Module B1 Study Book - the Graduate School of the Environment

4. Equipment
h. gain
No. of equipment
KW / equipment G a i n
(Tell machines and printers)
(kW)
3 0.2 0.6
5. Lighting heat gain Floor m 2 Light energy kW/m 2
G a i n
Low energy lighting
(kW)
150 0.025 3.7
Total heat gain to be ventilated = 16.3 kW
Less stratification effect (less 5% from 4m to 5m)
Net heat gain = 15.5 kW
= 0.8 kW
Maximum ventilation required due to the above heat loads
Net heat gain = 15.5 kW
Dinning hall volume = 630 m3
Air density = 1.2 kg /m3
Temperature difference (dt) = 5 Co
Specific heat of Air (cp) = 1.01 kJ/ kg K
Rate = 2.56 m3/ second = 14.6 ac/hr
Reduction factor / ventilation systems to reduce heat loading:
Estimated building infiltration rate = 0.5 ac/hr
Effective contribution from windows and doors = 4.0
Air flow required for Wind catcher = 10.1 ac/hr
Estimated ventilation rate
Table below is based on a 1 to 5 m/s wind speed range. The Met office states
an average wind speed across the UK is approximately 4 to 4.5 m/s. however
2 to 3 m/s is adopted as target wind speed for worst-case scenario.
Table-2
Air Flow Volume Ac/hr due to wind from 1 to 5 m/s at temperature difference 5 C o
Rate Dining 1 m/s 2m/s 3m/s 4m/s 5m/s
2 x 1000 360 5.1 8.5 12.2 16 19.8
Result
The Dinning Hall with a target heat gain of 15.5 kW and 10.2 ac/hr, it obvious
from the table-2 that two number of wind catchers are predicted to provide
the target ventilation rate to dissipate total heat gains.
B - Thermal Model for Summer Over Heating Conditions
In order to comply with the requirement of Building regulations, Approved
Document Part F, 2006 and Building Bulletin 101, 2006; for summertime
190 Student Essay: Ishaq Muhammad