ZEMCH 2019 International Conference Proceedings April.2020 | Page 44
105
50
95
48
90
/ h)
100
85
80
75
44
42
70
65
60
46
40
Pre-fiter
H11
H12
Pre-fiter
H13
H11
H12
H13
Filter Grade
Filter Grade
Figure 4. Variations of air flow rate by
the filter grades
Figure 5. Variations of power
consumption by the filter grades
3.1.2. Air leakage rate results
The air leakage rate test was performed through the CO2 generator, and the results of the air
leakage rate and amount of effective ventilation are shown in Figure 6. Table 3 shows the amount of
CO2 gas entering RA and released to SA. Air Leakage rate calculation formula is as formula (2). As the
grade of HEPA filter increased, the air leak rate increase and the effective ventilation amount decreased.
Experiments results show that the higher the filter, the higher the leak rate due to pressure changes. As
the leak rate increased, the effective ventilation of the heat‐recovery ventilator decreased.
9
97
96
7
95
6
94
5
93
4
92
3
8
Pre-filter
H11
H12
H 13
Filter Grade
Figure 6. Air leakage rate and effective ventilation amount according to filter grade
3.1.3. Total Heat Exchange Efficiency and Energy Factor
As a result of previous studies, the heat exchange efficiency is increased when the passing wind
speed of the heat recovery type ventilator decreases or the contact area between the air and the heat
exchange element is large. The higher the grade HEPA filter is used, the higher the pressure loss, the
smaller the wind speed and the higher the heat exchange efficiency. However, as the air leakage rate
increases, the effective total heat exchange efficiency decreases. Figure 7 shows the values of the total
heat exchange efficiency which were tested under the cooling and heating temperature conditions for
each filter and the effective heat exchange efficiency applied to the leakage rate. Figure 8 shows the
results for the energy factor, which is the correlation between power consumption and total heat
exchange efficiency. The change of the energy coefficient decreased with higher grade of filter. The H13
filter, when tested under heating temperature conditions, showed an energy coefficient of 14.777, which
is lower than 15.000, which is currently specified in the Korean Association of Air Conditioning
Refrigerating and Sanitary Engineersʹs standards.
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ZEMCH 2019 International Conference l Seoul, Korea