Pub Date : 2014-05-09DOI: 10.1080/10789669.2014.900315
A. Līckrastiņa, N. Talcis, E. Dzelzītis
The Imanta district heating plant began operation in 1974 as one of the main heating plants for the Riga district heating system. Until now, it has undergone several reconstructions. First, the ordinary boiler plant with steam and hot water boilers was reconstructed to be a natural gas-fueled combined cycle cogeneration plant supported with hot water boilers. Then, one of the cooling towers of the cogeneration section was replaced by an absorption heat pump/chiller, thus providing the closed cooling water circulation system and recovering 2 MWth (7 MMBTU/h) low-grade heat otherwise lost in the atmosphere. The driving force for the absorption heat pump is steam produced by the steam boiler (3 MWth = 10 MMBTU/h) already located at the boiler plant. The efficiency of the absorption heat pump is closely related to the operation of the cogeneration unit, outside temperature, and district heating water temperature regimes. The case study confirms that a more efficient energy production system reduces the fuel consumption with the same amount of the produced energy, thus lowering the expenses on energy production and reducing the amount of the polluting emissions into the atmosphere.
{"title":"Cogeneration unit with an absorption heat pump for the district heating system","authors":"A. Līckrastiņa, N. Talcis, E. Dzelzītis","doi":"10.1080/10789669.2014.900315","DOIUrl":"https://doi.org/10.1080/10789669.2014.900315","url":null,"abstract":"The Imanta district heating plant began operation in 1974 as one of the main heating plants for the Riga district heating system. Until now, it has undergone several reconstructions. First, the ordinary boiler plant with steam and hot water boilers was reconstructed to be a natural gas-fueled combined cycle cogeneration plant supported with hot water boilers. Then, one of the cooling towers of the cogeneration section was replaced by an absorption heat pump/chiller, thus providing the closed cooling water circulation system and recovering 2 MWth (7 MMBTU/h) low-grade heat otherwise lost in the atmosphere. The driving force for the absorption heat pump is steam produced by the steam boiler (3 MWth = 10 MMBTU/h) already located at the boiler plant. The efficiency of the absorption heat pump is closely related to the operation of the cogeneration unit, outside temperature, and district heating water temperature regimes. The case study confirms that a more efficient energy production system reduces the fuel consumption with the same amount of the produced energy, thus lowering the expenses on energy production and reducing the amount of the polluting emissions into the atmosphere.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"7 1","pages":"404 - 410"},"PeriodicalIF":0.0,"publicationDate":"2014-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78619875","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}
Pub Date : 2014-05-09DOI: 10.1080/10789669.2014.882678
S. Cai, L. Cremaschi, A. Ghajar
Condensate that appears on mechanical pipe insulation systems might deteriorate the insulation thermal performance and lead to failure of the pipelines. An optimized solution that accounts for cost and system energy efficiency must consider the rate of moisture absorption at various operating conditions, and how the pipe insulation thermal conductivity varies with moisture content. This article reviews the most up-to-date work available in the public domain and observes that a controversy may exist about the similarities and differences of thermal conductivity of pipe insulation systems and flat slab configurations. Since the dissimilar behavior can be associated with the testing methodology from which the thermal conductivity values are originally derived, this article first discusses the methodologies for measuring thermal conductivity of pipe insulation systems with the intention of providing some clarification about such controversy. Steady-state and transient methods are discussed, and the measurements from these two methods are critically compared. The thermal conductivities of several pipe insulation systems are also summarized under dry operating conditions. For wet insulation, four main methods for preparing the wet samples during laboratory measurements have been identified, and it was observed that they yielded very different results. The advantages and shortcomings of each moisturizing strategy discussed at length, and the thermal conductivities of a few available pipe insulation systems in wet conditions are compared. To date, challenges still exist with the measurement of actual thermal conductivity of pipe insulation systems with moisture ingress, and future research needs in this area are discussed.
