Essay: Manufacturing And Analysis Of Water Cooler Cum Refrigeration System

CHAPTER : 1
INTRODUCTION
 
Vapour-compression refrigeration is one of the many refrigeration cycles available for use. It has been and is the most widely used method for air-conditioning of large public buildings, offices, private residences, hotels, hospitals, theatres, restaurants and automobiles. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods and meats, refrigerated trucks and railroad cars, and a host of other commercial and industrial services. Oil refineries, petrochemical and chemical processing plants, and natural gas processing plants are among the many types of industrial plants that often utilize large vapour-compression refrigeration systems.
Refrigeration may be defined as lowering the temperature of an enclosed space by removing heat from that space and transferring it elsewhere. A device that performs this function may also be called a heat pump.
Simple Vapour Compressor Refrigerator Cycle:
A simple vapour compression refrigeration system consists of the following equipments: i) Compressor ii) Condenser iii) Expansion valve iv) Evaporator.
(Fig 1.1: Vapour Compression Refrigeration Plant-flow Diagram)
Basic Working Cycle Procedure:
Compression: The refrigerant being sucked to the compressor through the suction line. Afterward the refrigerant compressed into the compressor and the compressed refrigerant being discharged to the condenser unit through the discharge line.
Condensation: When the high pressure refrigerant vapour enters the condenser heat flows from condenser to cooling medium thus allowing vaporized refrigerant to return to liquid state.
Expansion: After condenser the liquid refrigerant is stored in the liquid receives until needed. From the receiver it passes through an expansion value where the pressure is reduced sufficiently to allow the vaporization of liquid at a low temperature of about — 10 degree centigrade.
Vaporization: The low pressure refrigerant vapour after expansion in the expansion valve enters the evaporator on refrigerated space where a considerable amount of heat is absorbed by it and refrigeration is furnished.
(Fig 1.2: Vapour Compression Refrigeration Temperature-entropy Diagram)
Unit of Refrigeration:
Domestic & commercial refrigerators may be rated in kJ/s, or Btu/h of cooling. One British thermal unit is equal to about 1055 Joules. It is the amount of energy needed to cool or heat one pound (0.453 kg) of water by 1 deg. Fahrenheit. Commercial refrigerators in the US are mostly rated in tons of refrigeration, but elsewhere in kW. One ton of refrigeration can freeze one short ton of water at 0 deg. C in 24 hours i.e. 2000 pounds of ice at 144 BTUs per pound (heat of fusion of water) = 288000 BTUs
288000/24 = 12000 BTUs/hr. or one ton of refrigeration.
 
Energy Analysis Of Refrigeration:
Consider a boundary enclosing a space in which a refrigerator is placed. It is clear that some heat q2 is given out at temperature higher than the surroundings. It is also clear that the foodstuff placed inside the refrigerator is cooled by giving out their heat to the refrigerator which in turn, so to say, absorbs heat q1, of course at lower temperature than the surroundings. Every refrigerator is supplied with energy wither in the form of heat or electricity, that is, some work (w) is provided to it. The refrigerating device, thus is absorbing heat at lower temperature and giving out at higher temperature; this is usually not possible in our day to day life, since heat cannot flow from lower to higher temperature, but in case of a refrigerator this is achieved at the cost of energy supplied to it. For the boundary total heat given out (q2) is equal to the total energy input in the form of heat absorbed (q1) and the work absorbed (w) Balancing them.
For a refrigerator device, we are interested in how much heat is extracted from food stuff and how little electrical energy we spend, minimizing our power bill. The ratio of heat absorbed to the work input in the form of electric energy (w) is called coefficient of performance (COP). The ratio should be as high as possible.
COP=Q1/W
COP=Q1/(Q1-Q2)
Theoretical COP is ratio of theoretical refrigerating effect (N), found from pressure heat content chart or temperature -entropy chart to the theoretical compressor work (W) or isentropic compressor work, found from the chart.
Actual COP is the ratio of actual cooling effect, to the actual energy supplied to the compressor known from watt-hour reading. Relative COP is the ratio of actual to the theoretical COP. It is a pure number without any unit.
 
