IZMIR INSTITUTE OF TECHNOLOGY Department of Mechanical Engineering THERMODYNAMICS I ME 206 Enthalpy of Fusion For Water Experiment 2 3rd May, 2011 Energy Lab. Room Z35 Spring 2011 Res. Asst. V. Egemen Ağakay 1. Introduction The enthalpy of a fluid is an important thermodynamic property that is inseparably connected with the first law of thermodynamics for open systems. The enthalpy of fusion for water is the energy removed from 0°C liquid water to make 0°C solid ice or vice-versa. The purpose of the experiment is to determine the enthalpy of fusion for water. 2. Theory and Principles In the experiment, hot water will be used to melt ice cubes at its melting temperature (0°C) in a styrofoam cup calorimeter. The ice cubes will remain at 0°C until it is melted. As the ice melts, hot water will loose heat to the ice and ice-water mixture occurs. The heat lost by hot water and ultimately the enthalpy of fusion of ice can be calculated by measuring the initial temperature of hot water and the final temperature of the mixture. The required equation is derived from the 1st Law of Thermodynamics. Heat gained by ice + Heat gained by mixture = Heat lost by hot water (m1)(hfus) + (m2)(Cp)(ΔT1)= - [(m3)(Cp)(ΔT2)] Where; m1 : mass of ice (kg) hfus : enthalpy of fusion of water (kJ/kg) m2 : mass of ice-water mixture (kg) Cp : specific heat of water (= 4.18 kJ/kgK) ΔT1 = (Tf -Tice): difference between final temperature of mixture and initial ice temperature (°C) m3 : mass of the hot water (kg) ΔT2 = (Tf -Ti): temperature difference between final temperature of mixture and initial hot water temperature (°C) 3. Experimental Set-up You are expected to set-up your experiment using the procedure given in Section 4. The materials that you will use for the experiment are listed below. All these materials will be provided by Energ and Fluid Mechanics Lab. and Geothermal Energy Research Center. 100-200 ml styrofoam coffee cup and lid, 100 ml graduated cylinder, Thermometer, Electronic scale or triple beam balance, Ice cubes or chips, Pure water, Heater, 400 ml beaker. 4. Procedure Styrofoam coffee cups will be used to obtain an insulated container in which ice and hot water will be mixed and phase change will occur. o Insert one cup into another as shown in figure below. The air in between two cups causes insulation. Having prepared the container, it is weighted by an electronic scale. Heat the water and measure its volume by a graduated cylinder or weight it. Put the hot water into the container and measure the hot water temperature. Add ice cubes or chips to the hot water and weight the whole system again. Insert the thermocouple into the ice-water mixture, cover the container by a lid and measure temperature until temperature change stops (steady-state). Record all the measurements. Repeat the experiment 3 times. 5. Results Present all recorded data in a table. Compute the enthalpy of fusion of water for each experiment and fill the table below (Exhibit the calculations for one experiment set). 1 2 3 Mass of the container (mc) Mass of hot water+container (mw) Mass of hot water+container+ice (mi) Initial temperature of hot water (Ti) Final temperature of mixture (Tf) Initial temperature of ice (Tice) Enthalpy of fusion for water (Hfus) Visualization of the results with tables, graphics, photos, videos etc. is strongly advised. Define these visualization elements well. Indicate the steps of the experiment, Define the parameters that you measured and the way you obtained these parameters. Give your comments and conclusions. Write a report with YOUR OWN WORDS. PLEASE DO NOT COPY FROM ANYONE AND HANDOUT. 6. References Show your references here in order of appearence in the text. Example:  Aprea, C., R. Mastrullo, and C. Renno, “Fuzzy Control of the Compressor Speed in a Refrigeration Plant,” International Journal of Refrigeration 27 (2004): 639-648.
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