Because thermal based desalination systems are still contributing a substantial share in the desalination industry in the GCC and MENA countries, there is a need to optimize their energy consumption in order to minimize oil consumption. The solution used in this paper is connecting the Multi Effect Desalination (MED) system to an Adsorption cooling (AD) system to improve the performance of existing MED plants. A transient mathematical model is developed to predict the performance of multi-effect parallel feed (MED-PF) evaporation desalination system integrated into an adsorption cooling system to achieve both cooling and potable water production. The study aims at examining the impact of operating conditions on the system performance and comparing the performance of different adsorbent materials (HKUST-1 and silica gel RD-2060) at similar operating conditions. It is found that the integrated system allows lowering the MED last effect temperature below the ambient temperature due to water vapor uptake by AD adsorbent bed. As a result, operational gap increases. Thus, the multi effect desalination system can have more effects within the extended flashing range, resulting in more distillate water production and better recovery of heat input. It is worth mentioning that the number of effects is the most influential parameter in increasing the production of multiple effect desalination systems. Parallel feed layout is selected as a preferred layout of MED systems. The average distillate water production increases by two to three times compared to the conventional MED cycle. Using the HKUST-1 instead of the silica gel reduces the last effect temperature by 9 °C. This leads to the use of more effects in the MED system compared with using silica gel in the adsorption sub-system.
{"title":"Hybrid Parallel Feed Multi-Effect Evaporation Desalination System With Adsorption Cycle","authors":"Hassan Al-Khalifah, R. Ben‐Mansour, M. Antar","doi":"10.1115/imece2022-96683","DOIUrl":"https://doi.org/10.1115/imece2022-96683","url":null,"abstract":"\u0000 Because thermal based desalination systems are still contributing a substantial share in the desalination industry in the GCC and MENA countries, there is a need to optimize their energy consumption in order to minimize oil consumption. The solution used in this paper is connecting the Multi Effect Desalination (MED) system to an Adsorption cooling (AD) system to improve the performance of existing MED plants. A transient mathematical model is developed to predict the performance of multi-effect parallel feed (MED-PF) evaporation desalination system integrated into an adsorption cooling system to achieve both cooling and potable water production. The study aims at examining the impact of operating conditions on the system performance and comparing the performance of different adsorbent materials (HKUST-1 and silica gel RD-2060) at similar operating conditions. It is found that the integrated system allows lowering the MED last effect temperature below the ambient temperature due to water vapor uptake by AD adsorbent bed. As a result, operational gap increases. Thus, the multi effect desalination system can have more effects within the extended flashing range, resulting in more distillate water production and better recovery of heat input. It is worth mentioning that the number of effects is the most influential parameter in increasing the production of multiple effect desalination systems. Parallel feed layout is selected as a preferred layout of MED systems.\u0000 The average distillate water production increases by two to three times compared to the conventional MED cycle. Using the HKUST-1 instead of the silica gel reduces the last effect temperature by 9 °C. This leads to the use of more effects in the MED system compared with using silica gel in the adsorption sub-system.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78324946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aniket S. Patankar, Xiao-Yu Wu, Won-Seok Choi, H. Tuller, A. Ghoniem
Solar Thermochemical Hydrogen Production (STCH) is a promising technology that uses high-temperature heat directly to split water. The authors have previously proposed a Reactor Train System (RTS) that addresses the largest source of inefficiency in state-of-the-art STCH systems — solid heat recovery — by using multiple moving reactors that exchange heat radiatively between STCH steps. In this work, another major source of inefficiency — oxygen removal during metal reduction — is addressed. Two oxygen pumping schemes are considered — vacuum pumping (VP) and thermochemical oxygen pumping (TcOP). For vacuum pumping, the modularity of RTS enables a ‘Pressure Cascade’ which reduces pumping work by a factor of four and the capex by a factor of five as compared to a single-step VP scheme. The optimized RTS + VP system achieves 31% heat-to-hydrogen conversion efficiency with ceria despite the low efficiency of vacuum pumps at low pressures. Thermochemical Oxygen Pumping (TcOP) uses a second redox material — SrFeO3 — to pump oxygen. This material is transported in reactors moving in the opposite direction to the main RTS train. The optimized RTS + TcOP achieves morethan 40% heat-to-hydrogen efficiency, while producing twice as much hydrogen per kilogram of ceria as the RTS + VP system.
