Wast heat recovery

This study aims to investigate the thermal behavior and aerodynamic phenomena in a heated channel with varied rib configurations using computational fluid dynamics (CFD) simulations. Incorporating ribs in such systems enhances heat transfer and increases flow resistance and manufacturing costs. Understanding heat exchanger theory, measurement methods, and numerical calculations are crucial for creating efficient heat exchangers. The current research employs numerical analysis to assess the impact of hybrid ribs on heat transfer enhancement in forward-facing contracting channels (FFS). A two-dimensional forced convection heat transfer simulation under turbulent flow conditions was performed, considering the presence and absence of ribs with dimensions of 1 cm by 1 cm and spaced 11 cm apart. The arrangement of the ribs causes symmetrical temperature and flow distribution after and before each rib. The results demonstrate that the use of hybrid ribs outperforms the use of individual ri...

The parameters considered for the study for thermo-hydraulic performance comparison Pressure drop, temperature difference, heat transfer coefficient and heat flux using LMTD analysis. The numerical results indicate that the pressure drop shows a big difference among the three patterns and is maximum for Triangular Pattern, the overall heat transfer coefficient is higher for rotated square pattern design, turbulent kinetic energy is maximum for the square pattern tube arrangement helps to create a turbulence flow of a fluid which in turn increases the heat transfer efficiency and for high difference in between hot and cold fluid inlet temperature rotated square pattern tube arrangement shows high heat flux, while at lower difference it is almost same for square and rotated square pattern tube arrangement.

Evaluating the performance improvement of different pneumatic hybrid boost Evaluating the performance improvement of different pneumatic hybrid boost systems and their ability to reduce turbo-lag systems and their ability to reduce turbo-lag PLEASE CITE THE PUBLISHED VERSION

Heat recovery from flue gas is an efficient technique to capture and reuse waste heat from industrial processes, contributing to energy conservation and reducing operational costs. In this study, we explore the implementation of heat recovery systems within the Effluent Treatment Plant (ETP) of an industrial facility. The ETP typically generates significant amounts of waste heat during the treatment of wastewater, which, if not properly managed, is lost to the environment through flue gas emissions. By integrating a heat recovery system into the ETP, we aim to recover this waste heat and redirect it to pre-heat incoming effluent, thus reducing the energy required for thermal treatment processes.

The proposed system uses a heat exchanger to transfer thermal energy from the flue gas to the effluent stream. This process not only improves the overall energy efficiency of the ETP but also helps lower the plant's carbon footprint by reducing the need for additional fuel. Furthermore, by optimizing the heat recovery system, the plant can achieve better thermal balance, lower energy consumption, and reduced operational costs.

This paper discusses the design and implementation of the heat recovery system, including the selection of suitable heat exchangers, control mechanisms, and integration strategies within the existing ETP infrastructure. Additionally, the environmental and economic benefits of the system are evaluated, demonstrating the potential for significant energy savings and enhanced sustainability within industrial effluent treatment processes.

As the global demand for sustainable waste treatment technologies grows, energy, syngas, and biochar production from waste emerges as a promising solution to mitigate climate change. This study explores the potential of carbon credits and environmental sustainability for biochar production through various thermochemical treatment approaches of wood as a representative waste type. Three distinct cases are evaluated: Case 1, involving traditional pyrolysis with syngas post-combustion; Case 2, incorporating partial syngas combustion; and Case 3, utilizing renewable energy-powered hot “inert” (non-oxidizing) gases.

The results demonstrate that Case 1, despite producing biochar, falls short in terms of sustainability due to high CO₂ and NOₓ emissions during the syngas combustion phase, which counteract the carbon sequestration benefits of biochar and disqualify it from carbon credit eligibility. In contrast, Case 2 offers a practical intermediate solution by reducing emissions and improving energy efficiency while producing valuable syngas for biofuel and chemical production. Case 3 represents the most sustainable option, utilizing hot inert gases from renewable sources such as solar or wind energy and releasing no CO₂ or NOₓ, thus offering a zero-emission solution. By integrating syngas reforming and renewable energy, both Case 2 and Case 3 significantly enhance the potential for carbon credit generation and align with circular economy principles.

However, it is crucial to consider not only the CO₂ emissions directly generated by the core thermochemical and chemical processes in Waste-to-X conversion, reforming, and recycling but also the emissions associated with producing the chemicals and materials required for these operations. Addressing these indirect contributions is vital to accurately evaluate the full carbon credit potential of Waste-to-X solutions and to ensure they deliver meaningful climate benefits.

This study underscores the importance of adopting advanced, holistic approaches to achieve authentic carbon-neutral biochar production, thereby contributing to climate change mitigation, enhancing resource efficiency, and offering strong economic incentives for sustainable and clean climate technologies.

Heat pumps are among the most promising technologies to reduce global warming emissions and to more rationally use energy. The full exploitation of the potential of heat pumps is used more rationally for energy conversion with environmental-friendly refrigerants and higher Coefficient of Performance (COP). It requires further technological progress with modification in the condenser. Heat pumps often provide efficient solutions for heating the water. Although there is a gap in improving the efficiency of the heat pump, in many industrial applications much larger energy savings can be achieved by improving the design and by using different refrigerants. This investigation deals with the standardization of Heat pump and performance analysis of refrigerants for the heating of water in the condenser and to study the COP of Refrigerant, heat transfer rate and Log Mean Temperature Difference (LMTD). The study was performed in a heat pump that includes basic refrigeration elements and the counter flow heat exchanging method is used in the condenser to heat the water from the refrigerant. The analysis performed by using R22 and R134a are Refrigerants which are most used. The experimental results indicate that the efficiency of R134a is much better than R22. The performance of the designed heat pump was evaluated and the value of the Coefficient of Performance indicated that significant energy savings could be realized.

