the impact of exterior environmental comfort on ... · space is the main area for exterior...

11412nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

The Impact of exterior environmental comfort on residential behaviour from the insight of building energy conservation: a Case study on Lower Ngau Tau Kokservation: a Case study on Lower Ngau Tau Kok: a Case study on Lower Ngau Tau Kok estate in HongkongHongkong

Y. XiongXiongThe Chinese University of Hongkong, Chinahe Chinese University of Hongkong, ChinaUniversity of Hongkong, China of Hongkong, China

the subjective responses of occupants’ behavior seldom are considered. Thus, there is a need of more in-depth studies, especially in the condition of Hongkong, low per capita residential area, many residents have to “bor-row” outdoors environment to gain bigger living space. Still exterior environment without considering of the di-versity of human behaviour always can not satisfy resi-dents’ needs indeed (Steemer, 2004). Lack of embedded research, designers can not completely understand why the residents’ behaviour is so different from what they assumed (e.g. the contrast of colorful activities in old colorful activities in oldcolorful activities in old public housing estate and poor activities in new privatepoor activities in new privateactivities in new private new privatenew private housing) and how establish more suitable design strate-gies for housing energy conservation considering hu-man behaviour. In this paper, the case study about Lower Ngau Tau Kok Estate in Hongkong will provide us some significant in-formation for debate on housing layout, building form, residential activities and building energy conservation. The forty years old public housing estate, most of resi-dents are elders, is full of open space and friendly com-munity activities. It will be very representative for the. It will be very representative for thet will be very representative for the research of impact of exterior environmental comfort on residential behavior from the insight of building en-ergy conservation.servation..

2. METHODOLOGYMETHODOLOGY

In this framework, the case study is conducted through four parts work. Firstly, investigation data on the pilot including building layout and form, air temperature, sun shading, wind velocity, wind direction will be recorded. Secondly, observation and interview about residents’ behaviors will be presented. Because most of the resi-dents are elders and some of them even can’t read and write, we use more interviews than questionnaires. Thirdly, computer simulation about wind and shadow ofwind and shadow ofshadow of buildings based on Airpak (one software based on Com-one software based on Com- software based on Com-putational Fluid Dynamics) and Ecotect (one softwareone softwaresoftware for analyzing building performance including energy analyzing building performance including energy building performance including energy efficiency, sun shading, etc.) will be done. The last step is to compare the investigation data with simulation re-sults and illustrate the coherence of residents’ behaviors

ABSTRACT

This paper presents the results of a case study in Low-paper presents the results of a case study in Low-a case study in Low- study in Low-study in Low-n Low- Low-er Ngau Tau Kok Estate in Hongkong, which try to in Hongkong, which try toHongkong, which try tokong, which try toong, which try to try to find the relationship between exterior environmental comfort and residents’ behaviors, especially for an elder’ behaviors, especially for an elder behaviors, especially for an elderbehaviors, especially for an elder, especially for an elder community. Filed thermal parameters measurement, observation and interview on residents’ behaviors andand interview on residents’ behaviors and on residents’ behaviors and’ behaviors and behaviors andbehaviors and and some simulation about wind and building shadow arebuilding shadow are are conducted. The results show residents’ behaviors are’ behaviors are behaviors are affected compactly with exterior environmental comfortcomfort based on physiological microclimate facts, such as wind velocity, air temperature and shading, and psychological facts including security, desire of communication anddesire of communication and self-cognition, perceived control of environment, etc., perceived control of environment, etc. All these elements must be considered in terms ofll these elements must be considered in terms ofthese elements must be considered in terms of elements must be considered in terms of housing design for encouraging more people to utilizencouraging more people to utilizeing more people to utilize outdoor space and reduce indoor energy consumption.indoor energy consumption. energy consumption.

