Opportunities For Energy Savings Research Articles

Energy audit, techno-economic, and environmental assessment of integrating solar technologies for energy management in a university residential building: A case study

This study presents the results of an energy audit and management performed on a university residential building in Borg El-Arab City, Egypt. The building’s energy consumption, areas of energy wastage, and energy-saving opportunities were investigated, and the corresponding energy metrics were quantified accordingly. Firstly, an energy consumption is estimated based on the building's electricity bills, meter measurements, and survey. Then, the energy consumption is analyzed and evaluated. Subsequently, the feasibility of integrating solar technologies (i.e., photovoltaics and domestic water heating) into buildings is appraised from techno-economic and environmental perspectives. The study employs ASHRAE Level 1 and 2 guidelines for conducting energy audits. The results show that electricity consumption is highest in air conditioning units (which consume ∼62%), followed by socket loads (∼25%), and lastly, lights (∼13%). Detailed analysis of the energy-use characteristics of the building revealed the mismanagement of electricity. Through light retrofits such as replacing the incandescent bulbs with LED bulbs, adopting sensory lights, and delamping, the building would save 4,432.6 kWh annually. Additionally, changing the AC unit type from non-inverter to inverter type would save approximately 61,194 kWh/year, representing 22.96% energy savings, with a payback period of 8.6 years. Overall, the proposed energy conservation measures will mitigate 30.8 tons of CO2 per year. Furthermore, incorporating PV and SWH systems will lead to annual energy contributions of 79,820 kWh and 38,048 kWh, with payback periods of 3.77 years and 2.49 years, respectively. Notably, the solar technologies will altogether abate approximately 91.5 tons of CO2 and provide a carbon credit gain of $1,830 annually.

Experimental air conditioning energy evaluation under Caribbean climate conditions

A 23 factorial design was performed to analyze the performance of a mini-split air conditioning system under several psychrometric air conditions at the evaporator inlet, similar to Tropical Caribbean region conditions. In addition, a search for new energy-saving opportunities was performed. The results showed that interactions between the temperature of the air inlet, the humidity of the air inlet, and the fan speed level are significant in the mini-split energy performance under Caribbean climate conditions. Hence, working on an oriented energy savings control strategy is necessary. Therefore, this study recommends developing a fan speed control scheme, generating energy savings of around 10% in the air conditioning unit.

Modelling of underlying social psychological effects on occupant energy-related behaviours

Occupant energy-related behaviour research practices based on objective factors may not provide helpful insights that can derive from social sciences perspectives. This study examined how motivation (i.e., attitudes, personal norms), opportunity (i.e., subjective norms, organisational support, behavioural interventions, accessibility to control), and ability (i.e., perceived behavioural control, perceived and actual knowledge) explain the occupant energy-related behaviours in offices. In-person and online questionnaires were distributed across the general population of office occupants in New Zealand, and 294 valid answers were achieved. The social psychological effects on the choices of occupant energy behaviours are evaluated using a partial least squares structural equation modelling (PLS-SEM) analysis. The results showed that improving energy-saving opportunities through subjective norms, organisational support, behavioural interventions, and accessibility to control increases the occupants' perceived behavioural control and perceived knowledge to perform occupant energy-related behaviours. These opportunities and ability drivers then improve the occupants' motivation, building a strong attitude and obligation to save energy in the office environment. Understanding these social psychological factors are essential, as they utilise the development of occupant energy-related behavioural tools and integrate them with building energy performance simulations. Furthermore, the study assists in designing buildings to suit occupants’ comfort preferences and actions.

