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Energy and Built Environment
Number of Followers: 1  Open Access journalISSN (Online) 2666-1233 Published by Ke Ai  [71 journals]
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- Electricity Demand Forecasting in Decentralised Demand Side Response for
Blocks of Buildings
Abstract: Publication date: Available online 27 January 2020Source: Energy and Built EnvironmentAuthor(s): A. Sean Williams, B. Michael Short The world is experiencing a fourth industrial revolution. Rapid development of technologies is advancing smart infrastructure opportunities. Experts observe decarbonisation, digitalisation and decentralisation as the main drivers for change. In electrical power systems a downturn of centralised conventional fossil fuel fired power plants and increased proportion of distributed power generation adds to the already troublesome outlook for operators of low-inertia energy systems. In the absence of reliable real-time demand forecasting measures, effective decentralised demand-side energy planning is often problematic. In this work we formulate a simple yet highly effective lumped model for forecasting the rate at which electricity is consumed. The methodology presented focuses on the potential adoption by a regional electricity network operator with inadequate real-time energy data who requires knowledge of the wider aggregated future rate of energy consumption. Thus, contributing to a reduction in the demand of state-owned generation power plants. The forecasting session is constructed initially through analysis of a chronological sequence of discrete observations. Historical demand data shows behaviour that allows the use of dimensionality reduction techniques. Combined with piecewise interpolation an electricity demand forecasting methodology is formulated. Solutions of short-term forecasting problems provide credible predictions for energy demand. Calculations for medium-term forecasts that extend beyond 6-months are also very promising. The forecasting method provides a way to advance a novel decentralised informatics, optimisation and control framework for small island power systems or distributed grid-edge systems as part of an evolving demand response service.
- Investigation of heat transfer of a building wall in the presence of phase
change material (PCM)
Abstract: Publication date: Available online 24 January 2020Source: Energy and Built EnvironmentAuthor(s): Rafid Jahangir Khan, Md. Zubayer Hossain Bhuiyan, Dewan Hasan Ahmed The energy consumption in buildings for heating, ventilation, and air-conditioning is increasing with the increasing demand for thermal comfort. Thermal energy storage with phase change materials (PCMs) has attracted growing attention for its role in achieving energy conservation in buildings with thermal comfort. This paper investigates the effect of PCM on the heat transfer rate in a building wall and the role of PCM on the indoor thermal comfort of the building. Two models of building wall fragments were developed for the experimental study. In one model, tests were conducted for different positions of the PCM layer in the building wall to identify the optimal position of the PCM layer inside the wall. In another model, tests were carried out integrating PCM, air gap, and other conventional building materials (brickbat and sand), one at a time, to investigate the role of PCM on the heat transfer rate in the building wall fragment. The results show that placing the PCM layer closer to the heat source gives a low-temperature gain of the cold water bath (indoor state) as compared with the PCM layer near the heat sink. With PCM, the temperature rise of the cold water bath (indoor state) of the building wall fragment was the lowest, and the slope of the temperature rise of the cold water bath becomes steadier with time i.e. fewer temperature fluctuations. There was a significant time delay for the cold water bath to reach a particular temperature. The heat required for a unit degree increase in the temperature of the cold water bath higher and the peak heat flux of the wall was lower relative to the other building materials.
- Simulation study on performance of a dual-source hybrid heat pump unit
with alternative refrigerants
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Chenguang Bai, Zongwei Han, Haotian Wei, Xiaomei Ju, Xinwei Meng, Qi Fu To solve the problems of single heat source heat pump systems in severe cold regions, a dual-source hybrid heat pump unit (DSHHPU) is proposed. The mathematical models of the DSHHPU when charging R134a or its alternative refrigerants R32, R290 and R600a were established respectively, and the performance was simulated and analysed. The results showed that the four refrigerants have different performance characteristics in different aspects. In heat pipe mode, the heating capacity and evaporating pressure of R32 are 36.94% and 59.94% higher than those of R134a. The heating capacity and evaporating pressure of R290 are 5.73% and 22.99% lower than those of R134a. The heating capacity and evaporating pressure of R600a are 43.29% and 68.08% lower than those of R134a. In vapour compression heating mode, the discharge temperature of R32, R290 and R600a are 184.88, 72.98 and 66.44% of that of R134a. The coefficient of performance (COP) of R32, R290 and R600a are 72.65, 111.59 and 117.94% of that of R134a. Finally, the effects of radiation intensity and ambient temperature on key performance parameters of the different refrigerants were analysed. The research results provide a reference for research on refrigerant replacements for multi-heat source composite heat pump systems.