{"title":"Efficient Solar Thermochemical Hydrogen Production in a Reactor Train System With Thermochemical Oxygen Removal","authors":"Aniket S. Patankar, Xiao-Yu Wu, Won-Seok Choi, H. Tuller, A. Ghoniem","doi":"10.1115/imece2022-94821","DOIUrl":"https://doi.org/10.1115/imece2022-94821","url":null,"abstract":"Solar Thermochemical Hydrogen Production (STCH) is a promising technology that uses high-temperature heat directly to split water. The authors have previously proposed a Reactor Train System (RTS) that addresses the largest source of inefficiency in state-of-the-art STCH systems — solid heat recovery — by using multiple moving reactors that exchange heat radiatively between STCH steps. In this work, another major source of inefficiency — oxygen removal during metal reduction — is addressed. Two oxygen pumping schemes are considered — vacuum pumping (VP) and thermochemical oxygen pumping (TcOP). For vacuum pumping, the modularity of RTS enables a ‘Pressure Cascade’ which reduces pumping work by a factor of four and the capex by a factor of five as compared to a single-step VP scheme. The optimized RTS + VP system achieves 31% heat-to-hydrogen conversion efficiency with ceria despite the low efficiency of vacuum pumps at low pressures. Thermochemical Oxygen Pumping (TcOP) uses a second redox material — SrFeO3 — to pump oxygen. This material is transported in reactors moving in the opposite direction to the main RTS train. The optimized RTS + TcOP achieves morethan 40% heat-to-hydrogen efficiency, while producing twice as much hydrogen per kilogram of ceria as the RTS + VP system.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"355 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77325771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar energy plays a vital role in the future of clean energy production due to its availability all year round. Some prominent solar energy technologies, e.g. concentrating solar power (CSP), have the ability to focus/concentrate sunlight for large-scale commercial use. Meanwhile for smaller-scale residential use, solar water heating (SWH) systems are often used to provide hot water for household applications, where the solar collectors are the main components of such systems. The type of solar collector of interest in this study is the heat pipe evacuated tube collector (HPETC). To enhance the system’s thermal and optical efficiencies, this study investigates the incorporation of a custom-made involuted reflector mirror to a single HPETC through employing SolTrace’s optical ray tracing method, where the heat flux around the circumference of the absorber tube can be obtained. The maximum and averaged heat flux is compared between a traditional HPETC system and the HPETC system with the involuted reflectors. The result from this study showed that the HPETC system with an optimized involuted reflector experiences up to ∼ 55.3 % increase in maximum heat flux, and an increase up to ∼ 81.2 % in average heat flux across the absorber tube. Consequently, the HPETC incorporating the custom-made involuted reflectors yields to more collected heat and is capable of providing more hot water to be used for residential SWH applications.
