PhamMinhMan TV pdf Thesis for Master Degree Development of an Eco friendly High Efficiency Heat Exchanger Providing Healthy Indoor Environment with a Minimum Energy Loss or Gain Pham Minh Man Departme[.]
Thesis for Master Degree Development of an Eco-friendly HighEfficiency Heat Exchanger Providing Healthy Indoor Environment with a Minimum Energy Loss or Gain Pham Minh Man Department of Mechanical and Automotive Engineering Graduate School, Inje University Advisor : Prof Dae Hee Lee Development of an Eco-friendly HighEfficiency Heat Exchanger Providing Healthy Indoor Environment with a Minimum Energy Loss or Gain Pham Minh Man Department of Mechanical Engineering Graduate School, Inje University A thesis submitted to the Graduate School of Inje University in partial fulfillment of the requirements for the degree of Master of Science Degree Advisor : Professor Dae Hee Lee Dec 2013 ABSTRACT Development of an Eco-friendly High-efficiency Heat Exchanger Providing a Healthy Indoor Environment with a Minimum Energy Loss or Gain Pham Minh Man (Advisor: Professor Dae Hee Lee) Department of Mechanical Engineering Graduate School, Inje University This thesis provides a new cross-counter-cross plate-type- aluminums heat exchanger with a minimum energy loss or gain The experimental results showed that the heat exchanger is highly efficient, which contributes an excellent idea of reducing energy loss from air-to-air flow streams It also showed that the cross-counter-cross heat exchanger unit, including eighty plates of 0.2 mm-thick aluminum sheets which are arranged in crosscounter-cross order of flow, achieved the highest efficiency It can minimize the temperature difference between indoor air and outdoor air, thereby keeping the indoor temperature nearly constant Besides, this heat exchanger is capable of supplying fresh outdoor air and exhausting contaminated indoor air, improving the quality of indoor air with a low carbon dioxide i concentration An additional innovative feature of this heat exchanger is to effectively remove dust from incoming outdoor air, using a filter unit which consists of a plurality of poles, each having a semi-circular cross-section so that turbulent eddies are generated when the outdoor air collides on the concave surface of pole and the dust falls down The current research results show that the carbon dioxide concentration inside the room decreased by 65% from 1350-ppm to 450-ppm, while the room temperature difference was maintained within ± 1.5oC before and after the operation of the heat exchanger The maximum effectiveness of 0.909 occurred at an air flow rate of 76.5m3/h The effectiveness of the heat exchanger takes into consideration the limitations of heat transfer between two airflows due to these parameters In addition, the performance of the heat exchanger is governed by various parameters like mass flow rates, pressures, and temperatures of working airflows Keywords: Plate-type Heat Exchanger, cross-counter-cross flows, Ecofriendly, Concentration of Carbon Dioxide, Heat Exchanger Effectiveness, İ NTU Method ii Tableofcontent Tableofcontent iii Listoftablesandfigures iv Nomenclatures vi I. Introduction .- - 1.Background - - 2.Research motivation and objectives - - II. Literature review - - 1.General review - - 2.Review of Heat exchanger system - 12 - 2.1 Enthalpy (Energy) exchanger - 12 - 2.2 Enthalpy Plate exchanger - 13 - 2.3 Enthalpy Wheel exchanger - 14 - 2.4 Hydrophilic Membranes exchanger - 16 - 3.Review of Indoor Air Quality - 18 - III. Experimental Apparatus and Procedure - 21 - 1.Experimental Apparatus .- 21 - 2.Experimental Procedure .- 24 - IV. Data Reduction - 27 - V. Discussion of Results .- 30 - VI. Conclusions and further studies - 39 - References .- 41 - Appendix A Experimental equipment selection - 44 - I Methodforselectingfans - 44 - II Methodformeasuringairflowrate - 53 - Appendix B Thermocouple Calibration .- 56 - Appendix C Raw Data - 62 - iii Listoftablesandfigures Figure Cross-flow and Counter-flow plate heat exchanger system -13Figure 2.Spiral plate and Flat-pipe Enthalpy heat exchanger system …-14Figure Hydrophilic Membranes and Enthalpy Wheel heat exchanger…………………………………………………………… …-15Figure Schematic of the cross-counter-cross flow plate-type exchanger -22Figure Details of component of filter unit and the airstream through the filter…………………………………………………………………… -23Figure Schematic diagram of the experimental apparatus the heat exchanger system…………………………………………………… -25Figure Photographs of the cross-counter-cross plate-type heat exchanger and the single piece of the heat transfer aluminum sheet………….……-31Figure Effectiveness versus spacing of aluminum plate for three air flow rates………………………………………………………………… …-32Figure Effectiveness in relation to length for three air flow rates… -34Figure 10 Effectiveness versus the air flow rate………………… ……-35Figure 11 The heat transfer rate versus the air flow rate………………-36Figure 12 Indoor and outdoor carbon dioxide concentrations with heat exchanger on and off .-37Figure 13 Detailed model of fans ventilation and combined with the heat exchanger system……………………………………………………… -38Figure 14 Actual pressure characteristics for fans ventilation ……… -51- iv Figure 15 Detailed schematic and photograph of fans ventilation….….-52Figure 16 Schematic diagram of the measurement apparatus of air flow rate…………………………………………………………….…………-54Figure 17 Setting positions of controllers for measure air velocity of fans………………………………………………………….………… -56- Table Basis specifications of the parameters used in the experiment -31Table Indoor standards for acceptable concentration of carbon dioxide [25]……………………………………………………………………….-37Table Detailed physical parameters of fans ventilation in heat exchanger system………………………………………………………………… -53- v Nomenclatures Atotal :Total surface area of heat exchanger [m2] c :Specific heat [J/kg°C] C : Capacity ratio, C C / C max Cmin :Capacity rate of the minimum fluid [W/°C] Cmax :Capacity flow of the maximum fluid [W/°C] h :Convection heat transfer coefficient [W/m2°C] kal :Thermal conductivity of aluminum [W/ m°C] m :Mass flow rate [kg/s] NTU :Number of Heat Transfer Unit Q :Heat transfer rate [W] t :Aluminum foil thickness [m] TOo :Temperature of outdoor air outlet [°C] TOi :Temperature of outdoor air inlet [°C] TIo :Temperature of indoor air outlet [°C] TIi :Temperature of indoor air inlet [°C] U :Overall heat transfer coefficient [W/m2°C] İ :Effectiveness of heat exchanger [%] İcross :Effectiveness of cross-flow arrangement [%] İcounter :Effectiveness of counter-flow [%] vi arrangement V :Volume flow rate [m3/h] vm :Mean specific volume [m3/kg] V :The ratio of the free-flow area to frontal area :The free-flow area [m2] c :The frontal area [m2] G :Mass velocity f 'p :The Friction factors f= [Pa] :Pressure-drop vii 24 Re