1.3 Domestic Refrigerator:
Most domestic refrigerators are of two types—either a single door fresh food refrigerator or a two-door refrigerator-freezer combination, with the freezer compartment on the top portion of the cabinet, or a vertically split cabinet (side-by-side), with the freezer compartment on the left side of the cabinet. They are completely self-contained units and are easy to install. Most refrigerators use R-22 refrigerant, normally maintaining temperatures of -17oC in the freezer compartment and about 1.66oC to 7.22oC in the refrigerator compartment. The technician must be able to perform various duties in the maintenance and repair of domestic refrigerators, water coolers, and ice machines. This section provides information to aid you in handling some of the more common types of troubles. But let us remind you that the information given here is intended as a general guide and should, therefore, be used with the manufacturer’s detailed instructions.
1.3.1 Basic Refrigeration Principle
If you were to place a hot cup of coffee on a table and leave it for a while, the heat in the coffee would be transferred to the materials in contact with the coffee, i.e. the cup, the table and the surrounding air. As the heat is transferred, the coffee in time cools. Using the same principle, refrigeration works by removing heat from a product and transferring that heat to the outside air. The principle involves the transfer of heat. We could discuss entropy and the laws of thermodynamics, but we’re not going to do that. That isn’t really necessary to understand this concept. It is one that we are all familiar with, whether we have any interest in science or not.
If you take your supper off the stove but don’t eat it right away, it gets cold. If you leave the milk out on the counter, it gets warm. Actually, your supper and your milk would become the same temperature, the temperature of the room. Because your supper is hotter than the room, heat energy moves from it into the room. Because you milk is colder than the room, heat energy moves from the room into the milk. This movement of heat energy affects the objects involved, your supper or milk, changing their temperatures. This concept of moving heat has a direct bearing on our lives. In the winter, we move heat from a fire, or a radiator, or an electric heater into our house, changing its temperature. In summer, we want to do the opposite, move heat from our house to somewhere else (we don’t really care where), again changing the temperature of our house.
(Fig 1.3: Principle of Refrigerator system)
1.4 Water Cooler
The purpose of water coolers is to make water available at a constant temperature irrespective of ambient temperature. They are meant to produce cold water at about 70C to 130C for quenching the thirst of the people working in hot environment. The warm or normal water can serve the physical requirement of our system for the proper functioning of the body organs but it does not quench the thirst especially in hot summers.
1.4.1 Types of Water Coolers
The water coolers are two types i.e. the storage type and the instantaneous type. In the storage type water coolers, the evaporator coil is soldered on to the walls of the storage tank of the cooler, generally on outside surface of the walls. The tank may be of galvanized steel or stainless steel sheets. The water level in the tank is maintained by a float valve. In this type of water cooler, run for long time to bring down the temperature of the mass of water in the storage tank.
Once the temperature touches the set point of the thermostat, the machine cycle is stopped. When the water is drawn from the cooler and an equal amount of fresh water is allowed in the tank, the temperature will rise up slowly and the machine starts again. As such there is always a reservoir of cold water all the time.
(Fig 1.4: cooling coil of instantaneous type cooler)
In instantaneous type water coolers, the evaporator consists of two separate cylindrically wound coils made of copper or stainless tube. The evaporating refrigerant is in one of the coils and the water to be cooled is in the other coil. The water is cooled by the refrigerant in evaporator by conduction.
 
