scholarly journals Development of an Air-Cycle Environmental Control System for Automotive Applications

2011 ◽  
Author(s):  
Christopher J. Forster ◽  
Patrick Lemieux
Keyword(s):  
Control System ◽  
Air Conditioning ◽  
High Performance ◽  
Environmental Control ◽  
Cooling Capacity ◽  
Test Stand ◽  
Compressed Air ◽  
Coefficient Of Performance ◽  
Intake Manifold ◽  
Working Fluid

The Reverse-Brayton cycle has been used for aircraft cabin cooling for many decades. However, air-cycle cooling hasn’t been popular in the automotive field yet. This study demonstrates that air-cycle technology can provide sufficient cooling for certain applications. The primary focus is a novel forced induction engine control system, where compressor bleed is used both to provide engine boost control and air-conditioning. The bleed-air drives an air-cycle machine (ACM) consisting of typical automotive components: a turbocharger, heat exchanger, and ducting. The components of an ACM system are lightweight and compact compared to those of a typical vapor compression system; both qualities are critical in high performance applications, where such a system seems to make most sense. The ACM was tested first on a test stand and then directly on an engine, in a bootstrap-cycle configuration. The turbocharged test engine’s intake manifold pressure was controlled by bleeding air from the outlet of the engine’s intercooler and feeding the ACM compressor inlet. Once the compressed air was supplied to the ACM it was further compressed by the ACM, cooled by the secondary intercooler, and expanded through the ACM turbine. The engine’s turbocharger was resized to compensate for the increased air flow during ACM operation. The results show that a dry-air-rated (DAR) coefficient of performance (COP) of 0.73 and a DAR cooling capacity of 1.5 tons are possible on a test stand, and a DAR COP of 0.56 and a DAR cooling capacity of 0.72 tons are possible on-engine. The data available from the on-engine testing was limited to lower ACM pressure ratios due to a bearing failure before full testing was complete; performance would likely increase with higher inlet pressures, as shown by the compressed air test stand results. The test results strongly suggest that continued development and in-vehicle testing will provide adequate air-conditioning and engine performance, using only the most benign and environmentally friendly working fluid: air.

Thermodynamic analysis of triple effect ammonia–water absorption compression (hybrid) cycle

2021 ◽  
pp. 095440892199568
Author(s):  
CP Jawahar
Keyword(s):  
Water Absorption ◽  
Energy Analysis ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Performance Parameters ◽  
Evaporator Temperature ◽  
Ammonia Water ◽  
Absorption Cycle ◽  
Hybrid Cycle

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.

scholarly journals KAJI PERFORMANSI REFRIGERAN R-290, R-32, DAN R-410A SEBAGAI ALTERNATIF PENGGANTI R-22

2021 ◽  
Vol 4 ◽  
pp. 133-139
Author(s):  
Rikhard Ufie ◽  
Cendy S. Tupamahu ◽  
Sefnath J. E. Sarwuna ◽  
Jufraet Frans
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Vapor Compression ◽  
Know How ◽  
Evaporation Temperature ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Refrigeration Capacity

Refrigerant R-22 is a substance that destroys the ozone layer, so that in the field of air conditioning it has begun to be replaced, among others with refrigerants R-32 and R-410a, and also R-290. Through this research, we want to know how much Coefficient of Performance (COP) and Refrigeration Capacity (Qe) can be produced for the four types of refrigerants. The study was carried out theoretically for the working conditions of the vapor compression cycle with an evaporation temperature (Tevap) of 0, -5, and -10oC, a further heated refrigerant temperature (ΔTSH) of 5 oC, a condensation temperature (Tkond) of 45 oC and a low-cold refrigerant temperature. (ΔTSC) 10 oC and compression power of 1 PK . The results of the study show that the Coefficient of Performance (COP) in the use of R-22 and R-290 is higher than the use of R-32 and R-410a, which are 4,920 respectively; 4,891; 4.690 and 4.409 when working at an evaporation temperature of 0 oC; 4.260; 4,234; 4.060 and 3.812 when working at an evaporation temperature of -5 oC; and amounted to 3,730; 3,685; 3,550 and 3,324 if working at an evaporation temperature of -10 oC. Based on the size of the COP, if this installation works with a compression power of 1 PK, then the cooling capacity of the R-22 and R-290 is higher than the R-32 and R-410a, which are 3,617 respectively. kW; 3,597 kW; 3,449 kW and 3,243 kW. If working at an evaporation temperature of 0 oC; 3.133 kW; 3.114 kW; 2,986 kW and 2,804 kW if working at an evaporation temperature of -5 oC; and 2,741 kW; 2,710 kW; 2,611 kW and 2,445 kW if working at an evaporation temperature of -10oC.