Purpose: This study aims to explore quality of life (QOL) during the first year of recovery after stroke in North Norway and Central Denmark. Method: Individual in-depth interviews with 11 stroke survivors were performed twelve months after stroke onset. An interpretative, inductive approach shaped the interview process and the processing of data. Results: We found that QOL reflected the individuals' reconstruction of the embodied self, which was identified by three intertwined and negotiating processes: a familiar self, an unfamiliar self, and a recovery of self. Further, we found that reconstruction of the embodied self and QOL could be framed as an ongoing and interrelated process of "being, doing, belonging and becoming". Enriching social relations, successful return to work, and continuity and presence in professional support during recovery enhanced the experience of QOL. Fatigue and sustained reduced function hindered participation in meaningful activities and influenced the perceived QOL negatively. Conclusions: The two countries differed in descriptions of continuity and support in the professional follow-up during the recovery process, influencing the degree of encouragement in reconstructing the embodied self. Reconstruction of the embodied self is a means of understanding stroke survivors' QOL during the first year of recovery, supporting an individualized and tailored rehabilitation practice.

The paper reports an experimental investigation of a newly proposed solar collector that integrates a closed-end pulsating heat pipe (PHP) and a compound parabolic concentrator (CPC). The PHP is used as an absorber due to its simple structure and high heat transfer capacity. The CPC has a concentration ratio of 3.4 and can be readily manufactured by three-dimensional printing. The CPC can significantly increase the incident solar irradiation intensity to the PHP absorber and also reduce the heat loss due to the decrease in the area of the hot surface. A prototype of the solar collector has been built, consisting of a PHP absorber bent by 4 mm diameter copper tube, CPC arrayed by 10 Â 2 CPC units with the collection area of 300 Â 427.6 mm 2 , a hot water tank and a glass cover. HFE7100 was utilized as the working fluid at a filling ratio of 40%. The operating characteristics and thermal efficiency of the solar collector were experimentally studied. The steady and periodic temperature fluctuations of the evaporation and condensation sections of the PHP absorber indicate that the absorber works well with a thermal resistance of about 0.26 °C/W. It is also found that, as the main factor to the the thermal performance of the collector, thermal resistance of the PHP absorber decreases with increasing evaporation temperature. The collector apparently shows start-up, operational and shutdown stages at the starting and ending temperatures of 75 °C. When the direct normal irradiance is 800 W/m 2 , the instantaneous thermal efficiency of the solar collector can reach up to 50%.

The solar organic rankine cycle is a promising technology which uses energy from the sun as a source of power and this does not affect the environment. However, due to the recent global warming, environmental pollution and energy crises coupled with the instability of oil prices, interest in renewable energy for mitigating these issues is growing once again. The aim of this study is to carry out a thermodynamic and sensitivity analysis of the system A thermodynamic analysis was carried out to see how feasible the power plant will operate on the chosen site, simulation were done in a Matlab environment, parametric and sensitivity analysis were also carried out to know the parameters that effect the system the most. The organic rankine cycle efficiencies and the overall solar organic rankine cycle efficiencies using R134a are 0.093, 0.086, 0.077 and 0.000028, 0.000030, 0.000032 respectively. The organic rankine cycle efficiencies and the overall solar organic rankine cycle efficiencies using R245fa are 0.200, 0.185, 0.167 and 0.000060, 0.000065, 0.000069 respectively.

Fluidized bed dryer is used to dry the silica sand used in core production in the casting industry. In this study, a heat recovery unit was designed in a drying system using waste heat recovery and the effects of specific energy consumption on heat recovery were investigated by performing energy, environmental and economic analysis. In this context, it is aimed to increase the drying efficiency, reduce carbon emissions and the effects of global warming with the heat recovery unit used in the preheating of the drying air blown by the fan. According to the results, a reduction of 12.815 m3/h in natural gas consumption and 0.032 tons CO2/h in carbon emissions will occur if the design with the 1st stage drying air preheating heat recovery unit is changed from the current design. If the current system is changed to a system with heat recovery unit, 1,428,753.81 TL can be saved annually and the payback period of the heat recovery unit was calculated 0.66 years. A reduction of 4.34 m3/h in natural gas consumption and 0.011 tons CO2/h in carbon emissions will occur if the design is changed from the current design to the design where the 2st stage in-plant water heating heat recovery unit. Thus, if the current system is changed to a system with heat recovery unit, 1,912,602,548 TL can be saved annually, and the payback period is calculated as 0.16 years. When this design is implemented, a more economical and sustainable drying system will be bringed to life.

This study aims to investigate the thermal behavior and aerodynamic phenomena in a heated channel with varied rib configurations using computational fluid dynamics (CFD) simulations. Incorporating ribs in such systems enhances heat transfer and increases flow resistance and manufacturing costs. Understanding heat exchanger theory, measurement methods, and numerical calculations are crucial for creating efficient heat exchangers. The current research employs numerical analysis to assess the impact of hybrid ribs on heat transfer enhancement in forward-facing contracting channels (FFS). A two-dimensional forced convection heat transfer simulation under turbulent flow conditions was performed, considering the presence and absence of ribs with dimensions of 1 cm by 1 cm and spaced 11 cm apart. The arrangement of the ribs causes symmetrical temperature and flow distribution after and before each rib. The results demonstrate that the use of hybrid ribs outperforms the use of individual ri...

