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1 Chapter 2 REVIEW OF RELATED LITERATURE             The researcher has found the following studies and literature as relevant to the prototype project being proposed. A. Related Literature Foreign In late 1800s, ammonia/water technology was use...

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Chapter 2 REVIEW OF RELATED LITERATURE The researcher has found the following studies and literature as relevant to the prototype project being proposed.

A. Related Literature

Foreign In late 1800s, ammonia/water technology was used for ice production prior to the introduction of vapor compression technology. Ammonia/water is an absorption fluid which uses ammonia as its refrigerant. The freezing point of the fluid is approximately -78 degrees Celcius. The capability of this fluid is to provide direct gasfired and air-cooled air-conditioning. This technology is rarely used to ventilate an area because of its toxicity factor. Chillers of this type have a coefficient of performance typically around 0.5. In 1921, Swedes Von Platen and Munters developed domestic refrigerator which is the origin of ammonia/water/hydrogen refrigerators. This technology is being used in hotel room refrigerators and operates silently. In 1755 at which refrigeration machine begins, a number of trial and error attempts to use air, water, ether, etc., as refrigerants for mechanical refrigeration was made. Until in 1870, mechanical compression and absorption refrigeration systems with NH3 are developed. In 1891, the refrigeration industry was established and after few years NH3, CO2 and SO2 systems replace the air refrigeration systems (Arora, 2010). As stated in the History of Refrigeration, IIR, 1979, in the 15 th century Leonardo da Vinci worked and invented a ventilation and cooling unit for the Duke of Milan. The details history of refrigeration is given by Anderson in year 1953. During 1755

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mechanical cooling was achieved and in year 1790, Thomas Harris and John Long obtained the first patent. In 1834, Jacob Perkins developed the hand-operated refrigeration system with the aid of ether. In 1851, Dr. John Gorrie of Florida used the first American patent for a cold air machine to produce ice. In 1860, Dr. James Harrison of Australia installed the world’s first refrigeration machine for brewery, using a steam engine for power and sulphuric ether as the refrigerant. In 1861, Dr. Alexander Kirk of England made a machine similar to Garrie’s in England. In this machine, air was compressed by a compressor, which was driven by a steam engine. It consumed 20kg of coal to produce 4 kg of ice (Arora, 2010). There are different types of chillers according to its refrigerant. Water/lithium bromide chillers, ammonia/water chillers, and ammonia/water/hydrogen refrigerators are they. Water/lithium bromide technology was first developed by several manufacturers in U.S. and has been used since 1950. Water/lithium is an absorption fluid which utilizes water as the refrigerant. Its refrigeration temperature ranges 0 degree Celcius and above. This chiller is typically used in air conditioning large buildings. Chillers of this technology have a coefficient of performance ranging from 0.7 to 1.2 (Herold, Radermarher, & Klein, 1996). During American Civil war, the supply of ice to Southern States was stopped which hinders Ferdinand Carre to develop the vapor absorption system. Willis Carrier, the Father of air conditioning, used air washer to design a central air conditioning plant which leads to a successful attempt to reduce air humidity and maintain it at the required level (Arora, 2010). Refrigeration systems were used for air conditioning which is the cooling and dehumidifying for summer comfort. Refrigeration machines or water chillers are designed to collect unused heat from buildings and reject that heat to the outside. The water chiller can use either the vapor compression refrigeration cycle or an absorption refrigeration cycle (the use of either lithium bromide or ammonia solutions) (Stanford III, 2011).

