Energy Consuming System Research Articles

Greywater treatment using lab-scale systems combining trickling filters and constructed wetlands with recycled foam glass and water spinach

A low energy-consuming system for greywater treatment was developed with a trickling filter (TF) followed by constructed wetlands (CWs). Roles of substrates, plants, and microorganisms were intentionally explored. TFs and CWs were filled with recycled foamed glass. Water spinach and parsley planted in the CWs provided additional value. Microorganisms in the system were characterized through carbon-utilization tests and 16S rRNA gene next-generation sequencing. In 5.5 months, TOC, TN, and TP removals from greywater were, respectively, 83.5, 85.5, and 92.1 %. TOC was removed in the TF at 22.6 g-C/m2/d. The CWs exhibited TN and TP removals at 0.44 g-N /m2/d and 0.19 g-P/m2/d. Water spinach was harvested at 792 g-wet/m2/week, accounting for 7.1 % and 12.6 % for TN and TP removals. Denitrification, microbial diversity, and carbon source utilization potentials were enhanced by water spinach. This is a sustainable wastewater treatment model by using recycled materials and edible plants.

Study of water-side free cooling technology for power lithium battery plant

Power lithium battery production process needs to consume a lot of energy. In this paper, an energy consumption analysis of a representative company was conducted, the energy consumption of the facilities that provide support for the process is higher than the energy consumption of the process equipment itself, which greatly affects the cost of battery manufacturing. Air-conditioning system as the most important energy-consuming system of the facilities, accounting for 25% to 45% of the total electricity consumption. The energy consumption of the cooling source system dominates, even in winter its energy consumption can reach 14% of the total energy consumption. On this basis, this paper analyzes the chilled-water-use characteristics of the air-conditioning terminal in winter through theoretical analysis, the chilled water temperature is therefore optimized according to the real-time outdoor humidity. The chilled water temperature is linearly increased after the humidity ratio fall below 7.5g/kg(a), reaching a maximum value of 12.1°C at 6g/kg(a). In addition, the cooling tower free cooling technology based on the optimized chilled water temperature is innovatively proposed to fully explore the energy-saving potential of the technology to achieve the energy saving of the cooling source system. TRNSYS simulation results show that after optimizing the chilled water temperature, the time period for cooling tower individual cooling under winter operating condition is extended by 60%, and cooling source system energy saving rate can reach 49.0% and the cost saving rate 48.0%, both of which are higher than 15% compared to the un-optimized chilled water temperature.

Passivity and higher-order sliding mode control for doubly-fed induction generation wind power system

To simplify the model of DGIG and improve the robustness, the variable speed and constant frequency (VSCF) DFIG wind power generation systems from the perspective of energy and robustness were studied. It was based on passivity and sliding mode control (SMC) theory. Firstly, the model of DFIG based on Euler-Lagrange (EL) equations was established, so the original DFIG wind turbine system is divided into electrical and mechanical subsystems. For two subsystems, the electrical subsystem was designed. In contrast, the mechanical subsystem is an energy-consuming system and is stable through selecting suitable design parameters. Hence, the system control algorithm is simplified. A high-order terminal SMC was designed to get a faster speed and better robustness for the speed loop. Simulation results show that the proposed controller is simple and effective. It can guarantee the wind power system outputs constant frequency. The motor speed can also track the reference speed quickly, so the performance of the wind turbine system is improved.

Prediction of thermal comfort indoors and cooling loads based on reasonable zoning using the improved HHO with multi-strategy fusion-FENN algorithm

