Proceedings of Conference: Air Conditioning and the Low Carbon Cooling Challenge, Cumberland Lodge, Windsor, UK, 27-29 July 2008. London: Network for Comfort and Energy Use in Buildings, http://nceub.org.uk. Environmental comfor t and energy use in public school buildings: case study in Campinas, Brazil Labaki, Lucila C.; Kowaltowski, Dor is; Nogueira, Flavia E. A.; Pizarro, Paula R. Department of Architecture and Building School of Civil Engineering, Architecture and Urban Planning University of Campinas, Brazil E-mail: lucila@fec.unicamp.br Abstract Thermal and luminous comfort considerations are usually neglected when dealing with school environment in Brazil. School buildings are not air-conditioned so that energy economy considerations are seldom taken into account. The design of public schools does not consider aspects of extreme importance in thermal comfort such as high temperatures in the classrooms in most of the year. Furthermore, appropriate illumination levels in the rooms and in the covered courtyards, possible glare conditions, direct sunshine incidence in the students are not considered. This work presents results of the evaluation of three public municipal schools in the city of Campinas, Brazil. The field research consisted of collecting the variables associated with the local thermal and luminous environment in periods covering distinct climatic seasons. Observations were done of design elements that affect the thermal and visual performance, such as orientation, opening areas, façades and external and/or internal shading devices. The methodology also included gathering of information among teachers and administrative staff of the schools about the environmental control of classrooms and the building as a whole. Data about monthly electrical energy consumption were collected. The analyses of the results lead to defining the ranges of the building constructive aspects related to the efficient energetic school consumption and the thermal and luminous comfort. Keywords: environmental comfort, energy efficiency, school buildings 1. Introduction 1.1 Comfor t in the school environment The school environment and the local comfort for users, pupils and staff, can be studied by more than one approach. The appropriate literature encompasses studies of design and of environmental comfort in its various aspects: thermal, illumination, acoustics, functionality, correlation between environment and learning efficiency and physical plant situation and the behavior of users. The performance of school buildings in relation to energy efficiency is also analyzed (Becker et al., 2007 and Erhorn et al, 2007). Post-occupancy evaluations frequently produce useful information (Kowaltowski et al., 2001). Post-occupancy evaluations of school buildings in Brazil have systematically indicated that good comfort conditions were not contemplated in the original projects (Ornstein & Borelli Neto, 1996; Kowaltowski et al., 2001, Ornstein, 2005). It is known that various aspects of comfort are interrelated. Choices associated to one aspect have significant influence on other aspects. For instance, the use of daylighting affects ventilation, due to the necessity of

drawing courtains at certain times of the day to avoid excessive sunshine incidence on pupils or unwanted glare from the blackboard. According to Graça & Kowaltowski (2004), in a school building it is not possible to obtain a maximum comfort quality in all aspects. This led them to propose a method they called multicriterial optimization for the design of schools. Other researchers reached similar conclusions from studies of school buildings in hot climates, independent of region and specific building details. Most schools were considered hot in the summer with insufficient ventilation. This results from inadequate orientation of windows in classrooms as well as insufficient protection elements thus allowing excess sunshine. The paper by Labaki & Bueno-Bartholomei (2001) presents basic recommendations appropriate to the climate of the Southeast region of Brazil that if followed will result in quite adequate thermal comfort. Even when the orientation is inadequate sunshading devices can be installed to avoid direct sunshine on the pupils resulting in better thermal comfort. Post-occupation evaluations of schools in Campinas (Kowaltowski, et al. 2001) have indicated that problems with thermal comfort can be mitigated at a low cost. As for luminous comfort, artificial lighting is very frequently used as a complement to natural lighting and if adequately designed and maintained will solve most of the detected problems. Associated with design details it is important to convey to pupils and teaching staff the importance of an environment consciousness therefore leading to the adequate use of solar protection devices and of artificial lighting. 1.2 Energy efficiency The relevance of properly dealing with environmental comfort factors in school projects on learning and energy saving has been pointed out by Monteiro et al, 1993; Gifford, 1997, Yannas, 1995. In spite of the high sunshine incidence in Brazil artificial lighting is widely employed due to the inadequate use of daylighting. In the subtropical Southeast region where this research was done adequate illumination, winter heating and summer cooling can be achieved through passive conditioning strategies that should as a rule be incorporated in the architectural project. This is important in Brazil where low budgets do not allow the use of heating and cooling systems in public schools. 2. Methodology The study began by choosing typical school buildings in the city of Campinas with its subtropical climate. In each case the building architecture details and environmental comfort parameters were registered. Campinas is situated at 22°54’S latitude and 43°3’W longitude at an altitude of 854 m. The temperatures are higher in January and February with average maximums at respectively 29.9ºC and 29.7ºC. The average lowest temperatures occur in June, 12.5ºC, and in July, 12.4ºC. The South façades receive direct sunshine only in summer during the whole day. The North façades receive abundant solar radiation during most of the year and from March to September for the whole day long. 2.1 Choosing the Samples A survey of technical documentation of all public schools belonging to the municipality of Campinas was made. It was then possible to select a few that are each characteristic of the several groups that were identified. The first criterion was to choose EMEFs, an acronym for Municipal School of Fundamental Education, basically because of age span of the students

