Energy Efficiency Rate Research Articles

Energy Efficiency of Desalination: Fundamental Insights from Intuitive Interpretation.

Desalination has become an essential toolset to combat the worsening water stress resulting from population and industrial growth and exacerbated by climate change. Various technologies have been developed to desalinate feedwater with a wide spectrum of salinity. While energy consumption is an important consideration in many desalination studies, it is challenging to make (intuitive) sense of energy efficiency due to the different mechanisms of various desalination processes and the very different separations achieved. This perspective aims to provide an intuitive, thermodynamics-based interpretation of energy efficiency by illustrating how energy consumption breaks down into minimum energy of separation and the irreversible energy dissipation. The energy efficiencies of different desalination processes are summarized and rationalized based on their working mechanisms. Notably, a new concept called the minimum mean voltage is proposed as a convenient tool to evaluate the energy efficiency of electrochemical desalination processes. Lastly, the intrinsic trade-off between energy efficiency and desalination rate and the relevance of energy efficiency in different desalination applications are discussed.

A The Analysis of Energy Efficiency and Emission Rate of a Cookware coated with Enamel Material

Metal cookware has been used many people for its better thermal conductivity. However this material also has some weaknesses for its reaction with acidic food which will contaminate the food. Metal-base material coated with enamel is one of the solutions. The hard and non-reactive surface has cause this material has been widely used for processing food. Lower thermal conductivity is one of the problems of enamel cookware. The experimental analysis has been conducted to investigate energy efficiency, emission rate and thermal conductivity. The efficiency is calculated by comparing the useful energy (work) with the input energy. The emission rate is calculated by multiply energy consumption with emission factor. Meanwhile the thermal conductivity is calculated by using simply conduction heat transfer equation. Based on the analysis, enamel cookware has much lower thermal conductivity than aluminum cookware. However this physical property does not much affects the efficiency. The most dominant factors which should considered are type of fuel and technology of stove which consume higher energy inefficiently and emits much higher hazardous gas

A Novel Reliable Adaptive Beacon Time Synchronization Algorithm for Large-Scale Vehicular Ad Hoc Networks

The time synchronization in vehicular ad hoc networks (VANETs) has gained significant attention in recent times. In this paper, we focus on the time synchronization in large-scale VANETs and propose an adaptive beacon time synchronization (ABTS) algorithm to enhance timing message synchronization. ABTS algorithm selects the best time synchronization pairs to decrease the number of timing messages transmitted. To guarantee the reliability of synchronization, the clock offset of the connected vehicles periodically readjust to provide a better degree of synchronization accuracy with minimum energy consumption. Based on two-way timing message synchronization, we derive maximum likelihood (ML) estimation and its equivalent Cramer-Rao lower bound (CRLB) for clock offset design in the generalized sender-to-receiver system by assuming a Gaussian noise model. We propose node pair selection algorithms to improve pairwise beacon message timing synchronization. The simulation results validate that our proposed ABTS algorithm performs better than other protocols in terms of synchronization accuracy, the rate of convergence and energy efficiency.

Hybrid Pre-Coding Based on Minimum SMSE Considering Insertion Loss in mmWave Communications

Hybrid pre-coding design is a promising research direction in large antenna array millimeter wave (mmWave) systems. The insertion loss is an inherent and significant feature of hybrid pre-coding, resulting in lower energy efficiency and inferior bit error rate (BER) performance. This paper takes the minimum sum-mean-square-error (Min-SMSE) considering the insertion loss as the optimization objective function, which aims at increasing the sum-rate and improving the BER performance. Then a hybrid pre-coding is designed based on this criterion with an adaptive overlapped subarray (OSA) architecture. It is proved that the optimization problem is non-convex. Thus, we decompose the optimization problem into two sub-optimum ones. One is to design the digital pre-coding based on the Min-SMSE criterion under the equivalent channel condition. The other one is to design the analog pre-coding based on the simplified Min-SMSE with the insertion loss objective function. Theoretical analyses of the proposed scheme are conducted, including the upper bound of the average BER, the lower bound of the average sum-rate, and the computational complexity. Simulation results show that our proposed scheme outperforms three representative hybrid pre-coding schemes with different architectures in both BER and sum-rate, when the numbers of the phase shifters and combiners are relatively small.

