Pub Date : 2021-09-23DOI: 10.1142/s2010132521500292
Zahra Bouramdane, A. Bah, Mohammed Alaoui, N. Martaj
Although thermoacoustic devices comprise simple components, the design of these machines is very challenging. In order to predict the behavior and optimize the performance of a thermoacoustic refrigerator driven by a standing-wave thermoacoustic engine, considering the changes in geometrical parameters, two analogies have been presented in this paper. The first analogy is based on CFD analysis where a 2D model is implemented to investigate the influence of stack parameters on the refrigerator performance, to analyze the time variation of the temperature gradient across the stack, and to examine the refrigerator performance in terms of refrigeration temperature. The second analogy is based on the use of an optimization algorithm based on the simplified linear thermoacoustic theory applied for designing thermoacoustic refrigerators with different stack parameters and operating conditions. Simulation results show that the engine produced a high-powered acoustic wave with a pressure amplitude of 23[Formula: see text]kPa and a frequency of 584[Formula: see text]Hz and this wave applies a temperature difference across the refrigeration stack with a cooling temperature of 292.8[Formula: see text]K when the stacks are positioned next to the pressure antinode. The results from the algorithm give the ability to design any thermoacoustic refrigerator with high performance by picking the appropriate parameters.
{"title":"CFD Modeling and Performance Analysis of a Thermoacoustically Driven Thermoacoustic Refrigerator","authors":"Zahra Bouramdane, A. Bah, Mohammed Alaoui, N. Martaj","doi":"10.1142/s2010132521500292","DOIUrl":"https://doi.org/10.1142/s2010132521500292","url":null,"abstract":"Although thermoacoustic devices comprise simple components, the design of these machines is very challenging. In order to predict the behavior and optimize the performance of a thermoacoustic refrigerator driven by a standing-wave thermoacoustic engine, considering the changes in geometrical parameters, two analogies have been presented in this paper. The first analogy is based on CFD analysis where a 2D model is implemented to investigate the influence of stack parameters on the refrigerator performance, to analyze the time variation of the temperature gradient across the stack, and to examine the refrigerator performance in terms of refrigeration temperature. The second analogy is based on the use of an optimization algorithm based on the simplified linear thermoacoustic theory applied for designing thermoacoustic refrigerators with different stack parameters and operating conditions. Simulation results show that the engine produced a high-powered acoustic wave with a pressure amplitude of 23[Formula: see text]kPa and a frequency of 584[Formula: see text]Hz and this wave applies a temperature difference across the refrigeration stack with a cooling temperature of 292.8[Formula: see text]K when the stacks are positioned next to the pressure antinode. The results from the algorithm give the ability to design any thermoacoustic refrigerator with high performance by picking the appropriate parameters.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75802768","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 : 2021-09-01DOI: 10.1142/s2010132521500280
Vikas Kumar, G. Sachdeva, Sandeep Tiwari, P. Anuradha, V. Jain
A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.
{"title":"An Experimental Investigation on Vapor Compression Refrigeration System Cascaded with Ejector Refrigeration System","authors":"Vikas Kumar, G. Sachdeva, Sandeep Tiwari, P. Anuradha, V. Jain","doi":"10.1142/s2010132521500280","DOIUrl":"https://doi.org/10.1142/s2010132521500280","url":null,"abstract":"A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78478153","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 : 2021-09-01DOI: 10.1142/s2010132521500267
B. Prashantha, G. Narasimham, S. Seetharamu, K. Manjunatha
Thermoacoustic refrigeration is an emerging green, novel and promising alternate technology compared to vapor compression refrigerator systems for domestic cooling. It uses environmentally benign gases like air or helium or the mixture of inert gases as working substances and has no moving parts, no lubrication and no vibration. The cooler is designed and optimized with helium and air as refrigerants operating at 10[Formula: see text]bar with 3% drive ratio for the temperature difference of 28[Formula: see text]K and stack diameter of 200[Formula: see text]mm using linear thermoacoustic theory. In this paper, the effect of gas blockage (porosity) of the spiral-stack heat exchanger system ranging from 45% to 85% on the theoretical performance of the cooler is discussed. The one-third and one-fourth wavelength convergent–divergent resonator designs are optimized with air and helium as working substances, respectively, to improve performance and power density. The optimized coolers show best performance with 85% porosity. The theoretical results are validated with DeltaEC software simulation results. The simulation results show the coefficient of performance and cooling capacity of 0.93 and 219[Formula: see text]W for helium and of 0.50 and 139[Formula: see text]W for air, respectively, at the cold heat exchanger temperature of 0∘C.