AUDIT ENERGI LISTRIK GEDUNG BARU UNIVERSITAS MUHAMMADIYAH GRESIK

Daily use of electricity is increasing because all human activity requires electrical energy. The energy audit is one way to reduce the rise in electrical energy. In case a new building at Muhammadiyah University of Gresik, Energy audits carried out in this building include the use of lighting and air conditioning. Based on the Minister of Energy and Mineral Resources of the Republic of Indonesia No. 13 of 2012 regarding saving electricity consumption, it is necessary to do electrical energy management so that the intensity of electricity consumption can be managed properly and can be more efficient. In this study an audit of the lighting system and air conditioning system was carried out and in this study the energy audit method was used by calculating the Energy Consumption Intensity (IKE) value for the process of electrical energy efficiency. From the initial energy audit calculations, the IKE value for the new building of Muhammadiyah University of Gresik was 671 kWh/m2/year, this value exceeds the ASEAN-USAID standard of 240 kWh/m2/year. Then the Energy Saving Opportunities (PHE) that will be implemented in the new building of the Muhammadiyah University of Gresik are changing the types of lamps, reducing the use of lights during the day, turning off the AC when not in use, and using inverter AC in the air conditioning system. Application of the above method to determine PHE decisions which will be implemented with the aim of not exceeding ASEAN-USAID standards.

Maintenance policy optimization for buffered serial systems considering energy-saving based on dual time windows

This paper proposes a novel optimal maintenance policy considering energy-saving based on dual time windows is proposed for a serial production system with limited buffering. The machines suffer from degradation, and the degradation process obeys the Gamma random process. Based on the dual time windows, condition-based preventive maintenance and opportunistic maintenance are activated: when a machine reaches a set state (i.e., threshold deterioration state), the preventive maintenance action is taken, and the time of preventive maintenance performed is determined by the time window w; meanwhile, the time window W is used to determine whether the other machines need opportunity maintenance. To reduce energy consumption, and increase the proportion of effective energy in the manufacturing process, the energy-saving time window is used to find the energy-saving opportunities for the system. The impact of different maintenance thresholds and dual time windows on the maintenance cost per effective product is discussed through Monte Carlo simulation. A practical example of an automotive manufacturing system is provided, and comparative analyses with other maintenance policies are used to illustrate the superiority of the proposed policy in energy saving, cost reduction, and quality improvement.

Simulation and Optimisation of a Medium Scale Reverse Osmosis Brackish Water Desalination System: Energy Saving and Maintenance Opportunity

Simulation and Optimisation of a Medium Scale Reverse Osmosis Brackish Water Desalination System: Energy Saving and Maintenance Opportunity

Attention-Based Multitask Probabilistic Network for Nonintrusive Appliance Load Monitoring

Monitoring individual appliances’ operating state and energy consumption in a building enables significant energy-saving opportunities. These days, smart meters perform this task non-intrusively using sophisticated signal processing, machine learning, or deep learning approaches. To this end, this paper proposes a novel multi-task deep learning model that uses readily available low-frequency energy data from the smart meter for simultaneous appliance state detection and energy disaggregation. The model creatively adopts and customizes the famous transformer model from the field of language modeling for the above task. Further, the model output is produced as a mixture of probability density functions to handle uncertainties. The model performance is evaluated using the publicly available REFIT and UKDALE datasets. The test results indicate the proposed model’s superiority, generalizability, and transferability compared to other state-of-the-art models.

Analysis of Energy Saving Opportunities In Building A Regional Secretariat of Central Java Province and The Suitability of Green Building Criteria

The government through Law No. 30 of 2007 concerning Energy, seeks to manage the energy sector in Indonesia in a fair and equitable manner and provide benefits to all Indonesian people. The pattern of energy consumption which increases every year in line with the increase in population illustrates that a concerted effort is needed to increase the reliability of energy supply. This research is a quantitative research conducted by processing secondary data and observing on site to determine patterns of energy consumption, recommendations for energy saving opportunities and suitability of green building criteria . In this study, to obtain data regarding the condition of electricity in Building A of the Regional Secretariat of Central Java Province, primary data and secondary data were collected. Primary data was obtained from the results of a survey that was carried out in Building A of the Regional Secretariat of Central Java Province by collecting data on the type of Air Conditioner (AC) load and the lights used, data regarding the building envelope and measuring the intensity of light in each room which was assisted by a measuring instrument. Smart Sensor AS803 Digital Lux Meter