Performing Analysis of Quality of Service Parameters of 4G Long Term Evolution in Health Care System

Long Term Evolution (LTE) is a leading 4G wireless broadband technology developed by the Third Generation Partnership Project (3GPP) Release 8. LTE is expected to provide very fast, highly responsive and cost effective data services and appears itself to be the right technology at the right time. LTE is becoming an ultimate choice for 4G services around the world due to its higher data rates and lower latency objectives. E-Health services comprise a wide range of healthcare services delivered by utilizing information and communication technology. In order to help existing and emerging e-Health services over converged next generation network (NGN) architectures, there is a need for network QoS control mechanisms that meet the often stringent requirements of such services. The mobile Health (m-health) is currently uniting major academic research worldwide to achieve innovative arrangements in the areas of healthcare. However, there are several challenges and issues that need to be addressed. In this paper we have proposed m-health care system based on 4G LTE network communication instead of existing 3G communication system. We will be monitoring QoS parameters like Delay, Throughput, Jitter, Energy Efficiency and Packet Data Rate for comparing 3G and 4G LTE usage over health care applications. We will further experiment the parameters with graph based analysis.

Solar tracker platform development for energy efficiency improvement of photovoltaic panels

Solar energy systems have emerged over the last decades as the cleanest and most abundant renewable energy resources available worldwide. Solar trackers are devices specially developed to enhance the energy efficiency of solar energy systems. This paper presents the design and implementation stages of a reconfigurable hardware technology-based two-axis solar tracker platform, specially conceived to improve the energy efficiency of photovoltaic (PV) panels. The main module of this platform is the NI MyRIO ready-to-use development system built upon a high-performance Field Programmable Gate Array (FPGA) processor that controls the entire solar tracker unit. Optimal tracking of the sun movement and obtaining the maximal energy efficiency rate is achieved by simultaneous real-time controlling both the captured sunlight intensity and PV cell temperature magnitudes. In this way, a robust and versatile positioning system has been developed that performs a high precision and accurate tracking pathway. All the control algorithms are implemented there under the LabView graphical programming software toolkit. The final solution boosts in a useful and modularized tracking system that looks useful in a wide range of applications both in industrial and domestic project sites with different power scales.

Exergy, exergoeconomic and enviroeconomic analysis of a building integrated semi-transparent photovoltaic/thermal (BISTPV/T) by natural ventilation

Different parameters could contribute to the performance of Building Integrated Semi-Transparent Photovoltaic/Thermal (BISTPV/T) systems, for example amount of incident radiation, the location, the degree of semi-transparency of the PV system, orientation of the collector surface, and the mode of ventilation of the air within the double-skin façade (DSF). Nevertheless, the performance of the system could not be solely depended on energy efficiency but has to be analyzed in its entirety. Thus, exergy efficiency must be examined as well. The present work studies the exergy, exergoeconomic and enviroeconomic analysis of BISTPV/T system by natural ventilation. For a given meteorological conditions, the energy and exergy efficiency, net and ratio loss rate, CO2 emission and enviroeconomic reduction are calculated by solving a set of energy and exergy formulations. The results depicted that the BISTPV/T exhibits greater energy and exergy efficiency than the opaque BIPV/T, thus creating lower loss rate and eventually better impact economy and environment.

High efficient solar evaporation by airing multifunctional textile

Solar evaporation is important for many applications such as desalination, power generation and industrial drying. Recently, some studies on evaporation reported obtaining high energy efficiency and evaporation rate, which are based on floating evaporation setup (FES) with nanomaterials. Here, a new cheap and simple setup is proposed, named as airing evaporation setup (AES). Compared to FES, there are four advantages of AES: a better thermal design, a higher energy efficiency, a higher material utilization ratio, and multi-function. It shows that the energy efficiency of AES reaches up to 87% under 1 kW/m2 of solar irradiation, which is 14% higher than that of FES. Meanwhile, the total evaporation rate of AES is about 20% higher than that of FES. The theoretical analysis reveals that the main reason for a better performance of AES is the increasing evaporation area. More interestingly, AES could be used for designing portable systems due to its simplicity and flexibility. Furthermore, it is shown that AES and the corresponding wick material can be used in solar desalination, textile quick-drying and warm-keeping.

