Reduction Of Thermal Energy Consumption Research Articles

Estimating the potential for thermal energy efficiency in the industrial sector: A hybrid model integrating exergy analysis and long-term technology diffusion scenarios

Thermal energy for heating and cooling accounts for a significant portion of the total energy consumed in the industrial sector, and is predominantly provided by fossil fuels. Thus, effective thermal energy management is essential for reducing overall energy consumption, operational costs, and emissions in the industrial sector. While previous studies have explored energy efficiency in this sector, there is a lack of research specifically addressing the challenges of modeling thermal energy efficiency in industry. Therefore, this study proposes a novel hybrid methodological approach that integrates macroeconomic perspectives with detailed end-use analysis and exergy considerations, allowing for a more accurate assessment of recoverable energy in industrial processes in alternative technology diffusion scenarios over a long-term horizon. An empirical study focusing on the pulp and paper subsector in Brazil demonstrated the applicability of the proposed model and revealed significant potential for thermal energy efficiency improvements. The model identified that through optimal technology diffusion scenarios, the sector could achieve up to 25 % reduction in thermal energy consumption by 2050, with heat recovery systems accounting for approximately 40 % of these savings. Cost-effective technology adoption curves indicated that 60 % of this potential could be realized through economically viable investments with payback periods under 3 years. Overall, this study contributes to the field of industrial energy efficiency by offering a hybrid methodological approach that can be adapted to different industrial settings, and can help policymakers and industry stakeholders develop effective strategies to improve thermal energy efficiency and reduce emissions in the industrial sector.

Exergy efficiency improvement by compression heat recovery for an integrated natural gas liquefaction-CO2 capture-NGL recovery process

For liquefied natual gas production, cryogenic distillation offers lower thermal energy consumption and a more compact footprint for carbon capture unit than the widely used chemical absorption. However, the reduction in thermal energy consumption comes at the cost of increased power consumption. To reduce the power consumption of cryogenic distillation based natural gas lqiuefaction plants, an integrated process for liquefied natual gas production, cryogenic CO2 capture and natural gas liquids recovery is proposed, which is called the base process. This base process is further integrated with a heat recovery unit (Organic Rankine cycle or Kalina cycle) to investigate the optimal utilization of compression heat in the system. The proposed processes are modeled in Aspen HYSYS and optimized using a genetic algorithm installed in Matlab. The results show that specific power consumption of the base case is 0.385 kWh/Nm3 NG. Due to the lack of compression heat recovery, significant exergy loss occurs at the water coolers, accounting for approximately 37 % of the total system exergy destruction. Among the evaluated methods, the supercritical Organic Rankine cycle, using R1234ze as the working fluid, recovers approximately 60 % of the exergy from compression heat with an 8.7 % improvement in system exergy efficiency. The subcritical Organic Rankine cycle, using R600a as the working fluid, achieves a slightly lower exergy efficiency improvement of 7.1 %. The Kalina cycle, while less efficient, still improves the system’s exergy efficiency by 6.3 %. Economic analysis reveals that the total annualized cost of the base process is $8,441,416, with a levelized cost of $0.1411/kg. The subcritical Organic Rankine Cycle provides the most cost-effective solution, with the lowest total annualized cost of $8,305,154 and a levelized cost of $0.1402/kg. The Kalina cycle ranks second in cost-effectiveness, with a total annualized cost of $8,345,914 and a levelized cost of $0.1405/kg NG. Although the supercritical ORC requires the highest capital investment, it proves more cost-effective than the base process due to its reduced annual operating costs.