{"title":"Pipe insulation thermal conductivity under dry and wet condensing conditions with moisture ingress: A critical review","authors":"S. Cai, L. Cremaschi, A. Ghajar","doi":"10.1080/10789669.2014.882678","DOIUrl":"https://doi.org/10.1080/10789669.2014.882678","url":null,"abstract":"Condensate that appears on mechanical pipe insulation systems might deteriorate the insulation thermal performance and lead to failure of the pipelines. An optimized solution that accounts for cost and system energy efficiency must consider the rate of moisture absorption at various operating conditions, and how the pipe insulation thermal conductivity varies with moisture content. This article reviews the most up-to-date work available in the public domain and observes that a controversy may exist about the similarities and differences of thermal conductivity of pipe insulation systems and flat slab configurations. Since the dissimilar behavior can be associated with the testing methodology from which the thermal conductivity values are originally derived, this article first discusses the methodologies for measuring thermal conductivity of pipe insulation systems with the intention of providing some clarification about such controversy. Steady-state and transient methods are discussed, and the measurements from these two methods are critically compared. The thermal conductivities of several pipe insulation systems are also summarized under dry operating conditions. For wet insulation, four main methods for preparing the wet samples during laboratory measurements have been identified, and it was observed that they yielded very different results. The advantages and shortcomings of each moisturizing strategy discussed at length, and the thermal conductivities of a few available pipe insulation systems in wet conditions are compared. To date, challenges still exist with the measurement of actual thermal conductivity of pipe insulation systems with moisture ingress, and future research needs in this area are discussed.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"24 1","pages":"458 - 479"},"PeriodicalIF":0.0,"publicationDate":"2014-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87848626","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.888908
Zeqin Liu, Ge Li, Chen Zheng
A computational fluid dynamics (CFD) numerical simulation method was used in this study to simulate the indoor thermal environment affected by three air-supply modes, upper-supply bottom-return mode, upper-supply top-return mode, and bottom-supply top-return mode, in the condition of the fixed point heat source, and explored the change rule of the predicted percentage dissatisfied (PPD) affected by the three air-supply modes. A suitable air-conditioning supply mode might better meet the requirements of human to the indoor thermal environment. The results, based on the calculation and analysis of indoor air distribution, temperature field, and thermal comfort, showed that the mixing degree of supply air and indoor air of upper-supply mode was better than that of bottom-supply mode, and the uniformity of temperature distribution of upper-supply top-return pattern was better. Moreover, in the personal breathing zone (0.8–1.6 m), the pattern of upper-supply top-return obtained the lowest PPD value. It can be seen that the mode of upper-supply top-return is more comfortable according to the evaluation index of human thermal comfort.
{"title":"The simulation and calculation of indoor thermal environment and the PPD evaluation index affected by three typical air-conditioning supply modes","authors":"Zeqin Liu, Ge Li, Chen Zheng","doi":"10.1080/10789669.2014.888908","DOIUrl":"https://doi.org/10.1080/10789669.2014.888908","url":null,"abstract":"A computational fluid dynamics (CFD) numerical simulation method was used in this study to simulate the indoor thermal environment affected by three air-supply modes, upper-supply bottom-return mode, upper-supply top-return mode, and bottom-supply top-return mode, in the condition of the fixed point heat source, and explored the change rule of the predicted percentage dissatisfied (PPD) affected by the three air-supply modes. A suitable air-conditioning supply mode might better meet the requirements of human to the indoor thermal environment. The results, based on the calculation and analysis of indoor air distribution, temperature field, and thermal comfort, showed that the mixing degree of supply air and indoor air of upper-supply mode was better than that of bottom-supply mode, and the uniformity of temperature distribution of upper-supply top-return pattern was better. Moreover, in the personal breathing zone (0.8–1.6 m), the pattern of upper-supply top-return obtained the lowest PPD value. It can be seen that the mode of upper-supply top-return is more comfortable according to the evaluation index of human thermal comfort.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"90 1","pages":"344 - 350"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74939703","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.895641
Ruzhu Wang, Guangming Chen, Xuejun Zhang
