scope for power saving by use of solar photovoltaic (PV) based LED lighting with DC distribution system. In this paper, a hybrid system with combination of PV and grid power has been presented. In proposed system, PV source and grid power sourced converter (GSC) operate in parallel and both are directly connected to load. GSC is mainly used for supplying the gap between the maximum PV generation and load demand. Power converter is realised using single stage high power factor grid-source converter (GSC). Maximum power point (MPP) of PV source is tracked by incremental conductance (INC) algorithm and used as feedback to control power from utility bus to load. Proposed topology is validated using 150 VA laboratory prototype and results of experimentation are given in the paper.

Pre-insulated district heating pipes (DHP) have been in use during the last forty years. Many improvements and development have been done in the system. However, life-time prediction is still an uncertain issue. This paper is a part of a bigger project with the objective to determine mechanisms related to the deterioration of the mechanical and insulation properties of pre-insulated heating pipes as a result of ageing. The focus in this project is on degradation mechanisms of the PUR material at high temperatures. In this paper some results of the two types of exposure are presented. The first type comprises a condition where the new pipes are subjected to accelerated ageing at three different temperatures. The second type comprises condition, when the PUR material itself is aged in different atmospheres in order to identify different degradation mechanisms. The chosen ageing temperatures in the first condition were 130°C, (close to the supply temperature), 150°C and 170°C, (accelerated ageing temperature in EN 253 [1]). Changes in thermal insulation and the adhesion force between the PUR and the steel pipe were evaluated using the transient plane source (TPS) technique and the SP plug method respectively. The results of ageing show that the degradation of PUR is a multi-stage process composed of a rapid change in properties followed by a plateau phase which changes later to a gradual deterioration of the properties. The results of the PUR material exposure at 150°C in air and in nitrogen showed significant differences in the degradation characteristics between the two environments as were revealed by DSC and FTIR methods.

This paper presents experimental evaluations on the performance of a hybrid energy storage system to supply urban electric vehicles. The paper starts with a description of nickel chloride batteries and electric double layer capacitors with details on their related advantages. Then, a laboratory test bench is presented to experimentally evaluate the performance of the realized hybrid storage system, obtained through a controlled DC/DC bidirectional power converter, supplying an electric power-train in real operative conditions on standard driving cycles. The main results of this study shows the importance of using that power converter to take advantage of the power characteristics of the super-capacitor and to easily implement on board energy management strategies to increase the whole vehicle performance.

Along with the development of the Hybrid Electric Vehicles (HEVs), the permanent magnetic synchronous motor (PMSM) and the planetary gearbox is widely used because of its high power density. There is much significant electro-mechanical coupling phenomenon in the mechanical installations. The aim of this paper is the analytical study of a planetary gearbox by using the stator current signature analysis in the PMSM based on the electro-mechanical coupling mechanism. This paper proposes a mathematical framework based on the electro-mechanical coupling model of the PMSM-planetary gearbox system, considering the load torque oscillation and the time-varying mesh stiffness. The model simulation result shows that from the mathematical framework, the load torque oscillation frequency and the time-varying mesh stiffness frequency can be predicted through the current frequency. The proposed mathematical model is verified by the model simulation. And a test-bed based on a 60 kW three-phase PMSM connected to a planetary gearbox has been used. Fourier transform is applied to the demodulated torque signal and current signal for denoising and removing the intervening neighbouring features.

This paper presents the description and operation of solar powered heat engine for water pumping operation. The heat engine model has been developed to deliver 2L per stroke and at operating head of 5 meters. The design of the heat engine is based on thermal water pump cycle and uses organic working fluid. Working fluids like acetone and n-pentane were tried during the experimental investigation. The heat engine operates between 30 °C to 100 °C temperature. The major part of this paper reports the design of the heat engine, recognition of problems occurred during the actual operation of the system and finally the material compatibility test. Thermal performance test results have been presented with recommendations for further improvement.

This paper is an introductory prospect and experiment of generated force measuring of applying two-phase nozzle and an impulse turbine design for trilateral flash cycle heat engine. In this concept of trilateral flash cycle (TFC), pressurized working fluid (Isopentane) being heated by low temperature hot water and pumped through a two-phase nozzle to impact the impulse turbine blade. Then the generated force, measured by a load cell behind the turbine blade and isentropic efficiency of nozzle is discussed. Based on the investigations carried out so far, there is a high potential of power generation from low temperature heat recourses. Further the basic working principles of power generation system are presented followed by of the governing equations and the thermodynamics. The theory of this paper calculates isentropic efficiency of the nozzle based exit speed of the working fluid out of the nozzle and experimentally measured generated force from lab scale test rig. The initial results from experimental test shows, promising isentropic efficiency for the novel system is around 45%. Also it was observed that the trust generated force increased from 2.5N to 5N by increasing the working fluid temperature from 30°C to 70°C respectively.