This study explores the critical role of financial incentives, energy performance certifications, government policies, and advanced technologies in driving the adoption of energy-efficient building practices. Financial incentives, such as tax credits, rebates, and grants, are shown to significantly reduce the upfront costs associated with energy-efficient technologies, making these innovations more accessible to developers and building owners. The research highlights the effectiveness of energy performance certifications, like LEED and Energy Star, in enhancing the market value and energy performance of buildings by providing a structured framework for evaluating sustainability. Government policies and building codes, including the International Energy Conservation Code (IECC) and ASHRAE standards, are identified as key drivers of energy efficiency, compelling developers to meet stringent performance standards. Additionally, the integration of renewable energy technologies, such as solar panels and geothermal heat pumps, alongside smart building automation systems, plays a vital role in reducing energy consumption and improving operational efficiency. However, regional disparities in the availability of financial incentives and enforcement of policies present challenges to widespread adoption. The study concludes that expanding financial support, strengthening policy enforcement, and increasing public and industry awareness of the long-term financial and environmental benefits of energy-efficient buildings are essential for accelerating the transition to sustainable building practices. By addressing these challenges, the construction industry can make significant strides toward reducing energy consumption, lowering greenhouse gas emissions, and achieving global sustainability goals.

Present work studies the effects of microchannel height and Reynolds number on the temperature distribution behavior, pressure drop, and Nusselt number of a non-Newtonian nanofluid. The nanofluid is an aqueous solution of carboxy-methyl cellulose with a 1 percent volume fraction of copper oxide (CuO) nanoparticle, which is flowed at four Reynolds numbers of 250, 500, 750 and 1000, respectively, inside a rectangular microchannel with different heights size. Three dimensions in the order of H = 1 mm, H = 1.5 mm, and H = 2 mm are used for the microchannel height. Generally, it is concluded that increment of channel height and Reynolds number reduce temperature, whereas they increase heat transfer rate and Nusselt number due to their role in reducing thermal and hydrodynamics boundary layers thickness and flow concentration within the microchannel. Moreover, this phenomenon increases collision between hot and cold fluids due to decreasing their interval layer thickness. Also, increasing Reynolds number amplifies the pressure drop along the microchannel as well as increasing microchannel height. Therefore, it is concluded that the maximum temperature value of 430 K and maximum pressure drop of 7000 Pa have belonged to the case of studies with minimum and maximum microchannel height, respectively. On the other side, the maximum value of temperature is related to the minimum Reynolds number of 250, whereas maximum pressure drop is related to the maximum Reynolds number of 1000.

This study focuses on the experimental investigation of the efficiency of a humidifier-dehumidifier (HDH) desalination process. The system employs a closed-air cycle, utilizing a hybrid (solar-electric) air heater to increase the air temperature before entering the humidifier. Additionally, a Vapor Absorption Refrigeration (VAR) system is employed to decrease the temperature of the water before it enters the dehumidifier. The system is suitable for deployment in regions with high temperatures and humidity levels. Tests have been conducted under prevailing weather conditions. Temperature and relative humidity at various stages of the cycle are measured and recorded using a dedicated sensor. This study examines the effects of different parameters, including air mass flow rate (MFR) and air temperature at the humidifier inlet, on fresh water production (FWP), coefficient of performance (COP), and gained output ratio (GOR). The results section presents the experimental findings, which show that the maximum COP, GOR, and FWP achieved values of 2.1, 4.1, and 200 g/h, respectively. Furthermore, an increase in air MFR corresponds to an increase in both COP and FWP, while GOR values show a decrease. Based on the eco-analysis conducted for this investigation, the cost per liter (CPL) was calculated to be 0.

The study is dedicated to enhancing design and computational methodologies for thermosiphon waste heat boilers (WHB) within combined cycle power plants (CCPP). The optimized WHB design and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.

The existence of an anaerobic bioreactor that produces biogas can provide two benefits. First, it can produce sustainable energy. Second, it helps reduce greenhouse gas emissions and waste. Based on these two advantages, obstacles to its implementation must be overcome to realize regional energy security. The research method used is descriptive-quantitative and enriched by descriptive-qualitative by FGD, through in-depth interviews, direct observation of the field, and interviews of related parties. This research is to find the source of the problem for the gap that occurs between the real condition of biogas potential that is utilized and wasted as emissions. Based on the results of this study, there are three main obstacles that need to be optimized. The first is the difficulty of raw materials because most of them are imported. The second challenge is the price difference because the power purchase agreement was calculated before the new law came out. And third, the lack of government support. Based on these three constraints, the optimization strategy carried out is: first, facilitate regulations in the ease of procurement of supporting materials. Second, the government regulates and straightens regulations related to price differences. Third, central and local governments should actively support development by increasing training, education, and capacity building for policymaking and analysis in the field of new and renewable energy.