{"title":"Heat Flux Analysis of a Solar Thermal Collector Incorporated With Optimized Involuted Reflectors","authors":"C. Lim, Sarvenaz Sobhansarbandi","doi":"10.1115/imece2022-95829","DOIUrl":"https://doi.org/10.1115/imece2022-95829","url":null,"abstract":"\u0000 Solar energy plays a vital role in the future of clean energy production due to its availability all year round. Some prominent solar energy technologies, e.g. concentrating solar power (CSP), have the ability to focus/concentrate sunlight for large-scale commercial use. Meanwhile for smaller-scale residential use, solar water heating (SWH) systems are often used to provide hot water for household applications, where the solar collectors are the main components of such systems. The type of solar collector of interest in this study is the heat pipe evacuated tube collector (HPETC). To enhance the system’s thermal and optical efficiencies, this study investigates the incorporation of a custom-made involuted reflector mirror to a single HPETC through employing SolTrace’s optical ray tracing method, where the heat flux around the circumference of the absorber tube can be obtained. The maximum and averaged heat flux is compared between a traditional HPETC system and the HPETC system with the involuted reflectors. The result from this study showed that the HPETC system with an optimized involuted reflector experiences up to ∼ 55.3 % increase in maximum heat flux, and an increase up to ∼ 81.2 % in average heat flux across the absorber tube. Consequently, the HPETC incorporating the custom-made involuted reflectors yields to more collected heat and is capable of providing more hot water to be used for residential SWH applications.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85817122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Fajardo, Camilo Negrette, Camilo Cardona, D. Yabrudy, D. Barreto
Established or create new ones to plan the cleaning tasks of the heat exchangers. In this work, a maintenance strategy is developed for a preheating train under the Maintenance Centered on Energy Efficiency (MCEE) philosophy, where it is sought to integrate the information of the principles of the second law of thermodynamics with economic variables to use parameters. The modification of the maintenance justification parameter (J) is proposed, adding to the introduction of two new maintenance indicators (W and X). Each one seeks to evaluate an essential criterion for the maintenance area: economic viability, technical feasibility, and benefits. Towards the other exchangers in the network after cleaning a specific component. A criticality diagram and a criticality matrix are used. The heat exchangers are grouped into sub-assemblies, with the leading group consisting of the key heat exchangers (KHEX), the elements of which have a significant impact on the efficiency of the preheat train. For their part, the regions are composed of components whose performance is less considerable than that of the KHEX. In total, 34 maintenance activities will be carried out, distributed among the 25 interchanges of the network. The planning of a program of cleaning activities according to the maintenance strategy based on the philosophy of the MCEE establishes a substantial scientific contribution due to the almost null existence of exergetic studies applied to the management of maintenance tasks and focused mainly on the preheating of trains.
{"title":"Maintenance Centered on Exergy and Exergoeconomic Indicators of a Preheat Train of a Crude Oil Distillation Unit","authors":"J. Fajardo, Camilo Negrette, Camilo Cardona, D. Yabrudy, D. Barreto","doi":"10.1115/imece2022-90041","DOIUrl":"https://doi.org/10.1115/imece2022-90041","url":null,"abstract":"\u0000 Established or create new ones to plan the cleaning tasks of the heat exchangers. In this work, a maintenance strategy is developed for a preheating train under the Maintenance Centered on Energy Efficiency (MCEE) philosophy, where it is sought to integrate the information of the principles of the second law of thermodynamics with economic variables to use parameters. The modification of the maintenance justification parameter (J) is proposed, adding to the introduction of two new maintenance indicators (W and X). Each one seeks to evaluate an essential criterion for the maintenance area: economic viability, technical feasibility, and benefits. Towards the other exchangers in the network after cleaning a specific component. A criticality diagram and a criticality matrix are used. The heat exchangers are grouped into sub-assemblies, with the leading group consisting of the key heat exchangers (KHEX), the elements of which have a significant impact on the efficiency of the preheat train. For their part, the regions are composed of components whose performance is less considerable than that of the KHEX. In total, 34 maintenance activities will be carried out, distributed among the 25 interchanges of the network. The planning of a program of cleaning activities according to the maintenance strategy based on the philosophy of the MCEE establishes a substantial scientific contribution due to the almost null existence of exergetic studies applied to the management of maintenance tasks and focused mainly on the preheating of trains.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"200 S593","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91435503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Opetubo, S. Oyinbo, P. Oviroh, Ibitoye Ayotunde, T. Jen
Hydrogen is an alternative source of fuel to replace fossil fuels. Its byproduct is water, and it is environmentally friendly. To meet the United Nations goal of zero greenhouse gas emissions by 2050, hydrogen generation and purification must be capable of meeting the annual demand for fossil fuel. Vanadium (V) is a potential material to replace Pd-based metals due to its high diffusion. However, due to its high solubility, it suffers severe hydrogen embrittlement. Moreso, alloying with vanadium, such as Nickel (Ni), has lowered its solubility. Hence, this study used the first principle calculation technique based on density functional theory (DFT) to investigate the Hydrogen (H) atom’s adsorption, diffusion, and permeability characteristics on the V-Ni-Zr alloy surface. The hydrogen diffusion path from the hollow site (HS) through the bridge site (BS) to the tetrahedral interstitial site (TS) was investigated. Because of its low activation energy, the material may be employed for H2 storage and purification by changing the alloy composition. Before hydrogen embrittlement occurs, we also look at the diffusion rate over time. This research can be used as a starting point for the experiment.