A comfortable indoor thermal environment helps occupants work healthily and efficiently, and the air-conditioning system, as the most energy-consuming system in building operation, accurate energy modeling while balancing thermal comfort can provide effective control strategies for managers. Metaheuristic algorithms are widely optimized for various types of machine learning models for the study of data-driven. However, the majority of them currently use the default hyperparameter or random and grid search, which are prone to obtaining inaccurate prediction results. In this paper, a sizable commercial building in Shaanxi Province is used as a research sample. The regional per floor firstly is divided with business model distribution, the cross-validation of random forest and correlation analysis is used to extract features, and the input factors of the prediction model are decided, and then the fully elman neural network is optimized using a segmental fusion strategy combining Cauchy operator and reverse learning to promote harris hawks optimization algorithm, and the prediction model the IMFHHO-FENN (improved Harris Hawks Optimization with multi-strategy fusion-Fully Elman Neural Network) is trained and constructed, which is finally used for predicting thermal comfort and cooling load. According to verification results, it can be proved that the IMFHHO-FENN model has excellent performance compared to mainstream single and combined models and can provide accurate results of predicted models in the design phase of building energy efficiency and later operation management, reducing energy consumption waste while satisfying personnel thermal comfort as much as possible and supply marked theoretical and decision reference for building equipment management.

Electro-mechanical-thermal energy coupling characteristics analysis and EFMM-based energy modelling for machine tools considering dynamic thermal environment

Machine tool is an isolated thermodynamic and inefficient energy-consuming system, whose energy consumption is increasingly influenced by its internal thermal environment. While the thermal environment changes dynamically due to the complex electro-mechanical-thermal (EMT) energy conversion characteristics. Therefore, it is urgent to expound the multi-energy coupling mechanism to establish an accurate energy model for machine tool. However, the existing studies merely emphasize the electro-mechanical conversion that related to the material-removal (MR) process and fail to reveal the dynamic characteristics of energy caused by EMT, which results in inaccurate energy models. In light of this, the energy flow matrix modelling (EFMM) method, which can model the multi-energy flows automatically and accurately, is introduced to construct a generic energy balance matrix equation for machine tool, where the coupling relationship between electrical, mechanical and thermal energy are taken into consideration. Subsequently, the dynamic mechanical and thermal energy are analyzed, respectively. Based on this, the total energy consumption and cutting energy efficiency models for machine tool in a dynamic thermal environment are established. The reliability and accuracy of the constructed models are demonstrated by the case study and comparative analysis. The results indicate that the average relative errors of the proposed energy models are mostly within 5 %. The presented approach is conducive to understanding the multi-energy coupling characteristics and providing a feasible way for energy-efficient machine tools.

Experimental study and theoretical analysis on lateral stiffness of RC frame-frame truss composite wall

Two reinforced concrete (RC) frame-frame truss composite wall (FTCW) specimens with a scale of 1:2 are implemented for cyclic loading test. The test results of phenomenon, hysteretic curves, backbone curves and stiffness degradation curves are obtained, and the seismic performance of shear capacity, ductility, lateral stiffness are analyzed. The lateral stiffness of RC frame-FTCW and the horizontal displacement are mechanical analyzed, and the results are compared with the test results. The test behaviour shows that a multistage energy consuming system that FTCW works before RC frame and the internal diagonal struts work before the outer frame inside the FTCW, forming a multistage energy consumption system for the design purpose of earthquake resistant structures. The point that the embedded angle steel effectively extend the elastic stage of the internal diagonal struts and the point that the amount of FTCW is proportionateto the shear capacity and lateral stiffness are also concluded by the test results. The comparison results of lateral stiffness between mechanical analysis and test results show that the reduction coefficients in different stages and the mechanical analysis are practical and significant.

Research on Energy-saving Calculation of Navigational Lighting System Powered by Low Current in Green Airport

The airport navigation lighting system is an important energy-consuming system in the flight area. The annual energy consumption of large and medium-sized airports can reach millions of kilowatt hours. At present, the airport is replacing traditional halogen lamps with LED navigation lighting for energy conservation. For LED lighting under the traditional 6.6 A power supply system, the circuit loss is high, and the overall energy-saving effect of the system is not good. A low-current power supply energy-saving navigation lighting system is proposed. The primary cable, secondary cable, isolation transformer, and auxiliary lighting system in the navigation lighting circuit are studied by performing the energy-saving calculation of navigation lights under low currents. By building a set of navigation lighting systems to conduct energy consumption experiments and comparing them with theoretical calculations, a calculation model is proposed to provide a basis for energy-saving calculations for the application of a low-current power supply navigation lighting system.