1. INTRODUCTIONINTRODUCTION

A great deal of residential building energy consumption results from maintaining comfortable interior environ-ment for human activities, such as required temperature, humidity, ventilation, flesh air, lighting, etc. In order to reduce energy consumption, architects and engineers have developed many new technologies and building materials to enhance building’s energy efficiency per-formance. Most of these struggles are devoted to inte-rior physiological thermal comfort and dominated by a series of physical parameters. Actually, comfortable exterior environment, where attract residents go out and utilize more nature environment instead of staying home and consuming more energy, are also very impor-tant and effectual for building energy conservation. There have been some discussions about how the exte-rior environment comfort determined by housing layout and building form affect the residents’ behaviour (Nikol-opoulou et al, 1999, 2001, 2003; Marialena Nikolo-poulou et al, 2003; Steemer, 2004; Letícia Zambrano et al, 2006). However, these studies prefer to involve a mathematical model of the thermoregulatory employed for calculating the thermal comfort conditions, whereas

PALENC 2007 - Vol 2.indd 1141 7/9/2007 1:26:19 µµ

1142 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

to exterior environment. Certainly, there also are some explanations for how the complexity of residents’ be-haviors results in the gap between reality and assump-tion from psychology perception. The field work took place in August, summer time in Hongkong. 23 points on garden and playground (out-door) and 17 points at the entrance and open corridor (semi-outdoor) were recorded at the height of 1.1m from the ground surface. Three days of observation were conducted from 9:00am to 6:00pm involving al-most 100 objects and 17 interviewers.

3. BACKGROUND OF lOWER NGAU TAU KOK ESTAEThe Lower Ngau Tau Kok Estate was completed inin 1967, located at the northern part of Kwun Tong Dis-trict, next to Kowloon Bay (Fig 1). In that time Hon-gkong’s land supply was in short and there were many people in need of resettlement either living in squatter area or made homeless by natural disaster. The Lower Ngau Tau Kok Estate comprises of many improvement in provision for this type of low rent affordable housing. Some description of this estate as following::Apartment Configuration -Private Balcony with Toilet -Single room, self partitioning -Electricity and water supply -14-27sq.m for 4-8 personsBuilding Configuaration-Central Corridor Access -Lift access to 8/F and 13/FFacilities within the Estate -Schools and Kindergarten -Playground -Shops

Figure 1: Lower Ngau Tau Kok Estate’s location and buildings

In the case of Lower Ngau Tau Kok Estate, the open space is the main area for exterior activities. We can find seven spots which attractive elders mostly (Fig 2). Also, here is some commerce along the ground floor near to road and it is very important for local residents’ daily lives. Game zone and play ground mostly services for children and teenagers.

Figure 2: Lower Ngau Tau Kok Estate’s layout and main exterior space for activities

23 outdoor points and 17semi-outdoor points distribute as following figure (Fig 3), measure variables include air temperature, wind direction and velocity on these points.

Figure 3: Observation points distribution

4. RESULTS AND DISCUSSION

4.1 Behavior observation and interview observation and interviewWe can find many kinds of activities of elders in this es-tate, such as walking, sitting, reading, chatting, playing chess, sleeping, dining, taking exercise, etc. There are also some children playing games and teenagers play-ing basketball and football (Fig 4).Elders’ activities are for relaxation and killing time. They like to go to where there are lots people and with a good thermal comfort.Children and teenagers’ activities are for amusement and exercise. They always play at afternoon when they and their parents have time while ignoring their thermal comfort.



Figure 4: all kinds of activities in exterior area

Selection of occupancy condition is regarded as a form of behavioral adaptation (Junta, 2004). Because most of these activities are for leisure, residents prefer to stay at more comfortable place to enjoy their life. From the interview with elders (Tab 1), we find they don’t satisfy with this estate greatly because of dirty, noisy and the deficiency of facility for elders. But in generally, they like to live there and have a quiet room for their remain-der life. Many residents even can’t answer why they choose a place to stay; they just go out and sit with oth-ers. Feeling of adscription to a group is very important for these elders.Table 1: four interviewers’ response for there living environment

4.2 Measurement and Simulation results Based on Airpak, we simulate the wind environment of Ngau Tau Kok Estate. The simulation model is de-scribed as following:- Boundary size: 4000 x 5000 x 420m- Wind Speed: 4.3m/s- Wind Direction: 135°- Mash node number: 1165715- Other buildings included: Telford Gardens, Amoy Gardens, Siu King Building

