DESIGN AND DEVELOPMENT OF ECO-FRIENDLY REFRIGERATION SYSTEM

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1 DESIGN AND DEVELOPMENT OF ECO-FRIENDLY REFRIGERATION SYSTEM Ronald Reagon R 1, Chetan Kumar D S 2 1,2 Assistant Professor, Department of Mechanical Engineering, New Horizon College of Engineering, Bengaluru Abstract: The energy crisis persists all across the globe. The supply of continuous electricity is still not available in several areas of the world and also the climatic changes and global warming demand accessible and affordable cooling system in the form of refrigerators and air conditioners. These can be overcome by using Eco-Friendly refrigerant like LPG, Biogas, Natural gas etc.. Eco friendly refrigerant is available in cylinders at high pressure. When this high pressure refrigerant is passed through the capillary tube the pressure of refrigerant is dropped due to expansion and phase change of refrigerant occurs. Due to phase change from liquid to gas latent heat is gained by the liquid refrigerant and temperature drops. Thus it acts as a refrigerant and produces cooling effect. Keywords- Refrigeration, LPG, Eco friendly I. INTRODUCTION The term 'refrigeration' in a broad sense is used for the process of removing heat (i.e. Cooling) from a substance. It also includes the process of reducing and maintaining the temperature of a body below the general temperature of its surroundings. In other words, the refrigeration means a continued extraction of heat from a body, whose temperature is already below the temperature of the surrounding For example, if some space (say in cold storage) is to be kept at -2 o C, we must continuously extract heat which flows into it due to leakage through the walls and also the heat, which is brought into it with the articles stored after the temperature is one reduced to -2 o C. Thus in a refrigerator, heat is virtually being pumped from a lower temperature to a higher temperature. According to second law of thermodynamics, this process can only be performed with the aid of some external work. It is thus obvious, that supply of power (say electrical motor) is regularly required to drive a refrigerator. Theoretically, the refrigerator is a reversed heat engine, or a heat pump which pumps heat from cold body and delivers to a hot body. The substance which works in a heat pump to extract heat from a cold body and to deliver it to a hot body is called refrigerant When people hear the word refrigeration they immediately think of the refrigerator in their kitchen. However there are actually quite a few different kinds of refrigeration out three and they each have their own methods of functioning. One particular type of refrigeration is industrial refrigeration. This type of refrigeration is typically used for cold storage, food processing, and chemical processing The equipment is very large and made of industrial stainless steel. Industrial refrigeration, which frequently uses ammonia refrigeration to maintain temperature, is necessary for computer, foodstuffs, blood, vaccines, and quite a few other goods that must maintain a constant and steady temperature at all times_ Temperatures that are too high or too low may spoil certain goods or ruin them. As a result industrial refrigeration is especially important maintaining temperature is as All Rights Reserved 406