Cathodic hydrogen recovery using Y zeolites loaded nickel(II) Oxide instead of Pt/C in microbial electrolysis cell

ABSTRACT A highly efficient electrode material is required to explore and apply to microbial electrolysis cell (MEC) with high hydrogen evolution reaction (HER) efficiency. Pt/C was one of the most efficient catalysts for hydrogen production in current lab research, but it was expensive and some chemicals in wastewater were prone to Pt poisoning, which was a great limitation in application. Thus, a cheap and effective nickel(II) Oxide/Y (NiO/Y) material was prepared by using Y zeolites as carrier loaded with NiO in this study, which was used in MEC to evaluate the hydrogen evolution performance in comparison with Pt/C. The results indicated that NiO/Y composites showed a competitive HER performance to Pt/C. The linear sweep voltammetry (LSV) tests and Tafel plots showed that the NiO/Y composites exhibited the best catalytic activity for HER. In the MEC tests, the NiO/Y composites cathode was comparable with the Pt/C cathode in terms of current densities and energy efficiency. The coulombic efficiency, cathodic energy efficiency rate and hydrogen production rate obtained with NiO/Y cathode MEC was 85.88 ± 6.5%, 228.39 ± 3.2% and 0.83 ± 0.05 m3/m3d under, respectively, which were slightly higher than those obtained with the Pt/C cathode MEC. It was concluded that even with the cheap Y zeolites as the supports, the NiO/Y materials showed the superior performance, which was attributed to a good dispersing of the active component of NiO on the large specific surface area of Y zeolites and the fast escape of hydrogen bubbles from microporous and mesoporous structure of Y zeolites.

Energy Efficient Beamforming for User-Centric Virtual Cell Networks

This paper aims to design beamforming vectors and cluster formation scheme by formulating an energy efficiency (EE) maximization problem in the user-centric networks, where several multi-antenna access points (APs) form a virtual cell to serve each single-antenna user equipment (UE). Considering both rate requirements and power budgets, we study the feasibility of the original EE maximization problem. To verify the feasibility, we design a max-min rate problem. Then, instead of solving the original problem directly, we deal with two subproblems: 1) relaxed EE maximization subproblem and 2) total power minimization subproblem. Through applying the weighted minimum mean square error (WMMSE) approach, we first transform the nonlinear data rate expression into a quadratic form and then solve each subproblem via using the Lagrangian dual method, which fortunately has closed-form solutions. Moreover, a novel threshold forming scheme is proposed for AP cluster formation and a simple but effective method called K-dimension grid search is devised to obtain the near-optimal threshold. The extensive simulation results indicate that our proposed algorithm converges fast and is robust to the simulation environment. In addition, the proposed algorithm outperforms the benchmark algorithms greatly in terms of EE and data rate.

Secure and Energy Efficient Trust Aware Routing Protocol in IoT using the Optimized Artificial Neural Network: SEETA-IoT

