Natural Ventilation in UK Schools during the heating season: Window design and performance using CFD

Transcription

1 Natural Ventilation in UK Schools during the heating season: Window design and performance using CFD Charalampos Angelopoulos, 1 st year PhD Student Loughborough University Professor Malcolm J. Cook, School of Civil and Building Engineering, Loughborough University, LE11 3TU, UK Dr Christopher R. Iddon, SE Controls, Hood Innovation Centre, Wellington Crescent, Lichfield,WS13 8RZ, UK. Dr Stephen M. Porritt, School of Civil and Building Engineering, Loughborough University, LE11 3TU, UK

2 Introduction Natural ventilation could maintain thermally comfortable internal environments 1. Low ventilation rates and indoor air pollutants could cause health issues 2. Poorly ventilated classrooms can have negative impact on cognitive function 3. Poor indoor air quality for UK schools 4,5. Draft BB101 revision sets specific criteria for internal air temperature and velocity to avoid wintertime discomfort Ji, Y., Lomas, K. J. & Cook, M. J. (2009). Hybrid ventilation for low energy building design in South China. Building and Environment, 44(11), pp Mendell, M. J. and Heath, G. A. (2005), Do indoor pollutants and thermal conditions in schools influence student performance? a critical review of the literature, Indoor air 15(1), Coley, D., Greeves, R. & Saxby, B. (2007). The effect of low ventilation rates on the cognitive function of a primary school class. International Journal of Ventilation, 6(2), pp Iddon, C. R. & Hudleston, N. (2014). Poor indoor air quality measured in UK classrooms,increasing the risk of reduced pupil academic performance and health. The Grand Hall, The University of Hong Kong, Indoor Air: The 13th International Conference on Indoor Air Quality and Climate. 5. Spentzou, E., Iddon, C., Grove, M. & Cook, M. J. (2016). Priority school building programme: An investigation into predicted occupant comfort during the heating season in naturally ventilated classrooms. REHVA. 6. EFA, Building Bulletin 101: Guidelines on ventilation, thermal comfort and indoor air quality in schools-draft June, London: UK Government.

3 Aim The aim of this project is: How natural ventilation systems, sized for delivering summertime cooling, should be controlled to avoid wintertime discomfort.

4 Classroom geometry

5 Methodology Evaluation Criteria ΔT(min.maintained operative temp-plume air temperature) [K] 4 Maximum air velocity [m/s] 0.3 Maximum internal air temperature [ o C] 25 Ventilation rate [l/s/p] 8

6 Conclusions Single-sided natural ventilation suitable for: Outside air temperature above 8 o C. Wind speeds below 10m/s. The placement of furniture was essential to eliminate cold draughts. Majority of occupants most probably satisfied. Window configuration slightly affect the internal conditions. Positive correlation between wind speed & internal air velocities. Negative correlation between ventilation rate and wind speeds.

7 Natural Ventilation in UK Schools during the heating season: Window design and performance using CFD Charalampos Angelopoulos, 1 st year PhD Student at Loughborough University Professor Malcolm J. Cook, School of Civil and Building Engineering, Loughborough University, LE11 3TU, UK Dr Christopher R. Iddon, SE Controls, Hood Innovation Centre, Wellington Crescent, Lichfield,WS13 8RZ, UK. Dr Stephen M. Porritt, School of Civil and Building Engineering, Loughborough University, LE11 3TU, UK