This paper presents anew cycle for recovering the energy from low-temperature heat sources that combines the Organic Rankine Cycle (ORC) with the Trilateral Flash Cycle (TFC) via a cascade condenser. The performance of the combined cycle is evaluated for a heat-source of 120 o C and various values of the cascade-condenser temperature. The results show that a high temperature maximises the cycle's power and exergetic efficiency but minimises its thermal efficiency and vice versa. Therefore, a tri-objective (3O) optimisation analysis of the cycle is conducted that simultaneously maximises all three parameters. Compared to the temperature that gives the maxmimum power, the 3O optimised temperature reduces the power and exergetic efficiency by 16%, but increases the thermal efficiency by 17.1%. Compared to the temperature that gives the maxmimum thermal efficiency, the 3O optimised temperature reduces the thermal efficiency by only 4.4%, but increases the power and exergetic efficiency by 60.9%. The model uses special VBA functions to determine the fluid properties with Excel.To verify the functions,they were used to analyse the simple OCR by using R134a, R1234yf and R152a, propane (R290), n-butane (R600), iso-butane (R600a), and ammonia (R717) and the model'sresults are compared with published results obtained by using the EES software.

The circular life cycle of waste management, designed for waste-to-energy, can substantially contribute to efficient waste management, a precursor for sustainable energy and food production. This study evaluates knowledge, attitudes, and practices (KAP) related to waste management and identify its potential for improving energy and food production. Surveys, interviews, and data analysis were employed to investigate current waste management scenarios, socio-cultural perceptions, and policy frameworks in Oleh, Nigeria. Factor analysis was used to reduce the multitude of attitudinal variables collected during surveys and interviews. The results exposed gaps in waste management perception, principles, policy implementation, and waste-to-energy conversion. SWOT analysis was conducted to validate identified factors, highlighting significant strengths, weaknesses, opportunities, and threats associated with current waste management practices. To enhance energy generation and food security, a waste management model was proposed with recommendations for pathways promoting policy enhancements and community engagement strategies to foster a more efficient energy and food nexus.

In this paper, Turbine Inlet Temperature (TIT), Specific Work Output and Thermal Efficiency of combined cycle have been analysed at different Air Fuel ratios, pressure ratios and variable Supplementary heating. The Pressure ratios have been taken in the range of 4 to 20, Air fuel Ratio 50, 55, 60 and 65 and Supplementary heating from 0.1 to 0.5. The results show that the Specific Work Output and Thermal Efficiency improved at lower Air Fuel Ratio and lower Supplementary heating and at higher value of pressure ratio. In the analysis it was desirable that the actual exhaust temperature of gas turbine plus gas turbine bypass temperature should be above 813 K.

A substantial raise in recuperator effectiveness has been established in the past by improving the fabricating and joining configurations regarding the manufacturing of compact recuperators. Further advancement of state-of-the-art recuperators requires providing for increased temperatures and pressures. 1bis can only be achieved by incorporating high temperature materials into the recuperator design. Although many

The aim of this study is to improve the heat transfer in a double tube heat exchanger by using four samples of the inner tube (smooth tube, half circular finned tube, circular finned tube and circular helical finned tube). The experiments were carried out by using the four kinds of fluids flow, namely, (a parallel flow of cold water inside the inner tube, a parallel flow of hot water inside the inner tube, the counter flow of cold water inside the inner tube and the counter flow of hot water inside the inner tube). The comparative results of the finned tubes with respect to the smooth tube showed the highest values of heat transfer coefficient obtained at the circular helical finned tube instate of hot water flow inside the tube. The convection heat transfer coefficient increased by (250 and 165)% for both flows (parallel and counter), respectively in case of turbulent flow, while in state of the hot water flow on the outer surface of the inner tube, the heat transfer coefficient increased by 230 % for parallel flow and in the case of the counter flow increased by 260 %. The fanning friction factor was affected by a condition of the working fluids where in the case of hot fluid flows outside surface of the inner tubes, the min. values of fanning friction factors was obtained from smooth tube sample which is ranged from 0.01 to 0.05 and other samples are ranged from 0.008 to 0.05.

The amount of resources devoted to saltwater desalination is substantial and will only rise as the scarcity of water escalates globally. Desalination techniques for seawater, particularly thermal desalination techniques, require a lot of energy and utilize conventional energy sources. The goal of this article is to examine the integration of thermal desalination techniques with carbon capture and sequestration (CCS) power generation. This study utilizes an oxy-combustion-based zero-emission power plant and investigates the performance of a humidification-dehumidification (HDH) cycle integrated with the main cycle. The system constitutes two main cycles, namely (i) oxy-combustion power generation cycle (OPGC) and (ii) humidification-dehumidification (HDH) cycle. The performance of several bottoming cycles coupled with a closed-air-open-water water-heated (CAOW-WH) HDH system is studied to evaluate the thermodynamic feasibility of the system. The effect of top and bottom temperatures of the HDH system and mass flow rates are optimized for gain output ratio (GOR) and recovery rate (RR). A sensitivity analysis of the integrated system was also conducted, and the effect of oxy-combustion operating parameters on the net cycle efficiency was examined. This analysis offers crucial design considerations for such integrated systems to generate power with zero emissions and produces sweet water without additional energy costs.

The heat transfer and pressure drop in a microchannel heat sink with 02 mixing chambers with inclined walls were numerically studied. The transport equations have been resolved by the finite volume method using ANSYS Fluent software. The operating fluids are water and Al2O3-water. The results obtained for Reynolds numbers ranging from 187 and 705 show that adding a micro-mixing chamber with a rectangular rib in the microchannel improves the heat transfer and increases the pressure drop compared to conventional microchannels. The new shape of the mixing chamber studied shows a net decrease in pressure drop, which improves the performance of the micro heat sink by 5.6%.

