Volume 6B: Energy最新文献

{"title":"Heat Transfer Analysis of a Low-Temperature Heat Pipe-Assisted Latent Heat Thermal Energy Storage System With Nano-Enhanced PCM","authors":"M. Mahdavi, S. Tiari, Vivek R. Pawar","doi":"10.1115/IMECE2018-86609","DOIUrl":"https://doi.org/10.1115/IMECE2018-86609","url":null,"abstract":"In the current study, the thermal characteristics of a low-temperature latent heat thermal energy storage system are studied numerically. A cylinder container encloses a paraffin-based PCM, which is heated via a heat transfer fluid passing through a tube at the center. Heat pipes are incorporated into the PCM to enhance the heat transfer rate between the heat transfer fluid and the PCM. In addition, high thermal conductive nanoparticles are dispersed into the PCM to increase its thermal conductivity. A transient model is developed using ANSYS-FLUENT to simulate the charging process and study the impact of heat pipes and nanoparticles on the performance of the system. The effects of different parameters, such as the quantities of heat pipes as well as the nanoparticles types and volume fraction, are investigated.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124393515","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}

{"title":"Radiative Transport and Hydrodynamic Modeling of Microalgae Photosynthesis in Bio-Flow Reactors","authors":"Lea-Der Chen","doi":"10.1115/IMECE2018-87116","DOIUrl":"https://doi.org/10.1115/IMECE2018-87116","url":null,"abstract":"A simplified two-phase flow PCH (physicochemical hydrodynamics) model is developed for modelling and simulation of microalgae growth in bio-flow reactor. The model considers carbon balance through coupled gas-phase and liquid-phase transport equations. The transport model accounts for interfacial transport of CO2 from gas bubble/slug to liquid, and microalgae photosynthesis reactions. A simplified photosynthesis reaction is adopted in the model, which assumes a pseudo-first order reaction for glucose pathway. The reaction rate is calculated assuming that it is proportional to the solar absorption rate by microalgae in the liquid. The reaction model also includes a simplified photoinhibition sub-model which assumes that the rate of photoinhibition is proportional to the square-root of solar irradiation reaching the algae cell. The Beer-Lambert law is used to calculate the radiative transfer of solar flux in seeded microalgae liquid flow. Analytical solution was obtained for single-channel bio-flow reactor. Decrease of the CO2 concentration in gas bubble/slug and in liquid flow is assumed to be the result of the microalgae growth in bio-flow reactor. Two efficiency parameters are defined: CO2 conversion efficiency and photosynthesis efficiency. The conversion efficiency is calculated based on the decrease of CO2 between the bio-flow reactor inlet and exit. The photosynthesis efficiency is based upon the heating value of microalgae yield versus solar irradiation. The rate of microalgae yield is calculated by multiplying the mass stoichiometric coefficient of photosynthesis reaction to CO2 consumption rate. Model analysis provided some insight of the microalgae formation in bio-flow reactor as interpreted from the PCH-coupled photosynthesis model that includes a dimensionless number as a potential scaling parameter for gas-phase only CO2 supply operation; photosynthesis efficiency increases with increasing CO2 molar concentration (i.e., number of moles per unit volume) at the reactor inlet for both gas-phase and liquid-phase only CO2 supply; an optimal irradiation flux for maximum photosynthesis efficiency — a factor to consider should artificial light source be used for harvesting algae.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114649216","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}

{"title":"Longer Passage of Airflow in Multiple Packed-Bed Thin Tanks Versus in a Short Big Tank for Improved Thermal Storage Performance","authors":"Yan Wang, Peiwen Li, Zhifeng Wang, Bei Yang, Guofeng Yuan, Wenxun Tang","doi":"10.1115/IMECE2018-86123","DOIUrl":"https://doi.org/10.1115/IMECE2018-86123","url":null,"abstract":"A very challenging issue about solar thermal power generation is the use of a high temperature heat transfer fluid (water, oils, or molten salts) for heat transfer and thermal storage material, which may freeze at night or cold weather. When choosing air as the heat transfer fluid, the problem of freezing is eliminated. In order to increase the performance of thermal storage system which uses air as the heat transfer fluid passing through a packed bed (by ceramic spheres of Al2O3), multiple small-diameter tanks are considered to replace a single large-diameter tank with the same packed-bed volume and airflow rate in this paper. Analysis about the thermal storage performance in a short big tank and in cascade thin tanks has been made for comparison. A long passage of airflow and faster flow speed of air in the cascade thin tanks has been found significantly beneficial to thermal storage. Results about the increased thermal storage performance and increased pressure loss will be presented. Longer passage of airflow made it possible to have a longer time of high temperature of outflow air during discharging period. And faster speed of the fluid enhanced the heat transfer between air and thermal storage material. The total effective energy and thermal storage efficiency of cascade thin-tank thermal energy storage (TES) are higher. The thermal storage efficiency in the two types of thermal storage arrangement was compared for optimal design. The obtained results are of great significance to the development of using air as heat transfer fluid and rocks or ceramic spheres as the thermal storage material for thermal storage system in concentrated solar thermal power plants.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114248245","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}

