INTERNATIONAL International Journal of Mechanical JOURNAL Engineering and OF Technology MECHANICAL (IJMET), ISSN ENGINEERING 976 634(Print), AND TECHNOLOGY (IJMET) ISSN 976 634 (Print) ISSN 976 6359 (Online) Volume 3, Issue 3, September - December (212), pp. 638-644 IAEME: www.iaeme.com/ijmet.asp Journal Impact Factor (212): 3.871 (Calculated by GISI) www.jifactor.com IJMET I A E M E ENERGY CONSERVATION BY IMPROVING THE DESIGN OF COOK POT S. Mathana Krishnan 1, P. Barath 2, V. Manoj 3, M. Joseph Stalin 4 1 (Mechanical Department, Thiagarajar College of Engineering, Madurai, Tamilnadu, India Email:mathanakryshnan@gmail.com) 2 (Mechanical Department, Thiagarajar College of Engineering, Madurai, Tamilnadu, India Email:barath93ajith@gmail.com) 3 (Mechanical Department, Thiagarajar College of Engineering, Madurai, Tamilnadu, India Email:manojsa93@gmail.com) 4 (Mechanical Department, Thiagarajar College of Engineering, Madurai, Tamilnadu, India Email:stalin661@gmail.com) ABSTRACT Energy is the essence of the world. Nowadays, an enormous amount of energy is wasted in different forms and we are in search of harnessing energy. Energy is stored in various forms, where its utilization is not complete. Therefore, conservation of energy is prominent in fast growing economies. Large amount of people are cooking using Liquefied Petroleum Gas (LPG).Using Liquefied Petroleum Gas leads to large amount of calamities such as carbon emissions mainly Carbon monoxide, Nitrogen Dioxide, Sulphur Dioxide and also of Suspended Particulate Matters(SPM). Hence, here is a simple way of conserving energy by reducing the usage of Liquefied Petroleum Gas. A cooking pot was designed to save energy during the process of cooking using a biomass cook stove.the experimental pot utilized a comparatively larger area of heat transfer when compared to normal pot. Testing was done in different phases comparing the standard cook pot with the experimental cook pot.the first phase brought five litres of water to boiling and then the pot is experimented in the simmering phase.results shows that the energy saved using the experimental cook pot is higher than the standard pot with reduced energy of cooking.this would reduce large carbon emissions and other factors polluting atmosphere thereby reducing the global warming. Keywords: Energy efficiency; Reduction in carbon emissions; Improved design; Reducing global temperature. 638
I. INTRODUCTION In earlier days brass, clay, iron were some of the common materials used in cook wares. But nowadays cook pots are made of stainless steel. Since stainless steel is a bad conductor of heat, it is clad with copper to increase the efficiency of the vessels for cooking. Generally the materials used for cook wares are good conductors of heat in order to retain the heat and to cool down slowly. Nowadays, aluminium is sandwiched between the two layers of stainless steel for uniform heating throughout the cook pot. The bottom of the cookware is made heavy and is provided with copper for efficient cooking. The modern type of cookware is made of titanium which has better pros since it has a faster cook time and is very light in nature providing resistance to scratches. Non stick coatings such as polytetrafluroethylene (PTFE) are also used, but it has several cons such that overheating can produce decomposed products which are toxic. Different types of cook wares such as skillets, sauté pans, braising pans, casserole etc are used for cooking and because of their different design, they provide efficient cooking for different varieties of food items. Thus several types of materials were changed and clad to increase the efficiency of cooking. Even though different designs were changed for efficient cooking, still there involves wastage of fuel. Therefore a cook pot is designed in such a way, in order to reduce the wastage of fuel and simultaneously to cook the food efficiently for better use. DESCRIPTION An experimental cook pot was designed in such a way to save energy comparing to other standard pots. Evaporation is a major source of heat loss during cooking. Generally, a standard cook pot measures 28 cm diameter at the base and is 18 cm in height. The standard cook pot accommodates 5 litres of water when filled, having a clearance height of 2 cm from the base. Therefore in order to minimize the heat losses, a cook pot was designed so that