Sanayi sektoru, gerek yuksek enerji tasarruf potansiyeline sahip olmasi, gerekse de sanayide tuketilen enerjinin cogunlukla ticari enerji olmasi nedeniyle enerji tasarrufu calismalarinda oncelikle ele alinmasi gereken bir sektordur. Turkiye’de birincil enerjinin %24’unu, elektrigin ise %47’sini sanayi sektoru kullanmaktadir. Ulkemiz sanayisi agirlikli olarak emek ve enerji yogun alanlarda varlik gostermeye calistigindan dolayi OECD ulkeleri icinde enerji yogunlugu yuksek ulkelerin basinda gelmektedir. Bu ise isletmeleri diger ulkelerdeki isletmelerle rekabet etmesi anlaminda zor durumda birakmaktadir. Bu yuzden ustun nitelikli ana uretim prosesleri-teknolojileri, bu teknolojileri destekleyen atik isi geri kazanimi, kompenzasyon, otomasyon gibi destekleyici teknolojiler ve verimlilik felsefesi ile orulmus enerji yonetim anlayisinin benimsenmesi gerekmektedir. Bu baglamda sanayide enerji verimliligini artirmak icin, enerji muhasebesi, kontrol sistemleri, yalitim, yeni teknolojiler ve ...

Marine diesel engine is widely used in merchant ships as a propulsion system. The wasted heat of the diesel engines is one of the main drawbacks in this system. The aim of this paper is to recover this wasted heat to be used in designing combined heat and power plant. A bulk carrier WADI SAFAGA has been investigated as a case study. Power and electricity from Supercritical Organic Rankine Cycle will be produced as wasted heat recovery of the main engine. Maximum power, thermal efficiency and specific fuel consumption have been investigated according to the change of the evaporating pressure of organic fluid from 50 bar to 75 bar with increment of 5 bar. Heat exchangers must be redesigned due to the replacement of cooling water by refrigerant (R34a and R245fa). Also, parametric and economic studies will be taken into account. A comparison between diesel generator and SORC generator will be studied from economic and weight dimensions together with the specific power of generator point of view. The results showed that using SORC with R134a at working pressure of 50 bar have a satisfied performance with respect to the saving in specific fuel consumption, lubrication oil and cooling water. In addition, replacing three diesel generators by one SORC generator would decrease the weight by 12 tons, and would also decrease fuel consumption by 2.1 ton/day, shrinking the heat exchangers size, specific fuel consumption was decreased by 61 g/kW-h. Finally, the wasted heat of the main engine will decrease by 18%.

Pulsating heat pipe (PHP) is an implicit technique through a passive two-stage heat transfer sys- tem. This paper presents the experimentations on PHP contrived using copper with different in- ner tube diameters of 1, 1.5, 2, and 2.5 mm, respectively. The PHP is accused of acetone as a func- tional liquid with filling proportions varying from 50 to 90% of its volume with an increment of 10%. The effects of filling proportion and tube diameter on the thermal performance of PHP were investigated. The evaporator zone is electrically heated using a mica heater in the range of 20–80 W, and the condenser area is kept cool by the water circulation method. The results show that a 2 mm inner tube diameter performs best compared to other tube diameters, with a lower rate of thermal resistance of 0.49 K/W. Also, the performance of PHP is enhanced at a filling pro- portion of 60% for all the tube diameters. Further, CFD analysis was carried out for different fill- ing ratios for a 2 mm diameter pipe at a constant heat input of 80 W, and it revealed that test out- comes were in line with CFD results. The deviation between the experimental and numerical studies was 10%. Considering the optimized parameters, i.e., tube diameter and filling ratio, the work was extended by adding SiO2 nanoparticles to the base fluid with 1–5 % mass concentra- tion. The results showed a lower thermal resistance value of 0.3 W/K and a higher heat transfer coefficient of 828.64 W/m2 °K was obtained at 2% mass concentration of SiO2. Also, the proportional rise in heat transfer coefficient at 60 W is 11.46, 17, 14, 4.15, and 1.94% for 1, 2, 3, 4, and 5% mass concentration of SiO2 nanoparticles, respectively. Hence, the PHP operates better at a 2 mm diameter with a 60% filling ratio and 2% mass concentration of SiO2 nanoparticles.

The study is dedicated to enhancing design and computational methodologies for thermosiphon waste heat boilers (WHB) within combined cycle power plants (CCPP). The optimized WHB design
and an improved thermal calculation approach are shown. The efficiency of the proposed WHB has been improved by optimizing the area and arrangement of the surface. The novel method incorporates considerations for the internal thermal resistance within thermosyphons
and the graded velocity of natural circulation within the evaporation circuit. To refine the calculation method, empirical and experimental data concerning internal temperature gradient in thermosiphon functioning within a heat load spectrum of up to 17 kW/m2, were used. Important
findings include three categories. Firstly, increasing the number of sections will slightly increase capital costs and decrease WHB gas temperature, which could be neglected by the unification of
thermosiphon sections. Secondly, by applying this modified methodology to a power plant facility featuring a 6700 kW gas turbine engine (GTE), notable adjustments in thermal power were realized, amounting to 157 kW (approximately 6 %), along with corresponding electrical power adjustments of 149 kW (approximately 2 %). Third, the new method is limited to a GTE power of up to 10 MW due to the experimental data used for validation.