Energy Saving Opportunities through Glazing and Shading Alternatives

Windows are the weakest elements due to their high heat transfer coefficient and are responsible for 60% energy heat/gain loss. Healthcare buildings are one of the biggest consumers of energy due to continuous occupation hours and medical requirements, providing comfortable conditions for people in need of care and staff; yet recently less attention was given to healthcare buildings due to their unique operational requirements and advanced medical equipment. Thus, the main purpose of this study was to evaluate energy saving potentials of windows through glazing and shading alternatives over a case study. Within this study, a single patient room in Izmir Turkey has been chosen as a case study, and the room was simulated for sixteen scenarios generated by using four different glazing and shading systems. Each design scenario was simulated using DALEC for their lighting, heating, cooling, and total energy consumption. Results showed that lighting energy consumption constitutes the highest energy demand (up to 52%) and high transmitting glazing usage can reduce lighting loads. Finally, up to 16.3%, energy saving is possible only by changing shading and glazing types. Though there is a great diversity of glazing and shading types, this study’s outputs only reflect the selected four glazing and four shading system types that are offered by DALEC. Healthcare buildings spend a vast amount of energy to provide thermal and visual comfort for various user profiles. Considering the large number of patient rooms in healthcare facilities, only careful consideration of glazing or shadings can significantly contribute to energy savings. This study focuses on shading and glazing alternatives as an energy-saving strategy. For simulation, an underrecognized BES tool DALEC was hyped to show integrated thermal and visual energy consumption. The findings highlight that energy savings of up to 16.3% is possible.

Predicting industrial building energy consumption with statistical and machine-learning models informed by physical system parameters

The industrial sector consumes about one-third of global energy, making them a frequent target for energy use reduction. Variation in energy usage is observed with weather conditions, as space conditioning needs to change seasonally, and with production, energy-using equipment is directly tied to production rate. Previous models were based on engineering analyses of equipment and relied on site-specific details. Others consisted of single-variable regressors that did not capture all contributions to energy consumption. New modeling techniques could be applied to rectify these weaknesses. Applying data from 45 different manufacturing plants obtained from industrial energy audits, a supervised machine-learning model is developed to create a general predictor for industrial building energy consumption. The model uses features of air enthalpy, solar radiation, and wind speed to predict weather-dependency; motor, steam, and compressed air system parameters to capture support equipment contributions; and operating schedule, production rate, number of employees, and floor area to determine production-dependency. Results showed that a model that used a linear regressor over a transformed feature space could outperform a support vector machine and utilize features more representative of physical systems. Using informed parameters to build a reliable predictor will more accurately characterize a manufacturing facility's energy savings opportunities.

Combined effort opportunities of aggregated demand response flexibility and energy savings in households

This paper analyses possible synergies between demand response flexibility programmes and energy savings delivered by households. In the framework of the energy transition, European Union (EU) directives are endorsing energy consumers to become full-fledged participants of the energy market, mostly via independent aggregator intermediaries. The flexibility aggregators have a very arduous role in collecting, optimising and settling aggregated flexibility delivered from heterogenous sources on the energy market. Novel business models incorporating both flexibility and energy savings opportunities from households’ consumers could deliver revenue diversification for flexibility aggregators and support them in overcoming technical and motivational challenges for activating consumers in the energy market. This paper discusses the main pillars for a sustainable flexibility aggregator business model which sums up the potential for flexibility placement on energy, ancillary services and energy savings markets. The main challenge identified in this work are the requirements for programme establishment, allowing the recognition and proper interpretation of energy savings triggered by short-term events and obtained by an aggregator via explicit demand response actions. This paper proposes possible solutions for a joint venture of a flexibility and energy savings aggregator, thus alleviating possible data collection problems. Collaborative efforts have been recognised in the establishment and maintenance of information and communication technologies and infrastructure, therefore facilitating continuous monitoring and verification of flexibility programmes which are able to deliver energy savings.