The paper deals with some aspects related to the shape of an indoor surfing platform for an aqua park. The authors have proposed a method and a strategy to modify the shape of the platform in order to be suitable for different types of surfers, beginners or advanced. The membrane is basically a water mattress consisting of 6 independent cushions attached to one another, that will allow different inflation pressures, hence different slopes on the upper surface of the elastic membrane. The scope of the paper is to provide an answer to the questions what is the inflation/deflation time of the mattress and what is the energy consumption for this operation. Thecomputationshave been conducted using EPANETfreewareand the results have shown a total time of initial expansion of more than 3 hours, an inflation/deflation time around two hours and one hour respectively. The total energy consumption resulted of about 2.4 kWh for the initial expansion stage and 1kWh for the inflation stage.

This paper discusses some of the findings from a InnovateUK funded Building Performance Evaluation programme project, which finished in 2015, at a micro-community, of Low Carbon Dwellings in Wales, UK. The paper focusses on the 12 month (July 2013 to June 2014) monitoring of the buildings, in terms of temperature (external and internal) and performance of the heating systems. The case study micro-community consists of nine and four low impact single storey flats and two storey houses respectively. All the units at the scheme use exhaust air source heat pumps (EASHPs), deemed by their manufacturer to be smart efficient heating systems which are used extensively in Scandinavia to provide hot water and space heating needs, coupled with underfloor heating. The EASHP is a heating system that supposedly requires little human intervention for sustainable operation. The project monitoring and reporting completed in 2014 and 2015 respectively, and the findings discussed in this paper demonstrate that the installation, commissioning, operation and maintenance of the EASHPs has not been as-designed, such that a Performance Gap exists and is less than ideal for a sustainable future. Indeed, the weaknesses are multi-facetted including foremost the thermal performance of the component elements. This paper will be of interest to building services engineers, architects, housing associations, developers, building contractors, academics, policy makers and the manufacturer of the EASHP.

Energy optimisation and CO2 emission reduction cannot be achieved without a holistic analysis of transportation. This research performs a critical analysis of the China 2050 Pathways Calculator with emphasis on its ability to assess long-term energy optimisation and sustainability of the energy-dependent transport sector. It focuses on the structure, methods, assumptions and the energy mix, with emphasis on its application to the transportation system in China. Employing a hybrid energy flow- and meta-analysis, the paper holistically aims to find the relative quantitative importance of mitigation options in each set indicators available for energy optimisation in transport pathways. It compares the combined energy flows (input/output) data and assumptions by applying the formula Pw=kTI to identify the number of pathways (including energy-mix) available in the transport stream of the Calculator – holding all other sectors and their trajectories at default where k=1. Initial results indicate that there are 262,144 ways for selecting transport pathways alone. The framework of analysis and implicit normative assumption determine the focus of mitigating options, in terms of both descriptive emphasis and qualitative evaluation. The usefulness of predicting future energy-mix transformation for all energy-dependent sectors of an economy cannot be overemphasised. However, the huge data set needed and time required to gather such data, if available, to build the model creates too much room for assumptions that could mar the credibility of the outcomes. This research considers the cost involved to build such an integrated model to be a “turn-off” for most policy makers to start such an endeavour. Stemming from the lapses identified in the China 2050 Pathways Calculator, this paper suggests that considerable refinement should be made to the various assumptions in the trajectories to reflect achievable energy/climate change targets by 2050. Also, policymakers should develop an affinity for patience and be committed financially in the search for improved scientific solutions toward energy optimisation and GHG emission reduction.

The authors discuss in this paper the potential of a micro gas turbine (MGT) combustor when operated under unconventional conditions, in terms of variation in the fuel supplied. The authors’ expertise in the field of micro-combustor has addressed, in recent years, some topics of current interest, as the fuelling with gaseous and liquid biofuels and the NOx reduction through the optimization of the combustor. While the previous authors’ works were mainly referring to a tubular combustor of a 100kW MGT, the present proposal deals with an annular, reverse flow combustor of a 30kW MGT. In this case the particular location of both the injectors and of the secondary and diluting holes allows the combustor process to develop under nearly RQL conditions. This is of special interest when supplying the combustion chamber with low LHV fuels. In addition, recent authors’ papers have demonstrated that the integration of the MGT with a solar field leads the combustor to require a decreased fuel/air equivalence ratio because of the higher air entry temperature. Under these aspects, the existence of a Rich region within the combustor may be helpful for the early phases of the oxidation process. The pollutant formation rates should be effectively controlled by the secondary (Quick-mix) and diluting (Lean) air flows. The authors’ methodology relies on an advanced CFD approach that makes use of a reaction scheme coupled with an accurate study of the turbulent interaction of the reacting species. Extended kinetic mechanisms are also included in the combustion model. A preliminary set-up of the model will be based on the combustion analysis with boundary conditions provided by thermodynamic analysis of the micro-turbine. Several computational examples are discussed, namely: - The analysis of the combustor response with reduced equivalence ratios or changes in the inlet air conditions; - The comparison of combustion efficiency and pollutant production with different fuels.

