Measuring the Temperature Distribution in Fridge - Coursework Example

Design ReportDesign Report Template Measuring the temperature distribution in fridge Instrumentation and Measurement Engineering Design Process Executive Summary The paper provides a report on temperature measurement using a thermocouple. As such, temperature distribution in various points inside a fridge is monitored to establish the distribution of temperatures. The readings are taken when the fridge is filled to varying capacity into establish the rate of temperature drops and also to find out the final temperatures at different points in the fridge after the temperature has dropped to appoint of equilibrium with the environment. The readings are taken after each ten seconds with a span of fifteen minutes. The obtained data is then tabulated and analysed to determine the average rate of cooling. The results obtained indicate that there is a linear relationship between temperature decrement and the time taken for the soup to cool. Background In a thermocouple there is use of two different metals which are joined together resulting into voltage generation at the junction. The magnitude of voltage generation depends on the temperature at the junction. Thermocouples have the ability of measuring high temperature owing to their fast reaction time. Scope The project is focused on temperature measurement in various points inside the fridge. The readings taken from the experiment indicate the rate of cooling for various level of loading of the fridge and the temperature levels at various points at equilibrium point. Thus, the readings do not illustrated temperature of the external environment. Design Summary The design of the project entails calibration of the thermocouple to measure and monitor cooling rate of in the cooling chamber of the fridge and the final temperatures at various points in the chamber. This involved two metals being joined at a junction thus aiding in achieving higher effectiveness of temperature measurement in the experiment. TABLE OF CONTENTS 1.Introduction 5 1.1. Description of the Project 5 2.Implementation 5 2.1. Abstracting the Problem 5 2.2. Division of Tasks 6 2.3. Problems Faced 6 3.Sensor Selection 6 3.1. Identification of the Sensor Type 6 3.2. Performance Test of the Sensor 7 4.Measurement System Implementation 7 4.1. Hardware Configuration 7 4.2. Software Configuration 9 5.Conclusion 10 6.References 11 7.Appendices 11 1. Introduction In thermocouples there are two metals which are joined together in a junction either through welding of soldering and they are utilized in measurement temperatures at desired points. As such, the focus of this project is to establish the cooling pattern in the fridge (I et al., 1966). It is expected that the external environment and the level of loading will influence the cooling while different points in the fridge will have varying temperatures with the freezer being the coldest. The thermocouple creates an effective tool for the measurement of the cooling pattern. 1.1. Description of the Project This project involves fitting thermocouples at various points in the fridge. The temperature reading is recorded for all the thermocouple points and hen the fridge is put own with the level of cooling set medium. The temperature reading for every thermocouple is recorded after 10 seconds for about 20 minutes (this is the point when temperature remaining constant in the thermocouples). When there is no more cooling taking place the fridge is put off and left some time so that the temperature in the chamber rises to a point of no further rising in temperature. The fridge is then loaded with bottles filled with water and then power is put on. The process of temperature monitoring is taken with the result being recorded. The thermocouple is first calibrated prior to the experiment to ensure that correct readings are taken. 2. Implementation 2.1. Abstracting the Problem Being able to establish the cooling pattern in a fridge is important in establishing if the fridge is function as per the design. It is also important in establishing how the fridge can be utilized optimally so that cold drinks can available at the required temperatures while at the same time avoiding running the fridge unnecessarily so as to avoid wastage of power. Moreover, thermocouples make it easier for measuring very high temperature readings. 2.2. Division of Tasks The first step in this project is making the thermocouple where two metals are joined at two junctions. The metal junctions are able to indicate temperature deviations with time. The thermocouple is then calibrated to ensure that it has the potential of taking the correct readings for the substance in question. The thermocouples are to be fixed inside the fridge such that some will not be touching the fridge walls. This should be done by use of materials such as small plastic rods which 2.3. Problems Faced The major problem is lack of control on the surrounding weather condition and the temperature levels. This shortcoming is attributed to the fact that there is constant change of temperature in the atmosphere surrounding the set up. 3. Sensor Selection 