scholarly journals Thermal Performance Analysis of Low-GWP Refrigerants in Automotive Air-Conditioning System

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yousuf Alhendal ◽  
Abdalla Gomaa ◽  
Gamal Bedair ◽  
Abdulrahim Kalendar
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Air Conditioning System ◽  
Capacity Coefficient ◽  
Automotive Air Conditioning ◽  
Automotive Air Conditioning System ◽  
Compressor Power ◽  
Low Global Warming Potential

The energy and exergy of low-global warming potential (GWP) refrigerants were investigated experimentally and theoretically. Refrigerants with a modest GWP100 of  ≤ 150 can be sufficient for bringing down emissions which were concerned for the automotive air-conditioning system. Three types of low-GWP refrigerants, R152a, R1234yf, and R1234ze(E), were examined with particular reference to the current high-GWP of R134a. The effect of different evaporating and condensing temperatures in addition to compressor speed was considered. The purpose was to bring a clear view of the performance characteristics of possible environment friendly alternatives of R134a. The analysis was carried out with compressor power, cooling capacity, coefficient of performance, exergy destruction, and exergy efficiency. It was noted that the total exergy destruction of R1234yf was reduced by 15% compared to that of R134a. The refrigerant R1234ze(E) has the highest energetic and exergetic performance compared with the other investigated refrigerants.

scholarly journals Investigation on the improvement of car air conditioning system performance using an ejector

2018 ◽  
Vol 197 ◽  
pp. 08013
Author(s):  
Enang Suma Arifianto ◽  
Ega Taqwali Berman ◽  
Mutaufiq Mutaufiq
Keyword(s):  
System Performance ◽  
Test Procedure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Compressor Work ◽  
R 134A

The purpose of this research is to know the improvement of car air conditioner system performance using an ejector. The study was conducted on a car engine with power 100 PS (74 kW) @ 5000 rpm. The test procedure is carried out under two conditions: the normal refrigeration cycle mode and the refrigeration cycle mode with the ejector. The working fluid used in the refrigeration cycle is R-134a. Performance data was measured on engine revolutions ranging from 1500 - 3000 rpm. Finally, the results showed that ejector usage on AC system generates an increase in the refrigeration effect and coefficient of performance (COP) of 25% and 22%, respectively. This has implications to better cooling capacity and compressor work that is lighter.

A Hybrid Absorption System With Generator Level Optical Control and Variable Flow Rate

2019 ◽  
Author(s):  
Gleidson Souza ◽  
José V. C. Vargas ◽  
Wellington Balmant ◽  
Marcos C. Campos ◽  
Leonardo C. Martinez ◽  
...  
Keyword(s):  
Control System ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Air Conditioning ◽  
Energy Input ◽  
Waste Heat ◽  
Optical Control ◽  
Working Fluid ◽  
Vapor Compression ◽  
Regenerative Heat

Abstract Current refrigeration and air conditioning systems are mostly based on the vapor compression cycle, which require electrical energy input. Absorption systems have gained new interest due to the possibility of utilizing waste heat as energy input. In addition, the environmental impact generated by such systems is recognized as much smaller than vapor compression systems. Therefore, this work developed and characterized an absorption refrigeration system with an innovative generator level optical control and variable working fluid mass flow rate, with potential for use in industrial, commercial and residential heating, ventilation, air conditioning, and refrigeration (HVAC & R) systems. The system is hybrid, since it was designed to be fed with heat from the burning of different fuels and/or waste heat sources in complementary fashion. The system consists of: a condenser, an evaporator, two expansion valves, two absorbers, a centrifugal pump, a regenerative heat exchanger, a generator, a rectifier, a generator level optical control system, and two liquid accumulators. The developed level control system consists of 3 light Dependent Resistors (LDR) positioned inside a box built around a transparent level meter, and illuminated internally by a low power light bulb. A frequency inverter and a centrifugal pump allow for the working fluid solution inside the generator to be within a safe range for efficient cooling cycle operation. The system measured refrigeration capacity rate was 2.3 TR, which qualifies as a good performance, since the equipment was originally designed for 1 TR.