The Water cooler are classified as follows:
a) Bottle types,
b) Pressure types,
c) Self contained Remote types.
(a) Bottle type: As the name suggests, this type of instantaneous water cooler employs a bottle or reservoir for storing water to be cooled. No city main inlet connection is required as it is normally used to cool water supplied in 25 litre glass bottles, which are placed on top of the unit, as shown in Fig.
(Fig 1.5: Bottle types water cooler)
(b) Pressure type: In this type of instantaneous water cooler, as shown in Fig., water is supplied under pressure. The city main water enters the cooler through the inlet connection at the rear of the cooler. It then passes through a pre-cooler. The pre-cooler is cooled by the waste water of the cooler. As the waste water temperature is low, it is made use of cooling the supply water by passing through a pipe coil wrapped around the drainage line. This arrangement helps in reducing the cooling load for the cooler. The amount of cooling depends upon the quantity of waste water and the length of the pipe coil comprising of pre-cooler. The pre-cooled water then enters the storage chamber and loses its heat.
(Fig 1.6: Pressure types water cooler)
(c) Self contained remote type cooler: This type of cooler employs a mechanical refrigeration system. The water cooled from the remote cooler is supplied to desired drinking place, away from the system. This type of arrangement does not require extra space near the place of work and is quite useful.
(Fig 1.7: Self contained remote type cooler)
1.4.2 Capacity of Water Cooler
The cooling load for the water cooler (Q) may be obtained from the following relation:
Q=mw cp (Ti-To)
Where,
Mw= Rate of water consumption
Cp= Specific heat of water
To= Outlet temperature of water.
Ti=Inlet temperature of water
The amount of cold water requirements under various conditions is given. These figures are based on extensive statistical survey. The refrigerants such as ammonia, sulphur dioxide etc. are now-a-days not used because of safety reasons. Generally R-12 is the most common refrigerant up to one tonne refrigeration (1TR) capacity and R-22 for two tonne refrigeration (2TR) capacity and appropriate combination for larger size units.
The amount of wastage of cold water should be included while estimating the amount of water consumption. usually heavy insulation around 40mm to 60mm thick glass wool or thermocouple is provided rendering insignificant heat transfer through insulation. 
1.5 Problem Statement
Now a day’s refrigerator is not a luxury it has become part of requirements in every middle and lower middle class households. The refrigerator is used to store food items, medicines, beverages and such other materials. The useful life of foods and other items can be lengthened due to storing at low temperatures. The household’s refrigerator is also used for cool water and ice cubes. They are usually specified by the internal gross volume and the deep freezers volume. A storage temperature of 00c to 4oc is satisfactory for the preservation of most of the fresh foods.
The purpose of water cooler is to make water available at a constant temperature irrespective of ambient temperature. They are meant to produce cold water at about 7oc to 13oc for quenching the thirst of the people working in hot environment. The warm or normal water can serve the physical requirement of our system for the proper functioning of the body organs but it does not quench the thirst especially in hot summers.
In present days many families use refrigerator for both food preservation and water cooling. A sample survey conducted reveals that in many houses, the refrigerator door is frequently opened just to get the cool water bottles. Due to this frequent opening of the refrigerator door, the ambient hot air keeps on entering into the refrigerator cabin. It results in the increase of cabin temperature. To reduce the cabin temperature the compressor runs most of the time. It leads to more power consumption. Generally six or seven liters of water is kept inside the refrigerator cabin for drinking purpose. If we can keep the water outside the refrigerator cabin, the space saved can be utilized for keeping other products.
In the present work a domestic refrigerator is modified to serve both the purposes of refrigerator as well as water dispenser. Suitable design and operation conditions were made to save space, initial cost and maintenance cost.
 
CHAPTER : 2
HISTORY 
2.1 Brief History Of The Project
2.1.1 Brief History On Refrigerator
The domestic refrigerator using natural ice (domestic ice box) was invented in 1803 and was used for almost 150 years without much alteration. The domestic ice box used to be made of wood with suitable insulation. Ice used to be kept at the top of the box, and low temperatures are produced in the box due to heat transfer from ice by natural convection. A drip pan is used to collect the water formed due to the melting of ice. The box has to be replenished with fresh ice once all the ice melts. Though the concept is quite simple, the domestic ice box suffered from several disadvantages. The user has to replenish the ice as soon as it is consumed, and the lowest temperatures that could be produced inside the compartment are limited.
In addition, it appears that warm winters caused severe shortage of natural ice in USA. Hence, efforts, starting from 1887 have been made to develop domestic refrigerators using mechanical systems. The initial domestic mechanical refrigerators were costly, not completely automatic and were not very reliable. However, the development of mechanical household refrigerators on a large scale was made possible by the development of small compressors, automatic refrigerant controls, better shaft seals, developments in electrical power systems and induction motors.
General Electric Company introduced the first domestic refrigerator in 1911, followed by Frigidaire in 1915. Kelvinator launched the domestic mechanical refrigerator in 1918 in USA. In 1925, USA had about 25 million domestic refrigerators of which only 75000 were mechanical.
However, the manufacture of domestic refrigerators grew very rapidly, and by 1949 about 7 million domestic refrigerators were produced annually. With the production volumes increasing the price fell sharply (the price was 600 dollars in 1920 and 155 dollars in 1940). The initial domestic refrigerators used mainly sulphur dioxide as refrigerant. Some units used methyl chloride and methylene chloride. These refrigerants were replaced by Freon-12 in 1930s. In the beginning these refrigerators were equipped with open type compressors driven by belt drive.
In Japan the first mechanical domestic refrigerator was made in 1924. The first dual temperature (freezer-refrigerator) domestic refrigerator was introduced in 1939. The use of mechanical domestic refrigerators grew rapidly all over the world after the Second World War. Today, a domestic refrigerator has become an essential kitchen appliance not only in highly developed countries but also in countries such as India. Except very few almost all the present day domestic refrigerators are mechanical refrigerators that use a hermetic compressor and an air cooled condenser. The modern refrigerators use either HFC-134a (hydro-fluoro-carbon) or iso-butane as refrigerant.
 
