Basic Refrigeration System

Koya UniversityFaulty of Engineering

School of Chemical & Petroleum EngineeringChemical Engineering department

EXPERIMENT NUMBER SIX 

Thermodynamics

Basic Refrigeration System

Instructor: Mr.Rebwar & Mr.OmerExperiment Contacted on: 6/5/2014

Report Submitted on: 13/5/2014Group:A

BY:Aree Salah

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List of content:

Aim of this experiment: ………………………3

Introduction: ………………………..…………….4

Theory: ……………………………..………………..5

Technical Description: ……………………..….6

Instructions for use: ……………………………7

Table of Calculation:-……………………8 , 9 , 10

Discussion: ………………………….……..11 , 12

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Reference: ………………………………………..13

Aim of this experiment:

To assess the performance of the vapor compression cycle as a refrigerator and as a heat pump and its dependence on various parameters. To learn how to use the equipment to measure temperatures at various test points and the flow rates for liquids and gases.

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Introduction:

Refrigeration is the process of removing heat from an enclosed space, or from a substance, and moving it to a place where it is unobjectionable. The primary purpose of refrigeration is lowering the temperature of the enclosed space or substance and then maintaining that lower temperature. This book reviews research on refrigeration including an overview of up-to-date developments and technology in the field of magnetic refrigeration at room temperature (RTMR); an alternative approach based on artificial neural networks (ANNs) to determine thermodynamic properties of refrigerants; solar powered sorption refrigeration and air conditioning; the modelling of chilling and freezing processes and others.

{1}

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Theory:

One important application of the thermodynamic cycles is refrigeration. The transfer of heat from a higher temperature to a lower one is a natural phenomenon, but the unnatural reverse process happens in refrigeration cycles. The devices that produce refrigeration are called refrigerators and the working fluids are called refrigerants.

{2}

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Technical Description:

The system contains all of the components found in a normal household refrigerator. The fully functional refrigeration compartment is able to cool food or drinks. The individual components are clearly laid out in an open housing. Sight glasses in all sections of the refrigerant circuit enable the refrigerant and its physical state to be observed. The refrigerator uses a CFC-free refrigerant. {3}

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Instructions for use :

7

23456

8

1

7891011

1. Thermostat 2. Main Switch3. Lock4. Evaporator5. Capillary tube6. Filter7. Piston compressor8. Manometer

9 .Filler valve

10 .Condenser

11 .Refrigerant sight glass

Table of Calculation-:

1-B y chart

Table of Calculation-:

2-By table

H1 = Hg

H2 = Super heated

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Point Pressure(kpa)

Temperature( C)

Enthalpy (h)

1140 -20 470

2 800 50 570

3 800 110 336

4 140 42 336

H3 = H (fluid)

Point Pressure(kpa)

Temperature(c)

Enthalpy (h)

1140 - 20 239.16

2 800 50 286.96

3 800 31.31 95.47

4 140 - 18.77 95.47

H4 = H(fluid) .. because we have a (valve )

CALCULATION OF (COP ) FOR REFRIGERANT & HEAT PUMP

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1-B y chart 2-By table

1-a-cop (r )=h1−h4h2−h1 =

470−336570−470 = 1.33

b-cop (h)=h2−h3h2−h1 =

570−336570−470 = 2.34

2-a-cop (r )=h1−h4h2−h1 =

239.16−95.47286.96−239.16 =3

b- cop (h)=h2−h3h2−h1 =

286,96−95.47286.96−239.16 = 4

Discussion:

By Aree Salah

Are there any safety considerations for new refrigerants in chillers?

EPA believes that adherence to Standard 15 of the American Society of

Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) will ensure

the safety of technicians and building occupants. This standard applies to

the use of all alternative refrigerants. In addition, systems designed and

operated in accordance with ASHRAE Standard 3 will leak minimal

amounts of refrigerant, thereby reducing ozone depletion and global

warming impacts.

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2/ what is meant by refrigeration?

It is the process of reducing the temperature of an object from the

normal surrounding temperature in a controlled way in order to cool

them.

3/ Give some of the applications of refrigeration.

i. The making of ice.

ii. The Air-conditioning of industries.

iii. The metal manufacturing and their treatment.

4/ Can I put a refrigerator in my garage?

Yes. However, if you live in a region in which the temperatures drop below 50 degrees Fahrenheit (10 degrees Celsius), this is not a good idea. Such temperatures could cause the oil in the compressor to thicken, leading to premature compressor failure or other issues. Also, refrigerator/freezer units often won’t keep food frozen when the temperature of the garage drops below 35 degrees Fahrenheit (1.6 Celsius).

5/ what causes refrigerator burn? And is it safe?

Freezer burn is a common problem caused by food packaging. Food dehydrates due to exposure to the air in the freezer. Standard supermarket packaging for many foods is not designed to prevent dehydration. If you intend to store food in your freezer for more than a few days, you should place the food in airtight containers or zippered plastic bags specifically made for food preservation and freezer storage. It is absolutely safe to cook or eat freezer-burned food. However, most people find that the dehydration process destroys the food’s taste and texture. Dehydrated meat is said to be tough and tasteless after cooking.

6/ how cold should my refrigerator be?

Your refrigerator’s thermostat should be set to 36 to 38 degrees Fahrenheit (approximately two degrees Celsius) and your freezer’s thermostat from 0 to 5 degrees Fahrenheit (-18 degrees Celsius).

7/ is it easy to add an ice maker to my refrigerator?

Yes, if your freezer has the necessary internal wiring (most do), this is a do-it-yourself project

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Reference:

1:

https://www.novapublishers.com/catalog/product_info.php?products_id=12008

2:

http://refrigerationcycleexperiment.blogspot.com/2007/03/theory.html

3:

http://www.selkagmbh.com/product_info.php?pName=basic-refrigeration-system-p-1159

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