Total Energy Requirement Research Articles

Investigation of renewable methanol production from CO2 hydrogeneration based on spectral splitting and heat integration

This study concerns a green hybrid system of methanol production via CO2 hydrogeneration, where the full spectrum solar energy is separated by spectral beam splitter to generate high temperature heat and electrical energy for solvent regeneration in CO2 capture unit and water electrolysis in proton exchange membrane electrolyzer, respectively. Then, heat integration is conducted among the whole system to recover the internal waste heat and minimize the total energy requirement. Thus the intermittency solar energy can be efficiently stored into the transportable methanol product through energy carrier of H2. The entire integrated scheme is simulated using Aspen Plus, while energy, exergy and environmental performances are investigated comprehensively to reveal the improvements of proposed system. Results show that with the electrolytic power of 60 MW, methanol synthesis condition of 250 °C and 100 bar, space velocity lower than 10 m3/kgcat·h, the overall efficiency of the proposed system reaches up to 41.61% (MSCH). Through system-level heat integration and solar energy supplement, the heating and cooling utility is reduced by 60.38% and 42.10%, which significantly improves the overall efficiency to 54.31% in winter (MSCH-HI-W) and 81.77% in summer (MSCH-HI-S), with the largest energy loss obtained at electrolysis cell. From the standpoint of exergy, the overall exergy efficiency is 53.14% in winter (MSCH-HI-W) and 79.75% in summer (MSCH-HI-S). Consequently, 210.59 kmol/h of CO2 is taken in by the proposed system and ends up in valuable methanol of 170.15 kmol/h, highlighting the strong potential of heat integration for overall performance enhancement and providing guidelines for future development of renewable energy utilization and storage under low carbon vision.

Review: Harnessing extant energy and protein requirement modeling for sustainable beef production.

Numerous mathematical nutrition models have been developed in the last sixty years to predict the dietary supply and requirement of farm animals' energy and protein. Although these models, usually developed by different groups, share similar concepts and data, their calculation routines (i.e., submodels) have rarely been combined into generalized models. This lack of mixing submodels is partly because different models have different attributes, including paradigms, structural decisions, inputs/outputs, and parameterization processes that could render them incompatible for merging. Another reason is that predictability might increase due to offsetting errors that cannot be thoroughly studied. Alternatively, combining concepts might be more accessible and safer than combining models' calculation routines because concepts can be incorporated into existing models without changing the modeling structure and calculation logic, though additional inputs might be needed. Instead of developing new models, improving the merging of extant models' concepts might curtail the time and effort needed to develop models capable of evaluating aspects of sustainability. Two areas of beef production research that are needed to ensure adequate diet formulation include accurate energy requirements of grazing animals (decrease methane emissions) and efficiency of energy use (reduce carcass waste and resource use) by growing cattle. A revised model for energy expenditure of grazing animals was proposed to incorporate the energy needed for physical activity, as the British feeding system recommended, and eating and rumination (HjEer) into the total energy requirement. Unfortunately, the proposed equation can only be solved iteratively through optimization because HjEer requires metabolizable energy (ME) intake. The other revised model expanded an existing model to estimate the partial efficiency of using ME for growth (kg) from protein proportion in the retained energy by including an animal degree of maturity and average daily gain (ADG) as used in the Australian feeding system. The revised kg model uses carcass composition, and it is less dependent on dietary ME content, but still requires an accurate assessment of the degree of maturity and ADG, which in turn depends on the kg. Therefore, it needs to be solved iteratively or using one-step delayed continuous calculation (i.e., use the previous day's ADG to compute the current day's kg). We believe that generalized models developed by merging different models' concepts might improve our understanding of the relationships of existing variables that were known for their importance but not included in extant models because of the lack of proper information or confidence at that time.

Polymorphism at the CSN1S1 Locus and Energy Intake Level Affect Milk Traits and Casein Profiles in Rossa Mediterranea Goats.

