Energy-saving behaviour as a demand-side management strategy in the developing world: the case of Bangladesh Abstract Although demand-side management (DSM) needs to be more customer centred, either with or without smart technologies (e.g. smart grid), less attention has been paid to the developing world in relation to DSM strategy development. The main reasons have been lack of appropriate technology and capital costs. Importantly, there are alternative DSM strategies that require minimum or no cost to implement and provide immediate results, of which energy-saving behaviour of the occupants at residences is one. This study explores the potentiality of this energy-saving behaviour as a DSM strategy for the least developed economies, focusing particularly on Bangladesh. The literature suggests that energy-saving behaviour could reduce energy demand by a maximum of 21.9%. However, this potential DSM scheme seems underestimated in the national DSM programme of Bangladesh. The Energy Efficiency and Conservation Master Plan (EECMP) of Bangladesh (a DSM program) shows that efficiency improvement in the use of home appliances could reduce electricity demand in the residential sector by about 28.8%, but this does require a long time to be implemented, whereas the inclusion of energy-saving behaviour as a demand response strategy in residences along with the EECMP might achieve demand reduction of up to 50.7%. Although the findings from this study are specific to Bangladesh, these could be useful guidelines for the policymakers of other developing nations where national DSM strategy development is underway.

Ecological Footprint as a sustainability indicator to analyze energy consumption in a Portuguese textile facility Abstract The main objective of this paper is to apply Ecological Footprint methodology as a tool to analyze the Portuguese textile industry. This analysis is related to energy and resources consumption in dyeing, printing and finishing processes. It also includes identification of mitigation measures to increase energy efficiency, promoting at the same time the reduction of CO2 emissions and consequently the decrease in industry’s Ecological Footprint. Moreover, the analysis presents the Ecological Footprint reduction potential for each mitigation option proposed for an important textile facility located in the North Region of Portugal, used as a case study in this work. The results for the case study showed that the total Ecological Footprint accounted, for the year 2016, summed up to 4890 gha. Furthermore, the energy category corresponds to more than 50% of the total Ecological Footprint estimation, and natural gas was the most required fuel for the processes. The calculation of the Ecological Footprint in the textile facilities can be used as a tool to analyze the processes’ energy efficiency and to quantify the global impact of the implementation of mitigation measures in the energy field. The result is an indicator shown in a common unit, gha (global hectare) and it can be easily used to compare energy-intensive processes and industrial sectors. In addition, it can be used to analyze how each sector can impact the country’s total demand for resources.

Designing of stand-alone hybrid PV/wind/battery system using improved crow search algorithm considering reliability index Abstract In this paper, the design of a hybrid renewable energy PV/wind/battery system is proposed for improving the load supply reliability over a study horizon considering the Net Present Cost (NPC) as the objective function to minimize. The NPC includes the costs related to the investment, replacement, operation, and maintenance of the hybrid system. The considered reliability index is the deficit power-hourly interruption probability of the load demand. The decision variables are the number of PV panels, wind turbines and batteries, capacity of transferred power by inverter, angle of PV panels, and wind tower height. To solve the optimization problem, a new algorithm named improved crow search algorithm (ICSA) is proposed. The design of the system is done for Zanjan city, Iran based on real data of solar radiation and wind speed of this area. The performance of the proposed ICSA is compared with crow search algorithm (CSA) and particle swarm optimization methods in different combinations of system. This comparison shows that the proposed ICSA algorithm has better performance than other methods.