Design and Modeling of One Refrigeration Ton Solar Assisted Adsorption Air Conditioning System

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
M. Alkhair ◽  
M. Y. Sulaiman ◽  
K. Sopian ◽  
C. H. Lim ◽  
E. Salleh ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Hot Water ◽  
Activated Carbon Fiber ◽  
Coefficient Of Performance ◽  
Weather Data ◽  
Adsorption System ◽  
Water Storage Tank ◽  
Chilled Water

The modeling of the performance of a one refrigeration ton (RT) solar assisted adsorption air-conditioning refrigeration system using activated carbon fiber/ethanol as the adsorbent/adsorbate pair has been undertaken in this study. The effects of hot water, cooling water, chilled water inlet temperatures, and hot water and chilled water flow rates were taken into consideration in the optimization of the system and in the design of the condenser, evaporator, and hot water storage tank. The study includes analysis of the weather data and its effect on both the adsorption system and the cooling load. This is then followed by estimation of the cooling capacity and coefficient of performance (COP) of the adsorption system as a function of the input parameters. The results of the model will be compared to experimental data in a next step.

scholarly journals Modelling of the degradation of mechanical properties of glass fiber reinforced composites (GFRP) due to environmental aging

2017 ◽  
Author(s):  
Παναγιώτα Κελβερκλόγλου
Keyword(s):  
Mechanical Properties ◽  
Control System ◽  
Glass Fiber ◽  
Air Conditioning ◽  
Life Prediction ◽  
Environmental Control ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Glass Fiber Reinforced ◽  
Environmental Aging