(from 11 to 15 years of age), rooms equipped with computers and accessibility to the controls of equipment, basically lighting and ventilation, for staff and students. There are 42 EMEFs in Campinas of which 15 were chosen for detailed study. They were photographed in many details. Existing architecture projects were examined and user opinions were registered. In five schools a more detailed survey was possible by additionally interviewing their principals and part of the teaching staff. Furthermore, thermal and lighting parameters were measured and the energy consumption of the last three years was registered. Openings, façades, materials employed in the pavements, the use of artificial lighting and the presence of vegetation were characterized. The fifteen schools are situated in regions that present different social, cultural and economical characteristics. As was observed, this seems to cause marked differences in attitudes related to the conservation of buildings, the economy of energy and sensibility related to the adequate use of thermal and lighting devices. This work presents results referring to EMEFs Raul Pilla, Lourenço Belocchio and Ângela Cury Zákia, three schools with three different socio-cultural environments. 2.2 Measurements of environment parameters Data collecting in the three schools extended from August to December 2006, a period that encompasses the last month of winter to the beginning of summer. Measurements were taken three times, typically in the morning, at noon and in the afternoon, from 8 am to 5 pm, on week days. Flexibility was necessary not to interfere with ongoing teaching activities. Images were taken from the sunshine angle of incidence on transparent openings, the position of students and solar protection devices both inside and outside the classrooms. Air temperature, globe temperature, relative humidity and air speed were measured, both inside and outside by the classroom. Inside the classrooms the measuring station was placed at the central position of the floor 1.50m above it. The equipment consisted of digital anemometer Testo model 405 V-1, Instrutherm model TH-090 digital thermometers and globe thermometers. The operative temperature was chosen as a parameter for thermal comfort. According to Brazilian standards acceptable values for thermal comfort are 22.5ºC

� to

� 25.5ºC for 65%

relative humidity, and 23.0ºC �

to �

26.0ºC for RH 35%, for sedentary activities and 0.5 clo (summer conditions). Since most of measurements were done in warm or hot days, the summer conditions were considered. These values agree with the results obtained by Labaki & Bueno-Bartholomei (2001), in a thermal comfort evaluation of a school building in Campinas, when 25ºC ambient temperatures were considered comfortable. In the present research no meaning differences were found between ambient and operative temperatures. Horizontal illumination at the height of the top of the desks, 0.70m, was determined with a Minolta T-10 illuminance meter. This was performed in 9 internal points shown in Figure1.

Figure1- Measurement points in classroom

The IES recommendations of artificial illumination levels are followed in the Brazilian norm. This was the reference for the studies of visual comfort. The uniformity of illuminance levels and the presence of glare were studied. Therefore the measured values were classified according to Table1.