Study on the Model and Simulation of Single-Unit Isolated Grid Operation Using APROS

In order to solve the problem of imperfect control strategy and unstable control for steam turbine rotating speed of isolated grid operation in distributed generation system, based on APROS simulation support platform, the isolated grid system is divided into steam turbine system, energy-consuming system and throttle system to construct the model of single-unit isolated grid operation. The simulation results verify the accuracy of the steady-state model. The turbine energy-consuming system model can characterize the operating characteristics of the isolated grid, and the operating characteristics of the energy-consuming system will significantly affect the speed regulation of the turbine system. The establishment of the overall model lays foundation for the design and optimization of the control scheme of the single-unit isolated grid system.

Determiantion of energy characteristics of material destruction in the crushing chamber of the vibration crusher

The crushing equipment is characterized by a significant energy-consuming system during the crushing workflow. The current trend in the development of such processes puts forward requirements for the development of new or improvement of existing energy-saving equipment. The essence of the solution to the problem in this work is determined by using resonant modes, which are inherently the most effective. The practical implementation of the resonance mode has been achieved taking into account the conditions for the interaction of the resonant vibration crusher with the material at the stages of its destruction. The degree of the stress-strain state of the material is taken into account, which was a prerequisite for identifying the potential for the development of a vibration load. Composed equations of motion based on a substantiated discrete-continuous model of a vibration crusher and processing material. An approach is applied to determine the stepwise destruction of the material with the determination of the required degree of energy. This methodological approach made it possible to reveal the nature of the process of material destruction, where energy costs at the stages of crack formation, their development and final destruction are taken into account. It was revealed that the greatest energy consumption during the operation of crushers goes into the kinetic energy of the crushing plates and the potential energy of deformation of the springs. The proposed model is common for any design of a vibration machine and its operating modes. The stable resonance mode has made it possible to significantly reduce the energy consumption for the course of the technological process of material grinding. The results obtained are used to improve the calculation methods for vibratory jaw and cone crushers that implement the corresponding energy-saving stable zones of the working process.

Seismic behavior of a replaceable artificial controllable plastic hinge for precast concrete beam-column joint

To promote and effectively control precast structures' seismic performance, a novel bending-shear decoupled prefabricated beam-column joint with a replaceable Artificial Controllable Plastic Hinge (ACPH) was proposed in this paper. The ACPH was composed of two energy dissipation systems with energy-dissipation plates for bearing the bending moment and a connection system for bearing the shear force. To explore the seismic behavior of joint affected by ACPH, hysteresis tests of two beam-column joints with ACPH and one cast-in-situ beam-column joint were carried out. It found that the ACPH can significantly affect the failure mode compared with cast-in-situ specimen while offering excellent hysteresis behavior, sufficient ductility, and superior energy consumption capacity. Even if half of the energy-consuming system fails, the ACPH still maintains remarkable seismic performance except for reduced bearing capacity. Although only the location of the ACPH has been changed, the crack development, skeleton curve, and energy consumption performance have all undergone significant changes. The bearing capacity of the ACPH specimen was enhanced with the distance between ACPH and column surface increasing, while other seismic performances were affected at different levels. Besides, the calculation model and formula of yield bearing moment capacity for the ACPH were proposed.

Improvements of Micro-CHP SOFC System Operation by Efficient Dynamic Simulation Methods