{"title":"Investigation of Adsorption, Dissociation, and Hydrogen Diffusion Through V-Ni-Zr Alloys Surface for Hydrogen Purification: First Principle Method","authors":"O. Opetubo, S. Oyinbo, P. Oviroh, Ibitoye Ayotunde, T. Jen","doi":"10.1115/imece2022-96856","DOIUrl":"https://doi.org/10.1115/imece2022-96856","url":null,"abstract":"\u0000 Hydrogen is an alternative source of fuel to replace fossil fuels. Its byproduct is water, and it is environmentally friendly. To meet the United Nations goal of zero greenhouse gas emissions by 2050, hydrogen generation and purification must be capable of meeting the annual demand for fossil fuel. Vanadium (V) is a potential material to replace Pd-based metals due to its high diffusion. However, due to its high solubility, it suffers severe hydrogen embrittlement. Moreso, alloying with vanadium, such as Nickel (Ni), has lowered its solubility. Hence, this study used the first principle calculation technique based on density functional theory (DFT) to investigate the Hydrogen (H) atom’s adsorption, diffusion, and permeability characteristics on the V-Ni-Zr alloy surface. The hydrogen diffusion path from the hollow site (HS) through the bridge site (BS) to the tetrahedral interstitial site (TS) was investigated. Because of its low activation energy, the material may be employed for H2 storage and purification by changing the alloy composition. Before hydrogen embrittlement occurs, we also look at the diffusion rate over time. This research can be used as a starting point for the experiment.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"129 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89217283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rising energy prices and increasing competitiveness in the brewing industry challenge beer producers to reduce costs. To address this issue — and the environmental concerns over climate change — more energy-efficient brewing processes are required. The brewhouse consumes around one-quarter of the total energy demand in a brewery, especially wort boiling, where heat energy in the form of vapour is often wasted and presents a large potential for recovering energy. Although the technology for heat recovery during wort boiling is commercially available for large breweries, the development of equipment technology for craft and micro-breweries still lags behind. Based on a survey of Australian local craft and micro-breweries and a nano-brewery case study, we compare the evaporation rates during wort boiling for different operational parameters and use the results to verify a proposed mathematical model of evaporation from a kettle. We also propose and analyse options for re-utilising the recovered energy, such as pre-heating water for use in a subsequent process or storage for a later brew. Our study shows that the vapour released during the production of one litre of beer has the potential to heat 0.6 to 1.6 litres of water from ambient to 65°C. As for the potential energy savings and environmental impact, the case study nano-brewery can save approximately 5% of the brewhouse’s energy consumption or 2% of the energy required by the entire brewing process, while each surveyed brewery can spare 16 to 133 tonnes of CO2-e from being released into the atmosphere each year. These results reinforce the potential of recovering waste energy from wort boiling vapours in assisting breweries to become more energy-efficient, competitive and environmentally responsible.