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In the vapor compression cycle, a chemical substance alternately changes from liquid to gas and from gas to liquid. This cycle is composed of four distinct cycles: compression, condensation, expansion, and evaporation (Stanford III, 2011). Heat transfer applications are considered mainly to the problems in the field of engineering .These are some of the topics discussed: heat exchangers; mass transfer cooling and heat pipes. Other considerations in this topic are given to ; non-Newtonian fluids in heat transfer; thermal energy storage ;fluidized and packed beds; and heat additional topics which includes cooling tower ;heat transfer in buildings and geothermal heat transfer (Rohsenow, Hartnett, & Ganic, 1985). A common non-dimension correlation for predicting heat-transfer coefficients when film condensation of inside pipes is needed .It has been checked through a broad type of experimental data. The set of parameters includes decreased pressures from . 002 to .44, Saturation temperatures ranging from 21 to 310°C, vapor speed ranging from 3 to 300m/s, mass flux 39000-758000kg/m2 h and etc. The mean deviation was found to be 15.4% for the 474 data points checked. Scientific investigation was done to the flow of water in micro channel structures having hydraulic diameters of .133-.0367 mm and single phase forced convective heat transfer. The results explained that geometric configuration had important effect on the single phase heat transfer and flow processes. The laminar heat transfer was discovered to be dependent upon the aspect ratio and the ratio of the diameter to the centercenter distance of the very small channels. The resistance of the turbulent flow was found to be smaller than that assumed by classical relationships, and the Reynolds number for the transition of flow to really develop the turbulent flow decreases compared to the ordinary channel (Peng & Peterson, 1996). Experimental Data are issued on the heat transfer on three oils of largely different temperature coefficients of viscosity for heating and cooling. The outcome are correlated when it comes to the ratio of the mainstream fluid properties by a process which gives further attention to the viscosity gradient of the fluid in the tube to the

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viscosity of the fluid at its mainstream temperature and the viscosity of the tube wall temperature. This method of correlation has been applied to data in the pressure drop in both the turbulent and viscous regions, both heating and cooling agreed to this basis (Sieder & Tate, 1936). The Cross-sectional area of the accommodated ducts varies periodically in terms of stream wise direction that’s why the concepts of totally developed heat and flow transfer have been popularized. The identification of the characteristics of the velocity components and of a decreased pressure function allows the flow field analysis to be just a single isolated module, without involvement with the problem on the entrance region. A similar modular analysis can be done for the field of temperature, but the periodicity conditions are of unique nature compared on the thermal boundary conditions (Patankar, Liu, & Sparrow, 1977). To have the best and most comfortable thermal environment, the engineer must discover the most effective path for heat transfer from the device to an external cooling agent. The path for this transfer of heat is divided into internal and external parts, representing the heat transfer by the means of conduction through variable materials and interfaces dividing the devices from the package surfaces and heat transfer by the means of convection from the surface to the coolant material (Incropera, 1988). High-speed and still photographic techniques were used to account the characteristics of water droplets on the surface made up off hot aluminum. The velocity of drop and the surface temperature were two essential parameters comprising both ensuing heat transfer and the impact behavior (Bernardin, Stebbins, & Mudawar, 1997). Heat is the flow of energy across a certain boundary as a result of difference in temperature across that boundary. It is important to recall that in every aspect of dealing with heat transfer, since convective transport needs fluid motion. The need to describe the relationship between velocity distributions and concentrations distributions

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are mandatory. It will prove that many similarities exist between mass, heat and momentum transfer (Burmeister, 1993). For operating the vehicle, it must be provided with both internal combustion engine and an electric motor. The vehicle is provided with a duct so that the air will be discharge into a cabin for controlling the air temperature. When the electric motor starts operating the vehicle, the heat from the engine cooling water is brought to the heat exchanger for heating purposes when the temperature of the engine cooling water increases from its predetermined value (Numazawa & Suzuki, 1996). A numerical simulation was developed to predict the thermal environment inside the car or the car cabin. Long wave radiation, coupled analysis of solar radiation, heat conduction and CFD was used in this method. Ventilation inside the panel and air leaks from the interior parts was incorporated due to simplified cabin model. Even the artificial solar radiation was also studied in the laboratory. By considering both experimental error and the broadness of human perception, the numerical targets of the simulation accuracy were determined (Fujitaa, Kanemarua, Nakagawaa, & Ozekib, 2001). The accumulated heat of a vehicle parked under the direct sun affects the interiors inside the cabin, including the vinyl materials of the dashboard, the electronic components and the leather covers

.It also made the operating period for the

passenger uncomfortable. Experiments were made until it comes up to the solution that the use of sunshade or dropdown windows, having both sides, reduce the heat accumulation brought by the fresh air exchange outside the environment (Al-Kayiem, 2010). There is a child car seat that closes when being occupied due to the built-in cushion switch. This is use for additional safety that will catch up the attention of people outside the car, indicating the danger inside the car and that a child is trapped on it and needs help. A table of maximum rates of the change in temperature inside the car should be useful in teaching the public about the hazards of vehicle -related hyperthermia (Younse, 2006; Grundstein, Dowd, & Meentemeyer, 2010).