2 Since temperature is so important into industrial refrigeration companies offering this service must pay attention at all times to the temperature of the industrial refrigerators. II. TYPES OF REFRIGERATION 1) Cyclic Refrigeration 2) Non Cyclic Refrigeration 3) Thermoelectric Refrigeration 4) Magnetic Refrigeration III. ECO FRIENDLY REFRIGERATION In India, more than 80% of the domestic refrigerators utilize HFC 134a as refrigerant, due to its excellent thermodynamic and thermo physical properties. But, HFC 134a has a high global warming potential (GWP) of There is a need of assess various refrigerant option considering the existing refrigerators in the field and for the future market. CFC's are principally destroyed by ultraviolet radiations in the stratosphere; the chlorine released in the high stratosphere catalyzes the decomposition of ozone to oxygen; and ultraviolet radiations penetrate to lower altitudes. Credible calculations of the magnitude of the effect (Hoffman 1987) and his team predicted 3% global ozone emissions of 700 thousand ton s/year after a hundred years. The ozone impact of car air conditioners also cannot be ignored Hydro fluorocarbons (HFC's) can be thought of as a replacement, but unfortunately the radiation properties of HFC's like R-134a make them powerful global warming agents. HFC 134a and the HC blend have been reported to be substitutes for CFC 12, but they have their own drawbacks in energy efficiency, flammability and serviceability aspects of the systems. HFC 134a is not miscible with mineral oil, and hence, polyol ester oil is recommended, which is highly hygroscopic in nature. This hygroscopicity demands stringent service practices, Which otherwise results in moisture entry into the system. Thus, hydrocarbon refrigerants; particularly LPG serves as the best contender to replace CFC's from domestic refrigerator as well as car air conditioners LPG consists mainly of propane (R-290) and butane (R-600), and LPG is available as a side product in local refineries. In Cuba for already several decades LPG is used as a drop-in refrigerant. LPG mixtures have composition of a commercial LPG mixture suitable as 'drop-in' replacement for R-12 was calculated crudely as 64% propane and 36% butane by mass. Liquefied petroleum gas (LPG) of propane and 40% commercial butane has been tested as a drop-in suitable for R 134a in a single evaporator domestic refrigerator with a total volume of 10 ft3. The revival of LPG refrigerants in domestic and small commercial application in a happy accident (Vidal 1992) Engineers had known since the 1920's that LPG refrigerants performed well and in the 1980s refrigerators manufacturers again tested them (Kuijpers et al. 1988). Fear of a flammability campaign from the chemical industry deterred any manufacture. In March 1989, the Institute of Hygiene in Dortmund Germany needed a new cold storage room. The young idealistic director, Dr. Harry Rosin, could not consider using a CFC refrigerant and so tried propane and isobutane. Greenpeace Australia imported a Foron refrigerator in February 1993 and in December Ltd, Australia's largest appliance manufacturer, displayed prototype LPG refrigerators. In 1994, German manufacturer announced one by one their intention of switch to LPG All Rights Reserved 407

3 IV. PROPERTIES Colorless. Odorless. (It's normal to odorise LPG by adding an odorant prior to supply to the user, to aid the detection of any leaks). Flammable. Heavier than air. Approximately half the weight of water. Nontoxic but can cause asphyxiation. LPG expands upon release and I liter of liquid will form approximately 250 liters of vapour. V. DESIGN OF ECO FRINENDLY REFRIGERATOR Length = 260 mm Breadth = 210 mm Height = 360 mm Volume of the box (evaporator box) = Copper tube inner diameter = 0.8mm Copper tube outer diameter = 3mm Length of copper tube =2.88m Pressure gauge range = 0-7bar Flow meter range = Gas cylinder weight =19.5kg Thickness of plywood =10mm Thickness of thermo coal =10mm Length of pressure pipe =1m VI. CONSTRUCTION OF THE ECO FRIENDLY REFRIGERATOR High pressure cylinder consisting of LPG weighs about 19.5kg is connected to the rotameter which measure and control the flow rate of the fluid in deed it is connected to pressure gauge to measure the pressure of the fluid, the pressure gauge is connected to the capillary tube to drop the pressure of the fluid interns the temperature of the fluid decreases then the capillary tube is connected to the throttle valve which control the flow rate and decreases the pressure more prominently, the throttle valve is connected to the evaporation chamber to absorb the heat from the chamber and then it is connected to the pressure gauge to measure the pressure of the fluid which as absorbed the heat and then it is connected to the burner to burn the fluid in case of LPG and if the fluid is compressed air it is let out to the atmosphere. VII. WORKING ECO FRIENDLY REFRIGERATOR The basic idea behind LPG refrigeration is to use the evaporation of a LPG to absorb heat. - me simple mechanism of the LPG refrigeration working is shown in figure. Fig:working of eco friendly All Rights Reserved 408

