Multi-criteria approach to passive space design in buildings: Impact of courtyard spaces on public buildings in cold climates

Building and Environment 89 (2015) 295e307

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Building and Environment journal homepage: www.elsevier.com/locate/buildenv

Multi-criteria approach to passive space design in buildings: Impact of courtyard spaces on public buildings in cold climates Yehao Song a, b, Junjie Li a, *, Jialiang Wang a, Shimeng Hao a, Ning Zhu a, Zhenghao Lin a a b

School of Architecture, Tsinghua University, Beijing, 100084, PR China Key Laboratory of Urban-Rural Eco Planning ＆ Green Building, Ministry of Education, Tsinghua University, PR China

a r t i c l e i n f o

a b s t r a c t

Article history: Received 11 December 2014 Received in revised form 17 February 2015 Accepted 19 February 2015 Available online 13 March 2015

Passive design has widely been identified to be one of the most economical and effective strategies for sustainable building. However, the research on verification of passive design strategies is in its initial stages. Currently, its test method and verification conclusions are not sufficiently scientific to validate. This study introduces a new logical framework to assess building space performance. A multi-criteria approach has been developed to validate and optimize the influence of passive spaces on sustainable buildings from the perspectives of building environment quality and occupant satisfaction. Building environment quality was judged by fieldwork physical environment tests, including indoor thermal, lighting, indoor air quality and acoustics data in the operating phase. A voting method designed to test satisfaction was developed to evaluate the occupants' satisfaction with the building's overall environment and space efficiency. Considering both the relationship between the building and people, and the building and the environment, from the dual perspectives of building design and building environment control, a comprehensive judgment model for a Comfort e Satisfaction Matrix was developed to display the regulation capacity of the building's environmental performance in the passive space. Finally, an indepth fieldwork survey of six types of passive courtyard spaces in cold climates was conducted as an example to validate the developed multi-criteria approach. The results indicate the level of environmental performance of each object building, and highlight optimized possibilities for passive space and the whole building in the design and renovation phases. © 2015 Elsevier Ltd. All rights reserved.

Keywords: Passive space design Building physical environment Fieldwork test Satisfaction vote

1. Introduction 1.1. Research background The results show that energy use during the operating (80e90%) phase is a significant contributor to a building's lifecycle energy demand [1]. Passive design has widely been identified as one of the most economical and effective strategies for reducing energy demand [2e5]. The literature indicates that passive strategies can reduce more than 50% of the primary energy source's consumption [6]. It is therefore essential for buildings to reduce their lifecycle energy demands through both passive and active strategies during the building's operating phase [7e9]. However, research on the verification of passive design strategies in sustainable buildings is at an initial stage, and its test method and verification conclusions

* Corresponding author. Tel.: þ86 10 18500234716; fax: þ86 10 62785691. E-mail address: [email protected] (J. Li). http://dx.doi.org/10.1016/j.buildenv.2015.02.025 0360-1323/© 2015 Elsevier Ltd. All rights reserved.

are currently not scientific enough to validate [10]. Because they lack actual verification data to support their choices, architects' means and methods of selecting passive strategies in the design phase are still based on subjective judgments or computer simulations [11,12]. Without long-term and confirmable testing data, the effectiveness of passive strategies cannot easily be optimized [13]. With the construction of more green buildings, many studies have begun to return to the fieldwork study method to test the real practical effects of buildings' environment and verify the effectiveness of the design strategies and values [14e16]. In joint research conducted by Sergio Altomonte and Stefano Schiavon, a survey database was presented featuring 65 LEED certified and 79 nonLEED certified buildings, with 21,477 individual occupant responses (10,129 in LEED buildings) on occupant satisfaction with IEQ. The results showed that in nine of the 17 total IEQ parameters, occupants of LEED certified buildings expressed a lower level of satisfaction than occupants of non-LEED rated buildings. The survey research illustrated that not all low energy consumption buildings are capable of achieving the required level of user satisfaction [17].

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1.2. Passive space design Passive Architecture describes buildings that are designed to cope with the climate factors by providing comfortable indoor conditions enduringly and naturally [18,19]. The term “passive” conveys the idea of self-defense or self-protection on the part of users with respect to the local natural environment in the architectural design [20,21]. The theories of creating space where users coexist with their environment contain many widely known positive definitions [22e24]. For example, the theory of “Open Building” attempts to construct a “personalized” dynamic space. The main characteristic of the concept is to examine the built environment in a systemic and dynamic view and to study the mutual optimum relationship between architectural form and the dynamics social life with this as a starting point [25,26]. Hermann Hertzberger proposes adaptive “Polysemic Space” that corresponds to “flexibility” which means that some characteristics of space have the adaptive capacity to change along with usage requirements [27]. Kisho Kurokawa put forward the “Intermediary Space theory”, which holds that space with intermediary characteristics could combine opposite objects in a dynamic and vibrant symbiosis [28,29]. In the idea of “the new dynamic concept of space”, Aldo Van Eych believes that buildings should be creations that consider both internal and external space in which the dynamic space located between two extremes gives the same attention to both sides and buffers the contrariety between them [30]. From the perspective of architecture, passive space with vitality has two types of attributes: organic organization and dynamic compound. The organic characteristic embodies the organic connection between space and the overall building, and possesses natural vitality and organic symbiosis in harmony with the natural environment [31]. The dynamic characteristic embodies the notion that the space adapts dynamically to the climate, user habits and building function during the whole lifecycle [32]. Space types such as courtyards, atriums, wind towers, patios, light wells, sunspaces, double façades, and porches are involved in the passive space category. 1.3. Objective of this study This research is based on the influence of passive space validation and its optimization design, and pursues two goals: (1) to quantitatively verify the objective physical environment of passive space and surrounding space to improve the overall comfort of a building's physical environment and reduce energy consumption and (2) to establish a method for collecting occupant satisfaction votes regarding building spaces and built environments to improve user satisfaction with the building environment and space efficiency. On this account, this research emphasizes the necessity of monitoring the building's physical environment to optimize passive strategies for efficiency from the perspective of architectural design prototypes [33]. It relates to a comprehensive study of multidimensional information such as objective physical environments, occupants' subjective judgments, and building space information. Because this is a correlation evaluation among various systems, we call this a multi-criteria method. 2. Methodology This research begins with a general social survey, and follows the logic of a “problem found e problem defined e problem solved” process composed of five study stages. The first is a web-based questionnaire survey on sustainability directed toward architects and engineers. The results show a significant gap in attitude