{"title":"Opportunities for Energy Efficiency Improvements in Craft and Micro-Breweries","authors":"Laryssa Sueza Raffa, Nick S. Bennett, L. Clemon","doi":"10.1115/imece2022-94374","DOIUrl":"https://doi.org/10.1115/imece2022-94374","url":null,"abstract":"\u0000 Rising energy prices and increasing competitiveness in the brewing industry challenge beer producers to reduce costs. To address this issue — and the environmental concerns over climate change — more energy-efficient brewing processes are required. The brewhouse consumes around one-quarter of the total energy demand in a brewery, especially wort boiling, where heat energy in the form of vapour is often wasted and presents a large potential for recovering energy. Although the technology for heat recovery during wort boiling is commercially available for large breweries, the development of equipment technology for craft and micro-breweries still lags behind. Based on a survey of Australian local craft and micro-breweries and a nano-brewery case study, we compare the evaporation rates during wort boiling for different operational parameters and use the results to verify a proposed mathematical model of evaporation from a kettle. We also propose and analyse options for re-utilising the recovered energy, such as pre-heating water for use in a subsequent process or storage for a later brew. Our study shows that the vapour released during the production of one litre of beer has the potential to heat 0.6 to 1.6 litres of water from ambient to 65°C. As for the potential energy savings and environmental impact, the case study nano-brewery can save approximately 5% of the brewhouse’s energy consumption or 2% of the energy required by the entire brewing process, while each surveyed brewery can spare 16 to 133 tonnes of CO2-e from being released into the atmosphere each year. These results reinforce the potential of recovering waste energy from wort boiling vapours in assisting breweries to become more energy-efficient, competitive and environmentally responsible.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89281281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Elgamal, Jessica Sambi, D. Patel, Charuka Marasinghe, E. Pulikkottil, Kerwin Virtusio, A. Mwesigye, Simon Li
Direct expansion solar assisted heat pump (DX-SAHP) systems have the potential to provide the heat load required for domestic hot water (DHW) sustainably and with minimum emissions. DX-SAHPs utilize a solar thermal collector to evaporate a working fluid. By using less energy in the process, these systems can achieve higher coefficients of performance (COP) than those afforded by conventional air source heat pumps. With Calgary possessing the highest solar potential in Canada of about 2396 hours of sunlight available 333 days a year [1], the implementation of such systems would make technical and economic sense. In this paper, the design, fabrication, and testing of a DX-SAHP system for cold climates is presented. A mathematical model representing the system was developed by combining the Hottel-Whillier-Bliss equation for the solar collector and a control volume analysis using the first law of thermodynamics for the heat pump cycle. Theoretical results demonstrate that a COP in the range of 3.4–4.5 is achievable. With the promising theoretical results, an experimental test setup was designed, constructed, and instrumented to determine the long-term performance of a DX-SAHP under local climatic conditions.
{"title":"Design, Construction, and Thermodynamic Analysis of a Direct-Expansion Solar Assisted Heat Pump for Cold Climates","authors":"N. Elgamal, Jessica Sambi, D. Patel, Charuka Marasinghe, E. Pulikkottil, Kerwin Virtusio, A. Mwesigye, Simon Li","doi":"10.1115/imece2022-95940","DOIUrl":"https://doi.org/10.1115/imece2022-95940","url":null,"abstract":"\u0000 Direct expansion solar assisted heat pump (DX-SAHP) systems have the potential to provide the heat load required for domestic hot water (DHW) sustainably and with minimum emissions. DX-SAHPs utilize a solar thermal collector to evaporate a working fluid. By using less energy in the process, these systems can achieve higher coefficients of performance (COP) than those afforded by conventional air source heat pumps. With Calgary possessing the highest solar potential in Canada of about 2396 hours of sunlight available 333 days a year [1], the implementation of such systems would make technical and economic sense. In this paper, the design, fabrication, and testing of a DX-SAHP system for cold climates is presented. A mathematical model representing the system was developed by combining the Hottel-Whillier-Bliss equation for the solar collector and a control volume analysis using the first law of thermodynamics for the heat pump cycle. Theoretical results demonstrate that a COP in the range of 3.4–4.5 is achievable. With the promising theoretical results, an experimental test setup was designed, constructed, and instrumented to determine the long-term performance of a DX-SAHP under local climatic conditions.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77831815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study focuses on the effects on evaporation and combustion of a single component jet fuel surrogate. Due to an imbalance in the surface tension and aerodynamic forces, the large droplets have a tendency to deform. The effect of the shape change of a droplet on its combustion is studied at a moderate Reynolds number by varying the Weber number. A simplified chemical reaction mechanism for hydrocarbons is used for the combustion of the droplet. Through this study, the effect of different Weber numbers is investigated on the total evaporation rate, further on droplet combustion, and the flame shape. The results of this study show an increase of 2% increase in total evaporation rate (m) for higher Weber number We = 12 as compared to low Weber number (We = 1) case. Though, the increase in m is small, the results show a net positive effect of Weber number on the total evaporation. In terms of combustion, the combustion process stays unaffected by the droplet shape as the mass burning rate is nearly the same for low as well as high Weber number. The potential reasoning could be that the interaction between the flow and geometry of droplet in two dimensions (2-D) is insufficient to explain the physics. Moreover, it is possible that the reaction rate which is faster in nature is dominating over the evaporation rate. Such observations require more detailed work in three dimensions (3-D) for future.