{"title":"How Solar and Storage Can Reduce Coincident Peak Loads and Payments: A Case Study in Austin, TX","authors":"Arkasama Bandyopadhyay, J. Rhodes, Julia P. Conger, M. Webber","doi":"10.1115/IMECE2018-86482","DOIUrl":"https://doi.org/10.1115/IMECE2018-86482","url":null,"abstract":"This study builds a generalized tool to forecast the change of 4 coincident peak (4CP) loads and payments based on varying amounts of solar, storage capacity, and population estimates over a 10-year period for utilities within the Electric Reliability Council of Texas (ERCOT). It also incorporates an optimization model for the energy storage systems (ESSs) that maximizes the sum of the revenue earned from their operation as well as the net 4CP payments received by the utility by attempting to arbitrage the ERCOT energy market. The tool is illustrated by using empirical data from the municipally-owned utility in Austin, TX (Austin Energy). 4CP payments can be on the order of tens of millions of dollars. Results indicate that solar and storage capacity can substantially lower these payments. For example, a 20 MW increase in solar capacity in 2018 would reduce Austin Energy’s payment by an estimated $200,000 for each subsequent year. By using the novel approach of incorporating coincident peak demand charge reductions at the DSP level, this study highlights the economic value of local generation and storage.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128319451","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}

{"title":"Large-Eddy Simulation of Offshore Wind Farms for Power Prediction","authors":"M. Sandusky, Rey DeLeon, Inanc Senocak","doi":"10.1115/IMECE2018-87965","DOIUrl":"https://doi.org/10.1115/IMECE2018-87965","url":null,"abstract":"Offshore wind turbines are mega structures that span a critical section of the lowest part of atmospheric boundary layer while experiencing significant wind shear. A detailed knowledge of the wind field through a wind farm as part of the atmospheric boundary layer is essential to design efficient farm layouts and estimate power production for grid integration. To address these needs, we present a micro-scale wind prediction model based on a large-eddy simulation paradigm. We consider actuator disk models with and without rotation to simulate the influence of turbines on the wind field and apply our computational capability to the well-known Horns Rev offshore wind farm in Denmark to estimate power production. Instead of using manufacturers power curve to estimate power production, we propose an alternative approach based on the control volume analysis of kinetic energy conservation around turbines.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126209099","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}

{"title":"Non-Isothermal Phase Change Behaviors of Binary Mixtures of D-Dulcitol and Pentaerythritol As Novel Heat Storage Materials","authors":"Xuefeng Shao, Jun Wang, Liming Fan","doi":"10.1115/IMECE2018-87643","DOIUrl":"https://doi.org/10.1115/IMECE2018-87643","url":null,"abstract":"As a promising Phase Change Material (PCM) candidate for low-to-medium temperature (100–250 °C) latent heat storage, sugar alcohols undergo serious supercooling during cool-down for crystallization. Technical efforts need to be dedicated to suppression or control of the supercooling of sugar alcohols. In this work, the supercooling of D-dulcitol, with a melting point of around 186 °C, was attempted to be reduced by mixing with a solid-solid PCM Pentaerythritol (PE) as the nucleation agent, which has a solid-solid phase transition temperature (∼186 °C) similar to the melting point of d-dulcitol. Such novel binary mixtures were prepared by dispersing PE powders at various mass fractions into d-dulcitol melt. The non-isothermal phase-change-related properties, with emphasis on the crystallization properties, were tested on a heat-flux differential scanning calorimeter at a constant heating/cooling rate of 5 °C/min. The preliminary results showed that both the crystallization point and latent heat of crystallization strongly depend on the mass fraction of PE, and both decrease in magnitude with the increasing in mass fraction of PE. The degree of supercooling of the binary mixtures also depend on the mass fraction of PE, and a reduction of up to 10 °C was obtained at 50 wt.% PE, as a result of the decrease in the melting points of the binary mixtures.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115971534","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}