Energy saving potential in steam systems: A techno-economic analysis of a recycling pulp and paper mill industry in Morocco

The industrial sector represents nearly 40 % of global energy consumption, with steam systems accounting for 30 % of energy use in manufacturing. As the need for cleaner processes intensifies within African and global energy transitions, adopting energy efficiency practices becomes imperative. Governments are focusing on reducing energy losses in fossil fuel-dominated manufacturing industries, which are major producers of greenhouse gas emissions. Despite their significant energy consumption, industrial heat processes are often overlooked in efforts to reduce costs and emissions. To address this, the study examines thermal energy processes and identifies energy-saving opportunities within steam systems through a techno-economic analysis of a recycling pulp and paper mill in Morocco. This is the first study focusing specifically on steam systems within a particular industry in the country. The research uses a system approach covering steam generation, distribution, end-use, and recovery. The current system is benchmarked through a rating questionnaire, and proposed energy-saving actions include leak repair, pipe insulation, blowdown management, and improved boiler combustion efficiency. An economic study evaluates the cost-effectiveness of these opportunities. Findings reveal a 6 % reduction in thermal energy consumption, annual savings of $417 899 and nearly 482 TJ, a 6 % decrease in GHG emissions (2158.5 tons of CO2 per year), and water savings of approximately 5300 m³ per year (13 %). The total investment of $8750 has negligible payback periods. Despite diverse industrial activities, this work is useful for other industries since the fundamental components of the steam system are widely shared. Moreover, it supports the African Union's Agenda 2063 and United Nations Sustainable Development Goals by providing practical insights and recommendations for enhancing industrial energy efficiency.

Modernization of local heat distribution stations of city heat supply system

The PURPOSE of this work is to develop technical solutions to increase the efficiency of functioning of centralized urban heating systems by modernizing local heat distribution stations. The article considers the issues of functioning of district heating systems with open water intake. The work presents technical solutions that increase the efficiency of the local heat distribution station with a hot water supply unit. A technological scheme has been developed, the selection of equipment has been made. The feasibility of using the developed technical solutions is confirmed by technical, economic and investment indicators. The objectivity of determining the technical and economic effect of the modernization of the local heat distribution station is ensured by comparing the obtained indicators of the modernized and similar facilities.METHODS. To fulfill the objectives of the study, the following methods were applied: full-scale tests on a real object; processing of experimental data using application programs; feasibility study in the municipal heat power industry.THE RESULTS show an improvement in the technical and economic performance of the heating and hot water supply system of an apartment building in Yoshkar-Ola city: reduced network water consumption by 36–39%; temperature drop in the return pipeline was 13.5%; the heat content of hot water has been reduced to 0.168 Gcal/m3 (normative heat content is 0.145 Gcal/m3), the required circulation was ensured in all risers of the hot water supply system. The total losses from October 2021 to September 2022 are 3486,4 Gcal or 11.4% of heat supplied to consumers, which is less than 13% set by the tariff. Compared to a similar house without a regulation depending on the outside air temperature, the consumption of thermal energy during the heating season is reduced by 80 Gcal (10.9%).CONCLUSION. The new scheme of a local heat distribution station has been proposed, including the regulation of domestic hot water (DHW) recirculation, as well as the installation of a hydroelevator with weather regulation. The developed technical solution is relevant for district heating systems with open water intake. For the first time, an experimental study of the effect of the joint installation of the following equipment was carried out: a pump and a control valve on the DHW recirculation line before the recirculation mixing unit with the return pipeline of the heating system; hydraulic elevator with weather regulation. The results of the study can be used in the feasibility study of similar circuit solutions for the modernization of DHW systems. Operating experience has shown that the application of the developed technological scheme of local heat distribution station has positive effects: reduction of network water consumption, temperature in the return pipeline and heat losses; improvement of circulation in all risers of the DHW system; reduction of thermal energy consumption during the period of the “lower” cutoff of the temperature graph; curbing the growth of tariffs for thermal energy.