Figure 5: Simulation of wind velocity at 1.1m

From the simulation results, some findings can be drawn as follows.− Though the reference wind velocity is 4.3m/s and di-rection is 135 degree, the wind flows in this estate are relatively quiet and in very different directions.in very different directions. different directions.− Wind velocity and direction have a close relationship to building height and housing layout. At the same time, the windward building effect the wind flow badly, espe-cially for tall building. − Higher ratio of building height to between distances, worse wind environment will appearances. Higher speed wind always exits in the narrow gap between tall buildings. Compare the simulation results with the field measure-ment, we find they are not coherent very well (Fig 6). The reason comes from the disagreement of measuring time. We can’t ensure all the 23 points are recorded at


1144 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

the exactly same time. Real wind direction and velocity changed greatly.Using the simulation picture carried out by Ecotect, we can find the daylight of open space in this estate is com-fortable for elders in summer (Fig 7). Actually, even at noon, the main open space is in the shading of plants or shelter. Because our survey took place from 13th Octo-ber 12th December, the average outdoors temperature is around 24~30 Centigrade, elders are more like to stay at shady and cool area. We guess that elders prefer to stay in the playground or other areas full of sun light in winter.

Figure 6: Comparison of wind velocity and direction

Figure 7: from left to right, up to low, simulant building shadow in 1,1,2006 at the time of 7:10am, 10:00am, 12:00am, 14:pm, 16:00pm and 17:35pm

They temperature in shadow is lower because of less radia-tion coming from ground surface. This is why those areas

with more shadow can attract more people usually. From the field investigation showed in the figure 2, we also can find the main seven points for activities are surrounded by lots of trees. But it also means elders will feel cramped in the main open space and surrounded by buildings.

4.3 Some discussions4.3.1 Thermal comfort and adaptationThermal comfort is the one important criteria by which evaluate the environment performance, especially for indoor space based the Heat balance models (Brager, 1998). Whereas in the buildings with natural ventila-tion, the conventional PMV model can not explain why people have wider comfort range (Humphreys, 1998). So, thermal adaptation was recognized and developed by many researchers. The adaptation can be classified into three categories: behavioral adjustments (personal, environmental, technological, or cultural), physiologi-cal adjustments (genetic adaptation or acclimatization) and psychological adjustments (habituation or expecta-tion) (Brager, 1998).In outdoor area, the same thing also happens. People can accept more rigorous thermal conditions, espe-cially when they have some psychological requirement. In this case study, elders in old public house want get more communication with others, so they choose rela-tive comfort areas to meet more people and kill time. Although these areas are not completely comfortable in terms of physiology, the elders can tolerate basing on their thermal adaptation.

4.3.2 Environmental psychology and elder’s behaviorsEnvironment and occupants’ behavior have some inter-active relationship, although it is not inevitable all the time (Canter, 1975). The occupants’ behaviors response to environmental physical stimulus through percep-tual judgment, learning, development, finally adapt to or modify environment. In other words, housing en-vironment can influence residents’ behaviors by forms, color, materials, smell, temperature, and so on which can stimulate occupants’ vision, hearing, touch, thermal sensation and feeling. On the other hand, the elders’ residential behaviors are very different to normal adults because of the ag-ing of their body organizations arouses degradation of physical function and sensation function. At the same time, elders quit the stage of work gradually and spend more time in home and living community. Good exte-rior environment in housing estate is especially impor-tant for elders. Their requirement for security, health, familiarity, stability, convenience and communication with others is obviously higher than normal people (Pu Congrong, 1998). In comfortable exterior environment design, all these criterias must be considered carefully.s must be considered carefully. must be considered carefully.



4.3.3 Limitation of this case studyThis study was carried on summer and only several diur-nal circumstances were investigated. We can’t predict the elder’s behaviors characters out of the period of 9:00am to 6:00pm in one day and in other seasons. At the same time, we only recorded air temperature, wind direction, wind velocity and building shadow. Many important parameters, such as radiation temperature, illumination, humidity, clothing value and acoustic value, should be monitored in later study for more accuracy and validity.