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The hazard of leaving infants or toddlers

unattended inside the car has been

well documented. There are no different codes for finding vehicle –related hyperthermia deaths in the international classification of diseases(ICD).However, vehicle –related hyperthermia deaths in infants and children sin the United States have been questioned from news accounts. Guard and Gallagher (2005) reported an average of 29 deaths per year from the span of seven years, while Null (2009) reported an average of 37 deaths per year in the span of 11 years. 54 % of cases involve caregivers who forgot their children; however, 27% of vehicle-related hyperthemia deaths involve children that were intentionally left inside the car (Guard and Gallagher 2005). In some cases, parents are unaware of how quickly the car could heat up and they leave their child sleeping for they did not want to disturb them. Such behavior shows a clear lack of knowledge by parents and caregivers in line of the danger of leaving children inside the car (K. Roberts, 1976, E. Roberts, 1976). The interior of a car, together with the common case of a child strapped into a child seat, represents a distinct environment that may develop particularly hazardous conditions. A series of studies have investigated how shading, ventilation and different meteorological conditions may result to maximum cabin temperatures and rates of change in temperature. The maximum temperature of a car directly heated by the sun with no ventilation can reach to 70°C.These stunningly high temperature from the sun is caused by a greenhouse effect (Grundstein et al., 2010). The diagnosis of heat stroke is hard to develop in forensic medicine due to the lack of observations made on the victims. A recent case found concerning the death of two children in a vehicle was review by giving importance to thermophysiology. The outcome found allowed some hypothesis regarding the investigation to be checked, and adds to the data involving the subject. Each year, children die due to heat stroke after being left unattended inside the car (Schuliara, Savoureyb, Besnarbd, & Launeyb, 2001). Regardless of the outside temperature, the temperature rate rise inside the car was not significantly distinct. The average mean increase was 3.2°F per five –minute

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interval, with 80% of the rise in temperature occur during the first 30 minutes. The final temperature depends upon the ambient temperature, but even at the coolest ambient, internal temperatures reached 117°F. On average, there was a 40°F rise in internal temperature for ambient temperature increase in the vehicle. Vehicles heat up rapidly, within 15-30 minutes the majority of temperature rise to its climax (McLaren, Null, & Quinn, 2005). Temperatures approaching ambient were only gained with the ventilation given by windows at least 200mm (half) open. In such case, babies causes then excessive sweating that leads to dehydration in four hours. Usually the cerebral effects of heat stroke would ensue. Parents and pediatricians should be admonished of the hazard of heat stress if the children are left inside the car with no ventilation (King, Negus, & Vance, 1981). Safety systems for car cabin especially passenger vehicles, including automated system and methods for avoiding entrapment of disabled children, infirm and aged persons, or pets from being left inside the vehicles under the direct sunlight, so that they will not suffer from heat. This discovery is made by use of one or more systems to detect the temperature inside the car cabin and the occupancy state, and provide multi outputs which can be employed to give interior and exterior warning of trapped passenger in a dangerous hot car (Dulin & Seip, 2005). A small fan with an electric power motor is given, the rotor of which is patterned as a blade wheel hub and as a cup shaped outer rotor. The outer wall of the blade wheel hub widens in the direction of air flow and forms the inner wall of an air flow duct. The fan blades are attached on this outer wall, it is conical shaped and is inclined as an outer lining over the cup-shaped outer rotor (Papst & Wrobel, 1986). The stator is strengthened by a bearing tube formed of plastic, which is connected together. An axial flow fan for ventilating electronic and electrical equipment comprises a brushless, DC external rotor-type central drive motor.