Table1: I llumination cr iter ia

I lluminance level (lux) Classification

< 150 Insufficient

150 to 250 Adequate

250 to 750 Ideal conditions

750 to 1000 Excessive illuminance

> 1000 Possibility of glare

EMEF Raul Pilla This school is situated on the East section of Campinas, in a poor district. The building is frequently vandalized. Some of its young students are in a process of social reintegration and rather difficult to deal with. Students attend classes at four time shifts. The various buildings that form this school are scattered (Figure 2) making it difficult to monitor students out of the classrooms. All classrooms are built according to a pattern due to FDE1 that positions windows in an upper position on the wall opposite to the main entrance. Two classrooms in the main building referred to as rooms 1 and 2, and two other rooms near the main hall referred to as room 3 and multipurpose room were the places chosen for all measurements. The multipurpose room was supposed to lodge a science laboratory, however, due to lack of teaching space is being used as a classroom. Details of the buildings are given in Table 2.

1 Fundação para o Desenvolvimento da Educação do Estado de São Paulo (Foundation for the Development of Education of the State of São Paulo)

Figure 2: Layout of EMEF Raul Pilla

Table 2 - Data refer red to EMEF Raul Pila Character istics Classrrom 01 Classrrom 02 Classrrom 03 Multipurpose

room Window-wall ratio 52.5 % 52.5% 58.4 % 21.05 % Wall materials Bricks Bricks Bricks Bricks Roofs Ceramic tiles Ceramic tiles Ceramic tiles Ceramic tiles Orientation of the façade NW SE NW NE Ceiling Concrete slab Concrete slab Concrete slab Concrete slab Floor area 42 m² 42 m² 46.20 m² 82.84 m² Roof edge 1.50 m 1.20 m 2.00 m 1.20 m Curtains Yes Yes No No Area of the façade 24.00 m 24.00 m 23.10 m 34.20 m Ventilators Yes Yes Yes Yes

EMEF Lourenço Bellochio EMEF Lourenço Bellocchio is also situated in a poor neighbourhood from where come most of its students. Students attend classes at two time shifts. The terrain is not leveled. There are nine nearly identical classrooms, that differ only by orientation (Figure 3). Measurements were performed in four rooms, two with SE orientation and two with opposite orientation. There is no solar protection in the windows, only the roof edge slightly mitigates the sunshine. The courtyard has roofing. Ceramic tiles cover all floors. Originally the roofs were made of ceramic tiles which later were substituted by metallic sheets. Table 3 contains details of the building.

Figure 3 EMEF Lourenço Bellocchio

Table 3– Data refer red to EMEF Lourenço Bellocchio Character istics Classroom 2 Classroom 3 Classroom 5 Classroom 8 Window-wall ratio 34.14 % 34.14% 35.0 % 34.14% Walls Bricks Bricks Bricks Bricks Roof Metallic sheets Metallic sheets Metallic sheets Metallic sheets Orientation of the façade SE SE NW NW Ceiling Concrete slab Concrete slab Concrete slab Concrete slab Floor area 52.48 m² 52.48 m² 51.20 m² 52.48 m² Roof edge 0.7m 0.7m 0.7m 0.7m Courtains Yes Yes Yes Yes Área of the façade 24.6 m 24.6 m 24.0 24.6 m Ventilators Yes Yes Yes Yes

EMEF Ângela Cury Zákia EMEF Ângela Cury Zákia is situated in a much better neighbourhood as compared to the previous ones. Classes are in three time shifts. It has only four classrooms that differ only in orientation. All windows have light coloured curtains. The ceiling is made of white PVC. Small trees are present in the external vegetation that reaches the neighbourhood of the courtyard with its floor covered with ceramic tiles (Figure 4).

a) bascule windows b) covered cour tyard c) external vegetation

Figure 4 EMEF Ângela Cury

Table 4 contains details of the building.