several amounts of energy could be saved which reduces the usage of Liquefied Petroleum Gas. The experimental cook pot was designed such that it has a small projection in the centre which would increase the area of contact thereby increasing the larger area of heat transfer when compared to standard pots. The experimental cook pot measures 28 cm diameter at the base and 2 cm in height. The projection at the centre of the experimental pot has 2 cm diameter at the top and measures 16 cm in height. It also accommodates the same 5 litres of water similar to the standard pot. Therefore, by increasing the area of heat transfer cooking was done in a considerable amount of time and a large amount of fuel is saved. METHODS Heating is done in different phases with both standard pot and experimental pot to show the efficiency of experimental pot over the standard pot. Generally, tests are done in three different phases. The first phase is that heating of water by keeping both the standard and experimental pot exposing it to open atmosphere. Second phase is experimented by enclosing both the pots by towel bath for insulation and the third phase is proceeded by mixing oil with water in both the pots and is heated. The first phase is the Water Boiling Test and is the most important one in this course since cooking is generally done in free atmosphere. This test is commenced by pouring 5 liters of water in the experimental pot of considerable capacity and its initial temperature is noted down. The experimental pot with water is placed in the LPG gas stove. When the stove is switched on the time taken for the water to reach 373K is noted down. The experiment is repeated for three times and the average of which is taken into account. The same procedure is handled with standard pot and the required data are noted down. 639
Second phase is the Towel Bath Test and this test is performed because if cooking done in closing with a lid should not affect the thermal efficiency since the design is altered. The same procedure should be followed by having towel bath enclosed over it. A thermometer is just kept in it. The time taken for the water to reach 373K is noted down. The procedure is repeated for three times and the average time is taken into account and hence a considerable amount of thermal efficiency could be described. Third phase of test is Oil Test and this is done since the oil acts as a thermal barrier for the evaporating water vapours thus drastically reducing the heat loss due to evaporation. Almost in all cooking involves addition of oil for taste so results of this test should not affect the thermal efficiency of cooking. Heat retention characteristics are found using oil test since a very thin layer of oil eliminates any type of heat loss due to evaporation. The procedure followed for first phase is carried out by adding 3 tea spoons of oil in it and the average time taken readings are noted down. Thus this test illustrates the heat retention characteristics of the designed experimental pot. Simmering tests are also done on both the pots for 3 minutes to find the energy required to simmer and also the evaporation rate. Temperatures are measured using thermometers by holding it at the centre of the pot. The readings are taken and with the aid of average values of readings, calculations are performed and are neatly tabulated. II. FIGURES AND TABLES 3 25 2 15 1 5 Water Boiling Test Oil Test Towel Bath Test Fig1: Average time to reach boiling point for each configuration 64
.4.35.3.25.2.15.1.5 Water Boiling Test Oil Test Towel Bath Test Fig 2: Average energy to boil per litre 9 8 7 6 5 4 3 2 1 Water Boiling Test Oil Test 72 7 68 66 64 62 6 58 Water Boing Test Fig3: Amount of water lost due to evaporation Fig4: Energy absorbed by the water 5 45 4 35 3 25 2 15 1 5 Water Boiling Test WBT EXP Fig5: Amount of water lost due to evaporation during the SIMMER for 3 minutes 641
TABULATION Configuration Average Std. Dev. % Reduction from WBT pot Time to boil (min) Energy to boil per lit (KW) Evaporation to boiling (g) Energy absorbed by the water (KJ) Evaporation to simmering for 3 min (g) (Towel Bath Test) (Towel Bath Test) (Towel Bath Test) 25.3 21.5.56 14.% 22.5.2 19.63 15.55% 2.2 17.47 15.% 338.54 11.8 291.14 19.2 14.% 34.69 9.4 257.29 24.7 15.55% 27.83 9.4 23.21 16.8 15.% 765.5 32.1 71.7 13.2 8.33% 63.79 5.2 31.89 2.3 5.% 628.5 1.7 711.79 6.4 13.33% 446.5 21.8 318.9 12.5 28.57% 642