Solid Oxide Fuel Cell (SOFC) technology is of high interest for stationary decentralized generation of electricity and heat in combined heat and power systems (CHP) for the residential sector. Application scenarios for SOFC systems in an electricity-regulated mode play an important role, especially in places where an electrical grid connection is not available or rather unstable. The advantages of SOFC systems are the high fuel flexibility and the high efficiencies also under partial load operation compared to other decentralized power generation technologies. Due to the long, energy-consuming system heat-up and the limited partial load capability, SOFC systems do not reach the performance of conventional power generation technologies. Furthermore, stack thermal cycling is associated with power degradation and should be minimized. In this paper, the improvement of these drawbacks are investigated for hotbox-based SOFC systems in the 1 kWel-class for residential applications. Since experimental investigations of the high-temperature systems are limited, modeling tools are established, enabling the visualization of internal system characteristics and providing the opportunity to simulate system operation in critical regions. To achieve this, a methodology for dynamic SOFC system modeling in a process engineering manner is developed based on the modeling language Modelica. A suitable approach is particularly important for modeling and simulation of the strong thermal interaction between the hot system components within the hotbox. The parametrized and validated models are used for the investigation of different dynamic effects, such as the system heat-up and the operation in low partial load points. A second reduced thermal system model aims for annual simulations of the SOFC system together with a battery to investigate the number of thermal cycles and the advantage of a hot standby operation. As a result, it is found that an adequate control of the power input at the start-up device and the cathode air flow has a high improvement potential to increase the stack heating rate and accelerate the heat-up in an energy-saving way. The hotbox-internal thermal management is identified as a crucial issue to reach low partial load points. To avoid the risk of stack cooling, lower heat losses and/or additional heat sources are of importance. Furthermore, the robustness of the tail gas oxidizer is found to be crucial for a higher load flexibility during partial load and the end of life stack operation. The annual simulation results indicate that operating the battery hybrid system with a hot standby mode requires much lower battery capacity for a high grid independence and a complete avoidance of system shutdown and associated power degradation.

Variable flow and optimization of chiller loading effect on energy saving for screw vapor compression-single effect absorption hybrid chiller plant in hospital mechanical room ‒ case study: Tehran heart hospital

Chiller plants are the most energy consuming system during summer season in residential, commercial and hospital buildings. The highly variable cooling demand of the buildings connected to a hybrid chiller plant included absorption and vapor compression chillers to achieve higher energy efficiencies is one of the important issues. Cooling load sharing strategies and apply the variable water flow system in chiller plant have a significant impact on energy consumption and consequently with more productivity and environmentally protected. This paper examines the behavior and pattern of energy consumption in a hybrid chiller plant that includes a combination of two air-cooled screw vapor compression and three single effect absorption chillers. In order to properly understand the pattern of energy consumption, an existing mechanical room in a hospital in Tehran has been studied for five months, and its energy consumption has been compared with the optimized model. The results indicate that the sequence of the chiller function and the way in which they are placed in the circuit during a partial load, is in highest importance in view point of energy saving also by Applying of variable water flow system for optimized chiller loading the more energy saving is achieved for hybrid absorption and vapor compression chiller plant.

Indirect Evaporative Cooling: An Efficient and Convenient Energy System

Evaporative cooling is now an alternative method for the conventional air cooling method. This method does not only save energy but also protect the environment from global warming and hazardous gases. Thus this system is highly efficient and eco-friendly. Evaporative cooling system is further divided into two categories that are direct evaporative cooling system and an indirect evaporative cooling system. The direct evaporative cooling system is not much efficient due to high wet bulb temperature and moisture thus rather than using the direct evaporative cooling system the indirect evaporative cooling system is preferred. This paper discusses comparative studies of performance, working principles, material selection criteria’s and various methods. It also explains the performance under different weather conditions, hybrid structure to reduce the load on the further system. It summarises various aspects like wick attained aluminium sheet is the best material for IEC or counter-flow heat exchanger is effective than parallel-flow heat exchanger. It finally results that indirect evaporative cooling system is moisture free, very effective and environment savings. That can be used in various residential and commercial sectors effectively as an alternative for conventional energy-consuming system.

Cell Division Protein FtsZ Is Unfolded for N-Terminal Degradation by Antibiotic-Activated ClpP.