5. CONCLUSIONS

Some findings from the case study on Lower Ngau Tauome findings from the case study on Lower Ngau Tau Kok Estate can be drawn as follows. − Wind velocity and direction have a compact relation-compact relation- relation-ship to building height and housing layout. Higher ratio of building height to between distances, worse wind en-vironment will appearances. − The opening on the ground floor, especially at the junction of two building slat, can bring cross ventila-tion. Elders like to sit there and observe other people passing by not because the comfort temperature but also the communication with others. − Shading plays an important role to attract elders to get together by supplying good temperature, ventilation and relative quiet area without interruption. People like the flourish in their group but so�e distance to outside for security and self-cognition.− Residents prefer to open front door and window to get natural ventilation if they have close relationship withclose relationship with relationship with their neighbors. This implies psychological security is pri-or to reducing cooling energy consumption for residents.cooling energy consumption for residents. energy consumption for residents. for residents.− If outside physical environment is not too bad, elders prefer to go out, though alone, because they can feel more adscription to the whole community.− Some black corners with good thermal comfort are not attractive for elders because they will feel lonelier and cannot control surroundings.− Outdoor thermal satisfaction range is wider than in-door. One of the reasons maybe is the more choices and freedom of behavior in outdoor environment. Residents’ thermal adaptation plays a very important role.The pilot study demonstrates the significant impact ofof exterior environmental comfort on residential behaviors.s. It is obvious that different housing layout and building form will create different environmental microclimate which effect residents’ activities because of physiologi-cal comfort. At the same time, the residential activities are influenced by psychological comfort through open space experience relating to security, perceived control of environment, desire of communication and self-cognition, etc. If designers want to stimulate residentsstimulate residents residents to participate into more outdoors activities instead of

staying home all day and consuming much energy, they must consider of both physiological and psychological environmental comfort corresponding to the complex-ity of residential behavior. The emphasis of this research focuses on elder’s be-havior relating to exterior environmental comfort and building energy conservation. For further research, the complexity of residents’ behavior determine that more comparative studies on different community catalogues should be carried out, such as classified from region, gender, age, health, earning, housing property, etc.

ACKNOWLEDGMENT

I offer my sincere appreciation to my supervisor, Prof. Tsou Jin Yeu, and my class tutor Benny K. M. Chow. Their valuable advices on my research topic and soft-ware learning make this project feasible and go on wheel. Also, I like to thank Leung Ka U and Yip Tak and Yip Takand Yip Tak Kei, my dear classmates, no their hard work in field ands, no their hard work in field and, no their hard work in field and in field and laboratory, no these final results.

REFERENCES

Brager, G. S. and R. J. de Dear, 1998. Thermal adaptation in the built environment: a literature review. Energy and Buildings 27(1): 83-96.Canter, D. V. 1975. Psychology for architects. New York, Wiley.Chavis David M, Stucky Paul E, and Wandersman Abraham. 1983. A social psychological perspective on energy conservation in residential buildings. American Phychologist. 38(4): 435-444.Harold M. Proshansky, William H. Ittelson, Leanne G. Rivlin, ed. 1976. Environmental psychology: people and their physical settings. New York: Holt, Rinehart and Winston.Junta Nakano, D. E. S.-i. T., D,Eng. 2004. Thermal Comfort and Adaptation in Semi-Outdoor Environments. ASHRAE Transac-tions: Symposia: 11.Koen Steemers, Mary Ann, ed. 2004. Environment Diversity in Architecture. New York: Spon. Leonard Krasner, ed. 1979. Environmental design and human behavior: a psychology of the individual in society. New York: Pergamon Press.Michael A.Hunmphreys & J. Fergus Nicol. 1998. Understanding the adaptive approach to thermal comfort. ASHRAE Technical Data Bulletin. 14(1): 1-14Marialena Nikolopoulou, S. L. a. M. K. 2003. Thermal comfort in outdoor spaces: field studies in Greece. the fifth international conference on urban climate, Lodz.Nikolopoulou, M., Baker, N. and Steemers, K. 1999. Thermal comfort in urban spaces: different forms of adaptation. RE-BUILD 1999: The Cities of Tomorrow, Barcelona.Nikolopoulou, M., Baker, N. and Steemers, K. 2001. Thermal comfort in outdoor urban spaces: the human parameter. Solar Energy 70(3).Nikolopoulou, M. S., Koen. 2003. Thermal comfort and psycho-logical adaptation as a guide for designing urban spaces. Energy and Buildings 35(1): 95-101.


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