Abstract
Biological fouling (biofouling) on cooling coil surfaces acts as thermal insulation, impeding heat transfer from air to coil surfaces, decreasing airside heat transfer coefficient and degrading coil cooling capacity. It is also a common cause of low ΔT syndrome in chilled water distribution systems. The effects of a commercially available ultraviolet germicidal irradiation system installed in a variable air volume system on the airside heat transfer coefficient, cooling coil capacity, and its potential to mitigate low ΔT syndrome were investigated via a field test. Energy-related measurements including chilled water supply/return temperature, water-/airflow rate and entering/leaving air temperature/relative humidity commenced 4 months before turning on ultraviolet lamps and continued for 10 months after ultraviolet germicidal irradiation intervention. The effects of the ultraviolet germicidal irradiation system were evaluated via a “before ultraviolet” and “after ultraviolet” comparison. After ultraviolet intervention, within the face velocity range of 1.5–3.0 m/s, the airside heat transfer coefficient increased by 11.8%–20.1%, which translated into 8.8%–10.2% increase in the overall enthalpy-based thermal conductance. The coil total cooling capacity and latent cooling capacity increased by 3.3%–3.8% and 4.5%–5.7%, respectively. The chilled water flow rate required to maintain the leaving air temperature set-point decreased by 8.0%–11.9% and the water-side temperature difference increased by 0.4°C–0.6°C.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 582-593 |
| Number of pages | 12 |
| Journal | Science and Technology for the Built Environment |
| Volume | 23 |
| Issue number | 4 |
| DOIs | |
| State | Published - May 19 2017 |
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All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Building and Construction
- Fluid Flow and Transfer Processes
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Effects of an ultraviolet coil irradiation system on the airside heat transfer coefficient and low ΔT syndrome in a hot and humid climate. / Wang, Yi; Sekhar, Chandra; Bahnfleth, William P.; Cheong, Kok Wai; Firrantello, Joseph.
In: Science and Technology for the Built Environment, Vol. 23, No. 4, 19.05.2017, p. 582-593.Research output: Contribution to journal › Article
TY - JOUR
T1 - Effects of an ultraviolet coil irradiation system on the airside heat transfer coefficient and low ΔT syndrome in a hot and humid climate
AU - Wang, Yi
AU - Sekhar, Chandra
AU - Bahnfleth, William P.
AU - Cheong, Kok Wai
AU - Firrantello, Joseph
PY - 2017/5/19
Y1 - 2017/5/19
N2 - Biological fouling (biofouling) on cooling coil surfaces acts as thermal insulation, impeding heat transfer from air to coil surfaces, decreasing airside heat transfer coefficient and degrading coil cooling capacity. It is also a common cause of low ΔT syndrome in chilled water distribution systems. The effects of a commercially available ultraviolet germicidal irradiation system installed in a variable air volume system on the airside heat transfer coefficient, cooling coil capacity, and its potential to mitigate low ΔT syndrome were investigated via a field test. Energy-related measurements including chilled water supply/return temperature, water-/airflow rate and entering/leaving air temperature/relative humidity commenced 4 months before turning on ultraviolet lamps and continued for 10 months after ultraviolet germicidal irradiation intervention. The effects of the ultraviolet germicidal irradiation system were evaluated via a “before ultraviolet” and “after ultraviolet” comparison. After ultraviolet intervention, within the face velocity range of 1.5–3.0 m/s, the airside heat transfer coefficient increased by 11.8%–20.1%, which translated into 8.8%–10.2% increase in the overall enthalpy-based thermal conductance. The coil total cooling capacity and latent cooling capacity increased by 3.3%–3.8% and 4.5%–5.7%, respectively. The chilled water flow rate required to maintain the leaving air temperature set-point decreased by 8.0%–11.9% and the water-side temperature difference increased by 0.4°C–0.6°C.
AB - Biological fouling (biofouling) on cooling coil surfaces acts as thermal insulation, impeding heat transfer from air to coil surfaces, decreasing airside heat transfer coefficient and degrading coil cooling capacity. It is also a common cause of low ΔT syndrome in chilled water distribution systems. The effects of a commercially available ultraviolet germicidal irradiation system installed in a variable air volume system on the airside heat transfer coefficient, cooling coil capacity, and its potential to mitigate low ΔT syndrome were investigated via a field test. Energy-related measurements including chilled water supply/return temperature, water-/airflow rate and entering/leaving air temperature/relative humidity commenced 4 months before turning on ultraviolet lamps and continued for 10 months after ultraviolet germicidal irradiation intervention. The effects of the ultraviolet germicidal irradiation system were evaluated via a “before ultraviolet” and “after ultraviolet” comparison. After ultraviolet intervention, within the face velocity range of 1.5–3.0 m/s, the airside heat transfer coefficient increased by 11.8%–20.1%, which translated into 8.8%–10.2% increase in the overall enthalpy-based thermal conductance. The coil total cooling capacity and latent cooling capacity increased by 3.3%–3.8% and 4.5%–5.7%, respectively. The chilled water flow rate required to maintain the leaving air temperature set-point decreased by 8.0%–11.9% and the water-side temperature difference increased by 0.4°C–0.6°C.
UR - http://www.scopus.com/inward/record.url?scp=84992522095&partnerID=8YFLogxK
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U2 - 10.1080/23744731.2016.1232115
DO - 10.1080/23744731.2016.1232115
M3 - Article
AN - SCOPUS:84992522095
VL - 23
SP - 582
EP - 593
JO - Science and Technology for the Built Environment
JF - Science and Technology for the Built Environment
SN - 2374-4731
IS - 4
ER -