Physical (As Built) System
The final (i.e. as-built) design of the complete PV system is shown here; some variations were made to the final design shown previously, and these have been discussed. Images have also been provided detailing the completed manufactured components relating to the final design along with a short description of how they were made and any important features.
1. Diffuser Head/Control Temperature Sensor
2. High Voltage Housing
3. Testing Frame
4. Solid Pipe Section/Heaters/Orifice Plate
5. Fan/Mounting
6. Low Voltage Housing
The manufactured high voltage housing can be seen here. The HV housing contains both the transformer and the system relays. Full details of the components contained in the housing can be found in the Control system - Hardware sub-page linked here. The housing is used primarily for electrical safety but also to assist with cable management. Connections to the HV housing are made though banana plugs and sockets as shown.
The diffuser head was manufactured using 3mm hardboard which was cut, glued and varnished. The as-built design shows a slight variation from the final design generated from CFD. The difference was due to manufacturing constraints, and the final design held to the principles of the initial design. The control temperature sensor was also installed, through a small drilled hole, in the end of the flexible pipe before the diffuser head.
The testing frame for the experimental procedures was manufactured as a 0.5x0.5m wooden frame. The frame was strung with thin wire to give a square grid with spacing of 0.2m. On the intersections of the wires in the grid, 9 temperature sensors were mounted for the testing procedure. The numbering used for these sensors can be seen in the image provided. It is also worth noting that the humidity sensor was also positioned along with T5 in the centre of the testing frame.
A solid section of stainless steel pipe was used to mount the 40W cartridge heater elements. Holes for the heaters were drilled in a 2-1-2 arrangement: primarily to allow for adequate spacing for heat transfer, but with the added benefit of easily matching the heaters to the three relays.
Upon initial testing of the heaters we realised that they would quickly overheat and burn out. A decision was made to add small ring fins to the heaters, made from thin steel, in order to increase the surface area for heat transfer. Rough calculations indicate that the modified surface area is approximately 18 times greater than the initial surface area.
The initial fan selected was rated at 21m3/h. However, during the calibration period this was upgraded to a 40m3/h fan in order to provide a large velocity range during testing. The fan was mounted onto a small panel with a wire-mesh filter, and then glued to the first section of flexible pipe. The 60mm flexible pipe was made from durable plastic with wire reinforcement, outer diameter 72mm. The 5m pipe was cut into two 2.5m lengths which were attached to either end of the solid pipe section containing the heating elements.
The full manufactured low voltage housing can be seen here. The low voltage housing contains a number of components to allow the sensors to send data to LabVIEW via a 6008, send signals to operate relays and also a frequency operator to change the fan speed. Full details of the components obtained and their operation are shown in the Control System - Hardware sub page linked here. Once again the housing is used for electrical safety but also to assist with cable management. Connections to the LV housing are made though banana plugs and sockets again, along with a screw terminial for the live cables from the temperature sensors.