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Copper pipes which are largely used in the refrigerator industry can unusually work in high humidity atmospheres and in aggressive conditions which can result to dangerous corrosion phenomena of the pipes. The design of the refrigerator cooling circuit can cause corrosion problems with the reason that copper pipes are frequently in electrical contact with the aluminum pipes causing serious galvanic attack on the less noble metal (Fedrizzi, Deflorian, & Bonora, 1999). Embedded cooling pipes can be used to lessen the temperature increase in massive structures as a measure against thermal cracking. When air is used as coolant, large diameters with profile leading friction losses along the pipe are recommended. Heat transfer coefficients for the different types of cooling pipes have been considered for different pipe flows in fusion with various temperature levels (Hedlund & Groth, 1998). Embedded cooling pipes are used to lessen the risk of thermal cracking in early age concrete. Long ago, water has been used as the basic and most common cooling medium, but air cooling has been shown to be beneficial for many applications. The experimentally-determined heat transfer coefficient of cooling pipes have been used and proven in comparison of measurements at the Igelsta Bridge in Södertälje, Sweden. The close agreement between measured and computed temperatures of air-cooled sections seems to prove the use of the averaged heat transfer coefficients (Hedlund & Groth, 1998). A novel generator prototype, compact generator using active carbon-ammonia pair based on the plate heat exchanger idea has been built and designed. This prototype has low thermal mass and good heat transfer. To form adsorbent layers only 4 mm thick between pairs of liquid flow channels of very low thermal mass. In experimental performance report while driven with waste heat from engine coolant water (at 90 TC), a pair of the current prototype generator operating out of phase has produced an average cooling power 1.6 kW with about 2 kW peaks. An automotive air conditioning system that is free from conflict in transferring itself caused by power consumption in air

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conditioning means in an automobile having storage means, air conditioning means with an electric compressor (Telto, Metcalf, & Critoph, 2009). Car air conditioning system includes: air feeding device for feeding a fixed quantity of air; air-blow outlets for blowing air in different temperature inside the car; interior temperature detector for sensing temperature inside the car; blown-air temperature detector for sensing temperature of the air from the outlet; temperature controlling device for controlling a heating-cooling control signal to control the flow of heating-air and the flow of cooling-air that temporarily changes, on the basis of sensed interior temperature and the sensed blown-air temperature; and a temperature adjusting device which consist of a heating-cooling device for heating and cooling the air from the air feeding device and temporarily changing the temperature of the heating -air and the cooling-air, and mixing device for combining the heating-air and the cooling-air from the heating-cooling device and taking the combined air with the adjusted temperature to the air outlet (Taniguchi & Aoki, 1993). From the past, some natural working fluids were applied in refrigeration and airconditioning systems. However, the use of CFCs caused a large reduction in the usage of those fluids. Understanding of the environmental destruction of CFCs concentrated attention on alternative refrigerants. It is said that the natural one have minimum environmental effect (Riffat, Afonso, Oliveira, & Reay, 1997). An eco-friendly air conditioning system for an automobile is constituted by a heat energy accumulator, a car battery, cooler, and a solar collector panel lined to compressor, fan and condenser assembly, expansion valve, and fan and evaporator combination. An amount of cold energy produced in the system while in operation is stored in the heat energy accumulator and the cooler. And, when the car air conditioning system or the car engine is off state, power supply comes from the solar collector panel or in a battery operates the fan associated with the evaporator and cold energy initially stored in the heat storage accumulator is taken off to maintain the interior temperature of a car (Chen, 2002).

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Refrigeration circuits of car air conditioning systems modeled a design from a steady state computer simulator. This simulation model consist a variable capacity compressor and a thermostatic expansion valve combined to the evaporator and micro channel parallel flow condenser. In order to check output of the simulator an examination bench is used from the air conditioning system of a compact passenger vehicle. The variable capacity compressor of the circuit is run by an electric motor managed by a frequency converter. The simulator was used for the evaluation and simulation of the impacts on the system performance of various operational parameters such as compressor speed and return air in the evaporator and condensing air temperatures (Saiz, Gonzales, & Ianella, 2002). In an ordinary automobile air-conditioning system the power used to operate an absorption refrigeration system is from the exhaust gas of an internal combustion engine. By undergoing both laboratory and road-test conditions the theoretical design is verified. Concluding it, the prototype is installed in a ...