Innovative process integrating high temperature heat pump and direct air capture

Direct air capture (DAC) technology plays a crucial role in mitigating the effects of global warming by capturing carbon dioxide (CO2) directly from the atmosphere. A significant technical challenge for DAC is its high thermal energy consumption, which results in an unacceptable overall cost (600$tCO2–1). The combination of a high-temperature heat pump (HTHP) and DAC system offers a substantial reduction in thermal energy consumption, decreased reliance on renewable energy sources, and enhanced DAC system flexibility. This study presents three distinct thermal integration strategies that combine an HTHP with solid adsorbent-based DAC and verifies their effectiveness in reducing energy consumption and CO2 emissions compared to a traditional DAC system. Among them, the deeply integrated DAC-HTHP system (I-DAC) exploits low-grade adsorption heat and waste heat, providing direct heating and cooling energy to the DAC system via refrigerant condensation and evaporation processes. Simulation results indicate that the I-DAC system achieves an extremely low operating energy consumption of 2.77 GJtCO2–1, representing a 69.5% reduction than traditional DAC under the same conditions. Consequently, the I-DAC offers a cost-effective (32.0–46.2 $tCO2–1) negative emission solution. We also demonstrate that the I-DAC is promising for wide application in cities to recycle waste heat and remove CO2 from the air. The comprehensive implementation of the I-DAC in 105 cities could yield a net annual productivity of 980 MtCO2.

Evaluating Reduction in Thermal Energy Consumption across Renovated Buildings in Latvia and Lithuania

Currently, the optimization of thermal energy consumption in buildings is considered a suitable alternative in the construction of new buildings, as a result of which the overall energy efficiency of the building increases. Thus, this study examined the efficiency and efficacy of different building renovation packages conducted across several buildings in Latvia and in Lithuania (across a larger building stock). In the first section of this study, 13 multi-apartment residential houses with 3 building renovation packages have been investigated in the city of Daugavpils, Latvia, in order to determine the actual reduction in heat energy consumption across each of the renovation implementation packages. The study findings indicate that changes in Latvian building regulations regarding insulation thickness did not significantly impact thermal energy consumption in fully renovated buildings. However, the combination of facade renovations, upgraded heating systems, and improved ventilation systems resulted in substantial energy savings, with an average reduction of 50.59% in thermal energy consumption for space heating across the reviewed multi-apartment residential building stock. In the following section of this study, the impact of the Energy Performance of Buildings Directive (EPBD) on building energy efficiency in Lithuania has been examined. The results show that over a 10-year period in the 2000s, Lithuanian building stock experienced a 20% increase in energy efficiency, followed by an additional 6.3% increase between 2010 and 2016. The mandatory requirement for renovated buildings to achieve a minimum energy efficiency class has resulted in significant reductions in energy consumption for heating purposes. The findings underscore the effectiveness of building renovation packages and the EPBD regulations in enhancing energy efficiency and promoting sustainable building practices. The importance of heat metering, consideration of indoor air temperature, and the need to address indoor air quality during renovations were also highlighted.

Complex methodology for optimizing local energy supply and overall resilience of rural areas: A case study of Agrovoltaic system with Miscanthus x giganteus plantation within the energy community in the Czech Republic

The article presents a proposal for a comprehensive methodology designed to increase the energy self-sufficiency and overall resilience of rural areas. The methodology aims to maximize the synergy and economic benefit of the agrovoltaic system with the cultivation of the energy crop Miscanthus x giganteus and its use for energy production in CHP sources within the local energy community. Primary data from Miscanthus × giganteus cultivation from long-term field trials and commercial plantations and initial agrovoltaic experiments were used. The analysed data show the high resistance and adaptability of Miscanthus × giganteus to climate change and confirm its expected long-term high yields of around 15 t DM ha−1 y−1 with a Higher Heating Value of 17–19 GJ t−1. The application of the methodology to a case study in the Czech Republic shows a reduction in electricity consumption by more than 40% (2 GWh) and a reduction in thermal energy consumption by more than 15% (4 GWh). The technical-economic analysis shows the high potential, financial and non-financial benefits of local production of energy fuels from biomass as part of subsequent production and energy distribution in the agrovoltaic field.

