The traditional electrochemical caustic soda recovery system uses the generated pH gradient across the ion exchange membrane for the regeneration of spent alkaline absorbent from COsub.2 capture. ...This electrochemical COsub.2 capture system releases the by-products Hsub.2 and Osub.2 at the cathode and anode, respectively. Although effective for capturing COsub.2, the slow kinetics of the oxygen evolution reaction (OER) limit the energy efficiency of this technique. Hence, this study proposed and validated a hybrid electrochemical cell based on the Hsub.2-cycling from the cathode to the anode to eliminate the reliance on anodic oxygen generation. The results show that our lab-scale prototype enabled effective spent caustic soda recovery with an electron utilisation efficiency of 90%, and a relative carbonate/bicarbonate diffusional flux of approximately 40%. The system also enabled the regeneration of spent alkaline absorbent with a minimum electrochemical energy input of 0.19 kWh/kg COsub.2 at a COsub.2 recovery rate of 0.7 mol/msup.2/h, accounting for 30% lower energy demand than a control system without Hsub.2-recycling, making this technique a promising alternative to the conventional thermal regeneration technology.
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•The Paris Agreement goal of stabilizing temperature below 1.5C calls for a reduction of global energy consumption.•Energy Efficiency policies are necessary but not sufficient to ...reduce energy consumption.•Energy Conservation and Energy Sufficiency Policies complement Energy Efficiency policies, together they can reduce energy demand.•The article presents some existing and new policies which address sufficiency.•There is the need for coherent policy package with different types of policy instruments addressing efficiency and sufficiency.
There is a strong consent among scholars and policy makers that limiting current global energy demand and gradually reducing it towards a sustainable level of consumption is a key component of any strategies and pathways to reach the Paris Agreement climate target, and, in particular, carbon neutrality by mid-century. Given the stringency and urgency of the climate target and the current global increase of energy demand, in addition to investments in energy efficiency technologies, there is the need for a change of energy end-users behaviour and life style to obtain additional energy savings by limiting the demand for services. Traditionally, energy efficiency policies have mainly targeted and promoted energy efficient technologies (e.g., energy performance standards for vehicles, appliances and buildings, financial incentives for new technologies, etc.). In some cases, the energy savings achieved have been less than expected, due to a rebound effect, or because external factors (e.g., growth in populations or economies) have increased energy consumption. The “traditional” energy efficiency policies are still very necessary, but are not sufficient for reaching the Paris Agreement target and the rapid reduction of the energy demand.
Policies focusing on energy conservation and sufficiency principles complement efficiency policies, in particular those aiming at changing end-user consumer behaviour and lifestyle by imposing some limitation to the demand for energy services. The article first reviews the concept of energy savings compared to energy efficiency and introduce the concept of energy sufficiency. Then the article explores and discusses some existing and new policy instruments that can address energy conservation and sufficiency such as: personal carbon allowances; energy/carbon taxation; progressive appliance and vehicles standards, and progressive building codes. The article’s focus is mainly on individual end-users and on residential buildings. Finally, the article provides an ex-ante assessment of the policies analysed, including their limitations, and offers some policy recommendations, based on a combination of instruments.
The energy efficiency of irrigation systems is an aspect of great importance in all design and management processes; For this reason, an investigation was carried out in the "Tio Pedro" farm located ...in the municipality of Venezuela, Ciego de Avila province during the years 2021 and 2022 with the objective of estimating the general energy yield in the furrow irrigation system. During this period, the pump unit offers the following average operating regime: pump flow rate of 61.1 L s.sup.-1; pumping time of 2,8 hours and pumping head of 18.2 m. This behavior reduces a hydraulic power of 10.9 kW and a pump efficiency of 85.2%. The energy supplied in pumping was 429.4 kWh and the energy absorbed in the evaluated period was 631.9 kWh. In relation to the energy parameters of the system, an energy balance of the supply of 7,4 m was obtained; a system energy load index of 15.2 m; an energy efficiency of the pumping of 68.2% (excellent) and a general energy efficiency of the system of 34.0% (normal). Keywords: Hydraulic Efficiency, Hydraulic Power, Energy Efficiency of Pumping. La eficiencia energetica de los sistemas de riego es un aspecto de gran importancia en todos los procesos de diseno y manejo; por este motivo se desarrollo una investigacion en la finca "Tio Pedro" ubicada en el municipio de Venezuela, provincia Ciego de Avila durante los anos 2021 y 2022 con el objetivo de estimar el rendimiento energetico general en el sistema de riego por surcos. Durante este periodo la unidad de bombeo funciono con el siguiente regimen de operacion promedio: caudal de bombeo de 61,1 L s.sup.-1; tiempo de bombeo de 2,8 horas y carga de bombeo de 18,2 m. Este comportamiento determino una potencia hidraulica de 10,9 kW y rendimiento de la bomba de 85,2%. La energia suministrada en el bombeo fue de 429,4 kWh y la energia absorbida en el periodo evaluado de 631,9 kWh. En relacion con los parametros energeticos del sistema se obtuvo un balance energetico del suministro de 7,4 m; un indice de carga energetica del sistema de 15,2 m; un rendimiento energetico del bombeo de 68,2% (excelente) y un rendimiento energetico general del sistema de 34,0% (normal). Palabras clave: Eficiencia hidraulica, potencia hidraulica, rendimiento energetico del bombeo.