4 LPG is stored in the LPG cylinder under high pressure when the gas tank of regulators is opened then high pressure LPG passes in gas pipe. The LPG is passed through the rotameter and pressure gauge to measure flow rate and the pressure. Then LPG is going by high pressure gas pipe in capillary tube. High pressure LPG is converted in low pressure at capillary tube with enthalpy remains constant. After capillary tube, low pressure LPG is passed through evaporator. LPG is converted into low pressure and temperature vapour from and passing through the evaporator which absorbs heat from the chamber thus the camber becomes cools down. Thus we can achieve cooling effect in refrigerator. After passing through the evaporator low pressure LPG is passed through pipe and pressure gauge to the burner. And we can uses the low pressure LPG to burning processes. VIII. RESULTS Area 1 = = m 2, Area 2 = = m 2, Area 3 = = m 2, Area 4 = = m 2, Area 5 = = m 2, Area 6 = = m 2, Thermal conductivity of plywood kp = 0.12 W/mk Thermal conductivity of thermo coal kt = 0.02 W/mk Thickness of plywood =10 mm Thickness of thermo coal = 10 mm For LPG gas Trial -1 Time Inlet pressure in Bar Outlet pressure in Bar Evoparator temperature in o C Temperature of atmosphere = 37 o C = 310 K Temperature of evaporator = 24.9 o C = K Heat flow from area 1 due to conduction Q1 = (Ta-Te)/ (Rthp + Rtht) = (Ta-Te)/ ((Lp/KP.A) + (Lt/Kt.A)) = ( )/ [( ) + (5.3418)] = W Heat flow from area 2 due to conduction Q2 = W, Q3 = W, Q4 = W, Q5 = W Q6 = W Total heat flow from all areas due to conduction = W Heat flow from evaporator due to convection Inside heat transfer coefficient = 30 W/m 2.K Outside heat transfer coefficient = 10 W/m 2.K Rate of heat transfer Q [12] Q =U.A. All Rights Reserved 409

5 The overall heat transfer coefficient 1/U = (1/Uo) + (Lp/kp) + (Lt/kt) + (1/Ui) 1/U = U = 1.54 W/m2.K Rate of heat transfer from area 1 Q1 = ( ) = W Q2 = W, Q3 = W, Q4 = W, Q5 = W, Q6 = W International Journal of Recent Trends in Engineering & Research (IJRTER) Total heat flow from all areas due to convection = W Heat transfer due to radiation Q Q = σt4 = (37-(24.9)) 4 = W Total heat flow from evaporator due to conduction, convection and radiation Qt Qt = = W Refrigeration effect=(h2-h3)= ( ) 1 =331.7w Work input=qqgh (qgh=pressure difference(p1-p2)) =32*5 =170w COP = (h2-h3)/w =331.7/170 =1.95 IX. CONCLUSION After performing this project "eco-friendly Refrigeration", we conclude that refrigeration effect is produced with the use of LPG. From observation table, we conclude that, the regulating valve is fully open that, we achieve the evaporator temperature down from 38 o C to 23 o C in a 60 minute. We also conclude that, the capillary tube is maximum pressure of gas cylinder is reduces the less then of I Bar. The capillary tube is more suitable throttling device in LPG refrigeration system. This system is cheaper in initial as well as running cost. It does not require an external energy sources to run the system and no moving part in the system so maintenance is also very low. We also conclude that, we try the burnt to the exhaust LPG, the pressure of exhaust gas is less than 1Bar, the small flame produce by the burner. This system most suitable for hotel, industries, refinery, chemical industries where consumption of LPG is very All Rights Reserved 410

6 REFERENCES 1. S. J. Cleg, Thermodynamic analysis of LPG as refrigerant for industrial refrigeration and transportation, Institute of Transport Studies, University of Leeds, Working paper of 471, Ibrahim Hussain Shah, Kundan Gupta Design of LPG Refrigeration System and Comparative Energy Analysis with Domestic Refrigerator [1] 3. B. O. Bolaji, Investigating the performance of some environment-friendly refrigerants as alternative to R12 in vapour compression refrigeration system, PhD Thesis in the Department of Mechanical Engineering, Federal University of Technology Akure, Nigeria (2008). 4. Ajit kumar rai Et.al experimental study on a domestic refrigerator using LPG as a refrigerant, SSET, SHIATS All Rights Reserved 411