The Impact of Thermo-Modernization and Forecast Regulation on the Reduction of Thermal Energy Consumption and Reduction of Pollutant Emissions into the Atmosphere on the Example of Prefabricated Buildings

The paper presents an assessment of thermal energy consumption for heating in 10 buildings made in the OWT-67N prefabricated large-panel technology from 1983 to 1986. The work covers the years 2002–2020 in three periods: before and after thermal modernization and after the use of an innovative weather prediction heating system control in buildings. The analysis made it possible to assess the impact of carrying out a deep thermal modernization, and then installing a modern forecast regulation system in terms of reducing heat energy consumption for central heating purposes, as well as reducing greenhouse gas emissions, such as CO2, SOx, NOx, CO and benzo(a)pyrene, into the atmosphere. The implementation of deep thermal modernization in buildings allowed for savings of 19.8–35% of thermal energy consumption for heating. The use of additional regulation based on prediction saved from 4.8 to 23.5%, except for one building BU10, where there was an increase in final energy consumption by 2.1%. Replacing the weather regulation in heating stations with the forecast regulation additionally reduced the emission of pollutants by 11.1%, compared to the reduction of pollutants achieved as a result of the thermal modernization of buildings alone, amounting to an average of 29.7%.

Reduction of Energy Intensity in Broiler Facilities: Methodology and Strategies.

Broiler facilities consume a lot of energy resulting in natural source depletion and greater greenhouse gas emissions. A way to assess the energy performance of a broiler facility is through an energy audit. In the present paper, an energy protocol for an energy audit is presented covering both phases of data collection and data elaboration. The operational rating phase is analytically and extendedly described while a complete mathematical model is proposed for the asset rating phase. The developed energy audit procedure was applied to poultry chambers located in lowland and mountainous areas of Epirus Greece for chambers of various sizes and technology levels. The energy intensity indices varied from 46 to 89 kWh/m2 of chamber area 0.25–0.48 kWh/kg of produced meat or 0.36–1.3 kWh/bird depending on the chamber technology level (insulation, automation, etc.) and the location where the unit was installed. The biggest energy consumer was heating followed by energy consumption for ventilation and cooling. An advanced technology level can improve energy performance by ~ 27%−31%. Proper insulation (4–7 cm) can offer a reduction of thermal energy consumption between 10 and 35%. In adequately insulated chambers, the basic heat losses are due to ventilation. Further energy savings can be achieved with more precise ventilation control. Automation can offer additional electrical energy saving for cooling and ventilation (15–20%). Energy-efficient lights can offer energy saving up to 5%. The use of photovoltaic (PV) technology is suggested mainly in areas where net-metering holds. The use of wind turbines is feasible only when adequate wind potential is available. Solar thermal energy is recommended in combination with a heat pump if the unit's heating and cooling systems use hot/cold water or air. Finally, the local production of biogas with anaerobic fermentation for producing thermal or electrical energy, or cogenerating both, is a choice that should be studied individually for each farm.

Energy use and retrofitting potential of heat pumps in cold climate hotels

Tourism, and thereby hotels, play a crucial role in the European economy. The hotel sector features high energy consumption, which greatly contributes to the global warming effect. Thus, there is a need to investigate environmentally friendly technologies that have the potential to reduce energy usage within this sector. Information regarding the current status of the energy consumption in hotels is essential. Therefore, a study of 140 hotels in Norway and Sweden is presented in this paper to identify successful and sustainable measures to reduce energy consumption and related emissions.The energy use, available energy sources and thermal systems in the hotels are studied over a five-year period to identify consumption trends. The results reveal that 70% of the hotels have a mean annual energy consumption between 150 and 250 kWh/m2. A shift towards sustainable energy sources is observed in the hotels from 2015 to 2019, where application and overall consumption of district heating and cooling have increased, while electrical energy consumption has been reduced. District heating is the most prominent source of heating and is applied as the primary heat source in 70% of the hotels. The specific energy consumption for the group hotels that apply district heating is 218.9 kWh/m2/year, which is nearly 25% higher than the specific energy consumption of the 9% of hotels that apply heat pump solutions as a primary heat source. Thus, there is a potential to reduce the specific energy consumption in hotels. Two integrated transcritical carbon dioxide (CO2) heat pumps were investigated as a sustainable measure to reduce energy consumption. The results reveal that a reduction of thermal energy consumption of approximately 60% can be achieved.

