1. Air-conditioner -IDU Air-conditioner 2D Simplified model for Analysis

2. Domain size is 10 times the size of Cross flow fan diameter The atmospheric pressure is taken as the pressure boundary conditions at the inlet and outlet of the flow. The heat exchanger is modeled as the porous media, whose viscous damping factor and inertial damping factor can be obtained from the measured pressure drop across the two terminals of heat exchanger as functions of the inlet velocity. Inlet - Pressure Inlet (Stagnation Pressure) Outlet - Pressure Outlet RPM - 850-1150 Heat Exchanger- Porous Media Computational Domain Boundary Condition Grid-Independent Study

3. From the study, it is concluded that the thickness of the blade determines the total flow area and flow rate delivered. When the internal blade angle is at 90°, shock free entry is incurred and maximum flow rate can be achieved. The external blade angle should be within 20 to 45 degrees, to avoid rapid drop of pressure coefficient and efficiency. Lastly, the formation of the eccentric vortex zone inside the cross flow fan and flow field pattern are observed. The forming location and size of the zone determines the total air flow rate delivered and the amount of flow leakage through the tongue. Thus, the efficiency of the fan is highly sensitive to the flow structure in this zone. Cross Flow Fan parameters Blade Thickness Cross Flow Fan Parameters Flow Rate Comparison

4. Cross Flow Fan Geometry parameters Geometrical Parameters Geometry Analysis of Blade Profile

5. The study here clearly has shown that each design parameter of the cross flow fan influences the performance of the air conditioning unit. The following parameters are summarized as below a. The best performances for internal and external blade angles are at 90º and 25º, respectively. b. The effect of the fan diameter is examined by using the ratio of internal to the external diameters (D1/D2) where the optimum range should be within the range of 0.7 to 0.85. c.It is deduced that narrower shapes will give more space for the air flow to pass through while a wider shape will restrict the air flow passage as the overall flow area become less. d. The formation and position of the eccentric vortex zone will affect the air flow rate delivered by the particular cross flow fan. e. The gap between the tongue and fan moderately affect the flow rate because the gap allows some reverse air flow instead of being fully discharged out of the impeller. a. Improper design of casing affects the performance of the heat exchangers and eventually, affects the heat duty of the air conditioning unit. Literature Findings

6. Air flow test data sheet

7.  For the lower material cost and less refrigerant charge, fin-and-tube heat exchangers with smaller diameter tubes(smaller than or equal to 5 mm) gradually replace those with 7 mm or large diameter tubes.  The fin pitch, which depends on the tube diameter, is also decreased. These may decrease the heat transfer capacity and increase air side pressure drop. (Air-Side)  On refrigerant side, smaller tube may increase the refrigerant pressure drop, and decrease the heat transfer area of tube. (Refrigerant side)  In order to have a good performance of the air conditioner with smaller diameter tubes, it is necessary to propose a principle of designing fin-and-tube heat exchangers, including designing of fin configuration and tube circuits.  In fin configuration designing, the fin size and fin pattern which mainly affect heat transfer capacity and air pressure drop are designed by Computational Fluid Dynamic (CFD)-based method. indoor heat exchanger chooses the fin-and-tube with 5 mm diameter tubes, and the outdoor heat exchanger chooses the fin-and-tube with 7 mm diameter tubes which has larger fin pitch to prevent performance degradation due to frost in heat pump condition. Because fin-and-tube with 7 mm diameter tubes is already used in current air conditioner, this section will present the designing of fin-and-tube with 5 mm diameter tubes. Heat-Exchanger Fin