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What is suction pressure required of refrigerant 404a in cold storage ?

Self study to make a future July 21, 2023 No comments Edit

The suction pressure required for a refrigerant like R-404A in a cold storage system depends on various factors, including the desired temperature inside the cold storage and the specific design and operating conditions of the refrigeration system.

R-404A is a blend of refrigerants commonly used in low-temperature applications, including cold storage and freezer systems. It is known for its low-temperature capabilities and is widely used as a replacement for older refrigerants that are harmful to the ozone layer, such as R-502.

To maintain the desired temperature inside the cold storage, the suction pressure (also known as evaporator pressure) should be set based on the refrigerant's temperature-pressure relationship. As the refrigerant evaporates in the evaporator, it absorbs heat from the cold storage space, cooling it down. The evaporator pressure needs to be carefully controlled to achieve the desired storage temperature.

The specific suction pressure required for R-404A in a cold storage application will depend on factors like:

1. Cold Storage Temperature: The desired temperature inside the cold storage will determine the corresponding evaporation (suction) temperature for R-404A.

2. Cold Storage Load: The amount of heat that needs to be removed from the cold storage space per unit time (cooling load) will affect the evaporator pressure.

3. Evaporator Design: The size, type, and efficiency of the evaporator used in the system will influence the required suction pressure.

4. Superheat and Subcooling: Proper control of superheat (the temperature rise above the refrigerant's saturation temperature at the evaporator outlet) and subcooling (the temperature drop below the refrigerant's saturation temperature at the condenser outlet) is essential for efficient and stable operation.

5. Compressor Performance: The compressor used in the system must match the refrigeration load and have the capacity to handle the required suction pressure.

6. Ambient Temperature: The ambient temperature surrounding the refrigeration system can impact its overall performance.

Due to these and other factors, it is essential to consult with a qualified refrigeration engineer or technician who can evaluate the specific cold storage system's requirements and determine the appropriate suction pressure for the R-404A refrigerant in that particular application. Proper system design and maintenance are crucial to ensuring efficient and reliable operation in a cold storage environment.

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Open Air Refrigeration Cycle

Self study to make a future May 25, 2021 No comments Edit

Open Air Refrigeration Cycle

In an open air refrigeration cycle, the air is directly led to the space to be cooled allowed to circulate through the cooler and then returned to the compressor to start another cycle. Since the air is supplied to the refrigerator at atmospheric pressure, therefore, volume of air handled by the compressor and expander is large. Thus the size of compressor and expander should be large. Another disadvantage of the open cycle system is that the moisture is regularly carried away by the air circulated through the cooled space. This leads to the formation of frost at the end of expansion process and clog the line. Thus in an open cycle system. a drier should be used.

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Rs khurmi

Refrigeration and air conditioning

Air refrigeration Cycle

Self study to make a future May 24, 2021 6 comments Edit

Introduction

In an air refrigeration cycle, the air is used as a refrigerant. In olden days, air was widely used in commercial applications because of its availability at free of cost. Since air does not change its phase i.e. remains gaseous throughout the cycle. therefore the heat carrying capacity per kg of air is very small as compared to vapour absorbing systems. The air-cycle refrigeration systems, as originally designed and installed. are now practically obsolete because of their low coefficient of performance and high power requirements. However. this system continues to be favoured for air refrigeration because of the low weight and volume of the equipment. The basic elements of an air cycle refrigeration system are the compressor, the cooler or heat exchanger, the expander and the refrigerator. Before discussing the air refrigeration cycles, we should first know about the unit of refrigeration, coefficient of performance of a refrigerator and the difference between the heat engine, a refrigerator and a heat pump.

Units of Refrigeration

The practical unit of refrigeration is expressed in terms of 'Tonne of refrigeration'.
A tonne of refrigeration is defined as the amount of refrigeration effect produced by uniform melting of one tonne (1000 Kg) of ice from and at 0° in 24 hours.