Impact of thermal renovation on selected characteristics of partition walls and the consumption of heat energy

Renovation of multi-family residentials, including mainly thermal renovation, which includes adding thermal insulation, contributes to the improvement of living conditions. Above all, it reduces the operating costs of renovated buildings by reducing the consumption of heat energy for central heating. This article discusses the impact of light wet thermal renovation on the temperature distribution in the vertical cross-section of the partition wall and the calculation value of the temperature on the inner surface of the partition wall, as well as on the reduction of thermal energy consumption in buildings. The subject of the research was residentials erected in the large-panel, large-block, and traditional technology between 1984 and 1994, managed by Łomża Housing Cooperative (ŁSM).

Interaction of glazing parameters, climatic condition and interior shadings: performing energy and cost analysis in a residential building in Iran

In this paper, the interaction between various window specifications and different climate conditions is investigated. For this purpose, simultaneous effects of several aspects including glazing system, glass type, filling gas, glass thickness, window frame fraction, and interior shading are considered under three different climatic conditions. To evaluate the energy performance of various considered alternatives, the energy simulation of a base case building is evaluated in a computer environment. Using the validated model, the energy analysis is quantitatively performed, and cost-benefit analyses from the viewpoints of both residents and government are carried out based on the domestic and international prices of energy carriers, respectively. Moreover, three levels of energy consumption are considered for the cost-benefit analysis to present a better insight about the effects of occupants’ behavior on the results of the financial investigation. Based on the results of the study, argon gas can be recommended to be applied in the window glazing systems in cold-dominated climate zones from both energy and economical points of view. This gas in addition to the Low-e coating is very efficient to be applied in all considered climate zones from the viewpoint of the government. The payback period of using these two items is less than 4.5 years in cold, hot, or semi cold-hot zones for the considered building. The positive effects of Low-e coating on the reduction of thermal energy consumption in cold cities are improved (by 60%) when the windows are covered by interior shadings. The study emphasizes the importance of considering interior shadings in energy simulation analyses because of their significant impacts on the results of the energy evaluation.

Thermal Performance of Electrochromic Smart Window with Nanocomposite Structure under Different Climates in Iran

Objective: This study investigated the optimization of thermal energy consumption using electrochromic components with a new nanocomposite layer (WO3+Ag) in a larger size (window) for a room with an educational application for five cities with different climatic conditions in Iran (Yazd, Tehran, Bandar Abbas, Tabriz, and Sari). Materials & Methods: For this simulation platform, the software was implemented in Energy Plus. This feasibility study was modeled by DesignBuilder software which reported reduced thermal energy consumption across all climates in Iran (hot and dry, warm and semi-humid, warm and wet, moderate and dry, and mild and humid.). Four strategies were considered for better comparison. The first strategy used for common double-glazed windows, while the second to fourth strategies involved the use of the electrochromic window in three different modes; bleached mode (Off), colored mode (On), and switchable mode (controlled below comfort conditions). Results: The third and fourth strategies indicated a reduction in thermal energy consumption in different climates from 25 to 45% relative to typical windows. The best result of cooling energy consumption was observed in Tehran. Conclusion: For this climate, the average energy consumption dropped to 34% for the warm months of the year and even 42% for the warmest month of the year (August).

Uticaj toplotne izolacije na smanjenje gubitaka energije u industrijskim i energetskim postrojenjima

Smanjenje potrošnje toplotne energije postiže se primenom odgovarajućih tehničkih rešenja. U cilju smanjenja gubitaka toplote u industriji i energetici primenjuje se toplotna izolacija opreme i instalacija. Pri projektovanju od posebnog značaja je izbor adekvatnog izolacionog materijala i debljine izolacije. Pored osnovnog zadatka koji se odnosi na smanjenje gubitaka toplote izolacijom se postižu i drugi efekti, kao što su: zvučna izolacija, protivpožarna zaštita materijala i zaštita pogonskih radnika od opekotina. U radu su prezentovane osnovne tehničke karakteristike i značaj toplotne izolacije. Na konkretnom primeru je izvršeno praćenja uticaja toplotne izolacije na smanjenje gubitaka toplote.