3.1. Identification of the Sensor Type The T thermocouple was selected as the appropriate sensor for the project, the reason for selection being on the basis of its capability of measuring a wide range of temperature ranging from -200 to 350. This characteristics makes it possible for the temperatures that are encountered in the project to measured and monitored effectively (Madison et al., 2013). T thermocouples are associated with high level of accuracy with an error limit being 0.75% or 1. Error of this magnitude does not have a negative on anticipated result of the project. Thermocouples also have a desirable level of accuracy with a range of medium to high in addition to exhibition of fairly good linear relationship (Fernandes et al., 2014). There is also low cost associated with cost ranging from $3 to $15. A thermocouple has the ability of sensing temperature in a distance of up to 100 meters with a very high response time with very complex computation being exhibited. Thermocouples to be used are able to withstand a corrosive environment and this makes it suitable to be used in this project without being affected by the chemicals contained in the instant tomato soup and the sensor being impacted negatively. 3.2. Performance Test of the Sensor Performance test reveal that thermocouples are associated with high level of performance, including high level of accuracy. The thermocouple has capacity to sense a wide range of temperature ranging from negative values to very high temperature values. The sensor also is not associated with any deformities or limitations when used in a wide range of environments including the chemical environment encountered in this project. 4. Measurement System Implementation 4.1. Hardware Configuration Figure 1 is a representation of the basic circuit of a thermocouple where there are two metals which are conjoined at the junction of open ends at hot and cold junctions. For calibration purpose a pair of thermocouple is put in the same area and then connected to a metre with a switch. The two are then heated when close together to ensure that there are exposed to the same temperature level. The temperature for the two are expected to be the same and in case of any difference metal modes are replaced. Schematic presentation of the thermocouple circuit Circuit fridge chamber temperature measurement The circuit used for the measurement of temperature for fridge cooling chamber is shown above. Such a circuit is constructed on solderless breadboard where the short thermocouple aids in temperature measurement for the ice point and the long one for high temperature measurement. 4.2. Software Configuration In the thermocouple set up metals are used which are dependent on thermal gradient that brings about generation of voltage. Thus, the measurement of voltage requires that conductors are to be connected to hot end so as to have the required gradient with magnitude of this gradient being also dependant of the type of metal put into use. The voltage generated takes place along the metal’s temperature gradient (Burg et al., 2012); where such voltage is expected have a linear relationship with temperature. Where a non-linear relationship is exhibited there is linearity correction to be done. 5. Conclusion Employing thermocouple for measurement of temperature is seen to be a very effective strategy where positive results are obtained where a wide range of temperature are involved with high level temperatures being measured with very high accuracy. Temperature drop rate in the fridge depends on level of load in the fridge and various points in the fridge cooling to different equilibrium temperatures. However, such a cooling rate attains is characterized of a linear relationship between temperature and the time for the cooling process. This cooling rate is easily determined through the use of thermocouples as the devices for temperature measurement. 6. References Burg, B. R., Tong, J. K., Hsu, W., & Chen, G. (2012). Decoupled cantilever arms for highly versatile and sensitive temperature and heat flux measurements. Review Of Scientific Instruments, 83(10), 104902. Fernandes, A., Amorim, P., Brito, C., Moura, A., Moreira, D., Costa, C., & ... Marins, J. (2014). Measuring skin temperature before, during and after exercise: a comparison of thermocouples and infrared thermography. Physiological Measurement, 35(2), 189-203. I., K. (1966). A PHENOMENON LEADING TO AN ERROR IN MEASURING THE CUTTING TEMPERATURE BY TOOL WORK THERMOCOUPLE METHOD. International Journal Of Production Research, 4(4), 329. Madison, D. P., Miers, S. A., Barna, G. L., & Richerson, J. L. (2013). Comparison of Piston Temperature Methods: Templugs Versus Wireless Telemetry With Thermocouples. Journal Of Engineering For Gas Turbines & Power, 135(6), 1-8. Philipona, R. R., Kräuchi, A. A., Romanens, G. G., Levrat, G. G., Ruppert, P. P., Brocard, E. E., & ... Calpini, B. B. (2013). Solar and Thermal Radiation Errors on Upper-Air Radiosonde Temperature Measurements. Journal Of Atmospheric & Oceanic Technology, 30(10), 2382-2393. 7. Appendices Appendix 1 Thermocouple characteristics Appendix 2 Thermocouple output measurement Read More