Thermoeconomic Analysis of Vapour Compression Refrigeration System With Dedicated Subcooler for High-Temperature Lift Applications

2021 ◽  
pp. 1-31
Author(s):  
Ranendra Roy ◽  
Arup Jyoti Bhowal ◽  
Bijan Kumar Mandal
Keyword(s):  
High Temperature ◽  
Point Of View ◽  
Single Stage ◽  
The Other ◽  
Economic Aspects ◽  
Refrigeration System ◽  
System Increase ◽  
Discharge Temperature ◽  
Vapour Compression

Abstract A single-stage vapour compression refrigeration system becomes inefficient and impractical when the temperature lift between the evaporator and the condenser becomes large. Under the high temerature lift, different losses in the system increase and more refrigerant vapour is formed at the end of the throttling process. The authors have attempted to analyze a vapour compression refrigeration system with dedicated subcooler for high-temperature lift applications using R134a in the main cycle and four low GWP refrigerants in the subcooler cycle. The modelling of the proposed system has been carried out in EES considering the energy, exergy and economic aspects for the simulation of the system. The predicted results show that the use of the proposed system is more beneficial from both performance and economy point of view for high temperature lift. Nearly 27% improvement in both energetic and exergetic performances are noted whereas cost is reduced by 2% when the proposed system is used instead of a typical refrigeration system. Finally, the present investigation concludes that the use of refrigerant R1234ze is much efficient than the other investigated refrigerants due to its low GWP and compressor discharge temperature, in spite of achieving better thermo-economic performances using R152a as subcooler refrigerant.

scholarly journals Analytical computation of thermodynamic performance parameters of actual vapour compression refrigeration system with R22, R32, R134a, R152a, R290 and R1270

2018 ◽  
Vol 144 ◽  
pp. 04009 ◽  
Author(s):  
Shaik Sharmas Vali ◽  
Talanki Puttaranga Setty ◽  
Ashok Babu
Keyword(s):  
Mineral Oil ◽  
Performance Parameters ◽  
Refrigeration System ◽  
Analytical Computation ◽  
Volumetric Capacity ◽  
Discharge Temperature ◽  
Thermodynamic Performance ◽  
Compressor Work ◽  
Refrigeration Capacity ◽  
Vapour Compression

The present work focuses on analytical computation of thermodynamic performance of actual vapour compression refrigeration system by using six pure refrigerants. The refrigerants are namely R22, R32, R134a, R152a, R290 and R1270 respectively. A MATLAB code is developed to compute the thermodynamic performance parameters of actual vapour compression system such as refrigeration effect, compressor work, COP, power per ton of refrigeration, compressor discharge temperature and volumetric refrigeration capacity at condensing and evaporating temperatures of 54.4oC and 7.2oC respectively. Analytical results exhibited that COP of both R32 and R134a are 15.95% and 11.71% higher among the six investigated refrigerants. However R32 and R134a cannot be replaced directly into R22 system. This is due to their higher compressor discharge temperature and poor volumetric capacity respectively. The discharge temperature of both R1270 and R290 are lower than R22 by 20-26oC. Volumetric refrigeration capacity of R1270 (3197 kJ/m3) is very close to that of volumetric capacity of R22 (3251 kJ/m3). Both R1270 and R290 shows good miscibility with R22 mineral oil. Overall R1270 would be a suitable ecofriendly refrigerant to replace R22 from the stand point of ODP, GWP, volumetric capacity, discharge temperature and miscibility with mineral oil although its COP is lower.

scholarly journals Development of Multi use Refrigeration System

2019 ◽  
Vol 8 (2) ◽  
pp. 2387-2390
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Point Of View ◽  
Small Scale ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Conservation Of Energy ◽  
Heating And Cooling ◽  
Vapour Compression

Conservation of energy is the important factor from global point of view. Waste heat recovery has become significantly necessary and instant effort should be made to conserve this waste energy. Presently the refrigerator system rejects a lot of heat through condenser. This heat can be used for a variety of useful purposes. A multiuse refrigeration setup has been developed in which, both heating and cooling will be done simultaneously with the help of single vapour compression refrigeration cycle. It has a waste heat recovery system from the compressor for heating effect. Here without disturbing refrigeration cycle, the waste heat energy is used for useful work. The study has shown that such a system is technically feasible and economically viable. This concept has a scope of applications in variety of products such as air conditioners, freezers, water coolers and small scale refrigeration plants. This project leads to hybrid heating and cooling application with same vapour compression refrigeration system

Comparison of Various Alternative Refrigerants for Vapour Compression Refrigeration Systems

2011 ◽  
Author(s):  
Ahmet Selim Dalkilic¸ ◽  
Somchai Wongwises
Keyword(s):  
Heat Exchanger ◽  
Single Stage ◽  
Refrigeration System ◽  
Performance Study ◽  
Alternative Refrigerants ◽  
Two Stage ◽  
Stage Process ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration ◽  
Vapour Compression