between the two groups regarding passive space cognition and value aspects requiring verification. The second phase is the problem definition stage, which includes three survey aspects. The first is to set up a logical framework of building information access through a method of measurement, calculation, and statistics to obtain the indicators affecting space performance. The second is a fieldwork test framework for objective physical environments such as indoor thermal, light, IAQ, acoustics environment, etc., to collect various running data during the operating phase. The third stage establishes a semantic differential to set up an occupant satisfaction voting framework regarding building space perception, judgment, and satisfaction. This research chooses six types of courtyard space as its passive space sample to be implemented into an in-depth fieldwork survey. The problem-solving process is conducted according to real instance validations to work out cross-analyses of a variety of information and to investigate the relationships between building information and building environment comfort and between building information and occupant satisfaction, and it also aims to analyze the comfort-satisfaction optimization approach of passive space design (as shown in Fig. 1). In the fifth stage, the research offers a comprehensive judgment model of the Comfort e Satisfaction Matrix to underscore the optimized possibility of passive space and whole buildings in the design and renovation phases. 2.1. Stage one: sustainable point of view survey of architects and engineers The data were collected via a web-based questionnaire survey regarding “views on the concept of building sustainability” that was distributed to frontier architects and engineers in China [34]. Overall, we collected 403 sets of data, including 356 valid sets. The valid data rate was 88.34%, which included 302 sets from architects and 54 sets from engineers (HVAC). With the goal of collecting basic, first-hand information in the workplace, the survey on the one hand aimed to make comparisons between architects' and engineers' views regarding sustainable buildings, strategies each group might employ, and differences in their respective perceptions of future trends. On the other hand, the survey's object was to offer those “improving a building's sustainable performance, reducing energy consumption, and improving IEQ comfort in building design prototypes” a further cognitive investigation into spatial cognition, spatial buffer utilization, passive strategy optimization, etc. The questionnaire survey was primarily directed to architects and engineers who perform design work in different departments. 77.5% of the participants selected for this research were younger than 40 years old, and 80.9% had been working in design jobs for 5e15 years in the architecture industry. These individuals' employers were distributed as follows: large and medium-sized stateowned design institutes (56.6%), local, small design institutes (12.6%), university research institutes (10.9%), and independent design studios (10.9%). The survey used a 7-point semantic differential scale [35,36] with the endpoints “not important” and “very important.” For the purposes of comparison, we assumed the scale to be roughly linear, and assigned ordinal values to each of the points along the scale, from 3 (not important) to þ3 (very important), with 0 as the neutral midpoint. The assessment categories are as shown in Table 1. A comparison of the results (as shown in Table 2 and Fig. 2) implies the following three conclusions: (1) both architects and engineers pay more attention to architectural design at the macro level, making sustainable decisions and designs on a city scale, but engineers believe the building prototype contributes more to the

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Fig. 1. Relation framework of research items.

building's sustainability level. (2) The obvious recognition differences between the two groups are “whether to use passive space, such as a courtyard, atrium, or patio (open space) in sustainable building design” and “whether to use passive space, such as a wind tower, light well, underground wind tunnel, or sunspace (technical space) in sustainable building design.” The space type considered to have the most important role in sustainable effects is very different for architects than for engineers. Especially concerning the design strategy of open spaces such as courtyards, atriums, or patios, the important vote value was 1.23 for architects, compared to only 0.45 for engineers. This shows a wide opinion gap and calls for further validation of respective spaces' effectiveness. (3) The concept of sustainable building design has gradually changed for both of these groups. A building's sustainable performance is no longer merely a matter of a label of “green” or an issue of “technique.” Simply increasing the green ratio of a building's roof and elevation or using more renewable energy are ranked as the strategies with the lowest levels of importance. The second conclusion from the survey (as shown in Table 1) underscores the core question this research intends to address: do

passive space designs such as courtyards, atriums, and patios play an important, positive role in sustainable building performance during the operating phrase as architects believe, or are they “not very important” as thought by many engineers? This paper therefore focuses on a typical passive spaced the courtyard e and uses a multi-criteria approach to verify its positive or negative influence in a cold climate zone, establishing an evaluation method based on the subjective “occupancy satisfaction” aspect and the objective “building's physical environment” aspect to provide references for future designers. 2.2. Stage two: information acquisition in the target building Space does not mean emptiness. Space is a dynamic system full of “three flows”: substance flow, energy flow, and information flow [37]. The study of space begins with an effective means of acquiring building information, achieved by setting up a logical method and framework. This research is based on an AHP (Analytic Hierarchy Process) methodology that decomposes complex issues into several group factors, and compares those factors to one another to

Table 1 Value assessment of sustainable building technologies from the views of architects and engineers. Category

Option

The least important

Ordinary

Macro: Urban scale

A. Building's relationship with the city layout B. Site selection, building layout, orientation C. Shape factor, window to wall ratio D. Uses passive space, such as courtyard, atrium, patio (open space) E. Uses passive space, such as wind tower, light well, underground wind tunnel, sunspace (technical space) F. Detail and air-tightness of building envelope G. Green ratio of roof and elevation H. Recycled material and pollution emissions I. Equipment type and efficiency J. Renewable energy such as solar energy K. Water reduction and recycle

3 3 3 3 3

2 2 2 2 2

1 1 1 1 1

0 0 0 0 0

1 1 1 1 1

2 2 2 2 2

3 3 3 3 3

3 3 3 3 3 3

2 2 2 2 2 2

1 1 1 1 1 1

0 0 0 0 0 0

1 1 1 1 1 1

2 2 2 2 2 2

3 3 3 3 3 3

Meso: Building scale

Micro: Detail scale

The most important

Table 2 Results of value assessments of sustainable building technologies from the views of architects and engineers. Question

Please score the importance of each sustainable building technology when designing a low energy consumption but high IEQ comfort public building.