Influence of Single Point Incremental Forming on Mechanical Properties and Chain Orientation in Thermoplastic Polymers

Incremental forming of thermoplastic surfaces has recently received significant interest due to the potential for simultaneous reduction in thermal energy consumption and in part-shape specific tooling. This paper examines the mechanical properties and the chain orientation of the formed material in single point incremental forming (SPIF) of amorphous polyvinyl chloride (PVC) and semicrystalline polyamide sheets. Tensile and stress relaxation properties of the formed polymers are compared to those of the unformed polymer. The effect of incremental depth and tool rotation speed on the above properties, and on the temperature rise of the sheet during SPIF, is quantified. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) are used to compare the chain orientation and crystallinity of the formed and the unformed polymers. It is observed that the formed material has greater toughness and ductility, but lower yield stress and reduced Young's modulus, as compared to the unformed material. We also observe deformation-induced chain reorientation in the formed polymer, with minimal change in the degree of crystallinity. The link between the SPIF process parameters, temperature rise of the polymer during SPIF, change in chain orientation, and change in mechanical properties of the polymer is discussed.

Análise de viabilidade econômica financeira para a implantação de uma central de massa em uma indústria cerâmica de Itaboraí, RJ

Este trabalho apresenta um estudo de viabilidade econômico financeira para a implantação de uma central de massa, com o objetivo de preparar a argila antes do processo produtivo, utilizando-se de técnicas adequadas e apropriadas, que proporcionam economia de matéria-prima, redução do consumo de energia elétrica, redução do consumo de energia térmica, aumento da produtividade, entre outros benefícios. Foram realizadas simulações em três tipos de cenários: pessimista, mais provável e otimista. Utilizaram-se os métodos tradicionais de avaliação: VPL, TIR e Payback Descontado. Em todos os três cenários os resultados determinam que o investimento é viável.

Economic and environmental benefits of thermal insulation of building external walls

Thermal modernization is viewed by its users in Poland mainly in terms of economic benefits. Nevertheless, it does not reduce the significant role of thermal modernization in lowering the environmental impact at the phase of a building use. The paper presents economic and environmental benefits due to thermal insulation of building external walls. Thermal insulation of building walls has a significant effect on the reduction of thermal energy consumption in buildings that leads to the reduction of CO 2 emissions. Making a thermal insulation of a building external wall can in terms of economic aspects be approached as an investment. In this investment the cost is related to the purchase, transport and laying the insulation, whereas the profits are linked to the reduction of thermal energy consumption necessary to heat a building. The author determines the optimum thickness of the insulating layer that gives the maximum net present value of thermal insulation investment. Several versions of thermal insulation are presented. The following criteria were taken into account: energy sources, wall constructional materials and insulating materials. Bearing the sustainable development paradigm in mind, the best possible thermal insulation versions were determined by means of a two-criteria optimization for the economic and environmental criterion.

Significant thermal energy reduction in lactic acid production process

Lactic acid is widely used as a raw material for the production of biodegradable polymers and in food, chemical and pharmaceutical industries. The global market for lactic acid is expected to reach 259 thousand metric tons by the year 2012. For batch production of lactic acid, the traditional process includes the following steps: (i) esterification of impure lactic acid with methanol in a batch reactor to obtain methyl lactate (ester), (ii) separation of the ester in a batch distillation, (iii) hydrolysis of the ester with water in a batch reactor to produce lactic acid and (iv) separation of lactic acid (in high purity) in a batch distillation. Batch reactive distillation combines the benefit of both batch reactor and batch distillation and enhances conversion and productivity (Taylor and Krishna, 2000 [1]; Mujtaba and Macchietto, 1997 [2]). Therefore, the first and the last two steps of the lactic acid production process can be combined together in batch reactive distillation (Fig. 1) processes. However, distillation (batch or continuous) is an energy intensive process and consumes large amount of thermal energy (via steam). This paper highlights how significant (over 50%) reduction in thermal energy consumption can be achieved for lactic acid production process by carefully controlling the reflux ratio but without compromising the product specification. In this paper, only the simultaneous hydrolysis of methyl lactate ester and the separation of lactic acid using batch reactive distillation is considered.