Single-stage vapour compression refrigeration system was compared with an actual vapour compression cycle, single-stage process with internal heat exchanger, and a two-stage process with economiser using the refrigerants of HCFC-22, CFC-502 and their alternatives such as HFC-134a, HFC-32, HFC-152a, HFC-404A, HFC-407C, HFC-507, HFC-410A. A theoretical performance study on a cascade refrigeration system was performed using two refrigeration cycles connected through the heat exchanger in the middle working as the evaporator for the high pressurized cycle and condenser for the low pressurized cycle. Other performance study was performed using a two-stage cascade refrigeration system having low and high pressure compressors connected through the mixing chamber in the middle. The condensation temperatures were between 30 and 50 °C, evaporation temperatures were between −50 °C and 5 °C and heat exchanger and economiser temperatures were kept as constant for the comparisons. Some of the alternative refrigerants’ coefficients of performance values are found to be higher than their base traditional pure refrigerants. The effects of the main parameters of performance analysis such as refrigerant type, degree of subcooling, and superheating on the performance coefficient, refrigerant charge rate and volumetric refrigeration capacity are investigated for various operating conditions as case studies.

The Comparative Analysis of R22 and R134a Applied in a Five-Stage Auto-Cascade Refrigeration System

2013 ◽  
Vol 291-294 ◽  
pp. 1740-1745
Author(s):  
Wei Zhao ◽  
Rui Xi Liu ◽  
Hai Dong Zhang ◽  
Hua Zhang ◽  
Shu Chun Zhang
Keyword(s):  
Comparative Analysis ◽  
High Temperature ◽  
Refrigeration System ◽  
Discharge Temperature ◽  
Cascade Refrigeration System ◽  
High Temperature Stage ◽  
Cascade Refrigeration

The mixed refrigerants R22/R23/R14/R740/R728 and R134a/R23/R14/R740/R728 are used in a five-stage auto-cascade refrigeration system for study in this paper. Through theoretic comparison of high temperature stage refrigerant R22 and R134a and repeated experiments we can get the results that the discharge temperature of the refrigerant R134a can be effectively controlled and a lower refrigeration temperature can be got than the refrigerant R22.

scholarly journals Mathematical Simulation of Fourth Generation Refrigerant R1243zf in Single Stage and Double Stage Vapour Compression Refrigeration System

2020 ◽  
Vol 9 (4) ◽  
pp. 1706-1710
Keyword(s):  
Mathematical Simulation ◽  
Single Stage ◽  
Fourth Generation ◽  
Maximum Pressure ◽  
Refrigeration System ◽  
Evaporator Temperature ◽  
Compression System ◽  
Condenser Temperature ◽  
Optimum Solution ◽  
Vapour Compression

In this paper a new fourth generation, environment friendly refrigerant R1243zf has been used in performance analysis between single stage and double stage vapour compression refrigeration system working between the same minimum and maximum pressure limits. The analysis has been done by mathematical simulation in Engineering Equation Solve (EES 10.439D, 2019). Results show that in low temperature cooling applications, a single stage vapour compression system does not perform well and a cascade system is the best optimum solution. In the given pressure limit, with the use of double stage vapour compression system, the increase in COP is 14% and decrease in compression work is 11.49%. The effects of evaporator temperature and condenser temperature have been seen on COP for both the systems and results show that with decrease in evaporator temperature, COP is decreasing, where as with decrease in condenser temperature COP is increasing.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

RHYNCHOLITES AND THE PROBLEM OF NARROW AND BROAD CONCEPTION OF TAXONS

2018 ◽  
pp. 12-17 ◽  
Author(s):  
I. R. Khuzina ◽  
V. N. Komarov
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Characteristics ◽  
Mass Scale ◽  
Individual Variability ◽  
Point Of View ◽  
The Other ◽  
New Taxon ◽  
Artificial System ◽  
Broad Understanding

The paper considers a point of view, based on the conception of the broad understanding of taxons. According to this point of view, rhyncholites of the subgenus Dentatobeccus and Microbeccus are accepted to be synonymous with the genus Rhynchoteuthis, and subgenus Romanovichella is considered to be synonymous with the genus Palaeoteuthis. The criteria, exercising influence on the different approaches to the classification of rhyncholites, have been analyzed (such as age and individual variability, sexual dimorphism, pathological and teratological features, degree of disintegration of material), underestimation of which can lead to inaccuracy. Divestment of the subgenuses Dentatobeccus, Microbeccus and Romanovichella, possessing very bright morphological characteristics, to have an independent status and denomination to their synonyms, has been noted to be unjustified. An artificial system (any suggested variant) with all its minuses is a single probable system for rhyncholites. The main criteria, minimizing its negative sides and proving the separation of the new taxon, is an available mass-scale material. The narrow understanding of the genus, used in sensible limits, has been underlined to simplify the problem of the passing the view about the genus to the other investigators and recognition of rhyncholites for the practical tasks.