The energy efficiency of irrigation systems is an aspect of great importance in all design and management processes; For this reason, an investigation was carried out in the "Tio Pedro" farm located ...in the municipality of Venezuela, Ciego de Avila province during the years 2021 and 2022 with the objective of estimating the general energy yield in the furrow irrigation system. During this period, the pump unit offers the following average operating regime: pump flow rate of 61.1 L s.sup.-1; pumping time of 2,8 hours and pumping head of 18.2 m. This behavior reduces a hydraulic power of 10.9 kW and a pump efficiency of 85.2%. The energy supplied in pumping was 429.4 kWh and the energy absorbed in the evaluated period was 631.9 kWh. In relation to the energy parameters of the system, an energy balance of the supply of 7,4 m was obtained; a system energy load index of 15.2 m; an energy efficiency of the pumping of 68.2% (excellent) and a general energy efficiency of the system of 34.0% (normal).
Improved energy efficiency is one of the key elements to decouple energy-related emissions from economic growth. Since the energy management practices in small and medium-sized enterprises are ...underdeveloped, most of the energy efficiency potential is left untapped. Studies show that several barriers pertaining to economic, technological, and organizational systems lead to poor implementation rates of energy efficiency measures. An energy efficiency network is considered effective in overcoming these barriers and promoting energy management practices in small and medium-sized enterprises. This paper explores the role of energy efficiency networks, and specifically the role of its functions in overcoming the identified barriers from literature. This study was carried out as a multiple case study including 13 industrial small and medium-sized enterprises using semi-structured interviews with participants from companies in a Swedish regional energy efficiency network program. Results show that energy efficiency networks are effective in overcoming some of the barriers to energy efficiency implementation and that the present functions are effective in addressing some barriers faced by small and medium-sized enterprises, e.g., energy efficiency implementation barriers such as lack of time and resources. However, some barriers still remain as constraints for energy efficiency implementation, even after energy efficiency network participation.
•Presentation of a novel methodology by using theory of barriers for network evaluation.•Energy efficiency networks reduce some of the barriers to energy efficiency.•The energy audit was the most favorable network function to network participants.•The energy audit and the lectures on efficiency were the network functions that reduced most barriers.
This paper considers an intelligent reflecting surface (IRS)-aided simultaneous wireless information and power transfer (SWIPT) network, where multiple users decode data and harvest energy from the ...transmitted signal of a transmitter. The proposed design framework exploits the cost-effective IRS to establish favorable communication environment to improve the fair energy efficient. In particular, we study the max-min energy efficiency (EE) of the system by jointly designing the transmit information and energy beamforming at the base station (BS), phase shifts at the IRS, as well as the power splitting (PS) ratio at all users subject to the minimum rate, minimum harvested energy, and transmit power constraints. The formulated problem is non-convex and thus challenging to be solved. We propose two algorithms namely penalty-based and inner approximation (IA)-based to handle the non-convexity of the optimization problem. As such, we divide the original problem into two sub-problems and apply the alternating optimization (AO) algorithm for both proposed algorithms to handle it iteratively. In particular, in the penalty-based algorithm for the first sub-problem, the semi-definite relaxation (SDR) technique, difference of convex functions (DC) programming, majorization-minimization (MM) approach, and fractional programming theory are exploited to transform the non-convex optimization problem into a convex form that can be addressed efficiently. For the second sub-problem, a penalty-based approach is proposed to handle the optimization on the phase shifts introduced by the IRS with the proposed algorithms. For the IA-based method, we jointly optimize beamforming vectors and phase shifts while the PS ratio is solved optimally in the first sub-problem. Simulation results verify the effectiveness of the IRS, which can significantly improve the system EE as compared to conventional benchmark schemes and also unveil a trade-off between convergence and performance gain for the two proposed algorithms.
•factors (e.g., efficient lightbulbs) have the largest impact on energy efficiency.•Owned residences were on average 6% more efficient than rented homes.•Families with at least one highly-educated ...member were on average more energy efficient.•The intent to save and actual savings were aligned in our sample.
This paper offers a novel method to rank residential appliance energy efficiency utilizing energy efficiency frontiers. The method is validated using a real-world case study of 4231 buildings in Ireland. Our results show that structural factors have the largest impact on energy efficiency, followed by socioeconomic factors and behavioral factors. For example, households with high penetration of efficient lightbulbs and double-glazed windows were on average 4 and 3.5% more efficient than others. Households with the head of household having higher education are on average 1.3% more efficient than their peers. Finally, households that track their energy savings are on average 0.4% more efficient than others.
Furthermore, installing heater timers, wall insulation, and living in owned residences were correlated with higher efficiency. Generally, families with kids who have full-time employment and are highly-educated are more efficient compared to families with no kids, or families with retirees or unemployed members. This result has important implications for both targeting and messaging of energy efficiency programs.
Some behavioral factors demonstrated significant impact on appliance energy efficiency. For instance, households that expressed interest in making major energy-saving lifestyle changes scored higher efficiency ranks on average. Conversely, households that expressed doubt about their motivation to save energy ranked lower in efficiency. This finding validates the role of educational programs to increase awareness about energy efficiency and its importance.
In short, our results show that a data-driven analysis of a population is needed to develop a balanced view of the drivers of energy efficiency, and to devise a targeted approach to improve homes’ energy efficiency.
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