Option item A Architect 1.5 Engineer 1.86

B 1.84 2.14

C 1.44 1.65

D 1.23 0.45

E 0.77 0.54

F 1.56 1.55

G 0.41 0.38

H 0.76 0.64

I 1.07 1.59

J 0.56 0.41

K 0.78 0.95

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Fig. 2. Column chart of value assessments of sustainable building technologies from the views of architects and engineers.

determine their relative importance [38,39]. Space properties can be classified into four main parts: dimensions, interface properties, internal related categories, and external related categories. These four factors can be subdivided into several sub-items that can then be quantified through a fieldwork survey method such as “measurement, calculation, statistics” to capture the building's information (as shown in Table 3).

equipment interference, people behavioral interference, misuse of testing instruments, etc., and used a mean value within the three days. This research focuses on the impact of a courtyard on a building's physical environment during the summer. As such, the fieldwork test chose 1:00 pm and 6:00 pm as the appropriate period for collecting the data. In addition, to make corresponding comparisons, we also used self-recording test equipment to record the outdoor thermal, lighting, IAQ and acoustics data.

2.3. Stage three: building the physical environment fieldwork test 2.4. Stage four: semantic differential survey regarding occupancy People spend 80e90% of their time in buildings [41]. The relationship between buildings and people, especially in terms of the health degree of the indoor environment, has a significant influence on human survival and sustainable development. It is also one of the premises for building artificial environments. This research categorizes indoor physical environments into several areas of human comfort, including the thermal environment, lighting environment, indoor air quality, and acoustic environment [42e44]. Using the fieldwork test method, we completed a comprehensive evaluation of the indoor physical environment of our test buildings (as shown in Table 4). To reflect the physical environment distribution more directly and clearly in the building space and to analyze visually the corresponding relationship between the spatial layout and the distribution of the physical environment, this research first adopted the grid-test fieldwork method to capture the entirety of the building's physical environment data. It then used a rhino & grasshopper software platform with an interpolation algorithm to express a type of data distribution cloud for the physical environment of the entire building in both horizontal and vertical directions. To ensure the stability and reliability of the test data, this test chose a 6e10 m grid (normally it also uses a construction grid size), and a typical three consecutive days to test the specific period of the physical environment. The data excluded unstable factors that may conduct instantaneous data mutations, such as weather mutations, active

For the past several years, the Center for the Built Environment (CBE) at the University of California, Berkeley has been developing a web-based survey system for Post-occupancy evaluation (POE) studies [45e48]. The subjective variables measured include occupant satisfaction and self-reported productivity with nine IEQ categories, including: office layout, office furnishings, thermal comfort, air quality, lighting, acoustics, cleaning and maintenance, overall satisfaction with the building and overall satisfaction with the work space [45,46]. In the satisfaction and self-reported productivity questions, this survey system uses a 7-point semantic differential scale with endpoints “very dissatisfied” and “very satisfied.” For the purposes of comparison, the scale was assumed to be roughly linear, with ordinal values for each of the points along the scale, ranging from 3 (very dissatisfied) to þ3 (very satisfied) and with 0 as the neutral midpoint [45]. For this research, we focused on an occupancy satisfaction impact validation of passive space in the whole building. We made further refinements to the “office layout” category based on CBE research of nine IEQ categories [45] to collect several sub-item evaluations of passive space from the aspect of the user's subjective feelings. The “passive space quality evaluation” factor was divided into four items e space quality, future expansion, functional organization, and share and communication e and sorted into 16 sub-items corresponding to space dimensions, interface

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Table 3 Building information acquisition framework for the passive space fieldwork test. Measurement items Space dimensions

Interface properties

Internal related categories

External related categories

Parameter type

Test content

Parameter unit

Layout shape Layout dimensions Space height Thermal performance of the building materials Window location and window to wall ratio Open window ratio Shading Inner-space green ratio Inner-space landscape to water ratio Inner-space occupied density Other functions

Distance measurement Size calculation Distance measurement Material thermal performance calculation Distance measurement, size calculation Statistics

Building layout, and space length and width First floor footprint and shape Building (space) height Material type, U-value of glazing and whole wall

m

Distance measurements: wall area and window area

% hour m2 m2, %

Relation type to surrounding space

Judgment

Area of open windows and open period Shading type and area Green area, ratio of occupied space Water area, ratio of occupied space Inner-space FTEs Services, kiosks, shops, exhibitions, assembly, transportation, other Judgment of relation type between passive space and its surrounding space: 1 direction, 2 directions, 3 directions, 4 directions Space transparence: open, semi-open, semi-closed, closed Outer-space (main space) FTEs

Distance measurement, size calculation Statistics

Relevance to main space Outer-space occupied density

Statistics

W/m2$K

FTE/h$100 m2 N/A N/A

% FTE/h$100m2

Note: P FTEs ¼ ∞ i¼1 ðni Ti Þ; T2½0; 1 (1) where, n is number of people who stay in the testing space at the same time, T is the occupied time within 1 h (unit: hour, T), FTEs is Full Time Equivalents [40]. For example, if three people occupy the space for 30 min, respectively, then the full time equivalent of the space is equal to 1.5 FTEs.) rO ¼ 100 NA (2) where, rO is the occupied density (unit: FTE/h$100 m2), N is the number of FTEs(n) per 1 h in working period, and A is useable floor area (unit: m2).

properties, internal related categories, and external related categories of building information. In this way, the voting data could be compared to the impact relationship between occupancy satisfaction and building information. The other eight occupancy satisfaction items were sorted into two categories according to their space evaluation and physical environment. These were compared and validated to obtain the impact relationship between occupancy satisfaction and physical environment test results (as shown in Table 5). 2.5. Stage five: comfort e Satisfaction Matrix The multi-criteria approach to impact verification in passive space design is not only related to the relationships between the building information in the target building, and the building's

physical environment and occupancy satisfaction, but it also includes comprehensive evaluation and verification for comfort and satisfaction with the target building. This research adopted a Comfort e Satisfaction Matrix method in considering the relationships between the building and people, and between the building and the environment, from the two aspects of building design and building environmental control, to examine the characteristics of the space environment and provide a comprehensive evaluation and analysis. S1 and S2 in Fig. 3 indicate that the building had excellent passive space that yielded a high level of occupancy satisfaction and a high or medium level of comfort with the physical environment. X1 and X2 indicate that the building needed to enhance its passive space quality design because it had a high or medium level of comfort with the physical environment but a low occupancy

Table 4 Building the physical environment fieldwork test framework. Measurement items Thermal environment

