Abstract: Truck platooning refers to a convoy of digitally connected automated trucks traveling safely with a small inter-vehicle gap. It has been identified as one of the most promising and applicable technologies towards automated and sustainable freight transportation. Although truck platooning delivers significant energy-saving benefits, it cannot be realized without good coordination of drivers’ shifts to lead the platoons subject to their mandatory breaks. Therefore, this study aims to route a fleet of trucks to their destinations using the least amount of fuel by maximizing platoon opportunities under the regulations of drivers’ mandatory breaks. We formulate this platoon coordination problem as a mixed-integer linear programming problem and solve it by CPLEX. Numerical experiments are conducted to demonstrate the effectiveness and efficiency of our proposed model. In addition, we also explore the impacts of drivers’ compulsory breaks on the fuel-savings performance. The results show a slight increase in the total fuel costs in the presence of drivers’ compulsory breaks, thanks to driving-while-resting benefit provided for the trailing trucks. This study may serve as a guide for the operators of automated freight transportation.
Abstract: Greenhouse cultivation is an energy-intensive process due to the high demands on cooling or heating according to external climatic conditions, which could be extreme in the summer or winter seasons. The thermal radiation rate inside a greenhouse depends mainly on the type of covering material and greenhouse construction. Using additional thermal screens under a greenhouse covering combined with a dehumidification system improves the insulation and could be cost-effective. Greenhouse covering material usually contains protective ultraviolet (UV) radiation additives to prevent the film wear, insect harm, and crop diseases. This paper investigates the overall heat transfer coefficient, or U-value, for greenhouse polyethylene covering contains UV-additives and glass covering with or without a thermal screen supplement. The hot-box method was employed to evaluate overall heat transfer coefficients experimentally as a function of the type and number of the thermal screens. The results show that the overall heat transfer coefficient decreases with increasing the number of thermal screens as a hyperbolic function. The overall heat transfer coefficient highly depends on the ability of the material to reflect thermal radiation. Using a greenhouse covering, i.e., polyethylene films or glass, in combination with high reflective thermal screens, i.e., containing about 98% of aluminum stripes or aluminum foil, the U-value reduces by 61%-89% in the first case, whereas by 70%-92% in the second case, depending on the number of the thermal screen. Using thermal screens made from low reflective materials may reduce the U-value by 30%-57%. The heat transfer coefficient is an indicator of the thermal insulation properties of the materials, which allows farmers to make decisions on the use of appropriate thermal screens depending on the external and internal climate conditions in a greenhouse.
Abstract: With rapid development of urbanization and improvement of living standards in the world, energy consumption and carbon emissions of the building sector are expected to increase in the near future; because of that, energy-saving issues have become more important among the engineers. Besides, the building sector is a major contributor to energy consumption and carbon emissions. The concept of efficient building appeared as a response to the need for reducing energy demand in this sector which has the main purpose of shifting from standard buildings to low-energy buildings. Although energy-saving should happen in all steps of a building during the life cycle (material production, construction, demolition), the main concept of efficient energy building is saving energy during the life expectancy of a building by using passive and active systems, and should not sacrifice comfort and quality to reach these goals. The main aim of this study is to investigate passive strategies (do not need energy consumption or use renewable energy) to achieve energy-efficient buildings. Energy retrofit measures were explored by eQuest software using a case study as a base model. The study investigates predictive accuracy for the major factors like thermal transmittance (U-value) of the material, windows, shading devices, thermal insulation, rate of the exposed envelope, window/wall ration, lighting system in the energy consumption of the building. The base model was located in Istanbul, Turkey. The impact of eight passive parameters on energy consumption had been indicated. After analyzing the base model by eQuest, a final scenario was suggested which had a good energy performance. The results showed a decrease in the U-values of materials, the rate of exposing buildings, and windows had a significant effect on energy consumption. Finally, savings in electric consumption of about 10.5%, and gas consumption by about 8.37% in the suggested model were achieved annually.
Abstract: Universitas Negeri Semarang (UNNES) is a university with a vision of conservation. The impact of the UNNES conservation is the existence of a positive response from the community for the effort of greening the campus and the planting of conservation value in the academic community. But in reality, energy consumption in UNNES campus tends to increase. The objectives of the study were to analyze the energy consumption in the campus area, to analyze the absorption of emissions by trees and the awareness of UNNES citizens in reducing emissions. Research focuses on energy consumption, carbon emissions, and awareness of citizens in reducing emissions. Research subjects in this study are UNNES citizens (lecturers, students and employees). The research area covers 6 faculties and one administrative center building. Data collection is done by observation, interview and documentation. The research used a quantitative descriptive method to analyze the data. The number of trees in UNNES is 10,264. Total emission on campus UNNES is 7.862.281.56 kg/year, the tree absorption is 6,289,250.38 kg/year. In UNNES campus area there are still 1,575,031.18 kg/year of emissions, not yet absorbed by trees. There are only two areas of the faculty whose trees are capable of absorbing emissions. The awareness of UNNES citizens in reducing energy consumption is seen in change the habit of: using energy-saving equipment (65%); reduce energy consumption per unit (68%); do energy literacy for UNNES citizens (74%). UNNES leaders always provide motivation to the citizens of UNNES, to reduce and change patterns of energy consumption.