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India

Rs Khurmi

United States

Modern Refrigeration and Air Conditioning

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Refrigerants

Self study to make a future May 24, 2021 No comments Edit

Introduction

The refrigerant is a heat carrying medium which during their cycle (i.e. compression. condensation. expansion and evaporation) in the refrigeration system absorbs heat from a low temperature system and discards the heat so absorbed to a higher temperature system. The natural ice and a mixture of ice and salt were the first refrigerants. In 1834. ether. ammonia. sulphur dioxide. methyl chloride and carbon dioxide came into use as refrigerants in compression cycle refrigeration machines. Most of the early refrigerant materials have been discarded for safety reasons or for lack of chemical or thermal stability. In the present days. many new

refrigerants including halo-carbon compounds. hydro-carbon compounds are used for air-conditioning and refrigeration applications. The suitability of a refrigerant for a certain application is determined by its physical. thermodynamic. chemical properties and by various practical factors. There is no one refrigerant which can be used for all types of applications i.e. there is no ideal refrigerant. If one refrigerant has certain good advantages. it will have some disadvantages also. Hence. a refrigerant is chosen which has greater advantages and less disadvantages.

Desirable Properties of an Ideal Refrigerant

We have discussed above that there is no ideal refrigerant. A refrigerant is said to be ideal if it has all of the following properties :

1.Low boiling and freezing point.

2.High critical pressure and temperature.

3.High latent heat of vaporisation.

4.Low specific heat of liquid. and high specific heat of vapour.

5.Low specific volume Of vapour.

6.High thermal conductivity.

7.Non-corrosive to metal.

8.Non-flammable and non-explosive.

9.Non-toxic,

10.Low cost.

11.Easily and regularly available.

12. Easy to liquify at moderate pressure and temperature—

13. Easy of locating leaks by odour or suitable indicator

14. Mixes well with oil.

15. High coefficient performance.

16. Ozone friendly

Classification of Refrigerants

The refrigerants may. broadly. be classified into the following two groups :

l. Primary refrigerants. and 2. Secondary refrigerants.

The refrigerants which directly take part in the refrigeration system are called primary whereas the refrigerants which are first cooled by primary refrigerants and then used for cooling purposes are known as secondary refrigerants.

The primary refrigerants are further classified into the following four groups .

l. Halo-carbon or organic refrigerants.

2. Azeotrope refrigerants.

3. Inorganic refrigerants. and

4. Hydro-carbon refrigerants.

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Rs Khurmi

Modern Refrigeration and Air Conditioning

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What is the full form of LPG refrigeration cooler?

Self study to make a future May 18, 2021 2 comments Edit

Liquefied petroleum gas

Liquefied Petroleum Gas is combination of Propane (C3H8) and Butane (C4H10). LPG is used as a fuel for domestic purpose, drying can industrial, LPG be horticultural, to agricultural, another cooking, heating fuel.

PROPERTIES OF LPG

 Colorless.
 Flammable.
 Heavier than air.
 Approximately half the weight of water.
 Nontoxic but can cause asphyxiation.
 A good mixture:
 Boiling Point:

WORKING

This work replaces the conventional refrigerant by LPG as a cooling medium in a refrigerator. It works on the principle that during the change of LPG from liquid into gaseous form, expansion of LPG takes place. Due to this expansion pressure drop occurs and increase in volume of LPG. It results in the drop of temperature and a refrigerating effect is produced and it is used for cooling purposes. In this refrigeration system the high pressure LPG is passed through capillary tube and it expands, after expansion the phase change occurs and it convert from liquid to gas. Then it passes through the evaporator where it absorbs the latent heat of the stored product and produces the refrigerating effect.

Psychrometric chart

Self study to make a future April 08, 2021 No comments Edit

Psychrometric chart

A Psychometric chart graphically represents the thermodynamic properties of moist air. Standard psychometric charts are bounded by the dry-bulb temperature line (abscissa) and the vapour pressure or humidity ratio (ordinate). The Left Hand Side of the psychometric chart is bounded by the saturation line. Figure 27.2 shows the schematic of a psychometric chart. Psychometric charts are readily available for standard barometric pressure of 101.325 kPa at sea level and for normal temperatures (0-500C). ASHRAE has also developed psychometric charts for other temperatures and barometric pressures (for low temperatures: - 40 to 100C, high temperatures 10 to 1200C and very high temperatures 100 to 1200C)

Measurement of psychrometric properties:

Based on Gibbs' phase rule, the thermodynamic state of moist air is fixed if the barometric pressure and two other independent properties are known. This means that at a given barometric pressure, the state of moist air can be determined by measuring any two independent properties. One of them could be the dry-bulb temperature (DBT), as the measurement of this temperature is fairly simple and accurate. The accurate measurement of other independent parameters such as humidity ratio is very difficult in practice. Since measurement of temperatures is easier, it would be convenient if the other independent parameter is also a temperature. Of course, this could be the dew-point temperature (DPT), but it is observed that accurate measurement of dew-point temperature is difficult. In this context, a new independent temperature parameter called the wet-bulb temperature (WBT) is defined. Compared to DIYF, it is easier to measure the wet-bulb temperature of moist air. Thus knowing the dry-bulb and wet-bulb temperatures from measurements, it is possible to find the other properties of moist air.