Outdoor temperature test

Parameter type

Test content

Test content

Temperature

Three consecutive days of outdoor temperatures; measurement interval was 5 min Temperature measurements for each (selected) floor in 8 m grid; measurement size at 1:00 pm and 6:00 pm for three consecutive days Three consecutive days of outdoor luminance; measurement interval was 5 min Luminance measurement for each (selected) floor in 8 m grid; measurement size at 1:00 pm and 6:00 pm for three consecutive days Three consecutive days of outdoor CO2 concentration; measurement interval was 5 min CO2 concentration measurement of each (selected) floor in 8 m grid; measurement size at 1:00 pm and 6:00 pm for three consecutive days Three consecutive days of outdoor decibel values; measurement interval was 5 min Decibel value measurement of each (selected) floor in 8 m grid; measurement size at 1:00 pm and 6:00 pm for three consecutive days



Indoor grid temperature test for each (selected) floor Light environment

Outdoor luminance test

Luminance

Indoor grid luminance test of each (selected) floor IAQ

Outdoor CO2 concentration test

CO2 concentration

Indoor grid CO2 concentration test of each (selected) floor Acoustical environment

Outdoor noise level test Indoor grid noise level test of each (selected) floor

Noise level

C

Lux/Daylight factor%

ppm

db/acoustic reduction factor%

300

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satisfaction level. Y1 and Y2 indicate that the building had a good passive space design but it needed further improvement because it had a high or medium level of occupancy satisfaction and a medium level of comfort with the physical environment. Finally, Z1, Z2 and Z3 indicate that the building had a low level of comfort with the physical environment and its passive space had little comfort function. 3. Results 3.1. Building information acquisition Based on the multi-criteria verification method, the search selected six buildings with six types of courtyards in summer weather as examples to illustrate the verification process. The six buildings were located in two cities in China with similar climate zones: Beijing and Xi'an. The first step in the fieldwork survey was the acquisition of building information. This was performed to obtain the data supporting the courtyard spaces. The building codes assigned to the six buildings were B1eB6. The corresponding courtyard spaces and main spaces were labeled Bc1eBc6 and Bm1Bm6, respectively. The functions of B1 and B5 were libraries, while B2, B3, B4, and B6 were office buildings. All of the six buildings had different sizes of regularly shaped rectangular courtyards. B1eB3 were 4-direction courtyards, while B4eB6 were 3-direction courtyards. The information details are shown in Table 6.

Fig. 3. Comfort e Satisfaction Matrix.

other average test point in the main body is labeled Mavg. From the test results shown in Table 8, we were able to analyze the physical environment of each building space.

3.2. Physical environment test result and analysis To ensure that the test data were evenly distributed for the whole building, to the extent possible the fieldwork survey chose stories with the same vertical height differences and approximately 8 m grid sizes in each building plan (as shown in Table 7). This physical environment test included temperature, lighting, and CO2 concentration. The data were recorded at the cross of the selected grid. The data were filtered and processed. The resulting data distribution cloud drawings of the thermal environment, lighting environment, and CO2 concentration are shown in Table 8. The data distribution clouds are displayed in uniformed ranges to ensure parallel comparisons among the six buildings. The temperature data in all of the test building spaces are over 24  C under summer weather conditions. The temperature cloud display range runs from 24  C to 28  C. The lighting cloud display range is 0 luxe1000 lux and the CO2 concentration cloud display range is 300 ppme800 ppm. Red represents the maximum values. Blue represents the minimum values. Cavg in Table 8 is short for the average test data in the courtyard space. MCavg is short for the average data collected in the test grid closest to the courtyard. The

3.2.1. Thermal comfort analysis Under summer weather conditions with high temperatures, it is obvious that the shape or type of courtyard will not affect the temperature regulation effect for the whole building (as shown in Figs. 4 and 5). The maximum value reduction from the outdoors to the courtyard occurred in B1 at noon. The temperature in the courtyard space was reduced 16% (5.4  C) below that of the outdoors. The minimum temperature difference appeared in B6 at 6:00 pm, and the rate of reduction was 0.6% (0.2  C). The sequence of the thermal environment's mitigating effects in the six buildings was B1 > B3 > B4 > B5 > B2 > B6 (as shown in Fig. 6). Comparing the building information provided in Table 6, we can draw the following conclusions: 4-direction courtyards have a better regulating capacity than 3-direction courtyards, small sized courtyards have a better thermal stability than larger ones, and the thermal performance of the building envelope and material plays a very important role in the capacity for thermal regulation (in B6). In summer weather conditions, most of the average data at the test grids closest to the courtyards were higher than the average

Table 5 Occupancy satisfaction voting framework. Test items Passive space quality evaluation

Space satisfaction

Physical environment satisfaction

Space quality Future expansion Functional organization Share and communication Satisfaction with passive space Satisfaction with work space Satisfaction with building Thermal comfort Lighting Air quality Acoustics Cleaning and maintenance

Parameter type

Test content

Test content

Vote

Web-based survey/fieldwork-based survey/human perception test

7-Point scale [3,2,1,0,1,2,3] SD of feelings about space's atmosphere

Vote

Web-based survey/fieldwork-based survey/human perception test

7-Point scale [3,2,1,0,1,2,3] very dissatisfied e very satisfied

Vote

Web-based survey/fieldwork-based survey/human perception test

7-Point scale [3,2,1,0,1,2,3] very dissatisfied e very satisfied

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Table 6 Building information of the six types of courtyard spaces. Code building information

Space dimensions

Interface properties

Building

Courtyard plan shape Courtyard space dimensions (L:W:H unit: meter) Courtyard space scale ratios (L:W:H) Material of envelope

B1

B2

B3

B4

B5

B6

Rectangle 25:16:8

Rectangle 54:40:24

Rectangle 28:32:12

Rectangle 31:12:25

Rectangle 38:23:23

Rectangle 24:30:50

1:0.64:0.32

1:0.74:0.48

1:1.14:0.43

1:0.39:0.8

1:0.61:0.61

1:1.25:2.1

ConcBlockrender with light tile surface 0.45 0.45 5% No 1300 60% 0 0 0.5 10 Garden 4 directions Closed 7.1

ConcBlock render with ceramic panels 0.4 0.5 5% No 180 20% 380 42% 0 6 Green roof 4 directions Closed 3.3

ConcBlock render with white stone surface 0.45 0.5 10% Yes 80 21% 0 0 0.15 0 Outdoor display space 3 directions Closed 4.7

