Positive Pressure Screening Cabinet for Reducing the Spread of SARS-CoV-2 to Healthcare Workers
Keywords:
positive pressure screening cabinet, COVID-19, UVC, ultra-low penetration air filterAbstract
This research aims to design and build a Positive Pressure Screening Cabinet (PPS-cabinet) to reduce the spread of COVID-19 among healthcare workers. The PPS cabinet has an internal area of 1.44 m2 and a height of 2 m. It is equipped with an inverter air conditioner. Behind the PPS cabinet is a set of decontamination and disinfection units. The variable-speed fan draws outside air through the decontamination and disinfection unit and sends clean air into the PPS cabinet. The 3-speed fan inside the air conditioner blows cold air at about 26 °C directly to the healthcare workers. The air then flows from the cabinet to the outside through the leaks of the cabinets, arranged in three levels: 187, 220, and 253 cm2. The air pressure inside the cabinet can be controlled to a value in the range of 5–15 Pa. The results showed that the appropriate fresh air flow rate to be fed into the PPS-Cabinet must have a flow rate in the range of 150–335 m3/h. The minimum fresh air flow rate of 150 m3/h corresponds to the fan operation
inside the air conditioner at the lowest speed, while the maximum air flow rate of 335 m3/h corresponds to the maximum leakage area of the cabinet of 253 cm2 making the pressure inside the PPS cabinet not more than 15 Pa. Therefore, to ensure that no air flow inside the cabinet returns to the air conditioner under all operating conditions, the fan flow rate in the air conditioner should be adjusted to the lowest speed. In terms of energy consumption, air conditioners use the most energy, followed by fans, disinfection lamps, and lighting at 46%, 35%, 11%, and 8%, respectively. When the PPS cabinet was used for 26 weeks, more dust and contaminants were clogging the filters. This results in an increase in the pressure drop across the filter unit by approximately 20–30 Pa, resulting in 15% more energy consumption compared to the new PPS-Cabinet.
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