Table 4 Data refer red to EMEF Ângela Cury

Character istics Classroom 02 Classroom 04 Window wall ratio 30 % 31,76 % Walls materials Concrete blocks Concrete blocks Roof materials Metallic sheets Metallic sheets Orientation of the façade N E Ceiling White PVC White PVC Floor area 52 m² 55,25 m² Roof edge 0.70 m 0.70 m Curtains Yes Yes Area of the studied façade 24.00 m 25.50 m Ventilators Yes Yes

Total energy consumption of each of the chosen schools in the three years preceding the one of the present study is shown in

Table 5. It can be seen that even when building area, number of pupils and time shifts are considered the three schools show different performances.

Table 5 Energy consumption (2003, 2004 and 2005) Yearly consumption

(KWh) School (EMEF)

2003 2004 2005

Average (KWh)

kWh/person/shift

kWh/m2

Raul Pilla (1290 m2,

1000 pupils, 4 shifts) 42,164 37,762 45,518 41,815 10.45 32.41

Ângela Cury Zákia (834m2, 360 pupils, 3

shifts)

9,579 10,058 12,243 10,627 9.84 12.74

Lourenço Bellochio (989m2, 590 pupils, 2

shifts)

21,434 24,458 25,245 23,712 20.09 23.98

3. Results and discussion EMEF Raul Pilla Very similar thermal conditions were observed in rooms with different orientations. This is attributed to the existence of roof edges and marquees. In the afternoon temperatures were slightly higher than the upper level for comfort (24°C). Figure 5 shows observed differences in interior and exterior temperatures near windows with different orientations in the four rooms. For the window with SE orientation in Classroom 2 both temperatures are almost identical and smaller than those measured in the other cases. Rooms 1 and 3 have identical orientation but temperatures in room 3 are smaller than those in room 1 as well as having a smaller difference between internal and external temperatures. This is attributed to the marquee that protects room 3 from direct sunshine a situation that does not occur in classroom 1. (Figure 6)

Figure 5 Operative temperature (13:30), 23/08/2006; Raul Pilla.

a) classroom 1 b) classroom 3 c) multipurpose Figure 6 classrooms 1 and 3 with sliding windows, c) multipurpose

The existence of sliding windows in this school, except for the multipurpose room with its bascule windows, favours cross-ventilation that contributes to thermal comfort. The other schools with bascule window do not present this feature. In rooms 01 and 02 adequate illuminance levels were observed without the need of artificial lighting. Some glare in the blackboard was present in the first day of observation. By chance the bushes in the fence were strongly trimmed and this caused a marked increase of the blackboard glare that could not be adequately reduced by drawing the curtains. It was then impossible to use the desks near the windows. Illuminance measurements in room 03 and in the multipurpose room were performed exclusively with artificial lighting on. There was a single switch for the whole floor. This did not allow measurements with and without artificial lighting because in parts of the floor artificial lighting had to be on. The observed illuminance levels were adequate. Room 03 presented the best thermal and visual comfort. The illuminance levels were perfectly adequate for classroom activities. There was no glare due to the fact that both external sides of this room have marquees above the windows.

The multipurpose room had the most homogeneous illumination of all four rooms studied. However the positions of the windows high up the walls near the ceiling do not allow to observe the exterior therefore causing visual discomfort. The room ventilation is poor due to the improper placement of the windows. EMEF Lourenço Bellochio During the hottest period all classrooms independently of orientation were thermally uncomfortable with temperatures near 30°C (Figure 7). Ventilation was poor due to the nature of the openings partly with fixed glass and partly with bascule windows with permanently drawn heavy curtains.

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Figure 7 Operative temperature (14:30), Lourenço Bellocchio – 27/10/2006 External temperatures present significant differences. For the exterior of room 02 with vegetation the temperature is quite smaller than that of room 08 whose exterior is covered with concrete and that of room 05 whose exterior consists of bare land (Figure 8).

a) external area to room 2 b) external area to room 5 c) external area to room 8

Figure 8 External areas - EMEF Lourenço Bellocchio

In this school the teachers can switch on and off the artificial lighting. Natural lighting on its own is adequate however the presence of pink curtains that must be drawn in the morning alter colours causing visual discomfort that is reduced by turning on the lights. (Figure 9).