In order to enhance the exchanges between Chinese researchers with those overseas, Zhejiang University founded the International Conference on Cryogenics and Refrigeration (ICCR) in 1989. The conference is co-sponsored by the International Institute of Refrigeration (IIR). The second ICCR was held in Hangzhou in 1998. After that, Zhejiang University and Shanghai Jiao Tong University agreed to host and co-chair the ICCR conference every five years. In 2003 they hosted the conference in Hangzhou, and in 2008 in Shanghai, returning to Hangzhou in 2013. Usually, there are 200–300 ICCR conference participants, with more than 30% of the participants traveling to the conference from abroad. All ICCR conference proceedings have been published as ICCR proceedings before, however, starting from 2013 the organizers agreed to recommend some conference papers to several journals for special issues. This topical issue for the ASHRAE HVAC&R Research journal contains ten selected papers of topics of interest to readers of the journal. These papers include adsorption refrigerator research, solar cooling combined with thermal storage, desiccant materials, indoor thermal comfort, fundamentals of liquid refrigerant droplet and numerical modeling and experimental studies for heat exchangers related to condenser and evaporators of heat pumps. New research on cryogenic plants is also discussed in this topical issue, which covers a wide range of refrigeration and HVAC research in China. Although it represents a relatively small scope of the entire Chinese HVAC&R research efforts, the issue offers a good sample of the current hot topic studies by Chinese researchers in our field. The guest editors hope the readers find the articles interesting and that they will become familiar with the research institutions whose work were shown within this issue. We invite you to participate in the next ICCR with us in Shanghai in 2018!
{"title":"Selected papers from ICCR2013","authors":"Ruzhu Wang, Guangming Chen, Xuejun Zhang","doi":"10.1080/10789669.2014.895641","DOIUrl":"https://doi.org/10.1080/10789669.2014.895641","url":null,"abstract":"In order to enhance the exchanges between Chinese researchers with those overseas, Zhejiang University founded the International Conference on Cryogenics and Refrigeration (ICCR) in 1989. The conference is co-sponsored by the International Institute of Refrigeration (IIR). The second ICCR was held in Hangzhou in 1998. After that, Zhejiang University and Shanghai Jiao Tong University agreed to host and co-chair the ICCR conference every five years. In 2003 they hosted the conference in Hangzhou, and in 2008 in Shanghai, returning to Hangzhou in 2013. Usually, there are 200–300 ICCR conference participants, with more than 30% of the participants traveling to the conference from abroad. All ICCR conference proceedings have been published as ICCR proceedings before, however, starting from 2013 the organizers agreed to recommend some conference papers to several journals for special issues. This topical issue for the ASHRAE HVAC&R Research journal contains ten selected papers of topics of interest to readers of the journal. These papers include adsorption refrigerator research, solar cooling combined with thermal storage, desiccant materials, indoor thermal comfort, fundamentals of liquid refrigerant droplet and numerical modeling and experimental studies for heat exchangers related to condenser and evaporators of heat pumps. New research on cryogenic plants is also discussed in this topical issue, which covers a wide range of refrigeration and HVAC research in China. Although it represents a relatively small scope of the entire Chinese HVAC&R research efforts, the issue offers a good sample of the current hot topic studies by Chinese researchers in our field. The guest editors hope the readers find the articles interesting and that they will become familiar with the research institutions whose work were shown within this issue. We invite you to participate in the next ICCR with us in Shanghai in 2018!","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"62 1","pages":"295 - 295"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85783140","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.890003
Liu Bin, Cai Bihao, Zhou Xiaojing, Diao Qianqian, Bennacer Rachid
An experiment of the development of two pure methanol droplets in array with different distances and sizes was investigated by the camera of DSA100 (Droplet Shape Analyzer). The contact angle and the baseline were recorded. Compared with the development of one droplet, the development is dependent on the distance between the two droplets and the cap ratio of the two droplets. It was observed that there were three distinct stages as the development of one droplet: the constant contact-angle stage (CA), the constant contact baseline stage (CD) or pinned triple-line stage, and the transition stage (TS) between CA and CD. The evaporation of the droplets in array will increase with the increasing of the distance between the two droplets and the decreasing of the cap ratio of the two droplets. The development of the two droplets in array also shows a characteristic of a lower evaporation rate and a shorter time of CA stage than that of single droplet. During the cross area, there is a negative effect on the evaporation of the droplets.