{"title":"Effect of Gas Blockage on the Theoretical Performance of Thermoacoustic Refrigerators","authors":"B. Prashantha, G. Narasimham, S. Seetharamu, K. Manjunatha","doi":"10.1142/s2010132521500267","DOIUrl":"https://doi.org/10.1142/s2010132521500267","url":null,"abstract":"Thermoacoustic refrigeration is an emerging green, novel and promising alternate technology compared to vapor compression refrigerator systems for domestic cooling. It uses environmentally benign gases like air or helium or the mixture of inert gases as working substances and has no moving parts, no lubrication and no vibration. The cooler is designed and optimized with helium and air as refrigerants operating at 10[Formula: see text]bar with 3% drive ratio for the temperature difference of 28[Formula: see text]K and stack diameter of 200[Formula: see text]mm using linear thermoacoustic theory. In this paper, the effect of gas blockage (porosity) of the spiral-stack heat exchanger system ranging from 45% to 85% on the theoretical performance of the cooler is discussed. The one-third and one-fourth wavelength convergent–divergent resonator designs are optimized with air and helium as working substances, respectively, to improve performance and power density. The optimized coolers show best performance with 85% porosity. The theoretical results are validated with DeltaEC software simulation results. The simulation results show the coefficient of performance and cooling capacity of 0.93 and 219[Formula: see text]W for helium and of 0.50 and 139[Formula: see text]W for air, respectively, at the cold heat exchanger temperature of 0∘C.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77492275","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 : 2021-09-01DOI: 10.1142/s2010132521500279
G. Sachdeva, B. Sharma
In this paper, exergy destruction analysis of a heat-assisted ejector cooling system has been carried out using a modified Gouy–Stodola equation. The modified Gouy–Stodola equation provides a more accurate and realistic irreversibility analysis of the system than the conventional Gouy–Stodola formulation. The coefficient of structural bond (CSB) analysis has also been executed to find the component whose operating variables affect the system’s total irreversibility at the most. Exergy analysis revealed that the maximum exergy loss happens in the ejector followed by the generator and condenser. The model predicted 40.84% of total irreversibility in the ejector at the designed conditions. However, total exergy destruction is found to be the most sensitive to the evaporator temperature. The CSB value of 12.97 is obtained in the evaporator using the modified exergy method. The generator appears to be the second sensitive component with the CSB value of 2.42, followed by the condenser with the CSB value of 1.628. The coefficient of performance of the system is found to be 0.18 at the designed conditions. The refrigerant R1234yf is considered in the system.
本文采用修正的Gouy-Stodola方程对热辅助喷射器冷却系统进行了火用破坏分析。修正后的Gouy-Stodola方程比传统的Gouy-Stodola公式对系统的不可逆性分析更准确、更现实。通过结构键系数(coefficient of structural bond, CSB)分析，找出其运行变量对系统总不可逆性影响最大的组分。火用分析表明，火用损失最大的是喷射器，其次是发电机和冷凝器。该模型预测了设计条件下喷射器总不可逆性的40.84%。然而，发现总火用破坏对蒸发器温度最敏感。采用改进的火用法，蒸发器的CSB值为12.97。发电机似乎是第二个敏感部件，CSB值为2.42，其次是冷凝器，CSB值为1.628。在设计条件下，系统的性能系数为0.18。系统考虑制冷剂为R1234yf。
{"title":"Exergy Analysis of an Ejector Cooling System by Modified Gouy–Stodola Equation","authors":"G. Sachdeva, B. Sharma","doi":"10.1142/s2010132521500279","DOIUrl":"https://doi.org/10.1142/s2010132521500279","url":null,"abstract":"In this paper, exergy destruction analysis of a heat-assisted ejector cooling system has been carried out using a modified Gouy–Stodola equation. The modified Gouy–Stodola equation provides a more accurate and realistic irreversibility analysis of the system than the conventional Gouy–Stodola formulation. The coefficient of structural bond (CSB) analysis has also been executed to find the component whose operating variables affect the system’s total irreversibility at the most. Exergy analysis revealed that the maximum exergy loss happens in the ejector followed by the generator and condenser. The model predicted 40.84% of total irreversibility in the ejector at the designed conditions. However, total exergy destruction is found to be the most sensitive to the evaporator temperature. The CSB value of 12.97 is obtained in the evaporator using the modified exergy method. The generator appears to be the second sensitive component with the CSB value of 2.42, followed by the condenser with the CSB value of 1.628. The coefficient of performance of the system is found to be 0.18 at the designed conditions. The refrigerant R1234yf is considered in the system.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75273013","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 : 2021-08-28DOI: 10.1142/s2010132521300056