The structure, cooling principle and operation characteristics of transformer split type cooling system was different from conventional cooling systems. Such as the research work of simulation test equipment in the field was few, causing a lack of scientific basis for the equivalence of simulation test, and parameters set of split type cooling system without scientific and professional analysis. The result is that so many features and operation characteristics were not fully grasped before. Therefore, it was necessary to carry out the corresponding research work. The experimental study was carried out in this paper. This paper would research the simulation test method of split cooling system based on a 10kV distribution transformer. The test device can realize the flexible regulation for the vertical and horizontal position. According to the temperature-rise test method of transformers, performance test of split type cooling system was carried out based on the change of oil flow or radiator location. Finally, the research results of different pipe diameter, height and horizontal distribution were proposed. The study would provide more references for operation instruction of large power transformer's split type cooling devices.

Fatigue of the cell interconnectors is one of the main reasons for module failure. Especially with respect to module application in extreme climates new demands on solar cell interconnectors will arise. Optimizations in the manufacturing process to generate a product demand related microstructure are a key to improve the material behavior of interconnectors with respect to extreme climate loading conditions without increasing costs. For achieving this goal several aspects were considered in this paper: Influence of the annealing process on the fatigue behavior: Due to an optimization of the annealing process an increase in ribbon fatigue strength by a factor of four could be achieved. The effect consists of two parts: Firstly, annealing influences the geometrical shape generated during the fatigue experiment. Secondly, it affects crack formation and crack growth during fatigue. Influence of temperature on fatigue behavior: an increase in temperature leads to a significant reduction in fatigue strength (from 25 to 100 °C by factor 3). This results from increased dislocation creep at higher temperatures. Microstructural comparison of fracture patterns: The loading amplitude determines the roughness of the fracture surface: Smaller amplitudes lead to a coarser surface structure. This is important to compare accelerated lifetime testing in the lab and modules failures from the field. Simulation of temperature and microstructure dependent fatigue for lifetime prediction: Exemplarily it will be depicted how optimized fatigue behavior in the lab translates into real module lifetime under extreme climate conditions. Despite the actual numbers which show the potential of the approach, but could vary from sample to sample, the focus of the paper is the method itself and its physical background.

Solar distillation is a widely researched option for producing potable water in water-starved regions of the globe. Despite its technical simplicity and easiness-to-use, its efficiency has not sufficiently improved to promote its widespread use. The reasons for relative inefficiency of solar distillation are poor energy harvest at solar collectors, poor utilization of the harvested energy for evaporation of the water and suboptimum condensation of the humidified air in the condenser. A novel concept of solar still attempts to optimize the humidification-dehumidification cycle of a solar distillation unit to address these issues related to solar distillation units. The system works in a closed air open water humidification-dehumidification cycle. The energy source is solar irradiation, which heats up an air-water mixture. The driving force in the system is a small suction pressure induced in the system due to an aerator attached to the water inlet. A helical coil dehumidifier achieves efficient dehumidification in the system. The current paper describes experiments conducted to improve the efficiency of the dehumidifier attached to the novel solar distillation unit by optimizing the design parameters. The dehumidifier has the shape of a helical coil heat exchanger, which is cooled by the relatively cold water from a reservoir, which conversely, is heated by the heat of condensation. Even though there are sufficient studies on the design parameters of general helical coil condensers in literature, few studies are done to study their use in a humidification-dehumidification cycle involving non-condensable air. Further, a detailed parameter study of the helical coil dehumidifier is not yet done. The current paper discusses the various design parameters of a helical coil dehumidifier working in conjunction with a solar distillation unit as described above. Different design parameters of a helical coil dehumidifier discussed in this paper are pitch and diameter of the helical dehumidifier. Design insights for helical coil dehumidifier are thus obtained. The study reveals that the overall efficiency of a solar humidification-dehumidification cycle of a solar distillation unit could be considerably improved by optimizing the design of the helical coil dehumidifier used therein.