{"title":"Experimental observation of the development of two droplets of methanol in array on Teflon surface","authors":"Liu Bin, Cai Bihao, Zhou Xiaojing, Diao Qianqian, Bennacer Rachid","doi":"10.1080/10789669.2014.890003","DOIUrl":"https://doi.org/10.1080/10789669.2014.890003","url":null,"abstract":"An experiment of the development of two pure methanol droplets in array with different distances and sizes was investigated by the camera of DSA100 (Droplet Shape Analyzer). The contact angle and the baseline were recorded. Compared with the development of one droplet, the development is dependent on the distance between the two droplets and the cap ratio of the two droplets. It was observed that there were three distinct stages as the development of one droplet: the constant contact-angle stage (CA), the constant contact baseline stage (CD) or pinned triple-line stage, and the transition stage (TS) between CA and CD. The evaporation of the droplets in array will increase with the increasing of the distance between the two droplets and the decreasing of the cap ratio of the two droplets. The development of the two droplets in array also shows a characteristic of a lower evaporation rate and a shorter time of CA stage than that of single droplet. During the cross area, there is a negative effect on the evaporation of the droplets.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"34 1","pages":"367 - 373"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84105025","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.890460
D. Zhuang, Haitao Hu, G. Ding, G. Xi, Weizhe Han
In order to predict the performance of tube-finned heat exchangers under dehumidifying condition and to optimize the fin geometries, the behavior of a liquid droplet on vertical plain-fin surfaces needs to be investigated. The objective of this article is to develop a model for liquid droplet motion on vertical plain-fin surfaces. To achieve this goal, the mechanism of droplet motion is analyzed. The volume of fluid-continuous surface force method, with the contact angles of droplet being specified, is employed to simulate the liquid droplet motion. The sub-model for calculating varying contact angles of droplet under the interactions of gravitation, surface tension and airflow force is obtained based on the analysis of the acting forces. The prediction was verified by experimental data and verification results show that the relative deviations of minimum contact angle and velocity are within 0.4%∼1.8% and 5.7%∼10.0%, respectively.
{"title":"Numerical model for liquid droplet motion on vertical plain-fin surface","authors":"D. Zhuang, Haitao Hu, G. Ding, G. Xi, Weizhe Han","doi":"10.1080/10789669.2014.890460","DOIUrl":"https://doi.org/10.1080/10789669.2014.890460","url":null,"abstract":"In order to predict the performance of tube-finned heat exchangers under dehumidifying condition and to optimize the fin geometries, the behavior of a liquid droplet on vertical plain-fin surfaces needs to be investigated. The objective of this article is to develop a model for liquid droplet motion on vertical plain-fin surfaces. To achieve this goal, the mechanism of droplet motion is analyzed. The volume of fluid-continuous surface force method, with the contact angles of droplet being specified, is employed to simulate the liquid droplet motion. The sub-model for calculating varying contact angles of droplet under the interactions of gravitation, surface tension and airflow force is obtained based on the analysis of the acting forces. The prediction was verified by experimental data and verification results show that the relative deviations of minimum contact angle and velocity are within 0.4%∼1.8% and 5.7%∼10.0%, respectively.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"39 1","pages":"332 - 343"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78838275","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.888092
X. J. Wang, X. Yuan, Sh. H. Xu, Y. Liu
To realize the long-term storage of liquid hydrogen for space application, different cooling enhancement components to control the pressure of the cryogenic tanks to a safety condition have been developed in the past decades. In this article, a microgravity, three-dimensional model of a liquid hydrogen storage system with heat pipe and pump-nozzle unit was built. Focusing on significant factors to the cooling performance, such as the heat transfer efficiency of the cool tip (evaporation section), the spraying direction of the nozzle, and the number of the pump-nozzle units, numerical simulations of six tanks with different components were carried out. Typical distributions of velocity and temperature of the fluid inside the tanks are illustrated and studied in detail. The maximum temperature and standard temperature deviation in the storage tank were chosen to evaluate cooling effect and mixing effect, respectively. By comparing the synthesized chilling performances of the six different configurations, an optimal structure has been obtained. This research is helpful to improve the performance of cryogenic liquid storage system for space application.