Αντικείμενο της παρούσας Διατριβής είναι η ανάπτυξη μεθοδολογίας εκτίμησης χρόνου ζωής κατασκευών από ενισχυμένα με ίνες γυαλιού σύνθετα υλικά που λειτουργούν σε συνθήκες υγροθερμικής γήρανσης παρουσία μηχανικής φόρτισης και η εφαρμογή της μεθοδολογίας αυτής σε τμήμα του συστήματος κλιματισμού επιβατικών αεροσκαφών. Η εξέλιξη της τεχνολογίας απαιτεί την αναλυτική γνώση/μελέτη του υλικού από το οποίο αποτελείται μια κατασκευή και τη δομική ανάλυσή της κατασκευής, και προϋποθέτει συστημική προσέγγιση του προβλήματος. Αυτό κάνει την ανάλυση του συνολικού μηχανολογικού συστήματος δύσκολη αλλά εξαιρετικά ενδιαφέρουσα διαδικασία που ενσωματώνει πολυ-λειτουργικές εφαρμογές που αλληλεπιδρούν. Όλες οι σύγχρονες τεχνολογικές εφαρμογές βασίζονται σε μια πολύ καλά οργανωμένη συστημική συνεργασία των στοιχείων τους. Οι αεροπορικές κατασκευές είναι εξαιρετικό παράδειγμα της συστημικής προσέγγισης, όπου όλα τα επιμέρους συστήματα αλληλοεπιδρούν επιτυχώς. Το Environmental Control System (ECS) στα αεροσκάφη της πολιτικής αεροπορίας είναι πολύ σημαντικό υποσύστημα για την ασφάλεια και την άνεση των επιβατών. Χρησιμοποιείται για τον έλεγχο της ανακυκλοφορίας του αέρα και τη συμπίεση της καμπίνας του αεροσκάφους, και επομένως η ορθή λειτουργία του συστήματος αυτού είναι απαραίτητη σε όλη τη διάρκεια του προβλεπόμενου χρόνου ζωής του αεροσκάφους. Σκοπός της παρούσας διατριβής είναι να εκτιμηθεί ο χρόνος ζωής του Environmental Control System (ECS) με βάση διαφορετικούς παράγοντες που μπορούν να επηρεάσουν πολύ σημαντικά δομικά στοιχεία του Air Conditioning Pack (ACP - τμήματος του ECS)) όπως ο θάλαμος διάχυσης-εκκροής αέρα (plenum). Η μεθοδολογία αυτή βασίζεται στην υποβάθμιση ιδιοτήτων του υλικού της κατασκευής λόγω περιβαλλοντικής γήρανσης και έχει αναπτυχθεί με τέτοιο τρόπο ώστε να μπορεί να χρησιμοποιηθεί και σε διαφορετικές εφαρμογές/κατασκευές. Η διαδικασία βασίζεται αρχικά στην περιγραφή και τον χαρακτηρισμό των υλικών από τα οποία είναι κατασκευασμένο το plenum. Με βάση πειραματικά δεδομένα συμπεριφοράς του σύνθετου υλικού σε συνθήκες περιβαλλοντικής γήρανσης έχει αναπτυχθεί μια εφαρμογή μέσω της γλώσσας προγραμματισμού Python, με σκοπό να προβλέψει/συσχετίσει το ποσοστό απορροφησης υγρασίας, με την υποβάθμιση ιδιοτήτων, τη διόγκωση (swelling), την ανάπτυξη επιφανειακής τραχύτητας, την ανάπτυξη υγροθερμικών τάσεων και την υποβάθμιση της αντοχής του υλικού. Αυτή η εφαρμογή που στην παρούσα διατριβή καλύπτει το υλικό κατασκευής του air conditioning plenum, μπορεί να χρησιμοποιηθεί και από άλλες δομές όπου το βασικό υλικό της κατασκευής είναι πολυμερές ενισχυμένο με ίνες γυαλιού και χρησιμοποιείται για τον προσδιορισμό της προοδευτικής ανάπτυξης της βλάβης ως μοντέλο συμπεριφοράς του υλικού. Η προσέγγιση που έχει επιλεγεί για τη μελέτη της υγροθερμικής γήρανσης των συνθέτων υλικών περιλαμβάνει την υποβάθμιση των μηχανικών ιδιοτήτων και της τάσης αστοχίας του υλικού ως συνάρτηση της θερμοκρασίας και του χρόνου έκθεσης και με τον τρόπο αυτό εισάγει μια μεθοδολογία πρόβλεψης χρόνου ζωής της κατασκευής (Life Prediction Methodology). Όμως την ίδια στιγμή επειδή τα φορτία επάγονται στην κατασκευή από τη ροή του αέρα εντός της κατασκευής και τις στηρίξεις και η απορροφούμενη υγρασία μεταβάλλει τη γεωμετρία της κατασκευής και την τραχύτητα της επιφάνειας του σύνθετοιυ υλικού τα επαγόμενα φορτία μεταβάλλονται επί το δυσμενέστερο. Παράλληλα μεταβάλλεται και το θερμοκρασιακό πεδίο στο οποίο εκτίθενται η κατασκευή. Επομένως στο πλαίσιο της παρούσας Διδακτορικής Διατριβής έχει μελετηθεί η υγροθερμική γήρανση των συνθέτων υλικών, αλλά το επιλυόμενο πρόβλημα κατά την εφαρμογή της προτεινόμενης μεθοδολογίας λαμβάνει υπόψη του τη μεταβολή των μηχανικών και θερμικών φορτίων στα οποία εκτίθενται η κατασκευή κατά τη διάρκεια της λειτουργίας της σε συνθήκες υγροθερμικής γήρανσης. Προτείνεται ένα ολοκληρωμένο μοντέλο προσέγγισης της διάρκειας ζωής και της τελικής αστοχίας της κατασκευής με την εφαρμογή πρόβλεψης διάρκειας ζωής, που βασίζεται στην ανάλυση της κατασκευής, στο πλαίσιο των μεταβολών που έχουν περιγραφεί ανωτέρω.