Glass screen ConcBlock render with light tile surface wall

ConcBlockrender with dark tile surface U-value of building envelope 0.47 Window to wall ratio 0.15 Percentage of open windows 10% Shading No Internal related Green area 200 categories Green ratio 50% Water area 0 Water ratio 0 Occupied density in courtyard 0.8 Rest seat number 8 Other functions Garden External related Courtyard type 4 directions categories Connection status Closed Occupied density in main space 5.6

temperatures in the main building spaces in the six test buildings (as shown in Figs. 4 and 5). The maximum value difference from MCavg to Mavg occurred in B5 at noon. The MCavg temperature was 12% (3.9  C) above that of the main building space, while the minimum temperature difference occurred in B4 at noon, and the reduction rate was 2% (0.7  C). The sequence of temperature elevation gradients from Mavg to MCavg in the six buildings was B5 > B6 > B2 > B1 > B3 > B4, which means the higher the temperature difference, the more unstable the building's indoor thermal environment. This may be easily influenced by the outdoor environment (as shown in Fig. 7). Comparing the building information provided in Table 6, we can draw the following conclusions: the thermal performances of the building envelope and material play a very important role in the building's thermal stability. Furthermore, larger sized courtyards have more difficulty maintaining building thermal stability than smaller ones do. 3.2.2. Lighting environment comfort analysis The functions of the six test buildings were either library or office space, so the comfort range of the indoor lighting luminance was set in the range of 50e1000 lux [49]. The test results showed the lighting comfort sequence in six buildings to be B6(81.3%) > B1(78.6%) > B5(69.7%) > B3(69.3%) > B2(39.2%) > B4(35.7%). In an independent building, the lighting environment value is normally a geometric value in physics that can be calculated or simulated relatively accurately. However, for most buildings the built environment is more complex because of dynamic and uncertain issues such as building construction differences, number of occupants, differences in usage habits, green rating and height of courtyard

Table 7 Physical test information. Test information Building code B1

B2

B3

B4

B5

0.5 0.15 10% No 550 80% 0 0 0 0 n/a 3 directions Closed 9.5

2.4 0.8 5% Yes 210 29% 0 0 0.15 0 Main entrance 3 directions Semi-closed 4.2

differences, differences in the size ratio between the main space and the courtyard, etc. Figs. 8 and 9 show a comparison of the average luminance data during the two test periods, at noon and at sunset, in the outdoors, the courtyard, the nearest test grid to the courtyard, and the main building body. The maximum reduction of natural light occurred in B1, which had the smallest courtyard size, numerous tall plants, and a smaller window-to-wall ratio (0.15). From this information, combined with the thermal comfort data, we can see that B1 had the best thermal mitigation effect. This is because B1 had the highest inner space occupied density of the six test buildings: 0.8 FTE per hour for every 100 square meters. B1 also had the highest utilization efficiency, which reflects the other important factor in sustainable design: economy. 3.2.3. IAQ comfort analysis Indoor CO2 concentration is an important parameter that indicates indoor air quality and the amount of fresh air inlets, which further indirectly implies the concentration of other harmful or toxic gaseous pollutants [50,51]. Influencing the air composition, CO2 concentration is not always stable and instead fluctuates from 350 ppm to 500 ppm. Past research results have shown that occupants become uncomfortable and their work ability declines when CO2 concentration increases to more than 1000 ppm [52]. The CO2 concentration test results in all of the six buildings remaining in a comfortable range during the test period. If the highest CO2 concentration is limited to 800 ppm, after analysis of the data, point by point for the six buildings, it can be observed that some parts of B4 and B2 appear to be incompetent spaces, occupying 26.3% and 9.9% of the spaces, respectively. These two buildings had the highest inner-space occupied densities, 9.5 FTE/ h 100 m2 and 7.1 FTE/h 100 m2, respectively, which was the primary factor in this phenomenon. Moreover, B4 had the minimum window-to-wall value (0.15) of the six test buildings, a condition comprising the other major influence.

B6

Total number of 2-story 5-story 5-story 5-story 4-story 11-story building floors Test floor 1F/2F 1F/3F/5F 1F/3F/5F 1F/3F/5F 1F/2F/4F B2/2F/4F/10F Test grid size 10  10 6  8 6.9  8 8.7  7.8 7.5  7.5 8  8 (m  m)

3.3. Occupancy satisfaction survey results and analysis The third stage in the survey was a vote on feelings regarding the occupancy space's atmosphere and general satisfaction. We randomly chose 40 people in each building to complete the

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Table 8 Building physical test data and cloud drawing. Building code

Data

Thermal ( C)

Lighting (lux)

CO2 concentration (ppm)

13:00

18:00

13:00

18:00

13:00

B1

Data cloud

28.1 26.4 26.6 33.5

30.8 28.8 26.4 33.3

360 464 267 4150

4003 2013 402 3920

539 613 637 551

B2

Cavg MCavg Mavg Outdoor Data cloud

32.5 28.4 26.7 33.7

31.7 27 26.2 32.6

12,137 1478 242 14,420

2471 606 146 3120

430 647 681 449

B3

Cavg MCavg Mavg Outdoor Data cloud

28.9 28.1 27.2 33.3

28.6 28.1 27.5 31.2

1140 1215 273 4500

1800 558 345 4160

313 345 358 310

B4

Cavg MCavg Mavg Outdoor Data cloud

26.6 25.7 26.4 30.6

27.7 26.9 26.2 30.2

11,170 4034 246 29,300

4425 1615 323 5870

567 528 522 510

B5

Cavg MCavg Mavg Outdoor Data cloud

37.9 32.8 28.9 39.1

36.4 31.9 28.9 38.7

6175 5878 258 8570

6323 3046 141 4130

342 530 711 359

B6

Cavg MCavg Mavg Outdoor Data cloud

Cavg MCavg Mavg Outdoor

31.1 28.8 26.5 31.6

29 27.7 26.1 29.2

4760 3848 294 4790

4003 2753 354 3960

444 547 560 450

questionnaire. Occupancy satisfaction could reflect both social and economic factors related to a building's sustainable performance for people's health levels and the efficiency of the building's space utilization [53]. Table 9 shows the survey results for the test courtyard spaces in the six buildings. The voting score scale was 7 points, and the endpoint 3 was the negative adjective while 3 was the positive adjective. The research adopted the method of 16 subfactors corresponding to the four factors of: space dimension, interface properties, internal related categories, and external related categories in the building's information framework. These factors provided an opportunity to work out a correspondence

analysis between feelings regarding the atmosphere of the occupancy space and the building information (as shown in Table 10). As shown in Fig. 10, in the space dimension aspect the order from high to low in the six buildings is B6(1.51) > B4(1.28) > B1(1.01) > B5(0.93) > B3(0.78) > B2(0.38). In the interface properties aspect, the order from high to low in the six buildings is B6(2.09) > B4(1.41) > B1(1.12) > B5(1.09) > B3(1.01) > B2(0.36). In the internal related categories aspect, the order from high to low in the six buildings is B6(1.66) > B4(1.44) > B1(0.81) > B5(0.76) > B3(0.77) > B2(0.18).

