096280319013,9010,9020,9032, 9046

GUIDED BY: P.H.PATEL(LME)

INTRODUCTION TO REFRIGERATION INDUSTRY

WORKING OF WATERCOOLER LITERATURE REVIEW REFRIGERATION FUNDAMENTALS EXPERIMENTAL INVESTIGATION CONCLUSION REFRENCES WORKPLAN

The scope of refrigeration is far-reaching.

APPLICATION OF REFRIGERATION: Food processing, preservation and

distribution. Plays a key role in the healthcare sector:

safe vaccine storage, cryosurgery and cryo therapy have been made possible by the advent of advanced refrigeration;

Promotes economic and social development in hot countries thanks to air conditioning

Is used in industrial processes in the food, chemical, plastics and many other industries;

Enables liquid natural gas, an environmentally friendly source of energy, to be transported and stored;

Enables superconductivity to be applied in the medical field and other important applications.

Water cooler works on VCRC:

Refrigeration is the science of producing and maintaining temperatures below that of the surrounding atmosphere

Concept of refrigerator:

cop = Q/W

Simple Vapour Compression Cycle :In a simple vapour compression system fundamental processes are completed in one cycle.

These are :1. Compression. 2. Condensation.

3. Expansion. 4. Vaporization.

Vapor compression refrigeration cycle(VCRC).

P-h CHART OF VCRC Process 1-2: Heat absorbed in evaporator Qre = m (h2-h1)

(constant pressure heat addition process) Process 2-3: Work supplied to the compressor Wcomp = m (h2-h3) (adiabatic compressor) Process 3-4 : Heat rejected by condenser Qcond = m (h3-h4) Process 4-1: Throttling process h4=h1

WHY ARE CFCS TO BE REPLACED? CFCs (chlorofluorocarbons) such as CFC-12

and CFC-11, deplete ozone in the stratosphere. Ozone depletion is serious because it increases the amount of ultra violet (UV) light that reaches the earth’s surface

This increases the incidence of skin cancer and eye cataracts for humans and reduces crop yields. Increased exposure to UV radiation is harmful to all forms of life.

Higher GWP Of CFC AND HCFC Refrigerants.

THE MONTREAL PROTOCOL The Montreal Protocol is an international

agreement (signed at Montreal, Canada), which proposes a specific phase-out schedule for Ozone Depleting Substances (ODSs). The Protocol came into being in 1992, and more than 173 countries are currently its signatories. ODS includes CFCs and other substances, Halons, HBFCs etc

In the developing countries like India, CFC-12 and CFC-11 refrigerants will have to be phased out by 1st January 2010. However, HCFC-22 used as a refrigerant in air-conditioners, can be phased out by 1st January 2040

Production and consumption of CFCs in developing countries must stop by the year 2010

There are several refrigerants that can be used to replace CFCs as refrigerants. These fall into two main categories:

1. Hydro fluorocarbons (HFCs). 2. Hydrocarbons (HCs);

PROPERTIES OF CFC, HFC AND HC REFRIGERANTS

HYDROCARBON REFRIGERANTS: HC-600a is pure iso-butane and has a boiling

point of -12°C at atmospheric pressure; HC-600a is widely used in domestic refrigerators in many countries, especially China, Indian and in Europe. Its refrigerating capacity per unit volume is low (about 60% of that of CFC-12). The compressor has a higher displacement.

A blend (50% each by weight) of Propane / iso-butane (e.g. Care 30, ECFC-12,) has a boiling point of about -31°C at atmospheric pressure.The propane / iso-butane blend

Weight of hydrocarbon blend = 0.45 x weight of HFC-134a.

After completing shodh yatra and reviewing all literatures it is being decided to charge water cooler in our thermal engineering lab which is working on R-134a with mixture of isobutene-propane mixture (50%-50% by weight.) and study the performance of the water cooler.

TECHNICAL PARAMETERS OF WATER COOLER CHARGED WITH HC AS REFIRGERANT

Charging pressure : 76 PSI gauge. : 5.17 bar + 1.01325

bar : 6.18325 bar

Suction pressure :1.9 bar Discharge pressure :8.5 bar Current drawn by compressor :1.94 Amp Volts: 254V

Water cooler working with HC as refrigerant is used to cool 19.5L of water at the initial temperature of 23.0C

CALCULATION FOR ACTUAL COP OF WATER COOLER:

Wcomp =Work supplied to compressor = V*I * cosφ = 254 * 1.94 * 0.85 = 0.42 kw

Qre = Heat absorb in Evaporator = m*Cp*Δt/ Time= 19.5 * 4.18 * (23.0-8.1)/22*60= 0.92 kw

Actual COP = Qre/Wcomp

= 2.19

TECHNICAL PARAMETERS OF WATER COOLER CHARGED WITH R134a AS REFIRGERANT:

Charging pressure: 76 PSI gauge. : 5.17 bar + 1.01325

bar : 6.18325 bar Suction pressure :1.7 bar Discharge pressure :9.1 bar Current drawn by compre:1.84Amp Volts: 255V

Water cooler working with R134a as refrigerant is used to cool 19.5L of water at the initial temperature of 23.0C

 

CALCULATION FOR ACTUAL COP OF WATER COOLER:

Wcomp =Work supplied to compressor = V*I * cosφ = 255 * 1.84 * 0.85 = 0.398 kw

Qre = Heat absorb in Evaporator = m*Cp*Δt/ Time= 19.5 * 4.18 * (23.0-7.9)/ 22*60= 0.93 kw

Actual COP = Qre/Wcomp

= 2.34

A water cooler of thermal engineering Lab at G.P.Vadnagar is experimentally investigated by using two different type of refrigerant one is R134a and other is HC. Charging pressure of both the refrigerant is 6.2 bar. From the experiment it is found that actual COP of water cooler charged with R134a and HC is 2.34 and 2.19 respectively. COP of water cooler charged with R134a is slightly higher (6% more) then water cooler charged with HC but R134a has GWP equals to 1300 while HC has GWP as 3. Both the refrigerants have zero ODP. HC is less efficient but more eco friendly refrigerant compare to R134a and can be used to replace R134a in future.