This article presents a newly designed and realized system for heat recovery from waste water. The waste water is the heat source, the temperature of which is about 44-49 o C. The heat recovery process is performed using a plate heat exchanger and two heat pumps. The mentioned components are serially linked. The heat sink is clean water, which is pumped from a 40 meter deep well and is heated up from 13-14 o C to 50-55 o C. Waste water is cooled down from 44-49 o C to 13-14 o C. The mass flow rate of the clean and waste water is approximately the same. This heat recovery process reaches a significant coefficient of performance (COP) with 6.03-6.5 meaning that 83-85% of the energy demand for heating clean water is provided by the recovery process and electric energy is consumed only for 17-15%. From the aspect of energy efficiency: the plate heat exchanger participates by about 49%, the low temperature heat pump by 30%, the high temperature heat pump by 21% in the heat recovery.

This paper analyzes the energy efficiency of the heat pump and the complete heat pump heating system. Essentially, the maximum of the coefficient of performance of the heat pump and the heat pump heating system are investigated and determined by applying a new analytical optimization procedure. The analyzed physical system consists of the water-to-water heat pump, circulation and well pump. In the analytical optimization procedure the "first derivative equal to zero" mathematical method is applied. The objective function is the coefficient of performance of the heat pump, and the heat pump heating system. By using the analytical optimization procedure and the objective function, as the result, the local and the total energy optimum conditions with respect to the mass flow rate of hot and cold water i. e. the power of circulation or well pump are defined.

Treatment and disposal of sewage sludge has become an economically and environmentally sensitive problem. This necessitates cost-effective and innovative solutions whilst responding to environmental regulation and public pressures. This study examines the characteristics of a typical sludge samples as received following standard analytical procedures and its suitability for power generation. The results of the analysis revealed that the sample has good proxanal and ultanal attributes. The higher heating value of the sample on dry basis was found to be 21.21 MJ/kg. These characteristics are similar to qualities of standard coal used as fuel in power stations.

Los procesos que ocurren en una cavidad de dos dimensiones, llena con dos fluidos, son estudiados a traves de un modelo numerico. Los efectos de la tension superficial y de las fuerzas gravitacionales son incorporados en la discretizacion del problema. En adicion, la interface entre los fluidos es permitida que se deforme, y su posicion es obtenida como parte de la solucion del problema. En este articulo, la atencion es dirigida al estudio de los efectos de las condiciones de frontera en la evolucion de las distribuciones de velocidad y temperatura dentro de la cavidad.

The humidification-dehumidification system is one of the desalination technologies that can utilize non-fossil thermal sources and requires insignificant input energy. This system is usually suitable for rural areas and places far from the main sources of energy. The purpose of this study is to obtain the most suitable working conditions and dimensions of this system. In this research, thermodynamic modeling was first performed for a simple type of the system (water-heated); then, the effect of parameters on the system performance was investigated. Modeling was conducted through a numerical simulation; furthermore, the assumption of the saturation of exhaust air from the humidifier was also considered in the mentioned code. Afterward, a comparison was made between two different forms of the system, and the proper form was chosen for the rest of the research. Moreover, through heat transfer equations, the dimensions of the two main parts of the system, i.e., humidifier and dehumidifi...

In South Africa, there is an ongoing constraint on the electricity supply at the national grid to meet the demand. Eskom is implementing various measures such as the Integrated Demand Management and the promotion and encouragement of the use of energy efficient devices like an Air Source Heat pump (ASHP) water heater to replace the high electrical energy consuming conventional geysers for sanitary hot water production. The ASHP water heater market is fast gaining maturity. A critical mathematical model can lead to performance optimization of the systems that will further result in the conservation of energy and significant reduction in global warming potential. The ASHP water heater comprises of an ASHP unit and a hot water storage tank. In this study, a data acquisition system (DAS) was designed and built which monitored the energy used by the geyser and the whole building, the temperature at the evaporator, condenser, tank outlet hot water, tank inlet cold water, the ambient tempe...

Günümüzde artan enerji maliyetleri ve çevresel endişeler binalarda enerjinin verimli kullanımını zorunlu kılmıştır. Yapı sektöründe enerji tasarrufu sağlamak amacıyla yüksek enerji tüketimi olan üniversiteler odak haline gelmiştir. Üniversitelerde enerjinin verimli kullanılması ile hem enerji maliyetlerinin üniversite bütçesi üzerindeki yükü hafifletilebilecek, hem de sürdürülebilir üniversite kriterleri için önemli bir adım atılabilecektir. Bu yüzden, bu çalışmada Karamanoğlu Mehmetbey Üniversitesi’nin (KMÜ) enerji açısından mevcut durumu ortaya çıkarılmış ve enerji verimlilik potansiyeli incelenmiştir. Öncelikle, KMÜ yerleşkesine ait binalarda kullanılan enerji tüketim değerleri belirlenmiş, enerji tüketim noktalarında uygun cihazlar (termal kamera, baca gazı analizörü, ultrasonik debimetre vb.)  kullanılarak düzenli ölçümler alınmıştır ve bu noktalarda verimlilik artırıcı projeler önerilmiştir. Elde edilen sonuçlara göre, üniversitemizin 2016 yılı enerji tüketim değerinin 1422 to...

Vehicles could save ~110 million gallons of gasoline per year in the U.S. with heat exchangers acting as heat recovery ventilators in the air conditioning systems. Even more energy could be saved with in-vehicle heat exchangers by reducing heating energy in plug-in vehicles. Currently, vehicles do not have heat recovery ventilators because of the high cost of conventional metal heat exchangers. To overcome this challenge, low-cost expanded polymer microchannel heat exchangers were studied. Forward conduction laser welding was used to join 25-micron thick linear low-density polyethylene sheets, which were then fixed into shape and expanded. The microchannel polymer heat exchangers were tested at various air flow rates. At the maximum flow rate, the effectiveness was ~70% and the implications of this expanded heat exchanger in other applications are discussed.

