ZEMCH 2019 International Conference Proceedings April.2020 | Page 378
Figure 3. Temperature distribution with or without baffles inside air‐type PVT collector
Figure 4 is a graph showing the outlet temperature and the flow rate of each case of an air‐type
PVT collector with triangular baffles. Collectors with baffles (Case 1‐9) showed higher outlet
temperature and flow rate than reference collector. The higher the outlet temperature per case, the
slower the flow rate. The smaller the left and right spacing variable W1 (Case 1, Case 4, Case 7), the
faster the outlet flow rate and the lower the outlet temperature. This is because only the arrangement
had been changed while the baffle size was fixed, thereby creating a flow path space between all the
baffles. In Case 3, the length of W1 extended up to 144mm, and the outlet temperature was the highest
at 23.5 o C. In addition, as the number of baffles decreased with the change in the lengths of H1 and H2,
the outlet flow velocity was faster. In addition, in each case, the change in outlet temperature and flow
rate was greater when the length of H2 was longer than when the length of W1 was longer.
Figure 4. Outlet temperature and velocity of Air‐type PVT collector by Cases
3.2 Pressure Drop and Thermal Efficiency
Table 3 shows the pressure drop by case of the air‐type PVT collector with triangular baffles. Since
the reference collector had no baffles, turbulence did not occur, resulting in a low value of 0.2302 Pa.
Cases 1‐9 had a pressure drop caused by the baffles. However, the pressure drop did not differ
significantly by Case. This is considered appropriate because the collector material is aluminum, which
has a small coefficient of friction and is a single collector. There was a difference in the Pressure drop
value according to the length of W1, it can be seen that the longer the distance between the W1, the
more the vortex area reduced, the smaller the pressure drop value. In addition, the value of Cases 1‐6
were relatively low. It was analyzed that the number of baffles were higher than that of Cases 7‐9, but
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ZEMCH 2019 International Conference l Seoul, Korea