{"title":"Numerical study of zero boil-off storage system with heat pipe and pump-nozzle unit","authors":"X. J. Wang, X. Yuan, Sh. H. Xu, Y. Liu","doi":"10.1080/10789669.2014.888092","DOIUrl":"https://doi.org/10.1080/10789669.2014.888092","url":null,"abstract":"To realize the long-term storage of liquid hydrogen for space application, different cooling enhancement components to control the pressure of the cryogenic tanks to a safety condition have been developed in the past decades. In this article, a microgravity, three-dimensional model of a liquid hydrogen storage system with heat pipe and pump-nozzle unit was built. Focusing on significant factors to the cooling performance, such as the heat transfer efficiency of the cool tip (evaporation section), the spraying direction of the nozzle, and the number of the pump-nozzle units, numerical simulations of six tanks with different components were carried out. Typical distributions of velocity and temperature of the fluid inside the tanks are illustrated and studied in detail. The maximum temperature and standard temperature deviation in the storage tank were chosen to evaluate cooling effect and mixing effect, respectively. By comparing the synthesized chilling performances of the six different configurations, an optimal structure has been obtained. This research is helpful to improve the performance of cryogenic liquid storage system for space application.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"67 1","pages":"320 - 327"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83430267","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.888907
N. Gao, Guangming Chen, Yunyun Jiang, Yijian He
Desiccant cooling and drying systems have attracted considerable attention in recent years because they can enhance the quality of dried products and reduce the use of conventional source of energy. Calcium chloride (CaCl2) aqueous solution is the cheapest and most readily available liquid desiccant that could be used in desiccant cooling and drying systems, but it has the disadvantage of being instable depending on the inlet air conditions and the concentration of the desiccant in the solution. CaCl2 + LiCl (1:1 mass) and CaCl2 + Ca(NO3)2 (5:2 mass) mixtures are thought to be the two most potential liquid desiccants with their relatively high performance and high economic efficiency. The main purpose of this research is to obtain the basic thermodynamic properties (isobaric heat capacities) of the aqueous solutions of CaCl2 and its two specially composed mixtures. The measurements were carried out at temperatures range from 308 to 348 K and different concentrations determined under consideration of the working conditions of the liquids in systems. Scanning calorimetry was applied and a specialized experimental unit for heat capacity measurements of liquids was used in this research. Based on the results, semiempirical equations as functions of temperature and solute concentration were obtained. The deviation between the equations and experiment values showed good agreements, which confirmed the capability of these equations to be used in engineering applications.
{"title":"Isobaric heat capacity of potential liquid desiccant solutions containing calcium chloride and its mixtures","authors":"N. Gao, Guangming Chen, Yunyun Jiang, Yijian He","doi":"10.1080/10789669.2014.888907","DOIUrl":"https://doi.org/10.1080/10789669.2014.888907","url":null,"abstract":"Desiccant cooling and drying systems have attracted considerable attention in recent years because they can enhance the quality of dried products and reduce the use of conventional source of energy. Calcium chloride (CaCl2) aqueous solution is the cheapest and most readily available liquid desiccant that could be used in desiccant cooling and drying systems, but it has the disadvantage of being instable depending on the inlet air conditions and the concentration of the desiccant in the solution. CaCl2 + LiCl (1:1 mass) and CaCl2 + Ca(NO3)2 (5:2 mass) mixtures are thought to be the two most potential liquid desiccants with their relatively high performance and high economic efficiency. The main purpose of this research is to obtain the basic thermodynamic properties (isobaric heat capacities) of the aqueous solutions of CaCl2 and its two specially composed mixtures. The measurements were carried out at temperatures range from 308 to 348 K and different concentrations determined under consideration of the working conditions of the liquids in systems. Scanning calorimetry was applied and a specialized experimental unit for heat capacity measurements of liquids was used in this research. Based on the results, semiempirical equations as functions of temperature and solute concentration were obtained. The deviation between the equations and experiment values showed good agreements, which confirmed the capability of these equations to be used in engineering applications.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"1 1","pages":"328 - 331"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80000703","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.888369
Xilong Wang, J. Weisend, T. Koettig, W. Hees, C. Darve
The European Spallation Source (ESS) is a neutron-scattering facility being built with extensive international collaboration at Lund, Sweden. The ESS accelerator will deliver protons with 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The superconducting section of the ESS accelerator consists of a total of 208 SRF cavities in cryomodules (CMs) cooled with superfluid helium to 2 K. The CM contains one thermal radiation shield operating from 40 to 50 K. Additionally, 4.5-K gas helium is used to provide forced cooling to the fundamental power couplers for the cavities. The cryogenic cooling for these CMs is provided by one cryogenic plant connected to CMs via a cryogenic distribution line. This article describes the requirements and preliminary design decisions for the ESS accelerator cryoplant. The expected capacity, temperature levels and operating modes are given. Design choices to address important issues of turn-down capability, high availability, and timely restart after plant trips are discussed. Procurement options and schedules are described.
