the enhancement efficiency performance of evacuated tube with heat pipe
solar collector by additional fins using two-way variance analysis
Abstract
This research highlights the possibility of increasing the thermal
efficiency of evacuated tube solar collectors by adding fins to the
factory fin without changing it. The goal is to harness solar energy at
the lowest cost, smallest area, and best thermal performance by using a
solar collector with evacuated tubes and heat pipes. The evacuated tube
consists of two concentric glass tubes with a vacuum between them. The
inner tube contains a carefully selected absorbing layer to obtain the
highest absorption. The collector also contains an aluminum fin
connected to the absorbing surface on one side and the heat pipe on the
other side. Adding additional fins fixed between the fin on the
evacuated tube side and the side of the fin connected to the heat pipe,
and this addition leads to increasing the heat transfer efficiency
because aluminum has a higher conductivity than air, and holes in adding
fins get more turbulent, leading to cracking boundary layer and increase
heat transfer. Aluminum discs with holes of different diameters were
added. The diameters of the holes were calculated as follows (4, 6, 8,
and 10) mm, with the number of discs fixed at ten discs for each of the
five evacuated tubes in each case, as the experiment consists of two
solar collectors, each of which consists of five tubes, the first within
the factory specifications and the second to which the above discs were
added. To validate the results of the experiment, SPSS was used under
identical conditions for the two devices above, and the data were
analyzed. The output of the experiment was Tout, and the readings used
were the results of the two devices at a flow rate of (0.5, 1.0, 1.5)
l/min. The significance criterion was 95%, which was used to evaluate
the results of the study and the effectiveness of the additives by
comparing the significance calculated at a threshold of 0.05. The model
is ranked if the two elements on which the reliability depends are less
than a point or 0.05. It is effective in terms of flow rate and type of
improvement. If the estimated value exceeds the point or 0.05 limits, no
improvement or data analysis will be based on the flow rate and type of
increase.