Antibiotic acyldepsipeptides (ADEPs) deregulate ClpP, the proteolytic core of the bacterial Clp protease, thereby inhibiting its native functions and concomitantly activating it for uncontrolled proteolysis of nonnative substrates. Importantly, although ADEP-activated ClpP is assumed to target multiple polypeptide and protein substrates in the bacterial cell, not all proteins seem equally susceptible. In Bacillus subtilis, the cell division protein FtsZ emerged to be particularly sensitive to degradation by ADEP-activated ClpP at low inhibitory ADEP concentrations. In fact, FtsZ is the only bacterial protein that has been confirmed to be degraded in vitro as well as within bacterial cells so far. However, the molecular reason for this preferred degradation remained elusive. Here, we report the unexpected finding that ADEP-activated ClpP alone, in the absence of any Clp-ATPase, leads to an unfolding and subsequent degradation of the N-terminal domain of FtsZ, which can be prevented by the stabilization of the FtsZ fold via nucleotide binding. At elevated antibiotic concentrations, importantly, the C terminus of FtsZ is notably targeted for degradation in addition to the N terminus. Our results show that different target structures are more or less accessible to ClpP, depending on the ADEP level present. Moreover, our data assign a Clp-ATPase-independent protein unfolding capability to the ClpP core of the bacterial Clp protease and suggest that the protein fold of FtsZ may be more flexible than previously anticipated.IMPORTANCE Acyldepsipeptide (ADEP) antibiotics effectively kill multidrug-resistant Gram-positive pathogens, including vancomycin-resistant enterococcus, penicillin-resistant Streptococcus pneumoniae (PRSP), and methicillin-resistant Staphylococcus aureus (MRSA). The antibacterial activity of ADEP depends on a new mechanism of action, i.e., the deregulation of bacterial protease ClpP that leads to bacterial self-digestion. Our data allow new insights into the mode of ADEP action by providing a molecular explanation for the distinct bacterial phenotypes observed at low versus high ADEP concentrations. In addition, we show that ClpP alone, in the absence of any unfoldase or energy-consuming system, and only activated by the small molecule antibiotic ADEP, leads to the unfolding of the cell division protein FtsZ.

Case studies on the effect of two-dimensional heliostat tracking on the performance of domestic scale solar thermal tower

Solar thermal system has been envisioned for utility scale applications. However, on the low end the domestic applications can be made realizable through low end automation. Performance of typical solar reflector can be significantly enhanced by using a solar tracking system. An efficient & low energy consuming system can result in improved energy harvesting. In the current study, an experimental analysis of automated domestic scale heliostat field using rack and pinion-based mechanism is performed. The mechanism is controlled using relay module with an Arduino UNO R3-SMD. Experiments are performed in actual working conditions of Taxila, Pakistan. The heliostat field is made to reflect the solar rays to a cavity type central receiver (CTCR) having stainless steel tubing. Experimentations were performed under three different scenarios-tracking using one dimensional (1D) with fixed position heliostats, tracking using two dimensional (2D) with 5 variable positioning heliostats, and tracking using 2D with 8 variable positioning heliostats. The performances of each setup is analyzed parameters such as heating fluid, temperature difference (ΔT), absorbed heat (Qabs), and overall efficiency (ƞ). Performance enhancement was observed using 2D tracking with 8 variable positioning heliostats where ΔT was 64.26 °C, Qabs was 489.89 W, with maximum ƞ was 52.8%. In 2D with 5 variable positioning heliostats and 1D with fixed heliostats, the values obtained were 50.3 °C, 385.5 W, 51.83% and 6.523 °C, 50 W, 45.86% respectively.

Ventilation and air conditioning system of deep-buried subway station in sub-tropical climates: Energy-saving strategies

Subway systems are rapidly developing, and their energy consumption is considerably growing. The ventilation and air conditioning system in the subway station is the key energy-consuming system. It consumes a large amount of energy every day to provide a comfortable environment for passengers, and it has therefore received increasingly more attention from researchers worldwide. In this work, the variation law of the ventilation and air conditioning system of a subway station is analyzed from three aspects (energy consumption, load, and temperature) based on field test data, and the problems existing in the operation and management of the system are analyzed. For example, the results show that the total load of fresh air in the station was as high as 34–37%, and about 30 min was required to adjust the indoor temperature to a stable state. In addition, three general models and seven energy-saving strategies are put forward, and their energy saving potentials are estimated. After optimization, the ventilation and air conditioning system is found to reduce energy consumption by more than 30%. Not only are common problems that exist in the actual operation of the subway station ventilation and air conditioning system found in this research, but valuable measured data is also provided for the theoretical research of the thermal environment of the subway and the design of environmental control systems.

A New Vacuum System for Steam Plant Condenser

Abstract In the current work, a simple and low energy consuming system is proposed for holding on the vacuum in the steam power plant system. The vacuum is created at the tip of an inverted U-pipe through which water flows by siphon effect due to the height difference in water surfaces of two tanks. This height difference and the elevation of the inverted U-pipe tip define the value of the vacuum to be grown. The U-pipe tip is connected to the discharge pipe of a compressor which draws a mixture of air, and water vapor from the steam condenser and raises their pressure a little higher than that of the inverted U-pipe tip. The mixture flows with the water down the inverted U-pipe till they depart the U-tube. A thermodynamic and fluid flow analysis is developed for predicting the performance of the proposed system. The results of this analysis show that the right selection of the mass flowrate ratio of water flowing in the inverted U-pipe to air and water vapor mixture sucked by the compressor from the steam plant condenser, in the range of 25,000, the height of the inverted U-pipe summit from the water level of the higher water tank greater than 9.2 m and the height difference of the water levels in the two water tanks small enough, in the range of 0.1 m saves the power of vacuum system by 80% less than that consumed when using compressor alone for venting the steam plant condenser.

Development of an Iot Based Energy Management System for Air Handling Unit

The emergence of automation and smart power management systems pave to create a better energy management system. Measuring energy savings and potential reduction of peak demand in a building due to adjustment of AHU (Air Handling Unit) setpoint during working hours is critical for ideal demand-side allocations. Since Air Handling Units are one of the major energy consuming system in a building. This has been a great challenge given too many variable physical characteristics and AHU system thermal dynamics in commercial buildings. Based on the building model, developed and authenticate against measured power consumption data from a smart energy meter, this project deals with how energy savings and peak demand reduction potentials of a building are impacted by AHU, setpoint changes during a working period. It is of the utmost necessity to make a prototype for an existing AHU in order to minimize wastage of power in older buildings without any major renovation. This can be achieved by making the existing system into a closed loop system by our model prototype.

An IoT framework for the assessment of indoor conditions and estimation of occupancy rates: results from a real case study

<p class="Abstract">In recent years, energy-savings policies have affected many aspects of everyday life. Considering a typical building, the heating, ventilation, and air conditioning (HVAC) system is the most energy-consuming system. This consideration is especially true for large public-access buildings, such as schools, and public administrations. In these cases, the energy saving of buildings depends on the capability to optimise the behaviour of the HVAC. Typically, the HVAC control system is based on static models of the building, which consider the average occupancy rate of each of the rooms. On the contrary, in this research work, a cognitive system based on an occupancy rate model that is able to take into consideration user habits and indoor air quality (IAQ) provided by IoT sensors is considered for the control of HVAC systems. This approach has been applied to the eLUX lab building of the University of Brescia, Italy. Data provided by IoT IAQ sensors (temperature, relative humidity, CO<sub>2</sub>) is used to refine the results of the occupancy rates for the models of the rooms of this building. The experimental results show, as in 22.15 % of the samples, the CO<sub>2</sub> concentration exceeded the 1,000 ppm threshold of the perception of fresh air and good conditions.</p>

Energy Saving Method for Operating CNC Machine Door

Energy is an important aspect in our day to day life. It is important to save energy wherever possible that to electric energy. We are suffering from electric energy crisis now-a-days. In order to save electric energy alternate system is chosen and it is implemented which would save electric energy. Wasting energy for supplementary or supporting works like machine door opening and closing considered as uneconomical. Energy consuming system consumes lot of energy for supporting works. In this energy saving concept two different types of system can be coupled to work as a single system which would save much energy than before. Our concept discusses about the same. Energy wastage for operating CNC machine door is taken for consideration in our work and analysis has been done on it. A new hydraulic operating system is proposed to overcome the difficulties.