A total of twenty-seven Rossa Mediterranea lactating goats, consisting of nine homozygous for strong alleles (AA), twelve heterozygous (AF) and six homozygous for weak alleles (FF) at the CSN1S1 locus, were used to evaluate the effect of genotype, diet and genotype × diet interaction on goat milk traits and casein profile. The goats were used in a 3 × 3 factorial arrangement of treatments, with three genotypes (AA, AF and FF) and three different energy intake levels: high (H), medium (M) and low (L). The diets supplied a complete pelleted feed containing 65% of alfalfa hay, respectively, at 150%, 100% and 70% of the total energy requirements. Milk yield was significantly affected by the genotype and diet: Lower levels were found in FF goats than in AA and AF genotypes (673.7 vs. 934.5 and 879.8 d/g, respectively; p = 0.002) as well as in goats fed with the L diet (651.5 vs. 1041 and 852.9 g/d for H and M diet, respectively, p < 0.001). The genotype influenced the casein profile. Specifically, AA goat milk exhibited higher concentrations of total casein and αs1-casein compared to AF and FF genotypes (for total casein and αs1-casein, respectively: 24.9 vs. 20.4 and 19.8 g/kg, p = 0.001; 7.2 vs. 3.7 and 0.7 g/kg, p < 0.001), while the FF genotype showed higher values for αs2-casein concentrations compared to homozygous AA and heterozygous AF goats (3.1 vs. 2.4 and 2.5 g/kg, respectively, p < 0.001). A significant genotype x diet interaction occurred for αs2-casein levels (g/kg) (p = 0.034) and αs1-casein yields (p = 0.027): The αs2-casein level was not affected by the diet in AA goats, whereas it increased with energy intake in AF and FF genotypes. Conversely, the αs1-casein yield gradually increased with energy intake in AA and AF groups, whereas the diet in FF goats did not modify it. The results demonstrated that high energy input, as well as the strong allele at the CSN1S1 locus, enhanced milk production and casein concentrations. Furthermore, they confirmed the existence of an interaction between αs1-casein polymorphism and diets, influencing the milk casein composition and yield.

Peripheral parenteral nutrition: An evaluation of its use, safety and cost implications in a tertiary hospital setting

Malnutrition is a common challenge among hospitalised patients and its associatiation with poor patient health-related outcomes places a significant financial burden on the healthcare system. Total parenteral nutrition (TPN) is the primary means for providing nutrition to individuals in whom enteral feeding is not possible but is costly and requires invasive central venous access. Peripheral parenteral nutrition (PPN) provides a suitable option for early nutrition provision in select patients; however, its routine use has been limited by safety and tolerability concerns, with high rates of phlebitis reported in previous studies. The objectives of this study were to review the use, safety, and costs of PPN in an Australian tertiary hospital. A single-site, prospective observational study was conducted over 15 months in a tertiary hospital. 139 participants (87 male and 52 female) were enrolled in the study. Data collected assessed the indication for PPN initiation, compliance with the hospital's protocols for PPN, total fasting days, the proportion of the patient's total energy and protein requirements provided by PPN, the incidence of phlebitis and potential cost implications associated with the use of PPN. 139 patients (62.6% male), median age 62 years (IQR (interquartile range) 48-74) were enrolled. Most patients had an emergency admission (80.6%) under a general surgical team (84.2%). Forty-eight patients (34.5%) were malnourished, as assessed by the Subjective Global Assessment tool (SGA). Patients fasted for a median of 3 days (IQR 2-5) before PPN commencement, with a median duration of PPN use of 3 days (IQR 2-4). PPN provided an average of 61.6% of the patients' required caloric intake and 46.4% of protein requirements. Progression to TPN was observed in 34.5% of patients. There were low rates of complications with phlebitis observed in 3.7%, extravasation in 1.1%, and no patients developed septicaemia, despite suboptimal compliance with the recommended cannula management guidelines for PPN (66.4% compliant). The cost of PPN was estimated to be AUD$187 per patient day. PPN is an effective short-term nutrient delivery solution to facilitate early feeding with small numbers of patients requiring transition to TPN. PPN was safe with low rates of cannula complications. Costs were favourable, with potentially significant cost savings as compared with TPN.