In this paper, we examine the ability of a hydropower cascade to balance variability from wind power. We consider a coordinated hydro-wind system that satisfies a single power balance, and we use a real-time control scheme to optimize system operations such that wind and load curtailment is minimized. The control scheme considers system hydraulics (including dynamic tailrace elevations and water travel times) and system constraints. Generation from an individual hydropower plant is modeled using a convex piecewise planar approximation. We give results from a case study involving hydro and wind power in the Pacific Northwest region of the United States. The objective of this paper is to present a framework for evaluating how the regulation of wind generation affects hydropower operations. Our intention is to use this framework in future work to perform a systematic study of balancing capability across different hydraulic conditions, system constraints, and wind generation scenarios., Energy Procedia, 87, ISSN:1876-6102, 5th International Workshop on Hydro Scheduling in Competitive Electricity Markets

Nowadays, the development of new power plants capable of effectively using non-conventional energy sources is strongly desirable in order to obtain a significant reduction in costs of energy. In this regard, this paper proposes a new small scale (about 100 kW) combined cycle plant which can be fired externally by any kind of biomass. Particularly, the research activity presented here is concerned with the preliminary design of this innovative plant, which will be built, by means of a project funded by “Apulia Region”, at the LabZero Research Centre of Polytechnic University of Bari in the south of Italy. The goal of the paper is to demonstrate the effectiveness of the plant in terms of energy efficiency and availability and reliability of its components. The plant is mainly composed of a centrifugal compressor and a centripetal turbine of an automotive turbocharger, with the working fluid (clean air) being heated in a high temperature heat exchanger (HTHE) by using hot flue gases produced in an external combustion chamber burning biomass. The clean hot air expands in the turbine and then feeds the combustion chamber, where biomass is burned. In order to increase the efficiency, the flue gases exiting the HTHE are delivered into a heat recovery steam generator to generate water steam which can finally expand through a rotary actuator. Two configurations, employing an open Rankine cycle and a close one respectively, are analysed, and the use of biomass is compared with methane.

The paper presents data resulting by the preliminary experimental campaign performed on a micro CHP (combined heat and power) pre-commercial version (5 kW el ) designed for dwellings. The engine employs the lubricant oil as the jacket coolant to simplify the heat recovery architecture and it was equipped by a condensing heat exchanger as well. The tests have been carried out at rated and partial load up to 2.9 kW el (59% of rated load) in condensing mode, fuelling the NG engine with hydrogen percentages equal to 0% vol. and 15% vol. In order to evaluate the CHP energy performance, the analysis was conducted for 160 h, using an alkaline electrolyser for hydrogen production, a static heat meter and two mass flow meters for both hydrogen and NG. The aim of this paper is to illustrate how the use of the hydrogen enrichment in a micro CHP plant, based on ICE technology, represents a foreseeable bridge solution to the forthcoming SOFC deployment.

From 1950 until 1975 approximately 1.3 million apartments were built in Sweden. Now, a considerable part of these are in need of renovation. This paper is part of an evaluation of a new DCV system developed especially for the renovation of these houses. The DCV automatically regulates the air change rate for each dwelling based on measurements of the indoor air. One of the measured parameters is the moisture supply. Simply put, the ventilation rate increases when the measured moisture supply exceeds the set point based on a PI-controller. In this paper, simulations have been carried out to determine an appropriate set point for the moisture supply for avoidance of moisture damage on biological building materials. A worst case scenario has been considered – and the general maximal set point is recommended to be 3g/m3.

International audience; This work addresses the use of humidity controlled ventilation with high buffering capacity building envelope. The humidity controlled ventilation rate is associated to the level of moisture in rooms. This paper fits into the idea of reducing the building energy consumption by reducing the duration of air ventilation rate which is usually quite high. This solution is not without consequences on building because it presents a risk of deterioration of indoor air quality (e.g. non evacuation of VOC) and apparition of mold. This paper aims to enhance water inertia of building walls in order to reduce the ventilation rate and study the risk associated with moisture excess. It is achieved for different scenarios of in-house production of vapor which can be met in reality and for different cases.

In this paper, a 300 Hz pulse tube cryocooler (PTC) driven by a double-acting thermoacoustic heat engine (DATHE) has been studied. A double-acting thermoacoustic heat engine incorporates several travelling-wave heat engine units, which are serially connected in a loop. Compared with the conventional thermoacoustic heat engine which involves a travelling-wave loop and a resonator, it has advantages of compact size and potentially high thermal efficiency. In this paper, a DATHE-PTC system was designed, optimized and studied in detail. Firstly, numerical simulation was conducted to design the system and optimum structure parameters of the system were obtained. With the operating condition of 4 MPa mean pressure and 300 Hz working frequency, a cooling power of 7.75 W at 77 K and a relative Carnot efficiency of 11.75% were achieved. In order to better understand the energy conversion characteristics of the system, distributions of key parameters such as acoustic work, phase difference were presented and discussed. Then, the coupling mechanism of the system was investigated. In addition, the influence of mean pressure on the system performance was studied.