{"title":"Combustion and Vaporization of Deformable Fuel Droplets Using Direct Numerical Simulation","authors":"Meha Setiya, J. Palmore","doi":"10.1115/imece2022-94475","DOIUrl":"https://doi.org/10.1115/imece2022-94475","url":null,"abstract":"\u0000 This study focuses on the effects on evaporation and combustion of a single component jet fuel surrogate. Due to an imbalance in the surface tension and aerodynamic forces, the large droplets have a tendency to deform. The effect of the shape change of a droplet on its combustion is studied at a moderate Reynolds number by varying the Weber number. A simplified chemical reaction mechanism for hydrocarbons is used for the combustion of the droplet. Through this study, the effect of different Weber numbers is investigated on the total evaporation rate, further on droplet combustion, and the flame shape. The results of this study show an increase of 2% increase in total evaporation rate (m) for higher Weber number We = 12 as compared to low Weber number (We = 1) case. Though, the increase in m is small, the results show a net positive effect of Weber number on the total evaporation. In terms of combustion, the combustion process stays unaffected by the droplet shape as the mass burning rate is nearly the same for low as well as high Weber number. The potential reasoning could be that the interaction between the flow and geometry of droplet in two dimensions (2-D) is insufficient to explain the physics. Moreover, it is possible that the reaction rate which is faster in nature is dominating over the evaporation rate. Such observations require more detailed work in three dimensions (3-D) for future.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85067944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phase change materials (PCM) tend to have high energy storage densities and can be an excellent option for thermal energy storage systems. However, the low thermal conductivity of PCM creates a critical problem in effectively transmitting heat energy into these thermal storage systems. One of the solutions is to design these heat exchangers to diffuse heat into the thermal storage systems effectively. Numerical simulations have been performed to investigate the thermal performance of two heat exchanger designs, fin base heat exchanger (FHE) and Helical coil-based heat exchanger (HCHE). Ansys, Fluent has been employed to carry out transient three-dimensional numerical simulations. These simulations are also compared with two different inlet velocities of 0.02m/sec and 0.1m/sec, corresponding Reynolds numbers of 2,012 (laminar regime) and 10,061 (turbulent regime), respectively. FHE melting rates were observed to be much more stable. Total accumulated energy stored during the charging process for the laminar flow regime is higher in HCHE than in FHE. Energy stored is comparatively higher in FHE when the flow is turbulent. The energy discharge followed the same trend as the charging cycle. FHE tends to maintain consistent energy charging and discharging rates compared to HCHE.