Introduction to air conditioning

Self study to make a future March 25, 2021 2 comments Edit

Introduction to Air Conditioning

Atmospheric air makes up the environment in almost every type of air conditioning system. Hence a thorough understanding of the properties of atmospheric air and the ability to analyze various processes involving air is fundamental to air conditioning design.

Psychrometry is the study of the properties of mixtures of air and water vapour. Atmospheric air is a mixture of many gases plus water vapour and a number of pollutants. The amount of water vapour and pollutants vary from place to place. The concentration of water vapour and pollutants decrease with altitude, and above an altitude of about 10 km, atmospheric air consists of only dry air. The pollutants have to be filtered out before processing the air. Hence, what we process is essentially a mixture of various gases that constitute air and water vapour. This mixture is known as moist air. The moist air can be thought of as a mixture of dry air and moisture. For all practical purposes, the composition of dry air can be considered as constant. In 1949, a standard composition of dry air was fixed by the International Joint Committee on Psychrometric data. It is given in .

Table 4.1: Composition of standard air

Based on the above composition the molecular weight of dry air is found to be 28.966 and the gas constant R is 287.035 J/kg.K. As mentioned before the air to be processed in air conditioning systems is a mixture of dry air and water vapour. While the composition of dry air is constant, the amount of water vapour present in the air may vary from zero to a maximum depending upon the temperature and pressure of the mixture (dry air + water vapour). At a given temperature and pressure the dry air can only hold a certain maximum amount of moisture. When the moisture content is maximum, then the air is known as saturated air, which is established by a neutral equilibrium between the moist air and the liquid or solid phases of water.

For calculation purposes, the molecular weight of water vapour is taken as 18.015 and its gas

constant is 461 •Ä

Dry bulb temperature (DBT) is the temperature of the moist air as measured by a standard thermometer or other temperature measuring instruments. Saturated vapour pressure (psat) is the saturated partial pressure of water vapour at the dry bulb temperature. This is readily available in thermodynamic tables and charts. ASHRA Esuggests the following regression equation for saturated vapour pressure of water, which is valid for O to 1000C.

Relative humidity is defined as the ratio of the mole fraction of water vapour in moist air to mole fraction of water vapour in saturated air at the same temperature and pressure. Relative humidity is normally expressed as a percentage. When is 100 percent, the air is saturated.

Humidity ratio (W): The humidity ratio (or specific humidity) W is the mass of water associated with each kilogram of dry air l. Assuming both water vapour and dry air to be perfect gases .

For a given barometric pressure pt. given the DBT, we can find the saturated vapour pressure Psat from the thermodynamic property tables on steam. Then using the above equation, we can find the humidity ratio at saturated conditions, Wsat.

It is to be noted that, W is a function of both total barometric pressure and vapor pressure of water.

Dew-point temperature: If unsaturated moist air is cooled at constant pressure, then the temperature at which the moisture in the air begins to condense is known as dew-point temperature (DPT) of air. An approximate equation for dew-point temperature is given by:

Degree of saturation : The degree of saturation is the ratio of the humidity ratio W to the humidity ratio of a saturated mixture Ws at the same temperature and pressure,

Enthalpy: The enthalpy of moist air is the sum of the enthalpy of the dry air and the enthalpy of the water vapour. Enthalpy values are always based on some reference value. For moist air, the enthalpy of dry air is given a zero value at OOC, and for water vapour the enthalpy of saturated water is taken as zero at OOC.

Since the second term in the above equation (W.Cpw) is very small compared to the first term, for all practical purposes, the humid specific heat of moist air, cpm can be taken as 1.0216 kJ/kg dry air.K

Specific volume: The specific volume is defined as the number of cubic meters of moist air p kilogram of dry air. From perfect gas equation since the volumes occupied by the individual substance are the same, the specific volume is also equal to the number of cubic meters of dry air per kilogram o dry air .

what is the meaning of refrigerant ?

Self study to make a future March 08, 2021 1 comment Edit

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.