Abstract: Theagenio" in Thessaloniki exists and works for three centuries now as a hospital. Since 1975, it has been operating as an Integrated Special Cancer Hospital and since 1985 it has been integrated into the National Health System. "Theagenio" Cancer Hospital is located at the central web of Thessaloniki residential complex and consists of two buildings, the "Symeonidio Research Center", which was completed in 1962 and the Nursing Ward, a project that was later completed in 1975. This paper examines the design of the Hospital Unit according to the requirements of the energy design of buildings. Initially, the energy characteristics of the Hospital are recorded, followed by a detailed presentation of the electromechanical installations. After the existing situation has been captured and with the help of the software TEE-KENAK, different scenarios for the energy upgrading of the buildings have been studied. Proposals for upgrading concern both the shell, e.g. installation of external thermal insulation, replacement of frames, addition of shading systems, etc. as well as electromechanical installations, e.g. use of ceiling fans, improvements in heating and cooling systems, interventions in lighting, etc. The simulation calculates the future energy status of the buildings and presents the economic benefits of the proposed interventions with reference to the environmental profits that arise.
Abstract: Focus on reducing energy consumption in existing
buildings at large scale, e.g. in cities or countries, has been
increasing in recent years. In order to reduce energy consumption
in existing buildings, political incentive schemes are put in place and
large scale investments are made by utility companies. Prioritising
these investments requires a comprehensive overview of the energy
consumption in the existing building stock, as well as potential
energy-savings. However, a building stock comprises thousands
of buildings with different characteristics making it difficult to
model energy consumption accurately. Moreover, the complexity of
the building stock makes it difficult to convey model results to
policymakers and other stakeholders. In order to manage the complexity of the building stock, building
archetypes are often employed in building stock energy models
(BSEMs). Building archetypes are formed by segmenting the building
stock according to specific characteristics. Segmenting the building
stock according to building type and building age is common, among
other things because this information is often easily available. This
segmentation makes it easy to convey results to non-experts. However, using a single archetypical building to represent all
buildings in a segment of the building stock is associated with
loss of detail. Thermal characteristics are aggregated while other
characteristics, which could affect the energy efficiency of a building,
are disregarded. Thus, using a simplified representation of the
building stock could come at the expense of the accuracy of the
model. The present study evaluates the accuracy of a conventional
archetype-based BSEM that segments the building stock according
to building type- and age. The accuracy is evaluated in terms of the
archetypes’ ability to accurately emulate the average energy demands
of the corresponding buildings they were meant to represent. This is
done for the buildings’ energy demands as a whole as well as for
relevant sub-demands. Both are evaluated in relation to the type- and
the age of the building. This should provide researchers, who use
archetypes in BSEMs, with an indication of the expected accuracy
of the conventional archetype model, as well as the accuracy lost in
specific parts of the calculation, due to use of the archetype method.
Abstract: Visual comfort is one of the major parameters that can be taken to measure the human comfort in any environment. If the provided illuminance level in a working environment does not meet the workers visual comfort, it will lead to eye-strain, fatigue, headache, stress, accidents and finally, poor productivity. However, improvements in lighting do not necessarily mean that the workplace requires more light. Unnecessarily higher illuminance levels will also cause poor visual comfort and health risks. In addition, more power consumption on lighting will also result in higher energy costs. So, during this study, visual comfort and the illuminance requirement for the workers in textile/apparel industry were studied to perform different tasks (i.e. cutting, sewing and knitting) at their workplace. Experimental studies were designed to identify the optimum illuminance requirement depending upon the varied fabric colour and type and finally, energy saving potentials due to controlled illuminance level depending on the workforce requirement were analysed. Visual performance of workers during the sewing operation was studied using the ‘landolt ring experiment’. It was revealed that around 36.3% of the workers would like to work if the illuminance level varies from 601 lux to 850 lux illuminance level and 45.9% of the workers are not happy to work if the illuminance level reduces less than 600 lux and greater than 850 lux. Moreover, more than 65% of the workers who do not satisfy with the existing illuminance levels of the production floors suggested that they have headache, eye diseases, or both diseases due to poor visual comfort. In addition, findings of the energy analysis revealed that the energy-saving potential of 5%, 10%, 24%, 8% and 16% can be anticipated for fabric colours, red, blue, yellow, black and white respectively, when the 800 lux is the prevailing illuminance level for sewing operation.