Nowadays, Internet of Things (IoT) has been widely used in many areas such as surveillance of battlefield, controlling of industry, pipeline monitoring, ecological monitoring, healthcare and medical science, defense and military affairs, etc. To make better IoT based applications, secure routing plays an imperative responsibility for Device-to-Device (D2D) data packet transmission. The most essential inventiveness behind this research is to design a Secure and Energy Efficient Trust Aware (SEETA) routing protocol in terms of detecting the fail/malicious nodes by utilizing the Artificial Neural Network (ANN) using Particle Swarm Optimization (PSO) Algorithm. To discover a secure and energy-efficient route, the trust-based approach is integrated with GOA and ANN. Therefore, this research focuses on the security enhancement of the IoT network using the concept of trust-based route maintenance mechanism. In IoT networks, communicating sensor nodes have limited energy resources and a rapid energy reduction of communicating nodes leads to the creation of energy holes in the network. To overcome this problem, an energy-efficient mechanism of trust aware approach is also one of the essential objectives of IoT routing protocols. To avoid unnecessary network failure and extra energy consumption rate, we had designed a model using the concept of PSO based ANN with a novel fitness function and for involvement in the routing process, sensor nodes should fulfill the fitness criteria; otherwise, the system considers as affected communicating nodes. From the experiments conducted, it is proved that the proposed SEETA routing protocol using the PSO and ANN, achieves significant performance improvement over the existing schemes in terms of security, energy efficiency and packet transmission rate. Besides, SEETA routing protocol also reduces the number of intermediates nodes in D2D route discovery mechanism for IoT networks which helps to decrease the energy consumption rate and also offers a proficient approach to discover secure routing support with maximum routing capacity and end to end data transmission rate. The QoS performance parameter of our routing protocol is analyzed with standard and existing work with several routing protocols and the experimental results validating the concept of optimized ANN. The experimental results indicate that the introduced SEETA routing protocol provides 8.74% less energy consumption rate and high data delivery rate and data delivery rate is improved by 92% as compare to exiting works.

RESEARCH OF THE DIRECTIONS OF IMPROVEMENT OF PLATE EXCHANGER HEAT EXCHANGERS

The article provides an analysis of the known schemes of plate heat exchangers, their advantages and disadvantages, as well as areas for improvement. Taking into account the results of the analysis conducted in the department of dairy products of the Institute of Food Resources of the National Academy of Agrarian Sciences of Ukraine, the All-Ukrainian Scientific Research Educational Consortium, the authors developed an improved plate heat exchanger scheme, which combines high reliability, energy efficiency and heating rate of the coolant with simplicity, compactness and low construction cost, with ease of maintenance and repair (easy disassembly and cleaning). The dependences for the calculation of the main design and operating parameters of an improved heat exchanger are given.

Thermoeconomic analysis and optimization of a solar micro CCHP by using TLBO algorithm for domestic application

ABSTRACTIn the present study, a micro solar Combined Cooling, Heating and Power (CCHP) system based on Organic Rankine Cycle (ORC) is thermodynamically and exergoeconomically investigated. Adding a storage tank will lead to the sustainable supply of energy for summer and winter seasons. The model of conservation of energy, conservation of mass, and conservation of linear momentum are applied in order to energy analysis, while a model based on the first and the second laws of thermodynamics are used to exergy analysis. Determining the effective parameters of the system efficiency, including turbine input pressure, turbine inlet temperature, turbine output pressure, and evaporator temperature leads to improve and optimize the system performance. The Teaching–Learning-Based Optimization (TLBO), for the first time in this paper, is employed for both single-objective and multi-objective optimizations of the system for three working fluids (R123, R134a, and R245fa). The accuracy of the proposed model is validated by data presented in three different papers. For the summer season, the values of the energy efficiency, exergy efficiency, and cost rate for R123 working fluid are calculated as 24.81%, 9.94%, and 5383$/year, respectively. The implementation of the multi-objective optimization using TLBO for R123 working fluid improves 27.85% thermal efficiency, 27.66% exergy efficiency and reduces 9.90% of the system cost rate.

A review on controlled vacuum lysimeter design for soil water sampling

Abstract Measuring water movement in unsaturated soil profile is inherently difficult. Equilibrium Tension Lysimeters have been introduced for collecting representative water samples (in terms of concentration and volume). In this method, suction level in sampler container is adjusted daily with soil matric pressure. Since soil–water tension changes over time, the vacuum level of sampler has to be adjusted accordingly. Automated Vacuum Lysimeters use electronic controllers as well as a set of vacuum sensors to keep the vacuum applied to porous plates in equilibrium with soil matric pressure. Automated Equilibrium Tension Lysimeter has no direct control on matric pressure right above the sampler. Therefore, accuracy of samples is questionable. Controlled Suction Period Lysimeter (CSPL) uses a tensiometer right above water sampler to address this issue. This method seems to be the most reliable method for collecting soil–water samples. However, it has some issues such as low energy efficiency and slow tensiometer response rate. In this review paper, different methods of measuring water movement in unsaturated soil profile are summarized and compared. A low resistance set up and a new controlling algorithm are suggested to significantly increase energy efficiency and accuracy of the system.