A finite difference model of a heat exchanger (HX) considered maldistribution, axial conduction, heat leak, and the edge effect, all of which are needed to model a high effectiveness HX. An HX prototype was developed, and channel height data were obtained using a computerized tomography (CT) scan from previous work along with experimental results. This study used the core geometry data to model results with the finite difference model, and compared the modeled and experimental results to help improve the expanded microchannel HX (EMHX) prototype design. The root mean square (RMS) error was 3.8%. Manifold geometries were not put into the model because the data were not available, so impacts of the manifold were investigated by varying the temperature conditions at the inlet and exit of the core. Previous studies have not considered the influence of heat transfer in the manifold on the HX effectiveness when maldistribution is present. With no flow maldistribution, manifold heat transf...

Exposure to cold temperatures is, often, a neglected problem in ICUs, CT, AND MRI scans it may cause several discomforts such as shivering, lung diseases, and artifacts in scan reports, etc., one of the leading influences of the overall sensation of cold discomfort is the cooling of the back. This study aimed to evaluate the effect of a heated ambulance mattress-prototype on body temperatures and thermal comfort in an experimental study. The endotherm patient warming mattress and ambulatory patient mattress are the preexisting projects. The Inditherm mattress is designed for use by all patients undergoing anesthesia who may be at risk of inadvertent pre-operative hypothermia, and for any patients who require warming in pre-operative, intra-operative, and postoperative settings the ambulatory mattress is generally a warming mattress. The main disadvantage is that these two technologies are not automated the operator has to set all parameters. In this project, we are designing a mattress that liberates heat depending on room temperature. The Lab VIEW controls on and off of the system it compares the room temperature with the present value and produces a suitable result. The main advantage is the project is fully automated and warms the patient only at the required time.

Full repowering of Be'sat steam power plant has been studied in this work. The methodology is used to simulate the new cycle according to its principal specifications and to optimize it based on the objective functions. Objective functions are electricity cost per kWh and exergy efficiency. These parameters are functions of the pinch and approach point temperature differences at high and low pressure points and at the pre-heater in the heat recovery steam generator (HRSG), steam turbine inlet flow rate, gas turbine (GT) isentropic efficiency, air compressor isentropic efficiency and compressor pressure ratio. Finally, considering the introduced objective functions, it is tried to achieve the most optimized techno-economic characteristics for Be'sat power plant repowering cycle using the genetic algorithm with two scenarios of single and multi-objective optimizations. The results show that the efficiencies of repowered cycle are 52.59% and 51.3% for two cases of unfired and fired duct burners, respectively.

This paper presents experimental measurements and analytical predictions of pressure loss and heat transfer through brazed woven textiles under forced air convection. The main characteristics considered include porosity, solid thermal conductivity, and surface area density. The heat transfer performance of woven textiles is compared with other heat exchanger media including metal foams.

In this research, the design and use of combined systems for the simultaneous production of water, heat, and energy have been proposed, and, to fulfill the water, electricity, and heat demands of a hotel, modeling of the multi-effect evaporative desalination (MED) and combined heat and power (CHP) generation system was done. Then, the design of these two systems was administered in a combined way. This design was applied in order to evaluate the economy of the combined system compared to separate systems. The performed scenario was executed every 24 h during the two seasons of the year. The genetic algorithm was used to optimize this system, and it was considered the objective function to minimize the annual costs. The results showed that the nominal capacity of the gas turbine and backup boiler in the CHP + MED + thermal energy storage (TES) system was (14%) larger and (8.2%) smaller, respectively, compared to the CHP+ MED system. In addition, by using the energy storage tank in the combined CHP + MED system, 5.1% of the annual costs were reduced.

This paper tells about what is a heat exchanger made of in terms of thermal analysis and the important tools and factors which play vital role in designing them through the help of concepts learnt from heat transfer and fluid mechanics. The main objective of this paper is to design a reliable, economical heat exchanging system for different applications by selecting specific material which has a good thermal conductivity or convectivity property, designing profiles with desirable cross sectional areas to maximise the heating process. Almost all of contents and the analysis of the paper are based on the literatures available on the related subject and disciplines and a number of scientific rules together with heat transfer theories and facts have been incorporated abundantly. As the overall size of the heat exchanger is an important factor, the analysis has presented the steps and procedures needed to determine this variable and the cost aspects, which is also one of the most important tool has been discussed with the help of material selection and the economical perspective of popular materials. Ultimately the optimum overall heat transfer coefficient has been predetermined based on the requirements of amount of heat energy to be transferred by considering the other useful factors like Area of the heat exchanger, length of the heat exchanger tubes and the type of economic material. And it is found that the overall heat transfer coefficient can be maximised or minimised depending on the design and configuration of the whole system and can serve as a measure of the heat exchanging system.

Although existing models of natural circulation in steam boilers involve numerous simplifications, the physical processes that occur in real-time are not considered. This study sought to improve the natural circulation model in the evaporation circuit of a thermosiphon waste heat boiler using an analytical solution and numerical simulation results. A modified natural circulation model was developed using ranked variables of velocity and heat flux in the evaporator ring channels. These results were obtained in the range of heat flux densities 1.074-9.973 kW/m 2 and temperatures of the thermosiphons hot zone 477.4-487.1 K which is typical for a waste heat boiler for cogeneration power plant with gas turbine engine 6700 kW power.

