what is the meaning of refrigerant ?

 A refrigerant is a medium of heat transfer through phase change such as evaporation at low temperature and pressure, of course with some exceptions where the sensible energy transfer occurs. There are many substances which are used in refrigeration system for energy transfer purposes. In view of easy specification of refrigerants and their choice for a particular system, the nomenclature and the comparative study are presented elaborately in order to reveal as to which Of the refrigerants will serve the best compromise.

Before invention of CFCs refrigerants, flammable, toxic or both, and some also highly reactive refrigerants were commonly used. Hence accidents were common. Propane was marketed as "the odorless safe refrigerant". In addition to above other used as refrigerants* are ammonia, carbon dioxide, air, sulphur- dioxide, methyl chloride (CH3Cl), ether, etc. The safer and better refrigerant R- 12 replaced methyl chloride or sulphur dioxide being extensible used in refrigerators in the t. Some of the refrigerants, which were common used and are now getting replaced are presented in used are shown in table 9.1. However, after Montreal Protocol due to ozone depletion by CFCs now getting replaced by the ozone friendly refrigerants. But the global warming impact of refrigerating system results partly from the refrigerant itself due to leaking from the system or escaping of refrigerant during servicing (direct effect). In addition there is indirect global warming due to the emission of C02 when power is generated to run the cycle and the energy used for manufacturing the refrigerant.

* However, despite the invention of CFCs refrigerants ammonia remained a popular refrigerant due to very cheap and many good thermodynamic properties. Even, the undersible properties such as noxious, flammable and irritating did not come in its way of popular use. 

 

 

However, these days these refrigerants are also under replacement. However ammonia an ever green refrigerant is still popular due to its both ODP and GWP as zero. The substitute for R-12 and R-22 is R-134a and for R-11 it is R-123. Carbondixoide is also becoming as an active refrigerant for automobile for re- placement of R-12. But the whole system has to be light. In refrigerators the hydrocarbons like propane for replacement of R-12 and R-22. Propylene has got acceptance for replacement of R- 12, R-22 and R-502.

★ABOUT THE BOOK:

The respected text delivers a comprehensive introduction to the principles and practice of refrigeration. Clear and straightforward, it is designed for students (NVQ/vocational level) and professional HVAC engineers, including those on short or CPD courses. Inexperienced readers are provided with a comprehensive introduction to the fundamentals of the technology. With its concise style yet broad sweep the book covers most of the applications professionals will encounter, enabling them to understand, specify, commission, use and maintain these systems. Many readers will appreciate the clarity with which the book covers the subject without swamping them with detailed technical or product specific information. New material in this edition includes the latest developments in refrigerants and lubricants, together with updated information on compressors, heat exchanges, liquid chillers, electronic expansion valves, controls and cold storage.

★RECOMMENDATIONS:
A textbook for all Engineering. Branches, Competitive Examination, ICS, and AMIE Examinations In S.I Units For Degree, Diploma and A.I.M.E. (India) Students and Practicing Civil Engineers.

• Language : English
• Paperback : 837 pages

★ABOUT THE BOOK:

“A Textbook of Refrigeration and Air Conditioning” is an aptly written textbooks for the students of Mechanical Engineering while also a must-read for anyone with an interest in the subject.
For 30 years, topics such as Air Refrigeration Cycles and Systems, Vapour Compression Refrigeration Systems (Simple and Compound), Refrigerants (incl. Compressors), Psychrometry and Applications of Refrigeration and Air Conditioning have been included and updated for students to conceptualise the subject in a complete manner. The chapters consist of various exercises, examples, and multiple illustrations that aid in understanding the subject better.

Key Features:

• Every concept has been treated individually and then linked within the chapter to provide not only information but also insight.
• Close to 800 examples, figures, tables and pictorial depictions aid to the concepts explained.
• More than 500 chapter-end (objective and subjective) and exercise questions add to the practice of the students.

Table of Content :

• Introduction
• Air Refrigeration Cycles
• Air Refrigeration Systems
• Simple Vapour Compression Refrigeration Systems
• Compound Vapour Compression Refrigeration Systems
• Multiple Evaporator and Compressor Systems
• Vapour Absorption Refrigeration Systems
• Refrigerants
• Refrigerant Compressors
• Condensers
• Evaporators
• Expansion Devices
• Food Preservation
• Low Temperature Refrigeration (Cryogenics)
• Steam Jet Refrigeration System
• Psychrometry
• Comfort Conditions
• Air Conditioning Systems
• Cooling Load Estimation
• Ducts
• Fans
• Applications of Refrigeration and Air Conditioning

• Language : English
• Paperback : 720 pages

About the Author

R.S Khurmi: He was born on 29 Aug 1939 in Sunam, a small town in Punjab. He completed his schooling in Sunam and then he completed his professional studies from Phagwara and Delhi. He started his career in Punjab Irrigation Department as an Engineer. After guidance from Professor Das of Chandigarh Engineering College, Dr. Khurmi came to Delhi and took up Teaching and Writing Engineering Text Books as a full time career. He had a great respect for his Guru Shri B.L. Theraja, who introduced him to S. Chand and Company. His books got a good market, not only in India but also abroad. According to the survey of UNESCO, he is the leading and No. 1 author of Engineering textbooks in Asia. He wrote his first book when he was just 26 years old. People in teaching profession always referred that Khurmi has revolutionized the way of writing Engineering Text Books. He was one of the founder members in Executive Committee of Afro-Asia Book Council.

★ABOUT THE BOOK:

This book contains exhaustive collection of more than 5000+ MCQs with solution explained in easy language for engineering students of Mechanical Engineering. In addition, the questions have been selected from various competitive exams to give the students an understanding of various types of exams. This book is essential to candidates appearing for U.P.S.C. (Engineering & Civil Services), State and Central Level Services Exams: Assistant Engineer /Junior Engineer, SSC-JE, PWD-JE,PHED-JE, DDA-JE, SDO, DRDO, ISRO, RRB-JE, PSUs Exams ( BARC, BEL,BBNL , BHEL,BPCL, BHPCL,DDA, DMRC, Coal India ,HPCL , HPVN, IOCL, NTPC, BPCL, OIL, NHPC, GAIL, BHEL, MECL, MDL, NLC and Metro Exams Like : DMRC, LMRC, NMRC, JMRC, BMRC, HMLR,KMRR,MMRR,PMRR , Rural Development and Panchayati Raj department and Admission/Recruitment Test and other Technical Exams in Mechanical Engineering.

★ABOUT THE BOOK:

Ssc: JE exam is conducted every year and is a preferred career choice of engineers. Ssc- JE: objective previous year solved papers: Mechanical Engineering is designed to help aspiring engineers to strengthen their grasp and understanding of the concepts of the subject. This book is also useful for the preparation of rrb-je (cbt-2). the title covers the Reasoning and Aptitude and objective part for Paper – I and of the exam. All the questions are bifurcated topic wise and are fully explained. The book has been thoroughly revised and updated with papers from 2007-2019.

★ABOUT THE BOOK:

Me editorial Board4400 MCQs: Mechanical Engineering - Practice book for ESE, GATE and psusmade easy publications English4400 MCQs: Mechanical Engineering - Practice book for ESE, GATE and plus.