Abstract: This paper presents a kind of analog circuit based
temperature control system, which is mainly composed by threshold
control signal circuit, synchronization signal circuit and trigger
pulse circuit. Firstly, the temperature feedback signal function is
realized by temperature sensor TS503F3950E. Secondly, the main
control circuit forms the cycle controlled pulse signal to control
the thyristor switching model. Finally two reverse paralleled
thyristors regulate the output power by their switching state. In
the consequence, this is a modernized and energy-saving domestic
electric heating system.
Abstract: This study attempts to identify the client’s main priority when delivering green projects. The aim is to compare whether clients’ interests are similar when delivering conventional buildings as compared to green buildings. Private clients invest more in green buildings as compared to government and parastatal entities. Private clients prioritize on maximizing a return on investment and they mainly invest in energy-saving buildings that have low life cycle costs. Private clients are perceived to be more knowledgeable about the benefits of green building projects as compared to government and parastatal clients. A shortage of expertise and managerial skill leads to the low adaptation of green buildings in government and parastatal projects. Other factors that seem to prevent the adoption of green buildings are the preparedness of the supply chain within the industry and inappropriate procurement strategies adopted by clients.
Abstract: Internal circulation two-platen clamping system for
injection molding machine (IMM) has many potential advantages on
energy-saving. In order to estimate its properties, experiments were
carried out in this paper. Displacement and pressure of the components
were measured. In comparison, the model of hydraulic clamping
system was established by using AMESim. The related parameters as
well as the energy consumption could be calculated. According to the
analysis, the hydraulic system was optimized in order to reduce the
energy consumption.
Abstract: Lightweight design represents an important key to
successful implementation of energy-saving, fuel-efficient and
environmentally friendly means of transport in the aerospace and
automotive industry. In this context the use of carbon fibre reinforced
plastics (CFRP) which are distinguished by their outstanding
mechanical properties at relatively low weight, promise significant
improvements. Due to the reduction of the total mass, with the
resulting lowered fuel or energy consumption and CO2 emissions
during the operational phase, commercial aircraft will increasingly be
made of CFRP. An auspicious technology for the efficient and
economic production of high performance thermoset composites and
hybrid structures for future lightweight applications is the
combination of carbon fibre sheet moulding compound, tailored
continuous carbon fibre reinforcements and metallic components in a
one-shot pressing and curing process. This paper deals with a hybrid
composite technology for aerospace industries, which was developed
with the help of a special innovation and development system.
Abstract: We present results from experimental price-setting oligopolies in which green firms undertake different levels of energy-saving investments motivated by public subsidies and demand-side advantages. We find that consumers reveal higher willingness to pay for greener sellers’ products. This observation in conjunction to the fact that greener sellers set higher prices is compatible with the use and interpretation of energy-saving behaviour as a differentiation strategy. However, sellers do not exploit the resulting advantage through sufficiently high price-cost margins, because they seem trapped into “run to stay still” competition. Regarding the use of public subsidies to energy-saving sellers we uncover an undesirable crowding-out effect of consumers’ intrinsic tendency to support green manufacturers. Namely, consumers may be less willing to support a green seller whose energy-saving strategy entails a direct financial benefit. Finally, we disentangle two alternative motivations for consumer’s attractions to pro-social firms; first, the self-interested recognition of the firm’s contribution to the public and private welfare and, second, the need to compensate a firm for the cost entailed in each pro-social action. Our results show the prevalence of the former over the latter.
Abstract: This paper deals the energy saving performance of GHP (Gas engine heat pump) air conditioning system has improved with time-series variation. There are two types of air conditioning systems, VRF (Variable refrigerant flow) and central cooling and heating system. VRF is classified as EHP (Electric driven heat pump) and GHP. EHP drives the compressor with electric motor. GHP drives the compressor with the gas engine. The electric consumption of GHP is less than one tenth of EHP does.
In this study, the energy consumption data of GHP installed the junior high schools was collected. An annual and monthly energy consumption per rated thermal output power of each apparatus was calculated, and then their energy efficiency was analyzed. From these data, we investigated improvement of the energy saving of the GHP air conditioning system by the change in the generation.
Abstract: Nowadays in applications of renewable energy sources
it is important to develop powerful and energy-saving photovoltaic
converters and to keep the prescriptions of the standards. In grid
connected PV converters the obvious solution to increase the
efficiency is to reduce the switching losses. Our new developed
control method reduces the switching losses and keeps the limitations
of the harmonic distortion standards. The base idea of the method is
the utilization of 3-state control causing discontinuous current mode
at low input power. In the following sections the control theory, the
realizations and the simulation results are presented.
Abstract: During recent years, attention in 'Green Computing'
has moved research into energy-saving techniques for home
computers to enterprise systems' Client and Server machines. Saving
energy or reduction of carbon footprints is one of the aspects of
Green Computing. The research in the direction of Green Computing
is more than just saving energy and reducing carbon foot prints. This
study provides a brief account of Green Computing. The emphasis of
this study is on current trends in Green Computing; challenges in the
field of Green Computing and the future trends of Green Computing.