B. S. Bibin, Edison Gundabattini
The creation of new age refrigerants might be the answer to the issue of an Earth-wide rise in temperature. Hence, while choosing new refrigerants a careful process is required. The general effect of any refrigerant substance on global warming, energy efficiency, ozone depletion, cost-effectiveness, chemical stability, and safety ought to be assessed. This paper sums up the experimental and numerical investigations directed with the globally accepted R1234yf refrigerant. The paper’s principal points are to assess the capability of the hydro-fluoro-olefin (HFO) refrigerant mainly R1234yf utilized in the refrigeration system (vapor compression systems, domestic refrigeration system) and to explore its utilization as an eco-friendly refrigerant. In the vapor compression refrigeration system, the cooling capacity and coefficient of performance of R1234yf are found to be less, 9% and 11%, respectively compared to that of R134a. But the power consumption of the system with R1234yf increased between 1.6% and 6.7% when compared to R134a. This paper likewise assists with recognizing the gap in the past research works and explores the possibilities for additional works.
{"title":"Properties and Performance of Eco-Friendly Hydro-Fluoro-Olefin (HFO) Refrigerant-R1234yf: Part I","authors":"B. S. Bibin, Edison Gundabattini","doi":"10.1142/s2010132521300056","DOIUrl":"https://doi.org/10.1142/s2010132521300056","url":null,"abstract":"The creation of new age refrigerants might be the answer to the issue of an Earth-wide rise in temperature. Hence, while choosing new refrigerants a careful process is required. The general effect of any refrigerant substance on global warming, energy efficiency, ozone depletion, cost-effectiveness, chemical stability, and safety ought to be assessed. This paper sums up the experimental and numerical investigations directed with the globally accepted R1234yf refrigerant. The paper’s principal points are to assess the capability of the hydro-fluoro-olefin (HFO) refrigerant mainly R1234yf utilized in the refrigeration system (vapor compression systems, domestic refrigeration system) and to explore its utilization as an eco-friendly refrigerant. In the vapor compression refrigeration system, the cooling capacity and coefficient of performance of R1234yf are found to be less, 9% and 11%, respectively compared to that of R134a. But the power consumption of the system with R1234yf increased between 1.6% and 6.7% when compared to R134a. This paper likewise assists with recognizing the gap in the past research works and explores the possibilities for additional works.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90719085","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 : 2021-08-26DOI: 10.1142/s2010132521300044
P. Jadhav, N. Agrawal
A detailed literature review on the flow characterization of the capillary tubes is presented in this paper. The flow behavior is reviewed for straight, helically, and spirally coiled capillary tubes at different operating and geometric conditions by considering various aspects in the tube. This paper summarizes experimental and numerical study on the adiabatic and nonadiabatic straight and coiled capillary tubes at different geometries conditions. The vital information of the range of the tube geometry and operating conditions are discussed, which can be utilized for further studies on the capillary tube. Various methodologies with generalized correlations are indicated. It has been observed that there are even more studies need to do with environmentally friendly refrigerants with various practical aspects in the capillary tube. It would be interesting to find the coiling effect on the design and simulation of the capillary tube. In addition to that more experimental and numerical studies need to explore the nonadiabatic coiled capillary tube. It would be fascinating to study the metastable condition in the capillary tube and set suitable relations to present its effect on the mass flow rate.