Asynchronous distributed optimization via dual decomposition for delay-constrained flying ad hoc networks

The rapidly changing network topologies bring some challenges to optimize congestion control, routing and power control in delay-constrained flying ad hoc networks (FANETs). Traditional methods designed for mobile ad hoc networks (MANETs) underperform due to their poor adaptability to the changing network topologies. In this work, we propose an optimization framework with end-to-end (E2E) delay constraint, and formulate the problems as a utility maximization problem with respect to link capacity, E2E delay and flow conservation by coupling data flows and decomposing the E2E delay constraint. Further, to optimize such a non-linear maximization problem, we employ primal–dual decomposition and the delay scale factors to cast the maximization problem into several sub-problems with lower complexity. Subsequently, we propose a delay-constrained path selection algorithm and an asynchronous distributed optimization method which requires only the local channel information and outdated messages to optimize different parameters. Finally, to highlight the advantages of the proposed method, we further give the related analysis from the viewpoint of the different solutions of the maximization problem. Simulation results demonstrate that the proposed framework obtains significant network performance in terms of energy efficiency and packet timeout rate, compared with traditional methods.

Analysis of Quantized MRC-MRT Precoder For FDD Massive MIMO Two-Way AF Relaying

The maturing massive multiple-input multiple-output (MIMO) literature has provided asymptotic limits for the rate and energy efficiency (EE) of maximal ratio combining/ maximal ratio transmission (MRC-MRT) relaying on two-way relays (TWRs) using the amplify-and-forward (AF) principle. Most of these studies consider time-division duplexing and a fixed number of users. To fill the gap in the literature, we analyze the MRC-MRT precoder performance of an N-antenna AF massive MIMO TWR, which operates in a frequency-division duplex mode to enable two-way communication between 2M = [N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</sup> ] single-antenna users, with α ∈ [0, 1), divided equally into two groups of M users. We assume that the relay has realistic imperfect uplink channel state information (CSI), and that quantized downlink CSI is fed back by the users relying on B ≥ 1 bits per-user per relay antenna. We prove that for such a system with α ∈ [0, 1), the MRC-MRT precoder asymptotically cancels the multi-user interference (MUI) when the supremum and infimum of large-scale fading parameters are strictly nonzero and finite, respectively. Furthermore, its per-user pairwise error probability converges to that of an equivalent AWGN channel, as both N and the number of users 2M = [N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</sup> ] tend to infinity, with a relay power scaling of P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = (2ME <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> /N) and E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> being a constant. We also derive upper bounds for both the per-user rate and EE. We analytically show that the quantized MRC-MRT precoder requires as few as B = 2 bits to yield a BER, EE, and per-user rate close to the respective unquantized counterparts. Finally, we show that the analysis developed herein to derive a bound on α for MUI cancellation is applicable both to Gaussian as well as to any arbitrary non-Gaussian complex channels.

Mass transfer enhancement and improved nitrification in MABR through specific membrane configuration

One of the main energy consumptions in wastewater treatment plants (WWTPs) is due to the oxygenation of aerobic biological processes. In order to approach to an energy self-sufficient scenario in WWTPs, Membrane Aerated Biofilm Reactors (MABRs) provide a good opportunity to reduce the impact of aeration on the global energy balance. However, mass transfer limitations derived from poor flow distribution must be tackled to take advantage of this technology. In this work, in order to improve mass transfer between biofilm and bulk water, a specific configuration was developed and studied at laboratory scale, aimed at compactness, energy efficiency and high nitrification rates. Nitrification rates were higher in the innovative configuration than in the conventional one, achieving a Volumetric Nitrification Rate (VNR) as high as 575.84 g NH4-N m−3 d−1, which is comparable with confirmed technologies. Regarding energy consumption due to aeration, a reduction of 83.7% was reached in comparison with aeration through diffusers with the same Oxygen Transfer Efficiency (OTE). These results highlight the importance of hydrodynamic conditions and the membranes configuration on treatment performance.