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Fig. 4. Temperature comparison at 1:00 pm in the six test buildings.

Fig. 7. Temperature increase ratio from the main space to the nearest test grid to the courtyard.

Fig. 5. Temperature comparison at 6:00 pm in the six test buildings.

In the external related categories aspect, the order from high to low in the six buildings is B6(1.64) > B4(1.45) > B1(0.91) > B3(0.89) > B5(0.76) > B2(0.29). The occupancy satisfaction vote was divided into an evaluation of the space designated for occupancy and an evaluation of the building's physical environment. The latter mainly related to the environment factor in the building's sustainable performance (as

Fig. 6. Temperature reduction ratio from the outdoors to the courtyard.

Fig. 8. Lighting comparison at 1:00 pm in the six test buildings.

Fig. 9. Lighting comparison at 6:00 pm in the six test buildings.

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Table 9 Vote results for feelings regarding space atmosphere in the six buildings. Vote item

Bc1

Bc2

Space quality

Bc3

1 Shape 1.4 0.14 0.45 2 Lighting 1.45 0.52 1.25 3 Landscape 1.5 0.00 0.75 environment 4 Connection to 0.2 0.10 0.25 exterior space Future expansion 5 Area 1.05 0.86 0.8 6 Interface division 0.2 0.33 0.25 7 Vegetation 1 0.71 0.1 8 Connection to 0.55 0.24 0.6 interior space Functional 9 Space utilization 0.85 0.57 0.6 organization 10 Number of 1 0.05 1.2 windows 11 Function 0.3 0.05 0.25 12 Occupied density 0.4 0.05 1 Share and 13 Space atmosphere 0.4 0.38 0.5 communication 14 Long-stay 1.2 0.38 0.6 15 Psychology 1.8 0.29 1.5 16 Acoustics 1.8 0.57 1.8

Bc4 Bc5

Bc6

1.35 1.4 1.55

0.85 2.1 1.3 2.03 1.15 1.8

1.2

0.05 1.6

0.6 0.6 1.7 0.2 0.9 1.65

1.2 0.95 0.65 0.55

1.1 2.2 2.1 1.1

1.25 1.03 0.4 2.3

0.05 0.35 2.5 0.2 0.5 0.7 1.05 1.35 2.05 1.35 2.65 1.55

1.3 0.65 2.2 1.6 1.9 2.4

shown in Table 11). The score scale also used 7 points, with endpoints of “very dissatisfied” and “very satisfied.” As shown in Fig. 11, in the evaluation of satisfaction with the occupancy space, the order from high to low in the six buildings is B4(2.3) > B6(1.94) > B1(1.62) > B5(1.57) > B3(1.05) > B2(0.86). In the evaluation of the building's physical environment, the order from high to low in the six buildings is B4(1.87) > B6(1.52) > B1(1.41) > B2(0.93) > B5(0.92) ¼ B3(0.92). 3.4. Comfort e Satisfaction Matrix Fig. 12 shows the results of the Comfort e Satisfaction Matrix in the six test buildings. The horizontal axis of the matrix corresponds to the level of comfort with the physical environment inside of the building. The data were used to calculate a comfort percentage obtained from the grid test results, and divided into three classes of 50%, 70% and 90%. The vertical axis of the matrix corresponds to the subjective analysis of occupancy space satisfaction, following with the 3~3 score scale outlined in the above research method. The

Table 10 Inclusion relationships among the four factors of building information and items related to feelings about space atmosphere. Vote item

Space dimension

Interface properties

Internal related categories

External related categories

Space quality

1 Shape: not characteristic e characteristic 5 Area: waste e economy

2 Lighting: discomfort e comfort

3 Landscape environment: poor e good 7 Vegetation: less e more

4 Connection to exterior space: closed e open 8 Connection to interior space: independent e coherent 12 Occupied density: crowded e empty

Future expansion

6 Interface division: rigid e flexible 10 Number of windows: less e more

9 Space utilization: low e high 12 Occupied density: crowded e empty 13 Space atmosphere: not Share and 13 Space atmosphere: not attractive e attractive communication attractive e attractive 14 Long-stay: unwilling e willing 14 Long-stay: unwilling e willing 15 Psychology: irritability e safe 15 Psychology: irritability e safe 16 Acoustics: noisy e quiet Functional organization

9 11 12 13

Space utilization: low e high Function: monotone e plentiful Occupied density: crowded e empty Space atmosphere: not attractive e attractive 14 Long-stay: unwilling e willing 15 Psychology: irritability e safe 16 Acoustics: noisy e quiet

Fig. 10. Curve of vote feelings regarding the atmosphere of the occupancy space.

13 Space atmosphere: not attractive e attractive 14 Long-stay: unwilling e willing 15 Psychology: irritability e safe 16 Acoustics: noisy e quiet

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Table 11 Occupancy satisfaction vote results. Vote item

Bm1

Bm2

Bm3

Bm4

Bm5

Bm6

Satisfaction with passive space Satisfaction with work space Satisfaction with building Thermal comfort Lighting Air quality Acoustics Cleaning and maintenance

1.7 1.55 1.6 0.9 1.7 0.85 1.45 2.15

0.86 0.81 0.90 1.10 0.76 0.24 1.10 1.43

0.95 1.25 0.95 0.25 1.5 0.1 1.35 1.4

1.9 2.3 2.7 1.65 1.4 1.45 2.35 2.5

1.35 1.45 1.9 0.35 1 0.3 1.35 1.6

1.42 2.1 2.3 0.9 2.1 1.2 1.10 2.3

occupancy satisfaction evaluation began at point 0 and was divided into three levels. The evaluation results (as shown in Table 12) illustrate that B2 and B5 had the lowest levels of comfort with the physical environment and occupancy satisfaction, meaning that both required optimization designs or space renovations. B4 and B1 each had high or medium levels of occupancy satisfaction and medium levels of comfort with the physical environment, meaning both had good passive space designs but needed further improvement. B3 had a medium level of comfort with the physical environment but a low level of occupancy satisfaction, which demanded a better space quality design. B6 had a medium level of occupancy satisfaction and a high level of comfort with the physical environment, which means it had excellent passive space. According to the Comfort e Satisfaction Matrix result (as shown in Fig. 12), a building with better occupancy satisfaction and physical environmental comfort performance could be clearly determined among the target buildings. For example, in the six buildings in this test, B6 shows the relatively highest satisfaction and comfort comprehensive performance, its comfort level reached 90.5%, and its satisfaction score is 1.68. The reason is largely due to the spatial information that was decided during the architectural design phase. In contrast to the four building information categories that we obtained in the beginning of this research, a higher comfort level is largely due to reasonable space geometry and having the best building and passive space orientation in the space dimensions category. Better shading devices accept less excessive solar radiation, and an appropriate window-wall ratio provides

