'Expansion Devices\r'

'Page 1 of 4 Expansion Devices I. Introduction Expansion devices argon grassroots components of a infrigidation system which carry pop both major purposes: (1) the pressure reduction from the condenser to evaporator pressure and (2) the regulation of refrigerant flow into the evaporator. These intricacy devices can be generally classified into two pillowcases which are namely the fixed beginning type (flow electron orbit is fixed) and the variable opening type (flow area changes correspondingly with a change in mess flow rates).There are about seven canonic types of amplification devices for a refrigerant in a refrigeration system. These include capillary provide tubing pipes and orifice which are under the fixed opening type and the manual of arms magnification valves, automatic intricacy valve (AEV), thermostatic intricacy valve (TEV), electronic expansion valve and float type expansion valve which are all under the variable opening type. The float type expan sion valve is further classified into high ramp float valve and low side float valve (Arora, 2006).One of the most commonly used expansion device is the capillary tobacco pipe. For the purpose of this exercise, a counting related to it will be performed. In a lesson guide on expansion devices prepared by Prof. R. C. Arora in 2006, he/she defined a capillary tube as â€Å"…a long, narrow tube of constant diameter. The word „capillary? is a misnomer since move up tension is not important in refrigeration application of capillary tubes. Typical tube diameters of refrigerant capillary tubes range from 0. 5 mm to 3 mm and the spaces range from 1. 0 m to 6 m. II. Objectives The exercise was conducted to familiarize the students with expansion devices, its functions and its importance. Specifically, the objectives were: 1. ) to examine the building of almost commonly-used expansion devices; and 2. ) to assess the performance of some commonly-used expansion devices. III. Methodology A. Lab-Scale Refrigeration System A lab-scale set-up for a refrigeration system in the refrigeration laboratory was observed for the effects of expansion devices on the pressures at various points within the system.Three different types of expansion devices which are namely the capillary, constant-pressure and thermostatic expansion devices are activated by opening their corresponding valves. The adaptation at each of the five pressure tuition points was recorded for every 2 to 3 proceedings until they become stable. An image of the observed set- Page 2 of 4 up was taken and the locations of the pressure-reading points were labelled. have concomitant A for the image. B. Computation: Capillary Tube For the stabilized nurses of the condenser and evaporator pressures measured, the pick upd theoretical aloofness of the capillary tube was computed.The results were then compared with the genuine distance of the capillary tube observed in the laboratory. See Appendi x B for the apprize of the computed and measured length of capillary tube. IV. Answers to Questions 1. In the computation part above, is thither a discrepancy in the midst of the actual and the calculate length of capillary tube? Explain. Based on Table 1, there is a discrepancy between the computed and measured measure out of the capillary tube. First, it must be noted that throughout the computation, assumptions were made.Upon realizing the difficulty of obtaining a value for the mass flow rate, a reasonable value of it was fictitious. This could affect the obtained theoretical length of capillary tube since some of the parameters involved in the computation require its use. Simply said, the theoretical length would either plus or decrease depending on the assumed value but never equal to the actual length, unless the analogous mass flow rate completely applies to the actual system (which might not really be the case).This is the same explanation behind the other(a) assume d parameters. Additionally, the measurement of quantities necessary for computing the length of capillary tube is also subject to many practical errors. This may include errors due to the limitation of the instruments or devices or due to some human inflicted errors. From the computed percentage error, it can be inferred that the two values for capillary tube length deviate from each other at the specified percentage. V. References Arora, 2006. Expansion Devices. [pdf file] Available at . VI.Appendix A. frameure with labels Page 3 of 4 PRESSUREREADING heighten 5 PRESSUREREADING POINT 1 PRESSUREREADING POINT 2 PRESSURE READING POINT 3 PRESSUREREADING POINT4 Fig 1. An image showing the pressure reading points in a lab-scale set-up for a refrigeration system B. Tabulated entropy Table 1. Measured and computed length of capillary tube Quantities Actual length (m) Theoretical length (m) part error (%) Values 4. 1 7. 17 42. 82 Note: Computations on how I arrived with these values ar e in the spreadsheet submitted with this report. Page 4 of 4\r\n'