2.1.2 Brief history on water cooler
Bottled water first came onto the market in 1968 in France and had grown fairly popular by the 1980’s (Horrocks, 2009). Yet, today we are seeing much opposition to the bottled water industry. In recent years, the sale of bottled water has surfaced as a source of debate among Canadian universities, and bottled water bans have emerged as a response to this issue. Many universities have already implemented a bottled water ban (such as Memorial, Acadia, Ottawa, Queens, Guelph, Ryerson), but few have focussed on water coolers, although the impact is just as negative as individual water bottles (Horrocks, 2009). Dalhousie has been discussing and evaluating the feasibility of a ban in recent years, but has not yet joined the growing list of sustainably‐focused schools that have. As water coolers do not fall under purchasing contracts and are not regulated through the purchasing department, a ban and removal of bottled water would not normally include these types. As Dalhousie strives to be a leader in the field of sustainability, incorporating the removal of water coolers into a prospective bottled water ban would encourage sustainable action surrounding all bottled water among other institutions. As a leader in sustainability, Dalhousie must go above and beyond current trends and standards. The application of this report toward a move away from bottled water of all kinds would further increase Dalhousie’s standing as a leading institution in sustainable practice.
 
CHAPTER : 3
LITERATURE SURVEY
 
1. Himanshu, Kartik Upadhyay, Prof. S.K Gupta at el (2014):
TITLE: Feasibility Study and Development of Refrigerator cum Air Conditioner.
ABSTRACT: This paper is about our attempt to merge Domestic Refrigerator and Air conditioner into a combined system such that an ordinary man can have a sound sleep which automatically increases his working productivity for the next day.
COCLUSION: The refrigerator’s defrost function is utilized to extract excessive coolness and is fed to an AHU to work like an Air conditioner which is used for personalized cooling. After this paper we conclude that a common man can have comfort of air conditioner at very low running cost or zero cost, which would prepare him for better productivity for the next day.
2. Dr.U.V. Kongrea, A.R.Chiddarwarb, P. C. Dhumatkarc at el (2013):
TITLE: Testing and Performance Analysis on Air Conditioner cum Water Dispenser.
ABSTRACT: The work on developing the heat pumps for space conditioning and water heating has been gone for half a century. The earlier water heating pumps and air to water heating pumps gives only hot water and space conditioning. But in this air conditioning cum water dispenser we get hot and cold water with hot and cold air, thus the system becomes multifunctional.
CONCLUSION: The air-conditioner cum water dispenser was manufactured for air, water & air-water cycle combined. The air cycle provides good results with conventional optimum efficiency. The water cycle also predicts better results, but then water cycle alone is not useful. Hence the combine air conditioner cum dispenser by utilizing conventional air-conditioning. The dispenser gives required efficiency in terms of coefficient of performance.
(Fig 3.1: Actual set-up of air conditioner cum water dispenser system)
 
3.U.V.Kongrea, M.B.Salunkheb, A.A.Pohekarc at el (2013):
TITLE: Design Methodologies of air-conditioner cum water dispenser.
ABSTRACT: Design of Air-conditioner cum water dispenser utilized as a Novel Air-conditioning system Now a days. Today market conditions demands utility of air-conditioner. This paper delivered the design contributions for evaporator, condenser and capillary tube. Based on conventional methodologies the design calculation were done. Further the paper discusses the designed methods which are suitable for combined conventional air-conditioning and dispenser.
CONCLUSION: The overall compression with an air conditioning system alone nearly same efforts were required to obtained the combination of dispenser. This work also suggest put efforts to understand material and size of condenser. Additionally the temperature difference between the condensing medium & vapour refrigerant. Finally evaporator, condenser and capillary tube were designed so as to run on both cycle that water and air.
4.Poonia M.P., Bhardwaj A., Upender Pandel at el (2011):
TITLE: Design and Development of Energy Efficient Multi-Utility Desert Cooler.
ABSTRACT: During present study efforts were made to make evaporative cooling system more versatile. In the process of study a cooler cum refrigerator has been developed which can be utilized for the purpose of air cooling, drinking water cooling viz. a viz. storing the vegetables and medicines without altering the performance of desert cooler. The energy saving by doing so is saved more than 30 W.
CONCLUSION:
1. In unloaded condition, WBT ( 21.2 deg. C) has been obtained only in 25 minutes contrary to 52 minutes when it is connected to the G.I. box having cooling water as well as drinking water in it.
2. Developed cooler performs better over its nearest rival i.e. clay pot which is most popular in desert areas for cooling the drinking water.
3. Vegetables can be stored up to five days without any decay in their properties.
4. Around 30W energy can be saved by using the developed attachment with the conventional desert cooler without affecting the performance of the cooler.
(Fig 3.2: Multi-Utility Desert Cooler) 
CHAPTER : 4
DESIGN DESCRIPTION 
4.1 Experimental Setup
The domestic refrigerator and water dispenser works on the vapour compression refrigeration system. The domestic refrigerator is used to preserve the food items and others. The water dispenser is used to cool water.
This project focuses to modify the domestic refrigerator to serve both the purposes, as refrigerator and also water dispenser. In this modified refrigerator the water to be cooled is stored in the tank fixed outside the cabin, at the top of the refrigerator. The water flows from the tank to the accumulator located below the evaporator, through copper pipe line. The refrigerant flowing from the evaporator outlet is made to flow through the pipe line wound around the accumulator. Hence the water inside the accumulator is cooled by the refrigerant flowing through the pipe line. The cool water from the accumulator is taken out from the outside of the refrigerator door by using a flexible pipe between the accumulator outlet and tap, which is arranged outside the refrigerator door.
(Fig 4.1: Experimental set up of water cooler Cum Refrigeration system)
(Fig 4.2: Principle of Refrigerator cum chilled water dispenser)
In this arrangement the refrigerator is served as refrigerator as well as water dispenser. In order to know the performance characteristics of the vapour compression refrigerating system the temperature and pressure gauges are installed at each entry and exit of the component.
 