Fig. 12. Test building Comfort e Satisfaction Matrix results.

natural lighting in the interface properties category. A semi-closed connection status ensures sufficient natural ventilation in external related categories. The higher satisfaction level is largely due to pleasing space geometry in the space dimensions category, pleasing and visually stimulating building material in the interface properties category, a pleasant landscape environment in internal related categories and a semi-closed to environment in external related category. 4. Conclusions This research was a trial set up for an effective verification and comprehensive optimization method model for use with passive space design strategies. The satisfaction and comfort of buildings'

Fig. 11. Occupancy satisfaction vote results curve.

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Table 12 Test building Comfort e Satisfaction Matrix results.

Comfort Satisfaction

B1

B2

B3

B4

B5

B6

87% 1.48

68.1% 0.9

75% 0.97

72.8% 2.03

54.1% 1.16

90.5% 1.68

built environment are directly related to the basic information from the beginning of the architectural design. Extracting spatial information requires scientific classification and quantification. This research aims to transfer fuzzy architectural space to hierarchical parameters that correspond to the “reasons” for the “result” of occupancy satisfaction and comfort to determine space design optimization strategies to conveniently meet the demand for sustainable architecture. This article primarily focuses on the following four aspects: 1). Establishing a new logical framework to assess a building's passive space environmental performance. The research adopted an analytic hierarchy process methodology to classify each building information factor and compared this information with the real fieldwork physical environment test data and occupancy satisfaction vote data to discern the key factors in passive space design and the particular building's advantages and weaknesses. 2). Developing software to display environmental test data distribution clouds in the entire building. This research used a rhino & grasshopper software platform with an interpolation algorithm to express a type of data distribution cloud for the physical environment of the entire building in both horizontal and vertical directions. Graphic language was used to make test data easier to understand. 3). Developing a semantic differential method to judge occupant satisfaction to the object space. The research adopted a semantic differential method of 7-point voting to establish a methods model of occupancy satisfaction under subjective assessment of building space. 4). Distributing a comprehensive judgment model of the Comfort e Satisfaction Matrix. The establishment of the matrix figure is advantageous in regard to comprehensively comparing multiple buildings when it is more obvious to display space performance evaluation results. Researchers or architects could make a decision on the improvement direction to research objects for the specific building based on S1 in the matrix as a reference model. Furthermore, building and space environmental performance could be comprehensively optimized through further subdivision levels of multiple comparisons among the building information, building physical environment performance data and occupancy satisfaction data. Acknowledgments This work is supported by the National Natural Science Foundation of China (Grant No. 51138004) and the National Science and Technology Support Program (Grant No. 2012BAJ10B02). It is derived from work undertaken by the corresponding author during PhD studies at Tsinghua University (China). References [1] Ramesh Tejavathu U, Prakash Ravi, Shukla KK. Life cycle energy analysis of buildings: an overview. Energy Build 2010;42(10):1592e600. [2] Filippin C, Larsen SF, Beascochea A, Lesino G. Response of conventional and energy-saving buildings to design and human dependent factors. Sol Energy 2005;78(03):455e70.