III. MODEL CALCULATION Water Boiling Test: Experimental pot: Average time taken to reach 373K, t =21.5mins Assumptions made for this experiment: 1. In a house the mass of the gas in the cylinder, m = 14.1 kg 2. Assuming that when cooking is done for 4 hours per day 14.1 kg of LPG gas will be depleted in 4 days 3. Maximum cooking time per day per house = 5 hours 4. Cost of 1 cylinder = $1. Mass flow rate, M = m/t =.3525kg/day M= 2.4479 *1-5 kg/s Specific Latent heat for LPG gas, L = 46.1 MJ/kg Note: Readings are calculated for volume of 5 Litres. Heat energy required to boil the water per sec, Q i = M * L Qi = 1.128 kw Heat energy required to boil the water for 21.5 min, Q = 1455.74 kj For 1 litre, Heat energy required to boil per litre, Q i =291.14Kj Evaporation of water vapour due to boiling: Change in volume of water after conducting test, dv = (π * d 2 * dh)/4 dv = 7.17 *1-4 m 3 Mass of water lost due to evaporation, m e = ῥ * dv m e =71.g Energy absorbed by the water: Heat absorbed by the water, Q a = m w * C v * ( T i - T f ) Q a = 711.79kJ Change in volume of water after conducting test due to simmering, dv = (π * d 2 * dh)/4 dv = 3.189 *1-4 m 3 Mass of water lost due to evaporation at simmering, m s = ῥ * dv m s = 318.9g Standard pot average time, t std = 25 min Experiment pot average time, t exp = 21.5 min It is assumed that maximum cooking time per day per house = 5 hours 643
For using 25 min cooking pot, we cook for 3 min (5 hours) per day per house. For using 21.5 min cooking pot, we cook for 258 min per day per house. Calculated mass flow rate, M =.881 kg/h Amount of gas saved per day per house =.617 kg Amount of gas saved per month per house = 1.85 kg Amount of gas saved per year per house = 22.2 kg 14kg of LPG gas equals 1 cylinder, thus 22.2 kg of LPG gas equals 1.57 cylinder which is saved per year. Cost of 1 cylinder = $1. Cost saved per year per house using this cooking pot = $15.7 Census shows that there are 33.6 million houses are using LPG gas in 21. By research it has been found out that for 1 tons of usage of LPG gas there will be 3 tons of Carbon emissions. By calculation we can save.7 million tons of LPG gas, thus in 1 year we can reduce 2.1 tons of emissions of Carbon by using this pot in every houses. IV. RESULTS AND CONCLUSION Today our green planet is destroying day by day mainly due to rise in temperature due to global warming. A fundamental cause for the global warming is because of Air pollution. Studies shows that nearly 6-7% of air is get polluted by the liberation of carbon compounds due to consumption of LPG gas for cooking purpose especially in developing countries. The best way to eradicate this problem is to use the microwave ovens or by usage of electric induction stove. But most of the people feel discomfort to use these cooking devices, since cooking in LPG gas stove is used since early days. So the best way to reduce the usage of LPG gas is to utilise the well designed cooking pot. Results have been shown that Experimental pot has good efficiency in all different phases of tests. This shows that by utilizing this cooking pot in each and every houses for our daily cooking purpose will lead to reduce in 2.1 million tons of carbon emissions which in turn will reduce the global warming. Thus we can save more than half a billion dollars of money and also rise in temperature of our planet can be reduced to 1.58 degree Celsius by adopting this small innovations. V. REFERENCES [1] Monitoring and evaluation of improved biomass cook stove programs for indoor air quality and stove performance. Energy for Sustainable Development, Volume 11, Issue 2, June 27. [2] Efficiency study of Bangladeshi cook stoves with an emphasis on gas cook stoves. Energy, Volume 26, Issue 3, March 21. [3] Report on the use of LPG as a domestic cooking fuel option in India www.iei-asia.org [4] Frank P. Incropera D, Dewitt P. Heat and Mass Transfer. Singapore: John Wiley & Sons (Asia) Pte. Ltd.; 26. [5] Cengel Y. Thermodynamics An Engineering Approach. 3rd edition. India: Tata Mc Graw Hill; 23. [6] A Study in Conserving Energy Using an Experimental Cook Pot Dr. Alan Berick Aprovecho Research Center September 17th, 26. [7] Berick, A. (26) Heat Losses in a Cook Pot at Constant Temperature. Aprovecho Research Center. [8] Boiling Heat Transfer- Heat Transfer, 27, R.W.Serth 644