b) drawn curtains: morning c) half-open curtains: afternoon

Figure 9 Cur tains. EMEF Lourenço Bellocchio EMEF Ângela Cury Zákia Two classrooms were studied. The operative temperatures were high, in the upper limits of comfort (>25ºC), (Figure 10) due to the presence of concrete blocks in the walls, metallic roofing and inadequate North and East orientations. The presence of vegetation reduces external temperatures and protects partially windows from direct sunshine. Ventilation is poor due to bascule Windows. Ceiling ventilators are constantly on. External covered areas are comfortable as a result of the use of vegetation (Figure 4). Illuminance levels smaller than 100 lux could not be adequately corrected by artificial lighting. Table 6 shows a comparison of the results for the three schools.

Figure 10 Operative temperature (13:00)- EMEF Angela Cury Zakia, 13/10/2006

Table 6 - Summary of the three cases: Comfortable (C) – Unconfotable (U) School (EMEF)

Classroom Orientation Thermal comfort

Visual comfort

kWh/person Comments

1 NW U C

2 SE C C

3 NW C C

Raul Pilla

Multipurpose NE U C

41.8

Teachers have no access to light switching, lights are permanently on. High windows affect ventilation Marquee protects room 3

2 N C U Ângela Cury Zakia 4 E U U

29.52 Insufficient illumination Metallic roof

2 SE U U

3 SE U U

5 NW U U

Lourenço Bellocchio

8 NW U U

40.19

Natural lighting sufficient but artificial lighting necessary to correct colour distortions. Thermal discomfort in all rooms

Most of the observed thermal and visual discomfort that result from inadequacies of the projects and building materials can be significantly diminished by adequate management, namely by the accessibility to controls of artificial illumination, the proper choice of curtains, changing where possible bascule windows with sliding windows and by the correct use of vegetation. The simple possibility to switch on and off the lights in individual classrooms can contribute significantly to energy economics. 4. References Becker, R., Goldberger, I., Paciuk, M. (2007) Improving energy performance of school

buildings while ensuring indoor air quality ventilation, Building and Environment, Vol. 42, pg 3261–3276

Erhorn, H., Mroz, T. Mørck, O., Schmidt, F., Schoff, L., Thomsen, K., (2007), The Energy Concept Adviser—A tool to improve energy efficiency in educational buildings, Energy and building, in press

Gifford, R. (1997) Environmental Psychology: Principles and Pratice. 2ed. Allyn and Bacon, Boston, USA. 1997.

Graça, V.A.C. da; Kowaltowski, D.C.C.K.; Petreche, J.R.D. (2007) An evaluation method for school building design at the preliminary phase with optimization of aspects of environmental comfort for the school system of São Paulo State in Brasil. Building and Environment, Vol.42, pp 984-999

Kowaltowski, D.C.C.K, et al. Melhoria do conforto ambiental em edificações escolares estaduais de Campinas – SP. Relatório científico de pesquisa – FAPESP. Universidade Estadual de Campinas. Campinas, SP. 2001.

Labaki,L.C.; Bueno-Bartholomei, C.L. (2001) Avaliação do conforto térmico e luminoso de prédios escolares da rede pública, Campinas – SP. Proceedings of ENCAC 2001, São Pedro, Brazil

Monteiro, C. et al. (1993) A satisfação como critério de avaliação do ambiente construído: um estudo aplicado ao prédio escolar. Proceedings of ENTAC 93. São Paulo, SP.

Ornstein, S.W.; Borelli Neto, J. O desempenho dos edifícios da rede estadual de ensino: o caso da grande São Paulo. Avaliação técnica – primeiros resultados. São Paulo: Faculdade de Arquitetura e Urbanismo da Universidade de São Paulo. 1996.

Rosenfeld, E. Mejoramiento de la efiencia energética y habitabilidad de los edificios escolares. Proceedings of III ENCAC, Gramado. p. 433-438. 1995.

Yannas, S. (1995) Educational buildings in Europe. Proceedings of III ENCAC Gramado, RS. p. 49-69. 1995.