Experimental investigations on thermal performance characteristics of a solar cavity receiver Abstract The experimentation is carried out to examine the influence of receiver aperture/opening ratio (receiver’s aperture diameter to the maximum diameter ratio, d/D), glass cover thickness and inclination angle of cavity receiver on its collection efficiency for various flow rates of ordinary water as a working fluid. Experimental tests have been conducted at lower incident energy, i.e., at lower cavity wall temperatures (less than 200 °C). The aperture ratio examined encompasses values as 0.46, 0.6, 0.7, and 0.93 for water flowing at flows of 0.8, 0.65, 0.5, and 0.4 LPM that corresponds to Reynolds numbers (Re) of 1880, 1525, 1175, and 938, respectively. The glazing thicknesses of 6, 4, and 2 mm were provided at an aperture. A modified cavity-type receiver is made inclined at angles 90°, 60°, 45°, and 30° (with 90° as down-facing receiver opening and 30° as close to sideway-facing of receiver opening). The tests have been conducted for cavity surface temperatures ranging from 90° to 180 °C. It is observed that an aperture ratio of 0.6 demonstrates maximum receiver performance for the values of Reynolds number studied, while the receiver performance exhibited reducing trend with reduction in receiver tilting angle from 90° to 30°.

Continuous two-step anaerobic digestion (TSAD) of organic market waste: rationalising process parameters Abstract Experimental tests on continuous two-stage anaerobic digestion (TSAD) were conducted, to assess its energetic performance, using organic market waste as a substrate. The systems were tested to ascertain the effects of external stressors, which allow the separation into two different microorganism consortia, that is, hydrogen-producing bacteria and hydrogen-consuming bacteria, to be maintained. Two bioreactors were run in series under different operational conditions, including pH, mixing rate, and initial inoculum, and three different decreasing hydraulic retention times were considered, with a fixed ratio of 1:10 in volume between the first bioreactor (hydrogen) and the second one (methane). The performance of the whole system was assessed over > 140 days to monitor the stability of the process, in terms of the reduction of the volatile solids and the energy productivity for each step. Each tested condition was scored using two parameters: efficiency and efficacy. The first corresponds to the fraction of recovered energy of the available (η) and the second (ξ) was used to compare the energy produced by the TSAD with that of one-step anaerobic digestion. The efficiency resulted to be (24–32)%, while the efficacy proved to be around 1.20. The share of energy, under the form of hydrogen, compared to the total energy recovery, was in the (8–12) % range. Finally, the oscillation behaviour of the quasi-steady-state condition was analysed in terms of the Fano factor to establish the most stable conditions.

Effects of butanol–gasoline blends on SI engine performance, fuel consumption, and emission characteristics at partial engine speeds Abstract The effects of using butanol–gasoline-blended fuels on performance, fuel consumption, and emission characteristics of a four-cylinder spark-ignition engine were experimentally investigated. The butanol-blending fraction was varied from 10 to 50% by volume. The engine speeds were tested at 2250 and 4250 rpm, while the throttle positions were set at 30% and 70%. The engine performance, specific fuel consumption, and emission properties have been carried out and compared. The results show that, at high throttle position, the flame propagation speed of combustion process as using the butanol–gasoline blends decreases as increasing the butanol-blending fraction and this becomes more obvious with the increase of engine speed. The engine brake torque and power are improved, as the butanol-blending fraction is less than 30% at low open throttle position, while those are gradually decayed as increasing throttle opening level. A significant reduction is observed in specific fuel consumption, as the butanol-blending fraction is less than 30% for all the tests. The emissions of CO, HC, and CO2 in the case of using butanol–gasoline blends are much better than those in the case of using pure gasoline. However, NOx emission is worse than that of the pure gasoline for all the test blends.

Developing a durable thermally insulated roof slab system using bamboo insulation panels Abstract Traditional roofs can be effectively substituted by reinforced concrete roof slabs while gaining multiple advantages such as cyclonic resistance, possibility of future vertical extension and possibility of utilizing as an extra working space or a rooftop garden. Further, it adds a significant economic benefit from land regaining. However, the immediate space beneath the roof slab results in thermal discomfort and hence the inventions related to insulated roof slab systems have been increased recently. Although the expected thermal comfort could be achieved, most of the inventions use artificial thermal insulation materials such as polystyrene. This paper introduces a novel roof slab insulation system which uses the natural material of transversely cut bamboo layer as the thermal insulator. The proposed system minimizes the negative environmental impacts induced by the use of artificial insulation materials. The optimum insulation layer thickness is found to be 25 mm, which has acquired a 53% peak heat gain reduction with a decrement factor of 0.61 and a 3-h time lag.