{"title":"A Review on Flow Characteristics of the Straight and Coiled Capillary Tubes","authors":"P. Jadhav, N. Agrawal","doi":"10.1142/s2010132521300044","DOIUrl":"https://doi.org/10.1142/s2010132521300044","url":null,"abstract":"A detailed literature review on the flow characterization of the capillary tubes is presented in this paper. The flow behavior is reviewed for straight, helically, and spirally coiled capillary tubes at different operating and geometric conditions by considering various aspects in the tube. This paper summarizes experimental and numerical study on the adiabatic and nonadiabatic straight and coiled capillary tubes at different geometries conditions. The vital information of the range of the tube geometry and operating conditions are discussed, which can be utilized for further studies on the capillary tube. Various methodologies with generalized correlations are indicated. It has been observed that there are even more studies need to do with environmentally friendly refrigerants with various practical aspects in the capillary tube. It would be interesting to find the coiling effect on the design and simulation of the capillary tube. In addition to that more experimental and numerical studies need to explore the nonadiabatic coiled capillary tube. It would be fascinating to study the metastable condition in the capillary tube and set suitable relations to present its effect on the mass flow rate.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82732164","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 : 2021-08-23DOI: 10.1142/s2010132521500255
Cleison Henrique de Paula, W. M. Duarte, Thiago Torres Martins Rocha, Raphael Nunes de Oliveira, A. Maia
In this work, a cascade refrigeration system operating with four different ecological refrigerant pairs was modeled. This system uses R744 (Carbon dioxide) in the low-temperature cycle and operates with R290 (propane), R1234yf (2,3,3,3-tetrafluoropropene), R152a (1,1-difluorethane), and R717 (ammonia) in the high-temperature cycle. Energetic, exergetic, environmental, and economic performance of the cascade system was investigated to determine the most appropriate ecological refrigerant couple. The parameters used in each mentioned performance were COP (Coefficient of Performance), [Formula: see text] (Exergy Efficiency), TEWI (Total Equivalent Warming Impact), ECOP (Ecological coefficient of performance), and [Formula: see text] (Total plant cost rate), respectively. The results showed that the cascade refrigeration system operating with R744/R717 provided the best performance for the thermodynamic conditions analyzed, presenting a COP of 2.10, [Formula: see text] of 56.9%, [Formula: see text] of 24 334 USD/year, ECOP of 4.86, and TEWI of 25.67 tons of CO2. Finally, evaluating the total plant cost rate of this cascade system, it was noted that the capital and maintenance cost rate [Formula: see text] corresponds to 89.1% of the [Formula: see text] value, the operational cost rate [Formula: see text] corresponds to 10.27% of the [Formula: see text] value and the environmental cost rate [Formula: see text] corresponds to 0.63% of [Formula: see text].
{"title":"Energetic, Exergetic, Environmental, and Economic Assessment of a Cascade Refrigeration System Operating with Four Different Ecological Refrigerant Pairs","authors":"Cleison Henrique de Paula, W. M. Duarte, Thiago Torres Martins Rocha, Raphael Nunes de Oliveira, A. Maia","doi":"10.1142/s2010132521500255","DOIUrl":"https://doi.org/10.1142/s2010132521500255","url":null,"abstract":"In this work, a cascade refrigeration system operating with four different ecological refrigerant pairs was modeled. This system uses R744 (Carbon dioxide) in the low-temperature cycle and operates with R290 (propane), R1234yf (2,3,3,3-tetrafluoropropene), R152a (1,1-difluorethane), and R717 (ammonia) in the high-temperature cycle. Energetic, exergetic, environmental, and economic performance of the cascade system was investigated to determine the most appropriate ecological refrigerant couple. The parameters used in each mentioned performance were COP (Coefficient of Performance), [Formula: see text] (Exergy Efficiency), TEWI (Total Equivalent Warming Impact), ECOP (Ecological coefficient of performance), and [Formula: see text] (Total plant cost rate), respectively. The results showed that the cascade refrigeration system operating with R744/R717 provided the best performance for the thermodynamic conditions analyzed, presenting a COP of 2.10, [Formula: see text] of 56.9%, [Formula: see text] of 24 334 USD/year, ECOP of 4.86, and TEWI of 25.67 tons of CO2. Finally, evaluating the total plant cost rate of this cascade system, it was noted that the capital and maintenance cost rate [Formula: see text] corresponds to 89.1% of the [Formula: see text] value, the operational cost rate [Formula: see text] corresponds to 10.27% of the [Formula: see text] value and the environmental cost rate [Formula: see text] corresponds to 0.63% of [Formula: see text].","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85960093","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 : 2021-08-19DOI: 10.1142/s2010132521300032
S. Salins, Shiva Kumar, S. Reddy, Avin Vivek Kuniyil, S. Kumar
Heating ventilation air conditioning (HVAC) design mainly deals with moisture and its control. The moisture may be present inside ducts, conditioned spaces, or outdoors. The process of humidification and dehumidification requires equipment for mass and heat transfer, where the transfer of energy and mass takes place at varying concentrations and temperatures. The exchange of mass or heat depends on the type of flow and is conceivably in the form of gas to liquid or liquid–vapor. This paper aims to review the effect of moisture in the buildings and modulate its effect with several humidifying and dehumidifying techniques as sustainable techniques depending upon the external weather conditions to maintain thermal comfort. Various humidification and dehumidification techniques have been discussed with both their merits, limitations, applications and future scope to meet sustainable energy demands.