[3] Lam JC, Yang L, Liu J. Development of passive design zones in China using bioclimatic approach. Energy Convers Manage 2006;47(04):746e62. [4] Badescu V, Laaser N, Crutescu R, Crutescu M, Dobrovicescu A, Tsatsaronis G. Modeling, validation and time-dependent simulation of the first large passive building in Romania. Renew Energy 2011;36(01):142e57. [5] Sadineni SB, Madala S, Boehm RF. Passive building energy savings: a review of building envelope components. Renew Sustain Energy Rev 2011;15(08): 3617e31. [6] Feist W, Schnieders J, Dorer V, Haas A. Re-inventing air heating: convenient and comfortable within the frame of the Passive House concept. Energy Build 2005;37(11):1186e203. [7] Day Julia K, Gunderson David E. Understanding high performance buildings: the link between occupant knowledge of passive design systems, corresponding behaviors, occupant comfort and environmental satisfaction. Build Environ 2015;84(01):114e24. [8] Zhang Hong, Li Junjie, Dong Lei, Chen Huanyu. Integration of sustainability in net-zero house: experiences in solar Decathlon China. 2013 ISES Solar World Congress Energy Procedia, vol. 57; 2014. p. 1931e40. [9] Yiing Chua Fuh, Yaacob Naziaty Mohd, Hussein Hazreena. Achieving sustainable development: accessibility of green buildings in Malaysia. Proc Soc Behav Sci 2013;101(11):120e9. [10] Russell-Smith Sarah V, Lepech Michael D, Fruchter Renate, Littman Allison. Impact of progressive sustainable target value assessment on building design decisions. Build Environ 2015;85(02):52e60. [11] Rodriguez-Ubinas Edwin, Montero Claudio, Porteros María, Vega Sergio, ~ aki, Castillo-Cagigal Manuel, et al. Passive design strategies and Navarro In performance of Net Energy Plus Houses. Energy Build 2014;03(11):10e22. [12] Li Bao-feng. The research on climatic-active design strategy of building skin in hot-summer and cold-winter zone. Beijing: Tsinghua university; 2004. p. 127e281. [13] Morrissey, Moore T, Horne RE. Affordable passive solar design in a temperate climate: an experiment in residential building orientation. Renew Energy 2011;36(02):568e77. [14] Li Junjie, Song Yehao, Zhao Yuanchao. Study on space layout effect of sustainable public building by field work physical environmental test. In: The 10th international conference on green building and building energy conservation. Beijing; 2014. p. 1e11. [15] Wong Siu-Kei, Lai Lawrence Wai-Chung, Ho Daniel Chi-Wing. Sick building syndrome and perceived indoor environmental quality: a survey of apartment buildings in Hong Kong. Habitat Int 2009;33(10):463e71. [16] Hummelgaard J, Juhl P, Sabjornsson KO, Clausen G, Toftum J, Langkilde G. Indoor air quality and occupant satisfaction in five mechanically and four naturally ventilated open-plan office buildings. Build Environ 2007;42(12): 4051e8. [17] Altomonte Sergio, Schiavon Stefano. Occupant satisfaction in LEED and nonLEED certified buildings. Build Environ 2013;68(10):66e76. [18] Zaki WRM, Nawawi AH, Ahmad SSh. Case study in passive architecture: energy savings benefit in a detached house in Malaysia. In: The 24th conference on passive and low energy architecture. University of Singapore; 2007. p. 259e66. [19] Szokolay SV. Passive climate control in warm-humid region. In: International symposium on sustainable energy & environment (ISEESEE), Kuala Lumpur; 2006. [20] Zaki WRM, Nawawi AH, Ahmad SSh. Energy savings benefit from passive architecture. J Can Centre Sci Educ 2008;03:51e63. [21] La Roche P, Quiros C, Bravo G, Gonzalez E, Machado M. Keeping cool: principles to avoid overheating in buildings. In: Szokolay SV, editor. PLEA notes, passive and low energy architecture international: design tools and techniques. New South Wales: Research, Consulting and Communications (RC&C); 2001. [22] Liang Lei. Pre-research on the relationship between interior environment control and form of space. Beijing: Tsinghua University; 2005. p. 12. [23] Pearson David. New organic architecture-the breaking wave. Berkeley and los angeles: University of California press; 2001. [24] Liu Yongde. Building space form, structure, meaning and combination. 1998 (in Chinese). Tianjin. [25] Kendall Stephen, Teicher Jonathan. Residential open building. E& FN spon; 2000. p. 38. [26] Lv Aimin. Climate responsive building. 2003. p. 101 (in Chinese). Shanghai. [27] Hertzberger Hermann. Space and learning: lessons in architecture 3. Rotterdam: 010 Publishers; 2008. [28] Peitong Yin. Kisho Kurokawa and metabolism. Word Archit 1984;06:114e7. [29] Kurukawa Kisho. The philosophy of symbiosis. Academy Press; 1994. p. 12 [Chapter 6& Chapter 8]. [30] Lammers Harm. Unravelling and reconnecting Aldo van Eyck in search of an approach for tomorrow. Eindhoven University of Technology; 2012. [31] Dai Zhizhong, Yang Zhen, Xiong Wei. Ideation analyse for architecture creation: ecology Bionics. 2006 (in Chinese). Beijing. [32] Dai Zhizhong, Li Haile, Ren Zhijie. Ideation analyse for architecture creation: adaptitude & Multi-attribute. 2006 (in Chinese). Beijing. [33] Song Yehao, Li Junjie, Zhu Ning, Wang Jialiang, Hao Shimeng. Fieldwork test research of the impact on building physical environment on six types of atrium space in cold climates. J Harbin Inst Technol 2014;08:99e105. [34] https://www.jinshuju.net/f/GxelAn.

Y. Song et al. / Building and Environment 89 (2015) 295e307 [35] Osgood CE, Suci GJ, Tannenbaum PH. The measurement of meaning. Urbana: University of Illinois Press; 1957. [36] Kang J, Zhang M. Semantic differential analysis of the soundscape in urban open public spaces. Build Environ 2010;45(01):150e7. [37] Mengchao Gu. Philosophy: architecture. Beijing: China Building Industry Press; 2011. p. 54e6 (in Chinese). [38] Junping Qiu. Evaluation science: theory method practice. Beijing: Science Press; 2010 (in Chinese). [39] Rainer Haas, Oliver Meixner. An illustrated guide to theanalytic hierarchy process. Insititute of marketing & innovation. https://mi.boku.ac.at/ahp/ ahptutorial.pdf. [40] Reference from USGB. LEED definition of FTE. [41] US Green building council. LEED for new construction. Version 3.0. 2009. [42] Sarbu Ioan, Sebarchievici Calin. Aspects of indoor environmental quality assessment in buildings. Energy Build 2013;60(05):410e9. [43] Heinzerling David, Schiavon Stefano, Webster Tom, Arens Ed. Indoor environmental quality assessment models: a literature review and a proposed weighting and classification scheme. Build Environ 2013;70(12):210e22. [44] Hai Ye. Comprehensive evaluation index of indoor environmental quality. Build Energy Environ 2000;19(01):31e4. [45] Abbaszadeh S, Zagreus L, Lehrer1 D, Huizenga C. Occupant satisfaction with indoor environmental quality in Green buildings. Proc Healthy Build 2006;(06):365e70.

307

[46] Zagreus Leah, Huizenga Charlie, Arens Edward, Lehrer David. Listening to the occupants: a web-based indoor environmental quality survey. Indoor Air 2004;(14):65e74. [47] Indraganti Madhavi, Ooka Ryozo, Rijal Hom B, Brager Gail S. Adaptive model of thermal comfort for offices in hot and humid climates of india. Build Environ 2014;74(04):39e53. [48] Brager Gail, Baker Lindsay. Occupant satisfaction in mixed-mode buildings. Build Res Inf 2009;07. [49] Standard for lighting design of buildings, GB 50034e2004. Ministry of Construction of the People's Republic of China. The people's Republic of China State Administration of Quality Supervision Inspection and quarantine; 2004. [50] Junfu Zhang. Indoor air quality testing and air distribution analysis in an office building. Xi‘an University of Architecture and Technology; 2012. p. 06. [51] Santamouris M, Synnefa A, Asssimakopoulos M, Livada I. Experimental investigation of the air flow and indoor carbon dioxide concentration in classrooms with intermittent natural ventilation. Energy Build 2008;40(10):1833e43. [52] ASHRAE (American Society of Heating, Refrigerating, and Air Conditioning Engineers). ASHRAE standard 62d1989.Ventilation for acceptable indoor air quality[M]. Atlanta, GA: ASHRAE; 1989. [53] Hui Sam CM. Sustainable architecture. 2002. Retrieved on March 21, 2010 from, http://www.arch.hku.hk/research/BEER/sustain.htm.