Effectiveness of air-well type courtyards on moderating thermal environments in tropical Chinese Shophouse
Summary (2 min read)
Introduction
- In tropical climates cooling and dehumidification accounts for a major portion of energy consumptions in buildings (Kubota and Toe 2008).
- Pervious research demonstrated that the use ofmultiple connected air-wells with staggered form, i.e. courtyards situated between buildings of different heights, was able to improve cross ventilation and to increase indoor air velocity of intermediate spaces in the CSH with deep plan (Kubota et al. 2017).
- This results in lower indoor air temperature during daytime peak hours.
- The air-well type courtyards used in the Southeast Asian CSHs compliments its long narrow form.
- Research is needed to understand the effectiveness of the air-well type courtyard on moderating indoor thermal environment in these tropical CSHs.
Methodology
- The city ofMalacca and selected shophouses Malacca is a tropical city located at 2°11′45′′.
- The seasonal climatic change is dominated by the monsoons.
- House 2 has one air-well type courtyard and a backyard.
- There are no high-rise buildings surrounding the site.
Fieldmeasurement
- Figures 13 and14 show temporal variations ofmeasured air temperature at different locations with the corresponding outdoor weather conditions.
- Rooms located between air-well courtyards and backyards also had lower heat gain during daytime which only resulted in a 0.2–0.6°C increase in daytime peak air temperature compared to the rooms located at the front of the two houses.
- Therefore, equal variance is not assumed and the results are interpreted using Welch ANOVA and Games-Howell post hoc test.
- During this period of time, when the outdoor air temperature is expected to be relatively low, temperature and HI show a statistically significant medium and negative association with indoor air velocity.
Airflow simulation
- Table 5 summarizes the means and standard deviations for normalized age of air and air velocity for the measured rooms under the three different scenarios in House 1 and 2.
- Results of one-way ANOVA for air temperature and HI for measured locations.
- Therefore, equal variance is not assumedand the results are interpretedusingWelchANOVAand followed up with Games-Howell post hoc analysis.
- In House 1 during scenario V2, the mean value of normalized age of air in R1 was statistically significantly higher than all other rooms in the house.
Discussion
- This study provides evidence for the potential of cross ventilation of intermediate spaces through the air-well in the Chinse Shophouse.
- Levene’s test for equality of Variances ANOVA Robust tests of equality of means Measured parameter Location Condition F Sig.
- The rooms located near air-well courtyards on the ground floor level had better overall day and night-time thermal environments compared to all other spaces in the houses.
- A significant increase in air velocity of 0.2m/s was observed in spaces between air-well courtyards (House 1-R2, R5) when the building was only ventilated from the air-well (V3) as opposed to supplemented ventilation from rear openings (V2).
- CSH which only had deep/closed type of air-wells (such as those found in the CSH used for this survey) had better thermal environments than those which had a combination of deep/closed type and small/staggered type.
Conclusion
- The CSH in Southeast Asia represents a climatic and socio-economic adaption from a subtropical to a tropical climate.
- This study investigates the effectiveness of the air-well type courtyard for indoor thermal environments in a tropical CSH.
- The cooling potential of wind induced ventilation through the air-well courtyard is apparent when the wind flows in parallel to the longer axis of the building and the intermediate spaces are cross-ventilated via several air-well courtyards.
- First, the field measurement was conducted on one fair weather day.
- The selectedCSHs in this research represent the deep and closed air-well type (Type5)which typically has lowerdaytime temperatures and higher night-time air temperature.
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Citations
155 citations
Cites background from "Effectiveness of air-well type cour..."
...In developing countries in the tropics, however, the practice of constructing sustainable and climate-responsive buildings with low carbon emissions and high building performance, such as traditional shop houses with courtyards in Southeast Asia, has a long history [28]....
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112 citations
40 citations
Cites background from "Effectiveness of air-well type cour..."
...In tropical climates, buildings are exposed to high solar radiation throughout the whole year; therefore, these buildings are greatly dependent on air-conditioning to provide occupants with comfortable thermal environments [3,4]....
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15 citations
Cites background from "Effectiveness of air-well type cour..."
...o bining field survey and F si ulation, ajishani a age provides evidence for the potential of cross ventilation of inter ediate spaces through the air- ell in the hinse Shophouse [55]....
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...Combining field survey and CFD simulation, Wajishani Gamage provides evidence for the potential of cross ventilation of intermediate spaces through the air-well in the Chinse Shophouse [55]....
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...Moreover, intermediate spaces next to the air-wells had significantly lower air temperature and heat index [55], the courtyard has a relatively small impact on the closed space, so the impact of courtyards on building energy consumption is not significant....
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...“ ourtyard buildings” ca e into being. o bining field survey and F si ulation, ajishani a age provides evidence for the potential of cross ventilation of inter ediate spaces through the air- ell in the hinse Shophouse [55]....
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8 citations
References
48 citations
"Effectiveness of air-well type cour..." refers background in this paper
...The passive performance of an indoor courtyard in a tropical climate is primarily dependent on shading and ventilation (Hoseini et al. 2014)....
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47 citations
"Effectiveness of air-well type cour..." refers background in this paper
...…research demonstrated that the use ofmultiple connected air-wells with staggered form, i.e. courtyards situated between buildings of different heights, was able to improve cross ventilation and to increase indoor air velocity of intermediate spaces in the CSH with deep plan (Kubota et al. 2017)....
[...]
...A comparison study of thermal environments in 16 air-well courtyards in Malacca reveals that daily maximum air temperature in the air-well is mainly influenced by its openness and depth (Kubota et al. 2017)....
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...The findings from the field measurement echo pervious research that spaces adjacent to air-wells had better thermal environments thanother spaces in a CSH (Kubota et al. 2017; Toe and Kubota 2015)....
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...Kubota et al. (2017) classified five air-well type courtyards found in the CSH according to their forms and characteristics that affect the profiles of their thermal environments....
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...Kubota et al. (2017) found that the design characteristics of air-wells had a significant influence on the daytime thermal environment of the CSH and did not significantly influence the night-time thermal environment....
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44 citations
"Effectiveness of air-well type cour..." refers methods in this paper
...Thewind tunnel experiment carried out by Karava (2008) was used for cross comparison with the CFD simulation to check the validity of the simulation tool....
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20 citations
"Effectiveness of air-well type cour..." refers background or methods in this paper
...Ground floor layout plan of CSH: (a) CSH in Malacca (adapted from Tan 1988), (b) CSH in Singapore (adapted from Davison and Tettoni 2011), and (c) CSH in Penang (adapted from Omar and Syed-Fadzil 2011)....
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...These CSHs’ like others found in the old cores of tropical port cities such as Singapore, Penang and Batavia have simple elongated plans, multiple air-wells and narrow corridors (Omar and Syed-Fadzil 2011) (Figure 4)....
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18 citations
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Frequently Asked Questions (2)
Q2. What future works have the authors mentioned in the paper "Effectiveness of air-well type courtyards on moderating thermal environments in tropical chinese shophouse author" ?
Further research is needed to validate the effectiveness of wind induced ventilation through the air-well at different wind speeds and orientations. This study needs to be extended to analyse the influence of other air-well typologies in the CSH and their combined influence on the effectiveness of cross ventilation through the air-well to improve the indoor thermal environment of the CSH.