{"title":"Sustainable Energy Techniques Adapted in Buildings to Regulate Moisture Transport and Enhance Thermal Comfort: A Review","authors":"S. Salins, Shiva Kumar, S. Reddy, Avin Vivek Kuniyil, S. Kumar","doi":"10.1142/s2010132521300032","DOIUrl":"https://doi.org/10.1142/s2010132521300032","url":null,"abstract":"Heating ventilation air conditioning (HVAC) design mainly deals with moisture and its control. The moisture may be present inside ducts, conditioned spaces, or outdoors. The process of humidification and dehumidification requires equipment for mass and heat transfer, where the transfer of energy and mass takes place at varying concentrations and temperatures. The exchange of mass or heat depends on the type of flow and is conceivably in the form of gas to liquid or liquid–vapor. This paper aims to review the effect of moisture in the buildings and modulate its effect with several humidifying and dehumidifying techniques as sustainable techniques depending upon the external weather conditions to maintain thermal comfort. Various humidification and dehumidification techniques have been discussed with both their merits, limitations, applications and future scope to meet sustainable energy demands.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87500156","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 : 2021-08-18DOI: 10.1142/s2010132521500243
Ayça Atamtürk, Serhan Küçüka
In this study, a modified auto-cascade refrigerating cycle is proposed. The cycle includes two evaporators and one compressor, and a separator is located after the refrigerator evaporator. The vapor phase from the separator is condensed through an internal evaporator and is mixed with some amount of the liquid phase taken from the separator. The condensed liquid is sent to the freezer evaporator at low pressure. Thermodynamic properties of the mixture R290/R600a, which is a zeotropic mixture as a cycle fluid, were determined using the REFPROP database. The variation of the cycle performance and total cooling capacity is investigated by changing the ratios of refrigerator and freezer loads. The results show that the volumetric cooling capacity increases and the compressor pressure ratio decreases as the load ratio of the refrigerator increases.
{"title":"Thermodynamic Analysis of an Auto-Cascade Freezer Cycle at Different Loads of Evaporators","authors":"Ayça Atamtürk, Serhan Küçüka","doi":"10.1142/s2010132521500243","DOIUrl":"https://doi.org/10.1142/s2010132521500243","url":null,"abstract":"In this study, a modified auto-cascade refrigerating cycle is proposed. The cycle includes two evaporators and one compressor, and a separator is located after the refrigerator evaporator. The vapor phase from the separator is condensed through an internal evaporator and is mixed with some amount of the liquid phase taken from the separator. The condensed liquid is sent to the freezer evaporator at low pressure. Thermodynamic properties of the mixture R290/R600a, which is a zeotropic mixture as a cycle fluid, were determined using the REFPROP database. The variation of the cycle performance and total cooling capacity is investigated by changing the ratios of refrigerator and freezer loads. The results show that the volumetric cooling capacity increases and the compressor pressure ratio decreases as the load ratio of the refrigerator increases.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74877890","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 : 2021-07-15DOI: 10.1142/S2010132521500231
Mohd Waseem Siddiqui, NishithKr. Das, R. Sahoo
An experimental investigation was carried out to study the performance evaluation of Modified Low-Temperature Cascade (MLTC) system, based on two-stage cascade type refrigeration system using the combination of R404A/R23 refrigerants. This system was developed using chilled water (CHW) in the condenser of high-temperature circuit (HTC) and pre-cooler (PC) in the low-temperature circuit (LTC). Isentropic compression efficiency is computed in this work and used here as an important parameter. Performance of MLTC system was compared with or without the introduction of PC into LTC. System’s coefficient of performance (COP) has also been compared with using CHW, cooling tower water (CTW), normal water (NW) into the HTC condenser. It has also been shown that COPs of the system are significantly affected by slight variation in the LTC and HTC evaporating temperatures. Presented parameters and comparisons are likely to help in developing a low-temperature (LT) refrigeration system with higher efficiency for industrial and other applications.
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