{"title":"Ecological Performance of a Generalized Radiative System Light-Driven Engine (LDE) With [A] ⇌ [B] Reacting System Improved by Controlling Piston Motion","authors":"H. Feng, K. Ma, Lingen Chen, Shaojun Xia","doi":"10.1115/IMECE2018-86252","DOIUrl":"https://doi.org/10.1115/IMECE2018-86252","url":null,"abstract":"This paper introduces the ecological criterion (EC) into the optimal configuration problem of an irreversible light-driven engine (LDE) under the assumption that heat transfer (HT) between the working fluid (WF) and the surroundings is presumed to abide by the generalized radiative heat transfer law (HTL) [q ∝ Δ(Tn) ]. The WF is made up of the reacting system [A] ⇌ [B] , and the primary irreversibilities corresponding to the practical engine are the piston friction and heat conduction with the WF operating at a nonzero rate and far from equilibrium. Meantime, in order to obtain the optimal paths (OPs) for maximum ecological performance (EP) of the engine, the optimal control theory (OCT) is utilized in this paper. Numerical calculations of the OPs at maximum EP with linear phenomenological (n = −1), Newton’s (n = 1) and radiative (n = 4) HTLs are performed. The results derived by maximum EP are compared with those derived by maximum work output (WO) and minimum entropy generation (EG) as well as different HTLs. The results obtained in this paper indicate that utilizing the maximum EC as the design objective could effectively accomplish the EG reduction with a little decrease in the WO. Moreover, the OPs for maximum EP with different HTLs are quite different.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131071450","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}

{"title":"Thermoeconomic Analysis of Reverse Brayton Cycle Based Cryocooler","authors":"A. Dhillon, P. Ghosh","doi":"10.1115/IMECE2018-87190","DOIUrl":"https://doi.org/10.1115/IMECE2018-87190","url":null,"abstract":"In the present study, the performance of an RBC cryocooler with 10 kW cooling load at 65 K has been analyzed using Aspen HYSYS V8.6®. Helium, neon and helium-neon mixture are used as working fluids for the process cycle. A thermodynamic and cost model for the RBC cryocooler has been developed using exergoeconomic tool to analyze the cycle. It has been previously reported that to have same impact on the cycle exergy efficiency improvement, a small improvement in the heat exchanger effectiveness is required in contrast to a substantial improvement in the compressor efficiency. But it will also increase the capital cost of the cryocooler. The exergy efficiency, relative cost ratio and exergoeconomic factors for each component have been found to identify the major sources of cost. The effect of using different working fluids on the thermoeconomics of the cycle have been presented in this paper. Conclusions from this study might be utilized by the scientist and design engineer in improving the cycle efficiency from the thermoeconomic point of view.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114331743","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}

{"title":"Experimental Investigation of Ejector Refrigeration System With Double Condensers","authors":"H. Sait, B. Habibullah, N. Turkman, H. B. Ma","doi":"10.1115/IMECE2018-88671","DOIUrl":"https://doi.org/10.1115/IMECE2018-88671","url":null,"abstract":"This paper presents the results of an experimental investigation of a steam jet refrigerator suitable for renewable or low-medium grade waste energy applications. An experimental system of an ejector refrigeration system was constructed and fabricated. Different parameters of the ejector refrigeration system were investigated, such as the high-temperature evaporator (HTE) temperature, low temperature evaporator (LTE) temperature, and back pressure. The coefficient of performance (COP) of the ejector refrigeration system was determined. In addition, the effects of the operating temperatures on the COP and critical back pressure were investigated. The results are expected to motivate the use of ejector refrigeration systems for air-conditioning.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129680592","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}

{"title":"Avoidable and Unavoidable Exergetic Destruction Analysis of a Nitric Acid Production Plant","authors":"J. Fajardo, H. Valle, A. Buelvas","doi":"10.1115/IMECE2018-87495","DOIUrl":"https://doi.org/10.1115/IMECE2018-87495","url":null,"abstract":"Exergy analysis for Nitric acid production plants are very few and many are outdated. This study aims to support existing scientific studies and incite new investigations of exergy analysis in modern times. An advanced exergy analysis was applied to a production plant with a capacity to process 350 tons/day of nitric acid at a concentration of 55%. The catalytic oxidation of ammonia, condensation and absorption of nitrous gases are considered as the principal process in the nitric acid production. The total destroyed exergy was 46772,55 KW. The component with the greatest impact was the catalytic converter, which presented 75.1% of the total avoidable exergy destruction rate of the plant. These findings are relevant as they can potentially reduce costs of nitric acid production.","PeriodicalId":306586,"journal":{"name":"Volume 6B: Energy","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127502957","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}