(Invited) Flexible Electrosynthesis of Fuels and Chemicals at Intermediate Temperatures at Idaho National Laboratory

Fuels and commodity chemicals make up a significant share of the potential energy savings opportunities for decarbonized economy and society. New innovative technologies are needed that can reduce the amount of energy and carbon intensity currently required to produce the key fuels and chemicals or associated building blocks. Electrochemistry is playing an increasingly important role in manufacturing as we reduce energy use and address uncertain supply chains driven by industrial electrification. In comparison to processes driven by heat and pressure, electrochemically-driven synthesis of fuels and chemicals provides unique opportunities for selective reactions and separations offering increased flexibility to manufacturing. As one of DOE’s premier multi-program energy research laboratories, Idaho National Laboratory’s (INL) mission is to ensure the nation’s energy security with safe, competitive and sustainable energy systems and unique national and homeland security capabilities. INL’s initiative, integrated energy systems (IES) provides carbon-free nuclear and renewable energy for downstream use in manufacturing and transportation. The manufacturing component of IES focuses on integrating clean, carbon-free electrons with waste/renewable heat and includes both manufacturing of electrochemical devices and implementing them in energy-efficient processes. In this talk, we will provide several examples for the pillar of energy to molecules and materials (E2M2) by utilizing the protonic ceramic electrochemical cells/membrane reactors (PCEC/PCEMR). The electrochemical route using PCEC/PCEMR offers a solution of process intensification and low carbon intensity. In addition to direct hydrogen production through water electrolysis at elevated temperatures, in situ use of hydrogen and protons with matching temperature for the industrial processes (e.g. Fischer Tropsch and Haber Bosch) has the advantage to leverage the existing infrastructures.

Experimental investigation of eutectic phase changing materials (KCL + Na2SO4) mixed with graphene (Gr) nano-particles on refrigeration test rig

There has been increasing interest of various researchers in sustainable solutions towards HVAC and R. As we know that Indian refrigeration market has had remarkable growth of around 8.1 % Compound Annual Growth Rate (CAGR) over the period 2021–27. In India, several industries introduced deep freezers, refrigerators, refrigerated trucks for the preservation of different commodities like fruits, veggies, milk, Ice-cream, meat, medicines, etc., at 0 to 15 °C temperature. Thus, an attempt has been given on energy-saving opportunities for power saving by considering the above scope of refrigeration and cold chain applications. In this context, the present research is to prolong the cooling period during a power outage and minimize the losses which are occurred due to temperature fluctuations of the evaporator cabinet of the refrigeration test rig by using Nano-phase change material (KCl + Na2SO4 + Graphene) with water as base fluid. The experimental setup is tested during power ON and OFF conditions and performance is studied on the basis of cooling time, power consumption, and COP. The dispensability of nanoparticles and PCM is observed with the help of Scanning Electron Microscopy (SEM). The experiments were tested for 1 % and 5 % (KCl + Na2SO4 + Graphene) Nano-PCM mixture and it has been found that the addition of graphene nanoparticles in phase change material results in an enhanced heat transfer as well as improvement in 12 % COP. Also, power consumed with the advancement of Nano-PCM in the evaporator side is 10 % lesser than that of the conventional one. It is observed that with the use of 5 % (KCl and Na2SO4) addition of 1 % (Gr) with water as the base fluid it is possible to maintain 7 to 9 degrees for 13 to 15 hrs time span even though a power outage exists. The temperature range 5 to 10 degree is standard temperature for storing the fruits, veggies and medicine/vaccine. It is observed that thermal energy storage by using Nano-phase changing material for lower temperature application is the most appropriate way and method to correct the gap between the demand and supply of energy in cold chain applications.