Evaluasi Kebutuhan Energi dari Teknologi Distilasi Spray sebagai Alternatif Hijau Proses Hilirisasi Bioetanol

Bioethanol downstream processing is consuming 40-60% of total energy requirement in production of bioethanol as fuel, with highest consumption being the evaporation and distillation process. One of the technologies currently in development stage is spray distillation. In spray distillation, ethanol-water mixture feed is dispersed as micro droplets into a heated column at 40oC, while counter current air is flown upward to collect the vapor and discharged into condensation column. Since the spray distillation principles has been tested in controlled laboratory scale, this research objective is to evaluate the energy requirement for such process and comparison to conventional distillation. Testing was conducted on 20 L batch stainless steel column distillation and spray distillation of the same capacity. The ethanol concentration in feed was set to 15%-v to simulate fermentation broth, and operating parameters were sets to obtain 80%-v product. Batch distillation was heated using LPG gas and calculation shows that heat requirement 3.34 MJ/L pure ethanol equivalent. Alternatively, spray distillation running with feed rate of 5.05 ml/s at 40oC only requires 2.2-2.6 MJ/L pure ethanol equivalent. The study shows potential of spray distillation technology in reducing the energy requirement in downstream processing of bioethanol to 62-79% of conventional distillation.

Environmental impact assessment of green ammonia coupled with urea and ammonium nitrate production

This study aims to explore more sustainable ammonia production routes for urea and ammonium nitrate fertilizers to support the rising global food demand and help achieve the Net Zero Emissions scenario by 2050. The research uses process modelling tools and Life Cycle Assessment methodology to evaluate the technical and environmental performance of green ammonia production compared to blue ammonia production, both pathways coupled with urea and ammonium nitrate production processes. The blue ammonia scenario uses steam methane reforming for H2 production, while the sustainable approach scenarios consider water electrolysis with renewable resources (i.e., wind, hydro and photovoltaics) and nuclear power as a carbon-free source for H2 generation. The study assumes an annual productivity of 450,000 tons for both urea and ammonium nitrate. The environmental assessment uses mass and energy balance data derived from process modelling and simulation. A cradle-to-gate environmental evaluation is conducted using GaBi software and the Recipe 2016 impact assessment method. Results show that green ammonia production requires less raw materials but has higher energy consumption due to electrolytic H2 production (i.e., >90% of total energy requirements). The use of nuclear power achieves the highest reduction in global warming potential (i.e., 5.5 times for urea and 2.5 times for ammonium nitrate production processes), while hydro power coupled with electrolytic H2 production shows lower environmental impacts in most categories (i.e., six out of ten impact categories). Overall, the sustainable scenarios prove to be suitable alternatives for fertilizer production towards achieving a more sustainable future.

Comparing the Effects of Consuming Almonds or Biscuits on Body Weight in Habitual Snackers: A 1-Year Randomized Controlled Trial

Background: Almonds are nutrient rich, providing a healthier alternative to many snacks. Studies report health benefits with regular almond consumption without adverse weight gain. However, most interventions have been relatively short or have included additional dietary advice. ObjectivesTaking a pragmatic approach, we compared consumption of almonds compared with biscuits on body weight and other health outcomes in a population of regular snackers of discretionary foods, hypothesizing the almonds will displace some of the less-healthful snacks in their current diets. MethodsWe randomly assigned 136 nonobese habitual discretionary snackers to receive almonds or biscuits daily for 1 y. These isocaloric snacks provided either 10% of participants’ total energy (TE) requirements or 1030 kJ (equivalent to 42.5 g almonds), whichever was greater. Anthropometry, blood biomarkers, diet, appetite, sleep, and physical activity were assessed at baseline, 3, 6, and 12 mo, and body composition and RMR at baseline and 12 mo. ResultsThe difference in changes for body weight from baseline to 12 mo was not statistically significant (geometric means: 67.1 and 69.5 kg for almonds and 66.3 and 66.3 kg for biscuits, P = 0.275). There were no statistically significant differences in changes for body composition or other nondietary outcomes (all P ≥ 0.112). Absolute intakes of protein; total, polyunsaturated, and monosaturated fat; fiber; vitamin E; calcium; copper; magnesium; phosphorous; and zinc, and % TE from total monounsaturated, and polyunsaturated fat statistically significantly increased from baseline (all P ≤ 0.033), whereas % TE from carbohydrate and sugar statistically significantly (both P ≤ 0.014) decreased from baseline, in the almond compared with the biscuit group. ConclusionsAlmonds can be incorporated into the diets of habitual snackers to improve diet quality, without evidence for changes in body weight, compared with a popular discretionary snack food. This trial was registered at the Australian New Zealand Clinical Trials Registry (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375610&isReview=true), registration number ACTRN12618001758291.

Novel Planning Methodology for Spatially Optimized RES Development Which Minimizes Flexibility Requirements for Their Integration into the Power System

An optimization model which determines optimal spatial allocation of wind (WPPs) and PV power plants (PVPPs) for an energy independent power system is developed in this paper. Complementarity of the natural generation profiles of WPPs and PVPPs, as well as differences between generation profiles of WPPs and PVPPs located in different regions, gives us opportunity to optimize the generation capacity structure and spatial allocation of renewable energy sources (RES) in order to satisfy the energy needs while alleviating the total flexibility requirements in the power system. The optimization model is based on least squared error minimization under constraints where the error represents the difference between total wind and solar generation and the referent consumption profile. This model leverages between total energy and total power requirements that flexibility resources in the considered power system need to provide in the sense that the total balancing energy minimization implicitly bounds the power imbalances over the considered time period. Bounding the power imbalances is important for minimizing investment costs for additional flexibility resources. The optimization constraints bound the installed power plant capacity in each region according to the estimated technically available area and force the total energy production to equal the targeted energy needs. The proposed methodology is demonstrated through the example of long-term RES planning development for complete decarbonization of electric energy generation in Serbia. These results could be used as a foundation for the development of the national energy strategy by serving as a guidance for defining capacity targets for regional capacity auctions in order to direct the investments in wind and solar power plants and achieve transition to dominantly renewable electricity production.

Pilot-scale crossflow ultrafiltration of four different cell-sized marine microalgae to assess the ultrafiltration performance and energy requirements

Four marine microalgae (e.g., Tetraselmis, Picochlorum, Dunaliella, and Synechococcus) with different cell sizes were harvested using pilot-scale ultrafiltration. Average permeate fluxes were 16.75, 19, 25.35, and 33.75 L/m2h at 60 min for Synechococcus, Dunaliella, Picochlorum, and Tetraselmis, respectively. The concentrating factors for Synechococcus, Picochlorum, Dunaliella, and Tetraselmis were 46.6, 42, 39.2, and 39.5, respectively. The highest and lowest microalgal biomass retention was 47.1 and 41.7% for Tetraselmis and Synechococcus, respectively. Due to higher microalgal biomass retention, initial crossflow velocities of 0.16 to 0.18 m/s were reduced to 0.02 to 0.05 m/s for Tetraselmis and Dunaliella sp. The total harvesting energy requirement by membrane and centrifuge was 16.44 – 28.48 GJ/tonne biomass; the smaller the cell size, the lower the energy requirement. The optimum biomass concentrating factor by the membrane filtration process also depended on size; for optimum total energy requirement, tangential flow filtration (TFF) could concentrate a smaller strain more than a larger strain.

Body Fat Percentage and Blood Donation are the Strongest Determinants of Iron Stores in Premenopausal Women Joining the New Zealand Army.

Suboptimal iron status is an issue for women joining the military because of its association with impaired aerobic performance, yet no studies have investigated dietary and non-dietary determinants of iron status simultaneously in this population. The purpose of this study was to explore associations between iron stores, dietary patterns (DPs), and potential non-dietary determinants of iron status in premenopausal women at the commencement of basic military training (BMT) in the New Zealand Army. During week 1 of BMT, demographic, body composition, lifestyle, medical history, and dietary data were measured as potential determinants of serum ferritin (SF) in 101 participants. Following univariate analysis, age, body fat percentage, previous blood donation, at least 6 h of exercise per week that raised the heart rate, and a vegetarian DP were analyzed using a multiple linear regression model. An increase in body fat percentage was associated with increased SF (P < .009), although blood donation in the past year decreased SF (P < .011) compared to those participants who did not donate blood. There was no association between SF and a vegetarian DP or hours of exercise per week. The model explained 17.5% of the variance in SF at the commencement of BMT. Body fat percentage and blood donation in the past year were the strongest determinants of iron stores in healthy premenopausal women commencing BMT. It is recommended that women joining the New Zealand Army are provided information to maintain or improve their iron status based on these findings. This includes clinical screening of iron status, advice for women considering blood donation, and dietary advice regarding total energy requirements and iron bioavailability.

Systematic bias in reanalysis-derived solar power profiles & the potential for error propagation in long duration energy storage studies

This study consolidates the literature relating to the systematic bias of model-derived irradiance data and further characterises the same for ERA-5 and MERRA-2, two reanalysis datasets that are frequently used to model renewable power in energy system modelling studies. The bias errors yielded when modelling Solar PV generation for solar parks in Australia and Northern Ireland are compared under the optics of typically clear versus typically cloudy respective climates. Evidence is presented that MERRA-2 exhibits a significant global overestimation bias, contrary to some literature that suggests local variation and underestimation in some locations. Based on the trends identified, it is proposed that overestimation bias proliferates in more cloudy climates for both reanalysis datasets. The implications of such bias for studies involving long-duration energy storage with low round-trip efficiency are investigated and an unfortunate mechanism for error propagation is highlighted. A simplified power system consisting of wind, solar, and energy storage is modelled to demonstrate this effect with solar power profiles derived from metered generation, ERA-5, and MERRA-2. It shown that greater systematic bias of MERRA-2, in combination with the opportunity for error propagation through low-round trip efficiency, has the potential to significantly distort the charging & discharging pattern, overall utilization, and total energy requirement of long duration energy storage infrastructure. ERA-5, despite also exhibiting systematic bias, was better able to reproduce the simulated results of the metered generation scenario. Finally, it is recommended that energy modellers using MERRA-2 data to simulate solar PV outputs should now migrate to ERA-5 if reanalysis data is to be used.

Life Cycle Assessment (LCA) of Greywater Treatment Using ZnCl2 Impregnated Activated Carbon and Electrocoagulation Processes: A Comparative Study

The growing worldwide population, climate change, and decaying water infrastructure have all contributed to a need for a sustainable greywater treatment technology. The adsorption and electrocoagulation processes have shown potential to contribute to this vision; however, its burden to the environment and economy is also a necessary aspect to study. The life cycle assessment of both processes is conducted in this study. The obtained results for the adsorption system demonstrate that the adsorbent production stage highly impacts the environment. The use of ZnCl2 in the impregnation of sawdust has an enormous influence on the environmental indicators, namely ADPE (99.9%), FAETP (79.5%), and ODP (76.5%). The coproducts formed during the adsorbent production stage are recycled, and the recovered energy has been utilized in its subprocesses to reduce the burden on the total energy requirement. On the other hand, the energy and raw material requirement in the electrocoagulation process are significantly less; hence, it shows an eight times lower global warming potential (GWP) toward the environment. The scenario analysis indicates that the environmental impact (for instance, ADPE, AP, EP, FAETP, HTP, POCP, and TETP) while using electricity from natural gas is comparatively lesser than other energy sources. The sensitivity analysis of both the adsorption and electrocoagulation processes was investigated by taking a ±20% difference in the values of process parameters. The cost analysis shows that the electrocoagulation process is more cost-effective than the adsorption process.

Total Energy Expenditure in Healthy Ambulatory Older Adults Aged ≥80 Years: A Doubly Labelled Water Study

Introduction: The life expectancy of older adults continues to increase; however, knowledge regarding their total energy requirements is lacking. This study aimed to compare the total energy expenditure (TEE) of older adults ≥80 years measured using doubly labelled water (DLW), with estimated TEE. The hypothesis was that the Mifflin, Ikeda, and Livingston equations will more closely estimate energy requirements than the commonly used Schofield equation. Methods: Resting metabolic rate (RMR) and TEE were measured using the reference methods of indirect calorimetry and DLW, respectively. Bland-Altman plots compared measured RMR and TEE with predicted RMR using equations (Mifflin, Ikeda, Livingston, Schofield) and predicted TEE (predicted RMR × physical activity level). Results: Twenty-one older adults (age range 80.7–90.1 years, BMI 26.1 ± 5.5 kg/m2) were included. The Schofield equation demonstrated the greatest bias from measured RMR, overestimating approximately up to double the mean difference (865 ± 662 kJ/day) compared with the three other equations. The Schofield equation exhibited the greatest bias (overestimation of 641 ± 1,066 kJ/day) compared with measured TEE. The other three equations underestimated TEE, with the least bias from Ikeda (37 ± 1,103 kJ/day), followed by Livingston (251 ± 1,108 kJ/day), and Mifflin (354 ± 1,140 kJ/day). Data are mean ± SD. Conclusions: In older adults ≥80 years, the Ikeda, Mifflin, and Livingston equations provide closer estimates of TEE than the widely used Schofield equation. The development of nutrition guidelines therefore should consider the utilization of equations which more accurately reflect age-specific requirements.