{"title":"ESS accelerator cryogenic plant","authors":"Xilong Wang, J. Weisend, T. Koettig, W. Hees, C. Darve","doi":"10.1080/10789669.2014.888369","DOIUrl":"https://doi.org/10.1080/10789669.2014.888369","url":null,"abstract":"The European Spallation Source (ESS) is a neutron-scattering facility being built with extensive international collaboration at Lund, Sweden. The ESS accelerator will deliver protons with 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The superconducting section of the ESS accelerator consists of a total of 208 SRF cavities in cryomodules (CMs) cooled with superfluid helium to 2 K. The CM contains one thermal radiation shield operating from 40 to 50 K. Additionally, 4.5-K gas helium is used to provide forced cooling to the fundamental power couplers for the cavities. The cryogenic cooling for these CMs is provided by one cryogenic plant connected to CMs via a cryogenic distribution line. This article describes the requirements and preliminary design decisions for the ESS accelerator cryoplant. The expected capacity, temperature levels and operating modes are given. Design choices to address important issues of turn-down capability, high availability, and timely restart after plant trips are discussed. Procurement options and schedules are described.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"24 1","pages":"296 - 301"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83219387","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}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.888302
Zeqin Liu, Lingyu Liu
This article explores the resident time of free-falling particle plume with the characteristics of gas-solid two-phase flow affected by horizontal crosswise wind speed. The computational fluid dynamic software FLUENT was adopted in this study. The numerical simulation was carried out to study the influence of horizontal environmental wind speed to the velocity of particle plume. In the simulation, the ambient wind speeds were assumed as 1, 1.2, 1.4, 1.6, and 1.8 m/s. The particle diameter was set as 567 μm and the mass flow was given as 5.2 g/s. The Euler and Lagrangian models were used to calculate the coupling pressure and velocities of the particles and the entrained air in the simulation. The simulation results showed that the greater the horizontal wind speed was the shorter the particle resident time and the shorter the time of particle velocity reached the maximum value.
{"title":"Numerical simulation of particle plume resident time affected by horizontal crosswise wind speed","authors":"Zeqin Liu, Lingyu Liu","doi":"10.1080/10789669.2014.888302","DOIUrl":"https://doi.org/10.1080/10789669.2014.888302","url":null,"abstract":"This article explores the resident time of free-falling particle plume with the characteristics of gas-solid two-phase flow affected by horizontal crosswise wind speed. The computational fluid dynamic software FLUENT was adopted in this study. The numerical simulation was carried out to study the influence of horizontal environmental wind speed to the velocity of particle plume. In the simulation, the ambient wind speeds were assumed as 1, 1.2, 1.4, 1.6, and 1.8 m/s. The particle diameter was set as 567 μm and the mass flow was given as 5.2 g/s. The Euler and Lagrangian models were used to calculate the coupling pressure and velocities of the particles and the entrained air in the simulation. The simulation results showed that the greater the horizontal wind speed was the shorter the particle resident time and the shorter the time of particle velocity reached the maximum value.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"22 1","pages":"362 - 366"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90058523","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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