Novel model predictive control by hypothetical stages to improve energy efficiency of industrial cooling tower

• Mathematical model of cooling tower based on analogy to distillation column. • Aspen Plus model was developed for cooling tower. • Both models were validated with real plant operating data. • Controller was designed to control performance of cooling tower with climate. • Resulted in 30% reduction in overall power consumption of cooling tower. Cooling towers are unit operations that are used in almost every industry to cool down process water either by natural draft or forced draft. The energy intensive components of cooling towers are draft fans and circulating pumps which in traditional practise run at full rated capacities throughout the year ignoring the underlying opportunities for energy savings. The efficiency of a cooling tower is a function of ambient air temperature, relative humidity and wet bulb temperature. This work brings out a novel model of cooling tower along with an energy harnessing control system based on prevailing climatic conditions thus improving the overall efficiency of the system. Based on analogy to a distillation column with hypothetical stages a model for cooling tower is developed. Then a model predictive control is designed to control the draft fan speed and pump flow rate of cooling tower based on climatic conditions. Both the model and control strategy was developed using Aspen Plus (V12.1), MATLAB (R2018b) and Simulink softwares and has been validated and trained based on plant operating data. The developed model was then tested at a pilot cooling tower facility of capacity 1 Ton of Refrigeration and was observed to attain approximately 30% reduction in energy consumption compared to the traditional operation.

Significantly enhanced sub-ambient passive cooling enabled by evaporation, radiation, and insulation

Passive cooling relying on evaporation and radiation, while offering great energy-saving opportunities, faces challenges with low ambient cooling powers, environmental heating, high water usage, and climate condition constraints. To overcome these shortcomings, here, we present insulated cooling with evaporation and radiation (ICER), which utilizes a solar-reflecting layer; an infrared-emitting evaporative layer; and an infrared-transparent, solar-reflecting, and vapor-permeable insulation layer. One major advantage of ICER is that it synergistically combines thermal insulation, evaporative cooling, and radiative cooling. Consequently, it consistently achieves below-wet-bulb temperatures with much less water consumption than pure evaporation while reaching 9.3°C below the ambient temperature under direct sunlight. With unfavorable climate conditions, ICER delivers 96 W/m2 daytime cooling power at the ambient temperature and shows a 300% enhancement over the state-of-the-art radiative cooler. During the summer months, without electricity, ICER can extend food shelf life by 40% in humid climates and 200% in dry climates with low water-refilling frequencies.

CO2 precooled dual phase expander refrigeration cycles for offshore and small-scale LNG production: Energy, exergy, and economic evaluation

Small-scale liquefied natural gas (LNG) processes have gained considerable attention owing to the development of offshore natural gas (NG) reserves. Low energy efficiency and high process costs are the major challenges associated with small-scale LNG processes. In this study, to reduce energy consumption and improve process economics, a dual-phase expander-based process assisted by carbon dioxide (CO2) precooling has been proposed. Three proposed cases were developed using two precooling refrigerants (propane (C3) and CO2) and dual-phase expander-based liquefaction cycles utilizing a mixture of high-boiling (ethane (C2) and propane (C3)) and low-boiling refrigerant (nitrogen (N2)). These processes were optimized with the multivariate Coggins algorithm to exploit the energy-saving opportunities. The results show that proposed case II (using CO2 in precooling and C2/N2 in liquefaction) is the most energy-efficient, with a specific energy consumption of 0.3790 kWh/kgNG. Proposed case II is 1.73% and 16.6% more energy-efficient than proposed cases I and III, respectively. The exergy analysis results show that proposed case II has the lowest exergy destruction, while the economic evaluation shows the lowest capital investment ($44.4 MM) compared to the other proposed cases. These results show the superior performance of case II among the proposed cases.