Enhancing the Energy Efficiency of Buildings by Shading with PV Panels in Semi-Arid Climate Zone

Solar energy is one of the most abundant and available forms of renewable energy. Reliance on the electricity network can be decreased and net-zero energy achieved by mounting photovoltaic power on the tops of houses. Photovoltaic arrays can also change how the roof’s surface reacts to its environment. The influence of the structural system of a roof and weather on the energy consumption of a building is important. This research is concerned with focusing on the indirect effect of solar photovoltaic rooftop panels (shading effect) on the roof surface to see whether this effect is worth studying and calculating the total electrical load in the residential sector. Photovoltaic panels were modeled as a shading device, and the Integrated Environmental Solution-Virtual Environment Software was used to anticipate the monthly decline and growth in heating and cooling loads associated with the roof level. The influence of a photovoltaic system on a building’s roof-related energy load was measured concerning low-rise residential buildings in Mafraq city, which belongs to a mild dry-warm temperature zone. The findings indicated that a solar roof structure decreased heat loss by 4.85% in the summer and boosted heat transfer by 5.54% in the winter. The results highlight that renewable energy is very important in our times due to climate change and the increased demand for electricity by the residential sector, which is stimulated to find multiple ways to decrease and adapt to this change, and the aim of this paper helps to encourage to use solar energy by identifying the indirect effect of solar panels on building’s rooftops. This investigation also focuses on the value of offering essential instructions to who is concerned to the utilization of alternative energy to heat and cool structures, also will educate the public on a building’s total energy requirements, which is critical for future green structure design.

Standalone hybrid PV/wind/diesel-electric generator system for a COVID-19 quarantine center.

This work is motivated by the need in overcoming the electricity crisis in Gaza, which is initiated due to political reasons and the spread of COVID-19. Building quarantine centers is one of the most important means used in combating the COVID-19, but connecting these centers to the electricity distribution network at the appropriate time is not always possible and increases the burden on the local utility company. This article proposed a hybrid off-grid energy system (HES) to effectively energize the quarantine COVID-19 center in Gaza economically and environmentally. To achieve this aim, the estimated load profile of the quarantine center is fed to the HOMER-Pro program. In addition, the various systems components are introduced to the program, then modeled, and optimized. The developed approach was tested using a real case study considering realistic input data. HOMER-Pro program is used to simulate and optimize the system design. The results revealed the potential of the HES to provide environment-friendly, cost-effective, and affordable electricity for the studied quarantine center, as compared to just the diesel generators system. For the considered case study, it is found that the PV-wind-diesel generators HES can cover the connected load with the lowest cost ($ 0.348/kWh) in comparison to other possible HES structures. Taking into consideration the price of harmful emissions, the wining system shows a reduction of 54.89% of the cost of energy (CoE) compared to other systems. For the considered case study, it is found that a combination of 150 kW PV, 200 kW wind, and two diesel generators with capacities of 500 and 250 kW can hold 100% of the electrical load required to keep the quarantine COVID-19 center in operation. The initial capital cost of this HES is $510,576 where the share of wind energy, solar PV, inverter, and diesel-electric generators are $320,000, $83,076, $25,000, and $82,500, respectively. The replacemen cost ($55,918) is due to diesel generators. The total operation and maintainance cost (O&M) is $268,737, that is, 25.6% for wind turbines, 1.2% for inverters, and 70.7% for diesel electric generators. The PV/wind/diesel generators HES generate 1,659,038 kWh of electricity. The total energy requirement of 1,442,553 kWh, which means a surplus of 212,553 kWh of energy/year. The total energy (kWh) is an integration of energy sources which are 427,276 (25.8%), 274,500 (16.5%), and 857,263 (57.7%), due to wind, solar and diesel generators respectively. The cost of yearly consumed fuel is $437,828.769. The payback period for the winning system is 1.8 years. Finally, it is proved that the developed approach gives a reasonable solution to the decision-makers to find a fast, economic and reliable solution to energize the quarantine centers.

Smart Room Lighting System for Energy Efficiency in Indoor Environment

The building sector absorbs 40% of global energy sources. Energy demand in the building sector is dominated by around 60 – 70% electricity, mainly used for air conditioning, water pumping machines, and lighting. On average, artificial lighting can consume 37% of the total electrical energy needs. Meanwhile, sunlight enters the room through the morning window from noon until the afternoon. Using unnecessary or excessive room lighting when there is a natural light source in the room consumes a relatively large total energy requirement of the building. There is a need for a smart lighting system specifically for indoors for efficient energy management and a lighting control system integrated with IoT, which utilizes the intensity of natural light in a room. In this paper, we proposed that the Smart Room Lighting System uses the fuzzy logic method based on ESP32 to control the lighting in the room to save electricity usage for a room lamp. The result of the tool's design, it can control the light starting from bright, dim, and lights go out. The results obtained by the Smart Room Lighting System can reduce power consumption by up to 93% and energy by up to 70%.