Steam jet refrigeration system

Self study to make a future March 03, 2021 2 comments Edit

                                           Steam jet refrigeration system

This system uses the principle of boiling the water below 100 C. If the pressure on the surface of the water is reduced below atmospheric pressure, water can be made boil at low temperatures. Water boils at 6 WIG the pressure on the surface is 5 cm of Hg and at 10 when the pressure is 6.5 cms of Hg. The very low pressure or high vacuum on the surface of the water can be maintained by throttling the steam through jets or nozzles. The general arrangement of the system is shown in the Fig.6.8 Consider a flash chamber contains 100 kg of water. If suddenly I kg of water is removed by boiling, as pressure is reduced due to throttling of steam through nozzles. Approximately 2385 kJ of heat will be removed from the water, which is equivalent to heat of evaporation of water. The fall in temperature of the remaining water will be

Evaporating one more kg of water reduces the remaining water temperature by 5.7 C
further. Thus by continuing this process, the remaining water can be made to freeze. Water is the
refrigerant used in the steam jet refrigeration system. As water freezes at
O C, then either refrigeration has to be stopped or some device is required to pump the
ice.

★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.

★ABOUT THE BOOK:

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

★ABOUT THE BOOK:

Review of Thermodynamics heat transfer reversed carnot cycle gas cycle Refrigeration simple vapour compression Refrigeration system properties of common refrigerants Compound vapour compression system multiple evaporator ; compressor system refrigerants compressors condenser expansion devices evaporator matching components in vapour compression system installation vapour compression Refrigeration system multiple
Unit installation Absorption Refrigeration steam jet Refrigeration cascade Refrigeration systems ; low temperature Refrigeration thermal insulation Psychrometry building survey ; heat load estimate applied Psychrometry (advanced) human comfort evaporative air Conditioning moisture transfer pressure losses and duct sizing ventilation systems air-conditioning systems ; applications all air-systems
fans food preservation indoor air quality refrigerant tables ; charts.

Lithium Bromide Absorption Refrigeration System

Self study to make a future March 03, 2021 No comments Edit

The lithium-bromide absorption refrigeration system uses a solution of lithium bromide in water. In this system, the *water is being used as a refrigerant whereas lithium bromide, which is a highly hydroscopic salt, as an absorbent. The lithium bromide solution has a strong affinity for water vapour because of its very low vapour pressure. Since lithium bromide solution is corrosive, therefore inhibitors should be added in order to protect the metal parts of the system against corrosion. for air conditioning in which low refrigeration temperatures (not below 00 C)** are required.

Fig. 3.4 shows a lithium bromide vapour absorption system. In this system. the absorber and the evaporator are placed in one shell which operates at the same low pressure of the system. The generator and condenser are placed in another shell which operates at the same high pressure of the system. The principle of operation of this system is discussed below :
The water for air-conditioning coils or process requirements is chilled as it is pumped through the chilled-water tubes in.the evaporator by giving up heat to the refrigerant water sprayed over the tubes. Since the pressure inside the evaporator is maintained very low, therefore, the refrigerant water evaporates. The water vapours thus formed will be absorbed by the strong lithium-bromide solution which is sprayed in the absorber. In absorbing the water vapour, the lithium bromide solution helps in maintaining very low pressure (high vacuum) needed in the evaporator, and the solution becomes weak. This weak solution is pumped by a pump to the generator where it is heated up by using steam or hot water in the heating coils. A portion of water is evaporated by the heat and the solution now becomes more strong. This strong solution is passed through the heat exchanger and then sprayed in the absorber as discussed above. The weak solution of lithium bromide from the absorber to the generator is also passed through the heat exchanger. This weak solution gets heat
from the strong solution in the heat exchanger, thus reducing the quantity of steam required to heat the weak solution in the generator.

Lithium-Bromide absorption refrigeration system.

The refrigerant water vapours formed in the generator due to heating of
solution are passed to the condenser where they are cooled and condensed by the cooling water flowing through the condenser water tubes. The cooling water for condensing is pumped from the cooling water pond or tower. This cooling water first enters the absorber where it takes away the heat of condensation and dilution. The condensate from the condenser is supplied to the evaporator to compensate the water vapour formed in the evaporator. The pressure reducing valve reduces the pressure of condensate from the condenser pressure to the evaporator pressure. The cooled water from the evaporator is pumped and sprayed in the evaporator in order to cool the water for air conditioning flowing through the chilled tubes. This completes the cycle.

Note: The pressure difference between the generator and the absorber and
the gravity due to the height difference of the two shells is utilised to create the pressure for the spray.

Refrigeration & air conditioning, Book

★ABOUT THE BOOK:

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

★ABOUT THE BOOK: