Natural Ventilation

in Traditional Courtyard Houses

in The Central Region of

Saudi Arabia

Data Analysis


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Thermal Performance

 

The indoor to outdoor air temperature, Figure 6.5, shows that when the outdoor air temperature increases, the indoor air temperature is lower by 5�C. When the outdoor air temperature decreases, the indoor air temperature is higher by 7�C. Table 6.2 illustrates diurnal temperature variation values and thermal lag obtained from the field work in the first and second case study only.

Room code  

Outdoor Air

Indoor Air  

Surface temperature  

Thermal lag

GR1H1  

16.67  

6.23  

1.99  

4 h

GR2H1  

16.67  

5.09  

1.9  

4 h

EBR1H1  

14.47  

4.39  

2.06  

4 h

SBR1H1  

14.47  

4.98

2.01

4 h

WBR1H1  

14.47  

4.76  

2.14

4 h 

GR1H2  

13.4  

3.29  

1.94  

2.5 h

EBR1H2  

13.4  

3.00  

0.81  

2.5 h

WBR1H2  

13.4  

2.73  

0.9  

2.5 h

 

Diurnal temperature variations for the first and second case study

 

The temperature related data will be used in connection with the computer modelling analysis of the thermal performance of the building presented in Chapter Eight.

 

Ventilation Rates

 

The smoke decay graphs relates to the rate of air change in each room. The primary requirement is that, each graph must be checked to locate the point of maximum smoke concentration and the point at which it starts to decline. This will be the point at which the smoke decay analysis started. When the curve reaches the zero level set previously, natural ventilation will have cleared the smoke from the room. This part of the curve, shown between the red lines in the previous smoke decay curves, is converted into a straight line, the slope of which is the rate of air change for the room.

The next  figure will show two curves, the first will exhibit the part of the smoke decay curve where the concentration is higher and at the same time starting to decay. The second curve is the logarithmic conversion (LN) of this first curve to obtain the slope which will represent the number of air changes in the room. The reminder of the figure is a regression analysis of the LN curve to obtain the slope of the line which will represent air changes per second. This number will be multiplied by 3600 so that the final value will be AC/ H.

 

 

 

 

Figure 6.35: Data analysis for GR1H1

 

 

Figure 6.50: Summary of the analysis of smoke decay tests in all tested rooms in all cases