In this paper, the high efficiency Cu(In,Ga)Se2 (CIGS)-based solar cells solar cells was analyzed and designed by SCAPS-1D software. This paper deals with the influence of a buffer layer on the performance of the CIGS-based solar cells. The photovoltaic parameters have been calculated in different buffer layer materials (CdS, ZnS, ZnSe), we give great alternative for Cadmium sulphide (CdS). Starting with a good structure, we simulated the J-V characteristics and showed how the absorber and buffer layers thickness, defect density influence the short-circuit current density (Jsc), open-circuit voltage (Vco), fill factor (FF), and efficiency (η) of solar cell. The optimized solar cell shows an efficiency of > 22% under the AM1.5G spectrum and one sun.

This paper develops an optimal control strategy for power dispatch of the grid tied photovoltaic (PV) - battery-diesel system to power heat pump water heaters (HPWH). The system comprises of the PV modules, grid, battery, HPWH, diesel generator (DG) and other domestic appliances. The PV can simultaneously feed-in the excess power to the grid and supply the loads. The battery is used as storage of cheaper-to-buy off peak grid energy dependent on the time-of-use (TOU) electricity tariff whilst the DG is a backup power source. The objective function of model is to minimize energy and fuel cost while maximizing PV energy trade-off for incentives. The TOU is an important control parameter in the model. The power flows from each source are the control variables. The optimal control showed a great potential for the realization of a practical net zero-energy building and as well as for demand side management, since the model meets both technical and operational constraints. A case study is done based on 3x16 kW HPWH installed at Pretoria hotel in South Africa. Simulations run over year on selected seasonal dates using the actual measured demand of the HPWH. The optimal control problem is solved using mixed integer nonlinear program and the results show how TOU affects the power dispatch to the HPWH. The energy and cost savings are presented in this paper.

In this paper, the prototype of a compact and small scale HCPV system with two-axis tracking mechanism for building integration purposes is presented and the experimental measurements are reported. The system is composed of 4 groups of optics and photovoltaic cells, each containing 8 receivers. The cells are triple junction III-V (Ga 0.5 In 0.5 P, Ga 0.99 In 0.01 As and Ge) and they have a circular shape with an active area of 4.15 mm 2 . The optics consists of a primary and a secondary optics: the former is a PMMA square Fresnel lens (75 mm – side) with constant pitch; the latter is a refractive optics (RTP) realized with dielectric material, that i) improves the light homogeneity on the cell area, ii) reduces the negative effects of the sun-tracking misalignment and iii) increases the concentration ratio. The overall geometrical concentration ratio is 1300x. The two-axis tracking system is a tip-tilt type driven by three stepper motors, one for the tip movement and the other two for the tilt movement. The alignment with the sunrays is guaranteed by an algorithm that controls the electrical motors. The HCPV prototype was tested at the Engineering Faculty of Universita Politecnica delle Marche in Ancona, Central Italy. The aim of the paper is to present the performance results, both simulated and experimental, of two different secondary optics and to assess the effect of the distance between the primary and the secondary optics on the concentration efficiency. In addition, two different solutions for the 3J cell receiver where tested, the Insulated Metal Substrate technology (IMS) and the Direct Bonded Copper (DBC). The electrical I-V curves are presented in order to assess the performance of the CPV system using the two different solutions. The experimental tests are realized under real outdoor operating conditions, therefore also the direct normal radiation (DNI) was taken into account.

The tunnel oxide passivated contact (TOPCon) is a promising technology improving the efficiency of Si solar cells by cutting recombination losses and simplifying the solar cell design (1D junction design). The objective of this paper is to investigate possible contact materials having a high/low work function for passivated contacts thereby enabling the realization of a double-sided contact Si solar cell featuring n-type TOPCon on the front and p-type TOPCon at the rear side. The main part of this paper deals with the eligibility of thin atomic layer deposited (ALD) AZO (aluminum doped zinc oxide) interlayers sandwiched between n-TOPCon and ITO (tin doped indium oxide) in order to avoid sputter damage. It will be demonstrated that the insertion of ALD AZO improved the efficiency by 0.8% abs. and lead to a maximum efficiency of 20.2%. Finally, WO x and MoO x which have a high work function are identified as promising contact layers for p-TOPCon.