The Franconian Basin thermal anomaly: testing its origin by conceptual 2-D models of deep-seated heat sources covered by low thermal conductivity sediments Abstract This study presents conceptual 2-D models for coupled fluid flow and heat transport simulations of the Franconian Basin in SE Germany to verify the plausibility of different hypothesis on the origin of a local temperature anomaly. The simulated geothermal systems consist of a deep-seated heat source within an impermeable basement (heat-producing granite or enhanced background heat flow), covered by low thermal conductivity sediments. Solely conductive or additional convective heat transport including the presence of a permeable fault was applied. We found that heat transfer in the model setups is strongly controlled by (1) the volume of the heat-producing granite, (2) the amount of the background heat flow, (3) the permeability of the basement rocks, (4) the thermal conductivity contrasts between the sedimentary cover and the basement, and (5) the type of heat transport. If there is no reliable information on these model parameters, a high degree of uncertainty with regard to quantitative statements on the heat transfer in the specific geothermal system can be expected. An equilibrium temperature log from the study area could only be reproduced by (1) an enhanced background heat flow of 0.115 W m−2, in combination with a permeable fault zone of permeability 1.0 × 10−13 m2 or (2) a heat-producing granite of large cross-sectional area (300 km2) in combination with an average background heat flow of 0.070 W m−2. Moreover, high temperatures were only achieved in the presence of a low conductive, insulating cover above the heat source.

A new approximate capacity factor method for matching wind turbines to a site: case study of Humber region, UK Abstract Wind-based power is one of the renewable base power sources that are tipped to play a great role in decarbonising the globe. To achieve this potential, more wind farms are likely to be built. The capacity factor of a wind farm and hence its profitability is dependent on whether it is properly sized and sited. In fact, some wind power plants have failed wholly or underperformed, because the wind turbine plant installed did not match the wind site. In this paper, a new approximate capacity factor equation has been derived for matching wind turbines to potential site for optimum yield and profitability. The indexes of capacity factor and cost of electricity were used as metrics in the model. The proposed model was applied to the climatic conditions and wind turbine characteristics of Kappadagudda and Mailiao wind farms in India and Taiwan, respectively. The result obtained showed good agreement with measured data for the two wind farms. With respect to the Kappadagudda wind farm, the model computed CF of 38% is close to the Kappadagudda real wind farm annual CF of 36% representing an absolute error of 2% and a mean square error of 0.96%. In addition, it was found that the proposed model followed the same general trend with other six existing models compared.

Assessing the duality of thermal performance and energy efficiency of residential buildings in hot arid climate of Laghouat, Algeria Abstract Thermal comfort is the main driver of buildings energy consumption; it has been classified by building occupants to be of greater importance compared with visual and acoustic comfort. To respond correctly and quickly to the increase in energy price and pollution, thermal regulations and comfort approaches have emerged. This paper compares the thermal performances and energy demand of a vernacular and a low-income modern dwelling using two major thermal comfort approaches (Givoni’s approach and adaptive thermal comfort recommended by The American Society of Heating, Refrigerating and Air-Conditioning Engineers in ASHRAE standards 55-2010) and the energy professional’s method presented in the French Thermal Regulations RT2012. It shows the effectiveness of bioclimatic and passive strategies in reducing energy demand, increasing the thermal comfort level for the buildings, and therefore reducing greenhouse emissions. The results show that the vernacular house was comfortable during the warm day, which approved a 100% cooling energy efficiency (the thermal comfort has been achieved in a passive way), contrary to the contemporary dwelling, in which the use of air-conditioning modern systems was essential to meet the occupant needs in terms of thermal comfort. The difference between the houses’ energy performances was estimated, including a 39% reduction in energy demand.