This article analyses the optimum energy-economic thickness of thermal insulation layer for external wall. The analysis was performed by applying a new method 'investment-savings'. An appropriate mathematical model was developed during the work. The mathematical model consists of energy and economic part. The economic part of the model contains algebraic equations for investment, exploitation and savings. The considered wall was made of brick and polystyrene was used as thermal insulation material. The heat transfer through the wall was steady-state. An analytical-numerical and graph-numerical methods were applied to solve the mathematical model. The minimum payback period of the investment was the optimization criterion. The numerical results obtained by the simulation are presented graphically. The optimum thickness of the thermal insulation layer is shown in the diagrams. In addition, by applying the developed mathematical model the optimum thickness of thermal insulation layer for energy-economic conditions in Serbia in 2014 was obtained. By applying the current prices in Serbia, the energy-economic efficient optimum thickness of the thermal insulation layer of the polystyrene is 6.89 cm which is rounded to ≈7 cm. Polystyrene can be bought in 1, 2, 3,. . ., 7,. . ., 10,. .. cm thickness only. The payback period is 1.22 years if the price of electric energy is 0.09 D /kWh. A significant result of the study: increase in thickness by 4.86 times, while investment increases only by 1.69 times.

Öz: Tüm dünyada nüfusun hızla artışına paralel olarak enerji arzı da artmaktadır. Enerji kaynaklarının sınırlı olması, enerji maliyetlerinin yüksek olması, enerji üretimi ve tüketimi sırasında ortaya çıkan emisyonların çevresel problemlere neden olması gibi durumlar enerjiyi verimli kullanmayı zorunlu kılmaktadır. Bu çalışmada, Bursa'da tekstil sektöründe faaliyet gösteren bir havlu üretimi tesisinde enerji etütleri yapılmış ve başlıca 7 iyileştirmenin uygulanması önerilmiştir. Bu iyileştirmeler; jet makinelerinin izole edilmesi, buhar kazanı su seviyesinin otomatik kontrolü, kondens dönüşlerinin toplanması, kondenslerde seviye kontrol sistemi uygulaması, kazan besi suyu şartlandırma sisteminin kurulması, kompresör emiş havasının düzenlenmesi ile ring hattı ve tesisat revizyonu şeklindedir. Bahsedilen iyileştirmelerden maddi tasarruf miktarı en az (3.141 TL/yıl) olan uygulama kompresör emiş havasının düzenlenmesi iken maddi tasarruf miktarı en fazla olan uygulama 175.583 TL/yıl ile kondens dönüşlerinin toplanmasıdır. CO2 emisyonundaki azalma oranlarının 2,7 ton/yıl ile 186 ton/ yıl arasında değişim göstereceği hesaplanmış olup önerilen iyileştirmelerin hem maliyet hem de çevresel açısından işletmelere fayda sağlayacağı sonucuna varılmıştır.

Humidification–dehumidification (HD) is a non-traditional desalination process in which water evaporates from a saline liquid stream and the vapour condenses into purified water. In nature, seawater is heated by solar radiation and evaporates from the air that moistens it. This is known as the rainy cycle. The artificial version of this cycle is called the HD desalination cycle. The latter has received a lot of attention in recent years, and many researchers have studied the complexities of the technology. In the present work, experimental work with a simple configuration was developed and built, consisting of a humidification column followed by a condenser, in which the humidified air is dehumidified to produce fresh water. A novel and unique packaging material was used in the humidifier, consisting of a cellulose plant grown on the banks of the River Nile. In all previous work, the main problem was the type of packaging material that could ensure intimate contact and uniformity be...

Artan nüfusla birlikte enerji tüketimindeki artış enerjiyi tüm dünyada olduğu gibi ülkemizde de önemli bir problem olarak karşımıza çıkarmaktadır. Özellikle sanayi ve konutlarda kullanılan enerjinin büyük çoğunluğunun ithal olması, araştırmacıları daha verimli sistemler tasarlamaya, mevcut sistemlerin verimini arttırmaya ve özellikle de alternatif enerji kaynaklarını kullanmaya zorlamaktadır. Alternatif enerji kaynaklarından biri biyokütledir. Pelet yakıtı da biyokütle kaynakları arasında yer almaktadır. Bu çalışmada güncel literatür incelenerek pelet yakıtlı soba ve kazanların teknolojileri, ısıl performansları ve emisyonları değerlendirilmiş, piyasa durumu belirlenmiştir. Sistemlerin ısıl verimlerinin %90 üzerinde gerçekleştiği, hava kirletici emisyonlarının toz hariç düşük seviyede olduğu görülmüştür. Kojenerasyon sistemleri gibi yeni uygulamalar için uygun ve gelişme potansiyeline sahip oldukları gözlemlenmiştir.

This paper is presented to study the effect of temperature using 5 % biodiesel blended on diesel engine performance. The one-dimensional numerical analysis of GT-Power software is used to simulate the commercial four cylinder diesel engine. The standard fuel data base of GT-Power does not contain any biodiesel. Therefore, the authors have measured typical physical properties of the fuel before it can be installed into the GT-Power data base. The diesel engine is simulated to study the characteristic of engine performance when the engine is operating with fuel blend as an alternative fuel. The simulations are conducted at full load condition where the temperature are varies from 300K to 500K. The simulation results show that the brake power and brake torque reduced maximum of 1.39 % and 1.13 % respectively for the engine operating with fuel blend at different temperatures. It was shown that the insignificant different is due to the small gap between energy content values. The decrease in the lower heating value caused an increase in the brake specific fuel consumption thus reduces the brake thermal efficiency of engine performance at full load.