Freezing-Based Acid Gas Removal and Its Integration with the Cold Section in an LNG Plant

Natural gas (NG) feed undergoes a series of liquefaction and upgradation processes to produce the final liquefied natural gas (LNG) product that meets customer specifications. LNG processes have a significant capital investment and a high energy requirement, and hence many researchers have focused on process improvement and optimization. While much of the previous research has concentrated on the development of more energy-efficient processes (such as acid gas removal unit (AGRU), liquefaction, natural gas liquid (NGL) recovery, and nitrogen removal), reducing the energy consumption of the whole LNG plant has received little attention. Moreover, the power needs of the LNG plant and LNG product and fuel gas quality constraints remain briefly addressed. The present work proposes an integration between the acid gas freezing unit (FAGRU) with the cold section and suggests multiple structural changes to the cold section. The results showcase that the proposed integration and structural design changes lower the total energy requirement by 16.6% and increase the production rate by 60 kt/a (1.76%). Both these reduce specific energy consumption (SEC) by 17.98%. The feed-to-fuel (FFF) ratio decreases from 6.94% for the base process to 5.7% for the integrated process.

The potential for hydrogen ironmaking in New Zealand

Globally, iron and steel production is responsible for approximately 6.3% of global man-made carbon dioxide emissions, because coal is used as both the combustion fuel and chemical reductant. Hydrogen reduction of iron ore offers a potential alternative ‘near-zero-CO2’ route, if renewable electrical power is used for both hydrogen electrolysis and reactor heating. This paper discusses key technoeconomic considerations for establishing a hydrogen direct reduced iron (H2-DRI) plant in New Zealand. The location and availability of firm renewable electricity generation is described, the experimental feasibility of reducing locally-sourced titanomagnetite ironsand in hydrogen is shown, and a high-level process flow diagram for a counter-flow electrically heated H2-DRI process is developed. The minimum hydrogen composition of the reactor off-gas is 46%, necessitating the inclusion of a hydrogen recycle loop to maximise chemical utilisation of hydrogen and minimize costs. A total electrical energy requirement of 3.24 MWh per tonne of H2-DRI is obtained for the base-case process considered here. Overall, a maximum input electricity cost of no more than US$80 per MWh at the plant is required to be cost-competitive with existing carbothermic DRI processes. Production cost savings could be achieved through realistic future improvements in electrolyser efficiency (∼ US$5 per tonne of H2-DRI) and heat exchanger (∼US$3 per tonne). We conclude that commercial H2-DRI production in New Zealand is entirely feasible, but will ultimately depend upon the price paid for firm electrical power at the plant.

Weight gain during the menopause transition: Evidence for a mechanism dependent on protein leverage.

Weight gain during the menopause transition: Evidence for a mechanism dependent on protein leverage.

Plug-in hybrid electric refuse vehicle routing problem for waste collection

Commercial waste collection is an essential service requiring efficient and reliable provision for customers. At the operational level, one of the most challenging problems is to design a set of refuse vehicle routes to collect waste from a set of bins. To be used multiple times, these vehicles must be emptied regularly throughout the day. This paper investigates a waste collection problem with a homogeneous fleet of plug-in hybrid electric refuse vehicles powered by two different power sources, i.e., electricity and compressed natural gas (CNG). In addition, realistic fuel consumption functions are used to estimate total energy requirements for each type of fuel, including refueling and recharging, and the detailed energy consumption along the path between two nodes of interest. We propose a Hybrid Threshold Acceptance (HTA) algorithm for this problem and denote it as the Hybrid Waste Collection Problem (HWCP). Extensive computational experiments confirm that the proposed HTA algorithm provides good results against current state-of-the-art algorithms designed for the electric vehicle routing problem. Out detailed computational results demonstrate the performance of our method considering either full or partial recharging, as well as the effect of different battery/tank capacities. Compared to the standard CNG or electric vehicles, we also show the benefits of using a fleet of hybrid electric refuse vehicles in terms of operational costs and total distance traveled.