Energy-Efficient Hybrid Precoding With Low Complexity for mmWave Massive MIMO Systems

Millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) utilizes large antenna arrays and is considered a promising technology for fifth-generation (5G) and beyond wireless communication systems. However, the high-power consumption of the radio-frequency (RF) chains makes it infeasible. To solve this problem, hybrid precoding is proposed, which is a combination of analog and digital precoding. The fully connected architecture hybrid precoding still requires a large number of phase shifters (PSs). The sub-connected architecture can greatly reduce the required power consumption, and however, it cannot obtain a satisfactory achievable rate. To avoid the high energy consumption and obtain a high resolution, we propose a novel partly connected architecture in this paper. In addition, we propose an energy-efficient successive interference cancelation (SIC) hybrid precoding based on the partly connected architecture, which transforms the problem of maximizing the total achievable rate with non-convex constraints into a series of sub-rate optimization problems. Furthermore, a low-complexity energy-efficient SIC hybrid precoding based on the partly connected architecture is developed, which uses the partial singular value decomposition (SVD) to realize the sub-rate optimization and significantly reduce the complexity. Theoretical analysis demonstrates the superiority of the proposed hybrid precoding in terms of complexity. The simulation results indicate that the proposed hybrid precoding algorithms enjoy better energy efficiency and achievable rate performance than some recently proposed hybrid precoding algorithms.

Optimal Resource Block Assignment and Power Allocation for D2D-Enabled NOMA Communication

A novel joint optimization framework for device-to-device (D2D)-enabled non-orthogonal multiple access (NOMA) networks is proposed. Our objective is to maximize the performance of the D2D communication by jointly optimizing the resource block (RB) assignment and the power allocation, by considering the SIC decoding order of the NOMA-based cellular user equipments (CUEs). We invoke the distributed decision making (DDM) framework to decouple the formulated problem into two sub-problems. For the RB assignment sub-problem with integer variables, we propose a differential evolution (DE) algorithm to obtain the optimal NOMA CUE group and RB assignment for D2D pairs. For power allocation sub-problem with continuous variables and decoding order variables, we first use a heuristic algorithm to optimize the power allocation for NOMA-based CUEs with given D2D power allocation. We prove that the power allocation for the NOMA-based CUEs is the optimal solution. We then invoke the successive convex approximation (SCA) and DE to find the sub-optimal power allocation of the D2D pairs. The numerical results validate the feasibility, fast convergence, and flexibility of the proposed algorithm, and the performance with our algorithm outperforms the conventional OMA technology in terms of energy efficiency and sum rate.

Multi-User Hybrid Precoding for Dynamic Subarrays in mmWave Massive MIMO Systems

Dynamic subarray achieves a compromise between the sum rate and hardware complexity of millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems, in which antenna elements are dynamically partitioned to radio frequency (RF) chain according to the channel state information. However, most prior works on multi-user hybrid precoding only considered the fully connected architecture or the fixed subarray architecture. In this paper, a novel multi-user hybrid precoding framework is proposed for the dynamic subarray architecture. Different from the existing schemes, the base station (BS) first selects the multi-user set based on the analog effective channel. Then, the antenna partitioning algorithm allocates each antenna element to the RF chain according to the maximum increment of the signal-to-interference-noise ratio (SINR). Finally, the hybrid precoding is optimized for the dynamic subarray architecture. By calculating the SINRs on the analog effective channels of the selected users, the antenna partitioning can greatly reduce the computation complexity and the size of the search space. Moreover, it also guarantees the user fairness because each antenna element is allocated to acquire the maximum increment of the SINR for all selected users. The extensive simulation results demonstrate that both the energy efficiency and sum rate of the proposed solution obviously outperform those of the fixed subarrays, and the proposed solution obtains higher energy efficiency with a slight loss of sum rate compared with the fully connected architecture.