Air conditioning systems for aeronautical applications: a review

2019 ◽  
Vol 124 (1274) ◽  
pp. 499-532
Author(s):  
M. Merzvinskas ◽  
C. Bringhenti ◽  
J.T. Tomita ◽  
C.R. de Andrade
Keyword(s):  
Air Conditioning ◽  
Environmental Control ◽  
Cooling Capacity ◽  
Vapor Compression ◽  
Water Separation ◽  
Technological Advances ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Air Conditioning Systems ◽  
Aircraft Conceptual Design

ABSTRACTThis paper presents a review of the various aeronautical air conditioning systems that are currently available and discusses possible system configurations in the context of the aeronautical environmental control systems. Descriptions of the standard vapor compression cycle and air cycles are provided. The latter includes, simple-cycle, bootstrap-cycle, simple-bootstrap cycle (3-wheel) and condensing cycle (4-wheel). Water separation and air recirculation systems are also explored. A comparison between vapor compression cycles and air cycles is provided, as well as a comparison between different air cycles. Air cycle units are far less efficient than vapor compression cycle units, but they are lighter and more reliable for an equivalent cooling capacity. Details regarding the aircraft conceptual design phase along with general criteria for the selection of an air conditioning system are provided. Additionally, industry trends and technological advances are examined. Conclusions are compiled to guide the systems engineer in the search for the most appropriate design for a particular application.

A Study on the Combined Driven Refrigeration Cycle Using Ejector

2021 ◽  
pp. 2150004
Author(s):  
Waseem Raza ◽  
Gwang Soo Ko ◽  
Youn Cheol Park
Keyword(s):  
Air Conditioning ◽  
Waste Heat ◽  
Primary Source ◽  
Mechanical Efficiency ◽  
Coefficient Of Performance ◽  
Cycle Performance ◽  
Working Fluid ◽  
Low Grade ◽  
Refrigeration Cycle ◽  
R 134A

The rising need for thermal comfort has resulted in a rapid increase in refrigeration systems’ usage and, subsequently, the need for electricity for air-conditioning systems. The ejector system can be driven by a free or affordable low-temperature heat source such as waste heat as the primary source of energy instead of electricity. Heat-driven ejector refrigeration systems become a promising solution for reducing energy consumption to conventional compressor-based refrigeration technologies. An air-conditioning system that uses the ejector achieves better performance in terms of energy-saving. This paper presents a study on the combined driven refrigeration cycle based on ejectors to maximize cycle performance. The experimental setup is designed to determine the coefficient of performance (COP) with ejector nozzle sizes 1.8, 3.6, and 5.4[Formula: see text]mm, respectively. In this system, the R-134a refrigerant is considered as a working fluid. The results depict that the efficiency is higher than that of the conventional refrigeration method due to comparing the performance of the conventional refrigeration cycle and the combined driven refrigeration cycle. The modified cycle efficiency is better than the vapor compression cycle below 0∘C, which implies sustainability at low temperatures by using low-grade thermal energy. For the improvement of mechanical efficiency, proposed cycle can be easily used.

Experimental analysis of the low-GWP refrigerant R1234yf as a drop-in replacement for R134a in a typical mobile air conditioning system

2012 ◽  
Vol 226 (11) ◽  
pp. 2713-2725 ◽  
Author(s):  
Yu Zhao ◽  
Zhaogang Qi ◽  
Jiangping Chen ◽  
Baixing Xu ◽  
Bin He
Keyword(s):  
Working Conditions ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Laminated Plate ◽  
Improve Performance ◽  
Air Conditioning System ◽  
Expansion Valve ◽  
Variable Displacement ◽  
Valve Opening

This study investigated the performance of a typical mobile air conditioning system using R134a and R1234yf as the working fluids under different working conditions. The system is composed of a microchannel parallel flow condenser, a laminated plate evaporator, a variable displacement compressor, and a thermal expansion valve. The different working cycles of each refrigerant were comprehensively compared. The optimum refrigerant charge amount of the R1234yf system was approximately 95% of the R134a system during drop-in tests. The performance of the R134a system was a little higher than that of the R1234yf system. The cooling capacity and system coefficient of performance of the R134a system were 12.4% and 9% larger, respectively. This result is mainly because of the thermophysical property differences between the two refrigerants and the improper expansion valve opening of R1234yf. Analysis on the whole cycle revealed that the R1234yf system could obtain a higher evaporating pressure and a larger superheat and subcooling. Redesigning the expansion valve for R1234yf could improve performance of the system.

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