CHAPTER : 5
COMPONENT
 
5.1 Refrigerant
The refrigerant flows through all the internal parts of the refrigerator. It is the refrigerant that carries out the cooling effect in the evaporator. It absorbs the heat from the substance to be cooled in the evaporator (chiller or freezer) and throws it to the atmosphere via condenser. The refrigerant keeps on recirculating through all the internal parts of the refrigerator in cycle.
5.2 Compressor
The compressor is located at the back of the refrigerator and in the bottom area. The compressor sucks the refrigerant from the evaporator and discharges it at high pressure and temperature. The compressor is driven by the electric motor and it is the major power consuming device of the refrigerator.
(Fig 5.1: cross section of compressor)
5.3 Condenser
The condenser is the thin coil of copper tubing located at the back of the refrigerator. The refrigerant from the compressor enters the condenser where it is cooled by the atmospheric air thus losing heat absorbed by it in the evaporator and the compressor. To increase the heat transfer rate of the condenser, it is finned externally.
(Fig 5.2: condenser)
 
5.4 Expansive valve or the capillary
The refrigerant leaving the condenser enters the expansion device, which is the capillary tube in case of the domestic refrigerators. The capillary is the thin copper tubing made up of number of turns of the copper coil. When the refrigerant is passed through the capillary its pressure and temperature drops down suddenly.
(Fig 5.3: Cross section of Expansive valve)
5.5 Evaporator or chiller or freezer
The refrigerant at very low pressure and temperature enters the evaporator or the freezer. The evaporator is the heat exchanger made up of several turns of copper or aluminium tubing. In domestic refrigerators the plate types of evaporator is used as shown in the figure above. The refrigerant absorbs the heat from the substance to be cooled in the evaporator, gets evaporated and it then sucked by the compressor. This cycle keeps on repeating.
(Fig 5.4: Evaporator)
 
5.6 Temperature control devise or thermostat
To control the temperature inside the refrigerator there is thermostat, whose sensor is connected to the evaporator. The thermostat setting can be done by the round knob inside the refrigerator compartment. When the set temperature is reached inside the refrigerator the thermostat stops the electric supply to the compressor and compressor stops and when the temperature falls below certain level it restarts the supply to the compressor.
(Fig 5.5: Thermostat)
5.7 Defrost system
The defrost system of the refrigerator helps removing the excess ice from the surface of the evaporator. The defrost system can be operated manually by the thermostat button or there is automatic system comprising of the electric heater and the timer.
Those were the some internal parts of the domestic refrigerator; now let us see the external parts of the refrigerator.
(Fig 5.6: Defrost system)
5.8 Thermostat control
The thermostat control comprises of the round knob with the temperature scale that help setting the required temperature inside the refrigerator. Proper setting of the thermostat as per the requirements can help saving lots of refrigerator electricity bills.
5.9 Crisper
The highest temperature in the refrigerator compartment is maintained in the crisper. Here one can keep the food items that can remain fresh even at the medium temperature like fruits, vegetables, etc.
(Fig 5.7: Crisper)
5.10 Switch
This is the small button that operates the small light inside the refrigerator. As soon the door of the refrigerator opens, this switch supplies electricity to the bulb and it starts, while when the door is closed the light from the bulb stops. This helps in starting the internal bulb only when required.
(Fig 5.8: Switch)