- Thermal models for avionics pod cabin based on Stochastic Configuration
Network (SCN)
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Liping Pang, Jie Zhang, Meng Liu, Hongquan Qu, Jun Wang The thermal failure of airborne avionics equipment is not optimistic. It is very necessary to establish relatively accurate thermal models for predicting thermal response of avionics equipment under different flight conditions. Traditional thermal modeling methods are often difficult to obtain accurate temperature response in complex conditions. This has severely restricted the application of these models. However, the Stochastic Configuration Network (SCN) model based on random algorithm can weaken the heat transfer mechanism and pay attention to the mining of experimental data, so that a more accurate thermal relationship might be obtained. In this paper, the SCN was used to analyze the experimental data of the avionics pod with a Ram Air Turbine (RAT) cooling system. The thermal models based on the SCN were finally built for avionics pod. Compared with the commonly used Random Vector Functional Link Network (RVFLN) thermal models, the SCN thermal models not only inherit the advantages of simple network structure and low computational complexity, but also have some merits, such as the better learning performance and the less human intervention. The presented SCN models provide a way to predict the thermal response of avionics pod cabin under the full flight envelope for a fighter.
- A new pin-to-plate corona discharger with clean air protection for
particulate matter removal
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Yuting Gu, Enze Tian, Fanxuan Xia, Tao Yu, Alireza Afshari, Jinhan Mo High concentration particulate matter (PM) has been a serious environmental problem in China and other developing countries. Electrostatic-based purification technology is a method to remove airborne particles, and can reduce the energy consumption of ventilation fans in buildings because of its low pressure drop. In this study, we developed a new pin-to-plate corona discharger with particle-free external air protection to prevent particles polluting the surface of discharge pins. By using an optical microscope, we observed a certain number of particles deposited on the non-protected (exposed pins) and few particles deposited on the protected pins after they operating for 3 weeks. We experimentally studied the long-term performances of the exposed and protected pins in single-pass PM removal efficiency and ozone production. The results showed that the protected pins produce less ozone and have higher breakdown voltage than the exposed pins. Experimental results indicated that the improved pin-to-plate corona discharger has better long-term performance and is safer than the exposed one. The results of the research can give an understanding of how to improve electrostatic-based purification technologies toward stable discharging for high removal efficiency of particles.
- A bi-objective optimization approach for selection of passive energy
alternatives in retrofit projects under cost uncertainty
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Farhad Amiri Fard, Fuzhan Nasiri Improving energy performance of buildings is of particular importance in new construction and existing buildings. Building refurbishment is considered a practical pathway towards energy efficiency as the replacement of older buildings is at a slow pace. There are various ways of incorporating energy conservation measures in buildings through refurbishment projects. As such, we have to choose among various passive or active measures. In this study, we develop an integrated assessment model to direct energy management decisions in retrofit projects. Our focus will be on alternative passive measures that can be included in refurbishment projects to reduce overall energy consumption in buildings. We identify the relative priority of these alternatives with respect to their non-monetary (qualitative) benefits and issues using an analytic network process. Then, the above priorities will form a utility function that will be optimized along with the energy demand and retrofit costs using a multi-objective optimization model. We also explore various approaches to formulate the uncertainties that may arise in cost estimations and incorporate them into the optimization model. The applicability and authenticity of the proposed model is demonstrated through an illustrative case study application. The results reveal that the choice of the optimization approach for a retrofit project shall be done with respect to the extent of variations (uncertainties) in expected utilities (benefits) and costs for the alternative passive technologies.
- Operational performance of a novel heat pump coupled with mini-channel
PV/T and thermal panel in low solar radiation
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Jinzhi Zhou, Xudong Zhao, Yanping Yuan, Jing Li, Min Yu, Yi Fan Here we describe a heat pump system coupled with novel PV/T and thermal panels for space heating in low solar radiation conditions. Existing solar indirect-expansion systems connect the solar panels and evaporator of the heat pump in parallel with the heat storage tank. For our system these three components are instead connected in series, which can stabilize the temperature at the inlet of the evaporator and decrease the inlet temperature of the solar panels, leading to improved energy efficiency and the production of much more thermal energy. The experimental results of this system show that the average electrical, thermal and overall efficiency of the PV/T panels are 15.9%, 33.4% and 49.3%, respectively. The average thermal efficiency of the thermal panels is 60.4%, the COP of heat pump is 4.7 and the room temperature is constantly over 18 °C. Based on the experimental results, some improvements are analyzed. We conclude that this operating model can meet the requirement of space heating in low solar radiation environments.
- A high-efficiency regenerative shock absorber considering twin ball screws
transmissions for application in range-extended electric vehicles
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Zhanwen Wang, Tianming Zhang, Zutao Zhang, Yanping Yuan, Yujie Liu Renewable energy technologies, particularly in electric vehicles (EVs), have received significant attention in recent years. The wasted energy in a vehicle's shock absorber can be converted into an alternative energy source by regenerative shock absorbers. In this paper, a high-efficiency regenerative shock absorber considering twin ball screws transmissions is proposed for application in range-extended electric vehicles. The proposed regenerative shock absorber can convert vibrational kinetic energy, which is traditionally dissipated as heat in suspension systems, into electricity. The proposed system is divided into four modules: suspension vibration input module, transmission module, generator module and power storage module. Induced by road roughness, the irregular linear oscillations of the suspension are transmitted to the suspension vibration input module. The reciprocating vibrations are converted into unidirectional rotation of the generator by a pair of ball screws, gears, and two overrun clutches in the transmission module. The utilisation of different screw pitches leads to different damping coefficients for upward and downward progress, enabling the shock absorber to fully utilise elastic elements to improve vehicle comfort when compressed and quickly absorb vibrations when stretched. The electricity produced by the generator is stored in supercapacitors to charge the battery and extend the range of EVs. The mechanical properties of the full-scaled fabricated prototype were studied by utilising a mechanical testing and sensing fixture. An average power output of 3.701 W in 1Hz-3 mm sinusoidal vibration input and a peak efficiency of 51.1% and average efficiency of 36.4% were achieved in a bench tests. The range can be approximately extended by 1 mile per 100 miles when EV is driving on the road of class B with a speed of 60 km/h, demonstrating that the proposed high-efficiency regenerative shock absorber is beneficial for harvesting renewable energy, and practical and significant for extending the range of EVs.
- Assessing the implications of submetering with energy analytics to
building energy savings
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Zhiqiang (John) Zhai, Andrea Salazar This paper analyzes the effect of the depth of submetering (i.e., from whole-building level to system level to equipment level and further to sensor level) on the energy savings that can be achieved in energy analytics or energy information system (EIS) implementations. An EIS is defined as a combination of software and hardware systems that gather energy-related data, feed it into an analytics engine, and present building operators with analyses that allow them to reduce energy consumption. Data regarding the energy savings, the depth of submetering in the EIS implementation, and the cost of submetering was gathered for 21 case (building portfolio) studies and analyzed to determine if there is a relationship between the depth of submetering and the energy savings achieved. It was found that in general, deeper submetering does in fact appear to enable deeper energy savings. The one exception to this is sensor-level data: the addition of detailed sensor level metering to other higher levels of metering data does not seem to enable deeper energy savings in EIS implementations. Detailed findings in energy savings, cost and cost-effectiveness were presented for different levels of metering that may provide insightful rule-of-thumb estimations for similar implementations.
- Preparation, Properties, and Applications of Natural Cellulosic Aerogels:
A Review
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Ahsan Zaman, Fei Huang, Man Jiang, Wei Wei, Zuowan Zhou With the depletion of fossil fuel and increasing environmental concerns, the modernized era of technology is urgently in need for sustainable and eco-friendly materials. The industrial sector certainly possesses enough resources for the production of available cost-effective, renewable, reusable, and sustainable raw materials. Ultralight, eco-friendly and renewable cellulosic aerogels are one of the most accentuated materials in the polymer research field due to their highly abundant and inexpensive raw material, biocompatibility, high specific surface area and other feasible properties. This review summarizes the recent progress in cellulosic aerogels, their main processing route, including a detailed description of versatile new solvents along with some essential properties of cellulosic aerogels and illustrate how their variety of chemical functionalities can be adjusted for applications in the fields of thermal insulation, fire retardant, antibacterial, CO2 capture and energy storage systems. A detailed morphological analysis has been elaborated and effect of processing route, solvent medium and drying procedure on the morphology of cellulosic aerogels is also decribed. Finally, we propose some suggestions to the functionalization such as silanized cellulosic aerogels and their applications in antibacterial activity yet they are still in progress and need further study for future research.
- Recent progress in liquid desiccant dehumidification and air-conditioning:
A review
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Xiangjie Chen, Saffa Riffat, Hongyu Bai, Xiaofeng Zheng, David Reay This paper presents a literature review on the recent research progress in liquid desiccant dehumidification and air conditioning systems. The physical features of various liquid desiccant materials and their dehumidification performances have been summarized. With the aim to improve the dehumidification characteristics, mixed solvents desiccants have become research hot topics recently. Various types of dehumidifiers and their integration with liquid desiccant dehumidification system have been reviewed. The combination of liquid desiccant dehumidification system with solar collector, vapour compression system, heat pump system, CHP system, etc. have been grouped and compared. It is shown that the majority of the recent research work for liquid desiccant dehumidification systems has concentrated on numerical simulations, a considerable amount of works are still required for the practical investigations of innovative material (mixed solvents) and hybrid systems.
- Solar aided power generation: A review
Abstract: Publication date: January 2020Source: Energy and Built Environment, Volume 1, Issue 1Author(s): Jiyun Qin, Eric Hu, Xiaohua Li Solar Aided Power Generation (SAPG) is the most efficient and economic ways to hybridise solar thermal energy and a fossil fuel fired regenerative Rankine cycle (RRC) power plant for power generation purpose. In such an SAPG plant, the solar thermal energy is used to displace the extraction steam by preheating the feedwater to the boiler. The displaced/saved extraction steam can, therefore, expand further in the steam turbine to generate power. The research and development of the SAPG technology started in the 1990s. This paper is trying to reviews and summarises the progress of research and development of the SAPG plant technology in last almost 30 or so years, including the technical and economic advantages of SAPG over other solar thermal power generation technologies (e.g. solar alone power generation), various modelling techniques used to simulate SAPG perforamnce, impacts of SAPG plant's configuration, size of solar field and strategies to adjust mass flow rate of extraction steam on the plant perforamnce, exergy analysis of SAPG plant and operation strategies to maximise plant's economic returns etc. In addition, the directions for future R& D about SAPG technology have been pointed/proposed in this paper.
- Quantitative analysis of coherent structures affecting instantaneous
fluctuation of point-source plumes based on PIV-POD method
Abstract: Publication date: Available online 29 November 2019Source: Energy and Built EnvironmentAuthor(s): Yukun Xu, Xin Wang, Fei Wang, Bingyan Song, Yujie Zhang, Chenlu Shi For an enclosed space like an industrial plant where devices and equipment generate a large amount of heat, the fluctuation characteristics of thermal plume become more crucial. This paper aims to study the unique air distribution of the point-source plume by shutting down all valves in a thermostatic chamber. 250 consecutive instantaneous flow fields (in each zone) were measured by a two-dimensional particle image velocimetry (PIV) system at a sampling frequency of 3 Hz to quantify the air distribution of the plume. Based on the experimental data, the indoor instantaneous velocity and vorticity fields were analyzed, and the transient velocity fluctuation characteristics of typical points were discussed. The fluctuation periods of the plume at different heights were initially estimated. Through the proper orthogonal decomposition (POD) analysis, the dominant coherent structures in complex instantaneous flow fields were excavated, and the turbulent kinetic energy of coherent structures was calculated. In addition, POD analysis provided a new method for validating and improving transient numerical simulation models.
- Potential for energy conservation: A portable desktop paper reusing system
for office waste paper
Abstract: Publication date: Available online 18 November 2019Source: Energy and Built EnvironmentAuthor(s): Tingsheng Zhang, Xinglong Liu, Yajia Pan, Zutao Zhang, Yanping Yuan Renewable paper reusing plays a significant role in the sustainable environment under the background of the shortage in forest resources and the pollution from the paper industry. The conventional reusing stream of waste office paper appears to have low reusing rates while consuming massive amounts of energy in intermediate steps. In this study, we developed a novel portable renewable desktop paper reusing system based on font area detection and greyscale sensor. The proposed system consists of two main parts, namely, a greyscale sensor and font area detection model and a polishing mechanism. Acting as an ink mark detector for waste desktop paper, the greyscale sensor and font area detection model can detect the font in the waste desktop paper using an adaptive dynamic compensation schematic. The polishing mechanism will grind the font area of the wasted desktop paper, and this paper reusing processing is non-chemical, energy saving and environmentally friendly. The proposed system is demonstrated through simulations and experimental results, which show that the proposed renewable desktop paper reusing system is portable and is effective for reusing waste office paper in the office. An accuracy of 99.78% is demonstrated in the greyscale sensor and font area detection model, and the average reuse rate of one piece of paper is 2.52 times, verifying that the proposed portable system is effective and practical in renewable desktop paper reusing applications.Graphical abstract
- A review of data mining technologies in building energy systems: Load
prediction, pattern identification, fault detection and diagnosis
Abstract: Publication date: Available online 16 November 2019Source: Energy and Built EnvironmentAuthor(s): Yang Zhao, Chaobo Zhang, Yiwen Zhang, Zihao Wang, Junyang Li With the advent of the era of big data, buildings have become not only energy-intensive but also data-intensive. Data mining technologies have been widely utilized to release the values of massive amounts of building operation data with an aim of improving the operation performance of building energy systems. This paper aims at making a comprehensive literature review of the applications of data mining technologies in this domain. In general, data mining technologies can be classified into two categories, i.e., supervised data mining technologies and unsupervised data mining technologies. In this field, supervised data mining technologies are usually utilized for building energy load prediction and fault detection/diagnosis. And unsupervised data mining technologies are usually utilized for building operation pattern identification and fault detection/diagnosis. Comprehensive discussions are made about the strengths and shortcomings of the data mining-based methods. Based on this review, suggestions for future researches are proposed towards effective and efficient data mining solutions for building energy systems.