{"title":"Thermal Performance of Phase Change Material Based Heat Exchangers","authors":"Abhinay Soanker, A. Oztekin","doi":"10.1115/imece2022-94810","DOIUrl":"https://doi.org/10.1115/imece2022-94810","url":null,"abstract":"\u0000 Phase change materials (PCM) tend to have high energy storage densities and can be an excellent option for thermal energy storage systems. However, the low thermal conductivity of PCM creates a critical problem in effectively transmitting heat energy into these thermal storage systems. One of the solutions is to design these heat exchangers to diffuse heat into the thermal storage systems effectively. Numerical simulations have been performed to investigate the thermal performance of two heat exchanger designs, fin base heat exchanger (FHE) and Helical coil-based heat exchanger (HCHE). Ansys, Fluent has been employed to carry out transient three-dimensional numerical simulations. These simulations are also compared with two different inlet velocities of 0.02m/sec and 0.1m/sec, corresponding Reynolds numbers of 2,012 (laminar regime) and 10,061 (turbulent regime), respectively. FHE melting rates were observed to be much more stable. Total accumulated energy stored during the charging process for the laminar flow regime is higher in HCHE than in FHE. Energy stored is comparatively higher in FHE when the flow is turbulent. The energy discharge followed the same trend as the charging cycle. FHE tends to maintain consistent energy charging and discharging rates compared to HCHE.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84428107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the current study, a new hybrid heat sink combining phase change material and water cooling for low concentrator photovoltaic thermal management is introduced and analyzed. Unlike the previously introduced systems, the proposed one meets the requirements for practical applications, such as higher cooling efficiency over a longer period of time, reliability, low operating and maintenance costs, and the ability to store and reuse the system’s extracted thermal energy, thereby increasing total system efficiency. Furthermore, the new system combines the benefits of both active and passive thermal regulation systems, achieving a significant reduction in solar cell temperature when compared to passive systems and saving energy when compared to active systems. The study compares the performance of the developed new system with phase change material and water cooling to that of the conventional system with only phase change material cooling under various operating conditions. To that purpose, a comprehensive two-dimensional model of photovoltaic layers integrated with the hybrid phase change material-water based heat sink is developed. The uncooled PV model and the combined PV-PCM model are verified with experimental results in the literature. The model incorporates thermo-fluid models that account for phase transition phenomena and liquid flow in the heat sink domain, as well as a thermal model for the entire solar cell layers. The findings of this study show that the incorporation of phase change material and water cooling attains a remarkable reduction in the solar cell temperature with reasonable temperature uniformity and efficient thermal energy management. The reduction of average temperature and efficient thermal energy management leads to an increase in generated electrical energy and more thermal energy storage in the heat sink, both of which are reflected by higher cumulative electrical, thermal, and total efficiencies. The present findings can open doors for further research into merging the advantages of passive and active thermal regulation for low concentrator photovoltaic systems.
{"title":"Performance Enhancement of New Concentrator Photovoltaic System Using Phase Change Material/Water Cooling Technique","authors":"Mohamed M. Elsabahy, Mahmoud A. Ahmed, M. Emam","doi":"10.1115/imece2022-95514","DOIUrl":"https://doi.org/10.1115/imece2022-95514","url":null,"abstract":"\u0000 In the current study, a new hybrid heat sink combining phase change material and water cooling for low concentrator photovoltaic thermal management is introduced and analyzed. Unlike the previously introduced systems, the proposed one meets the requirements for practical applications, such as higher cooling efficiency over a longer period of time, reliability, low operating and maintenance costs, and the ability to store and reuse the system’s extracted thermal energy, thereby increasing total system efficiency. Furthermore, the new system combines the benefits of both active and passive thermal regulation systems, achieving a significant reduction in solar cell temperature when compared to passive systems and saving energy when compared to active systems. The study compares the performance of the developed new system with phase change material and water cooling to that of the conventional system with only phase change material cooling under various operating conditions. To that purpose, a comprehensive two-dimensional model of photovoltaic layers integrated with the hybrid phase change material-water based heat sink is developed. The uncooled PV model and the combined PV-PCM model are verified with experimental results in the literature. The model incorporates thermo-fluid models that account for phase transition phenomena and liquid flow in the heat sink domain, as well as a thermal model for the entire solar cell layers. The findings of this study show that the incorporation of phase change material and water cooling attains a remarkable reduction in the solar cell temperature with reasonable temperature uniformity and efficient thermal energy management. The reduction of average temperature and efficient thermal energy management leads to an increase in generated electrical energy and more thermal energy storage in the heat sink, both of which are reflected by higher cumulative electrical, thermal, and total efficiencies. The present findings can open doors for further research into merging the advantages of passive and active thermal regulation for low concentrator photovoltaic systems.","PeriodicalId":23629,"journal":{"name":"Volume 6: Energy","volume":"467 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83043240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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