EFFICIENT AND SUSTAINABLE ENERGY MANAGEMENT FOR HOSPITAL BUILDING

The development of current environmental problems raises the concerns of investors or hospital lenders about the potential financial problems resulting from current environmental problems. A sustainable health care system can achieve high-quality care and improve public health without wasting resources. The health service sector is continuously encouraged to apply the concept of "Green Hospital" which is one example of the continuity of health services. This research focuses on emission reduction management in health care facilities. This study examines several published papers containing the terms sustainable, green infrastructure, and energy management. Guidelines for Efficient and Sustainable Energy Management in Hospital Buildings is the selected article. The articles used were obtained from the Google Scholar database. Data analysis was carried out descriptively using tables. This study took data from three countries, namely Thailand, Taiwan, and Indonesia, based on our team's observations during a virtual hospital visit to the two countries (Thailand and Taiwan), which we then compared with most hospitals in Indonesia. Currently, there is no Green Hospital standard for each of these countries. The application of the green infrastructure concept can have a positive impact on cost efficiency and hospital sustainability. Energy Saving Opportunities (PHE) is one method that can be used to save energy use in hospitals. The way to do this is to control the use of infrastructure that consumes a lot of energy, such as the use of lights and Air Conditioners (AC), as well as other infrastructure that is not included in vital equipment.

Plant-Wide Modeling and Economic Analysis of Monoethylene Glycol Production

Monoethylene glycol (MEG) is used to produce polyester fibers and polyethylene terephthalate resins. It is also utilized in antifreeze, pharmaceuticals, and cosmetics applications. In this research, we consider the development of a novel process plant that produces MEG from ethylene. The proposed ethylene-to-ethylene oxide (EO) plant is integrated with an EO-to-MEG plant to reduce utility costs and recover high-value products. Energy-saving opportunities are analyzed via heat integration tools. Furthermore, a multitube glycol reactor is used in conjunction with a novel MTO catalyst in the ethylene-to-EO reactor. Our results demonstrate that the integrated EO/EG plant produces ethylene glycols with that same purity and product recovery as conventional designs. A comparative economic assessment based on a 200,000 t/y plant indicates that process integration techniques can reduce costs significantly.

Analisis Intensitas Konsumsi Energi (IKE) pada Institut Teknologi Dirgantara Adisutjipto (ITDA) Yogyakarta

One of the main sectors that uses the largest electrical energy in a country is the commercial sector. One of the parts of this sector is education. This sector has a sub-sector. It is called a building. Electrical energy conservation efforts are needed to streamline electrical energy consumption by looking at energy-saving opportunities. This research was conducted at Halim Building and Wiweko Building in Institut Teknologi Dirgantara Adisutjipto (ITDA), Yogyakarta. The research was conducted by taking energy audit data regarding the level of electrical energy consumption as seen from the Energy Consumption Intensity (IKE) parameter. The research method began with the data collection. Furthermore, the data were processed using Ms. Excel, SPSS, and Matlab. Statistics analysis with ANOVA was carried out to conclude what parameters affected IKE. The results showed that the IKE value of the Halim Building was 30,48 kWh/m2/year and the IKE value of the Wiweko Building was 24,16 Wh/m2/year. The IKE value was still significant in the efficient category following ESDM & JICA Electric Power Development Co. LTD standards.

Fundamental modeling and experimental validation of hydrogen and oxygen transport through mixed ionic and electronic conducting membranes

Hydrogen transporting mixed ionic and electronic membranes offer tremendous opportunities for process intensification and energy savings in various applications such as reaction chemistries and heat/energy generation. Over the past several decades there has been significant advancement in the membrane materials science to produce improved molecular transport, but commercial adoption is still limited. To escalate implementation, a fundamental understanding of the solid state membrane transport and the water splitting phenomenon would bridge the gap for process conceptualization and design. This work presents a fundamental transport model, which quantifies the contribution of the water splitting phenomenon to the overall observed apparent flux of hydrogen and oxygen through ionic and electronic conducting membranes. The model predictions are rigorously validated against experimental data gathered in parallel. Membranes tested were based on the composition La0.87Sr0.13CrO3-δ-La5.4WO12-δ. These measurements include both apparent hydrogen/oxygen fluxes and the water splitting contributions over a range of operating conditions that included varying temperatures, hydrogen partial pressures, and hydration gradients across the membrane.