- Low-temperature compression-assisted absorption thermal energy storage
using ionic liquids
Abstract: Publication date: Available online 12 November 2019Source: Energy and Built EnvironmentAuthor(s): Wei Wu Thermal energy storage technologies play a significant role in building energy efficiency by balancing the mismatch between renewable energy supply and building energy demand. The absorption thermal energy storage (ATES) stands out due to its high energy storage density (ESD), high coefficient of performance (COP), low charging temperature and wider application flexibility. A hybrid compression-assisted ATES (CATES) using ionic liquid (IL)-based working fluids is investigated to address the problems of the existing ATES cycle. Models for mixture property and cycle performance are established with verified accuracies. Four ILs ([DMIM][DMP], [EMIM][Ac], [EMIM][DEP], and [EMIM][EtSO4]) are compared with H2O/LiBr. Results show that the CATES effectively avoid the crystallization, decreases the circulation ratio, lowers the charging temperature, and improves the COP/ESD. H2O/[DMIM][DMP] has the highest COP and performs better than H2O/LiBr with generation temperatures above 86°C, while H2O/[EMIM][EtSO4] shows the highest COP with generation temperatures below 75°C. Among the H2O/IL mixtures, H2O/[EMIM][Ac] shows the highest ESD with generation temperatures above 86°C, otherwise H2O/[EMIM][EtSO4] shows the highest. The optimal compression ratio is 1.6-2.8 for H2O/[DMIM][DMP] under the generation temperatures of 90-70°C with the maximum COP of 0.758-0.727. The ESD increases significantly with the compression ratio.
- Evaluation of stearic acid/coconut shell charcoal composite phase change
thermal energy storage materials for tankless solar water heater
Abstract: Publication date: Available online 8 October 2019Source: Energy and Built EnvironmentAuthor(s): Baoshan Xie, Chuanchang Li, Bo Zhang, Lixin Yang, Guiyu Xiao, Jian Chen This work presents a cost-effective and environment-friendly form-stabilized phase change material (PCM) and corresponding solar thermal application in the tankless solar water heater (TSWH). Coconut shell charcoal (CSC) as supporting material was modified by moderate oxidant of H2O2 with different concentrations, and then stabilized stearic acid (SA) to prepare composite PCMs through vacuum impregnation. It found that CSC support causes a 15.70% improvement of SA loadage after treated by 15% H2O2 due to coefficient enhancement by physical interaction and surface modification. The modified CSC15 support appears more super macropores which contribute to the impregnation of SA than non-modified CSC0 support verifying from SEM and BET results. And the content of oxygen functional groups was increased after oxidation modification, also motivating SA stabilization by hydrogen bond interaction in XPS analysis. FTIR results proved there is no chemical reaction happened between SA and CSC. Moreover, the latent heat and phase transition temperature of the as-prepared SA/CSC15 composite are 76.69 J g−1 and 52.52°C, respectively. All composites exhibit excellent thermal stability under a working temperature of 180°C and form stability during phase change. Thermal energy storage-release test within 70°C presents the composite has fast heat transfer efficiency than pure SA. The composite filled in TSWH system has 0.75 W m−1 K−1 thermal conductivity which is 2.88 times higher than that of pure SA (0.26 W m−1 K−1). Besides, the TSWH system with a flow rate of 0.004 kg s−1 could heat water effectively after sunset and the energy obtained from the thermal storage system within 1830 s testing times is about 0.15 kW h. In all, SA/CSC composite with good physical-thermo properties has potential in thermal energy storage application, especially in solar energy storage.