Birlikte Yaşama Kültürü Çerçevesinde Avrupa Birliği ve Türkiye Politikaları: Suriyelilere Yönelik Tutumun Sultanbeyli Örneği Üzerinden Değerlendirilmesi

2017 ◽  
Vol 4 (1) ◽  
pp. 41-61
Author(s):  
Pelin Sönmez ◽  
Abulfaz Süleymanov
Keyword(s):  
Civil Wars ◽  
Large Scale ◽  
Social Acceptance ◽  
Point Of View ◽  
The Other ◽  
Syrian Refugees ◽  
The European Union ◽  
International Protection ◽  
Legal Structure ◽  
Turkish People

Türkiye, Cumhuriyet tarihinin en yoğun zorunlu göç dalgasını 2011 yılından bu yana süren Suriye Savaşı ile yaşamaktadır. Suriye vatandaşlarının geçici koruma statüsü altında Türkiye toplumuna her açıdan entegrasyonları günümüzün ve geleceğin politika öncelikleri arasında düşünülmelidir. Öte yandan ülkeye kabul edilen sığınmacıların kendi kültürel kimliğini kaybetmeden içinde yaşadığı ev sahibi topluma uyumu, ortak yaşam kültürünün gelişmesi açısından önem arz etmektedir. Bu makalede, "misafir" olarak kabul edilen Suriyeli vatandaşların Türk toplumunca kabul edilmeleri ve dışlanma risklerinin azaltılmasına yönelik devlet politikaları ortaya konularak, üye ve aday ülkelere göçmenlerin dışlanmasını önlemek için Avrupa Birliği (AB) tarafından sunulan hukuki yapı ve kamu hizmeti inisiyatifleri incelenmekte, birlikte yaşam kültürü çerçevesinde Suriyeli vatandaşlara yönelik  toplumsal kabul düzeyleri ele alınmaktadır. Çalışma iki ana bölümden oluşmaktadır: göçmen ve sığınmacılara karşı toplumsal dışlanmayı engellemek için benimsenen yasa ve uygulamaların etkisi ve İstanbul-Sultanbeyli bölgesinde Suriyeli sığınmacılarla ilgili toplumsal algı çalışmasının sonuçları. Bölgede ikamet eden Suriyelilere yönelik toplumsal kabul düzeyinin yüksek olduğu görülürken, halkın Suriyelileri kendilerine  kültürel ve dini olarak yakın hissetmesi toplumsal kabul düzeyini olumlu etkilemektedir. ABSTRACT IN ENGLISHAn evaluation of the European Union and Turkish policies regarding the culture of living togetherThis article aims to determine the level of social acceptance towards Syrians within the context of cohabitation culture by evaluating EU’s legal structure and public service initiatives in order to prevent Syrian refugees from being excluded in member and candidate countries and by revealing government policies on acceptance of Syrians as “guest” by Turkish society and minimizing the exclusion risks of them. This article consists of two main parts, one of which is based on the effects of law and practices preventing refugees and asylum seekers from social exclusion, and the other is on the results of social perception on Syrians in Sultanbeyli district of Istanbul. At the end of 5-years taking in Syrian War, it is obvious that most of more than 3 million Syrian with unregistered ones in Turkey are “here to stay”. From this point of view, the primary scope of policies should be specified in order to remove side effects of refugee phenomenon seen as weighty matter by bottoming out the exclusion towards those people. To avoid possible large-scale conflicts or civil wars in the future, the struggle with exclusion phenomenon plays a crucial role regarding Turkey’s sociological situation and developing policies. In the meaning of forming a model for Turkey, a subtitle in this article is about public services for European-wide legal acquis and practices carried out since 1970s in order to prevent any exclusion from the society. On the other hand, other subtitles are about legal infrastructure and practices like Common European Asylum and Immigration Policies presented in 2005, and Law on Foreigners and International Protection introduced in 2013. In the last part of the article, the results of a field survey carried out in a district of Istanbul were used to analyze the exclusion towards refugees in Turkey. A face-to-face survey was randomly conducted with 200 settled refugees in Sultanbeyli district of Istanbul, and their perceptions towards Syrian people under temporary protection were evaluated. According to the results, the level of acceptance for Syrians living in this district seems relatively high. The fact that Turkish people living in the same district feel close to Syrian refugees culturally and religiously affect their perception in a positive way: however, it is strikingly seen and understood that local residents cop an attitude on the refugees’ becoming Turkish citizens.

Optimum Choice of Refrigerant for Miniature Vapour Compression Refrigeration System

2011 ◽  
Vol 3 (3) ◽  
pp. 134-136
Author(s):  
M. M. Tayde M. M. Tayde ◽  
◽  
Pranav Datar ◽  
Pankaj kumar ◽  
Dr. L. B. Bhuyar Dr. L. B. Bhuyar
Keyword(s):  
Refrigeration System ◽  
Optimum Choice ◽  
Vapour Compression
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