Stevens Institute of Technology, USA

Department of Civil Engineering, University of Thessaly, Greece

Department of Planning and Regional Development, University of Thessaly, Greece

Editors: A. Liakopoulos A. Kungolos C. Christodoulatos A. Koutsospyros

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Str. Exadaktilou 5 54635 Thessaloniki, Greece Tel/Fax: 2310-248272 E-mail: grafima@grafima.com.gr, grafima@gmail.com www.grafima.com.gr

Proceedings of the 12th International Conference on Protection and Restoration of the EnvironmentEditors: A. Liakopoulos, A. Kungolos, C. Christodoulatos, A. KoutsopsyrosISBN 978-960-88490-6-8

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Implementation of bioclimatic architecture principles to a settlement's

design

K. Lantitsou*, V. Stefanis, G. Panagiotakis, J. Kolokas Democritus University of Thrace, Dept. of Civil Engineers, Vas. Sofias 12, 67100, Xanthi, Greece

*Corresponding author: E-mail: klantits@civil.duth.gr, tel. +30 25410 29746

Abstract A building�s bioclimatic design refers to the design of its spaces based on the region�s climate, in order to assure best interior conditions. This study deals with the ab initio design of a two-storey and of a ground floor dwelling of a settlement. The settlement is suitably modulated so that there is no shadowing to the south sides at anytime during a whole year, aiming to maximize the solar earnings. Following the design, the percentage of energy saved due to passive systems is estimated, using the Ecotect Analysis software. For this purpose, results from similar houses (as far as floor planning and functional space organization are concerned) are compared to those without passive solar systems. The settlement was designed and studied based on Athens� climate. Keywords: bioclimatic design, passive solar systems, Ecotect Analysis 1. INTRODUCTION Bioclimatic architecture is defined as the buildings� designing process according which the researcher is taking into account a series of parameters, aiming the rational energy use targeting its conservation. Factors taken into account are the local climate in order to assure visual and thermal comfort using the solar energy, the various natural climatic phenomena, as well as other climate parameters such as the sunlight, the vegetation, the wind, the humidity, the outside air temperature, and the shading by other buildings. The main elements for a bioclimatic design are the passive systems which are incorporated in the buildings and aiming the exploitation of available environmental resources to provide cooling, heating and natural lighting for buildings. Applying the principles of bioclimatic design, energy saving is achieved due to the shell�s improved protection and better behaviour of structural elements that leads to the reduction of losses, conditions of thermal comfort are created and the requirements in heating are decreased, heat is produced via solar systems of direct and indirect profit. So, the needs of residence in heating are reduced, thus accomplishing to cover the needs of the building more economically and without great energy requirements. Moreover, the partial maintenance of air temperature in the interior in the ideal levels is achieved, depending on the season -high in the winter and low in the summertime- thus a need does not exist for the annexation of additional systems that will help in the maintenance of ideal levels. Benefits arising from the use of bioclimatic architecture can be are distinguished in: energy (via the saving of energy and the guarantee for thermal and optical comfort), economically (since both the needs and the cost for installation electromechanical are decreased), environmental (since pollutants, and CO2 emissions are decreased) but also socially, since the quality of life is improved. All these are achieved using techniques on the building�s construction, the planning, the orientation and the arrangement of the residence contributing in the restriction of dwelling needs in mechanical equipment for the heating or the cooling.

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2. SETTLEMENT�S DESCRIPTION The settlement is comprised of four ground floor and five two-storey dwellings. The arrangement of the buildings is shown in Figure 1. The settlement has been designed in such a manner, so as no shadowing exists to the south sides during the whole year. Based on the solar map and the shading calculator for 36 longitude, the required minimum distance was calculated. For the north-to-south axis for two storey dwelling: maximum height h=9 m tan 29 =h/x, hence the required x distance must be at least 16.20 m. Applying the same to the ground floor dwelling, for a maximum height of 6 m, the minimum distance from the house�s northern face must be 10.81 m.

Figure 1 Settlement�s topographic design

As far as the east-to-west axis is concerned, the buildings are placed with a 20 m distance between them because based on the solar map and the shadowing indicator, their insolation is not affected during the whole year. At the northern side of the model house a row of coniferous trees was placed as a shield for northern wind movement. At the western side deciduous trees were placed acting as sunshields during summer preventing shell overheat and optical blur. 3. STUDY DWELLINGS DESCRIPTION The standard two-storey dwelling consists of two levels, ground level occupying a total of 127.08 m2 and an upper floor of 130.45 m2. It was placed east to west aiming to offer the biggest surface exposure to the south for solar heat collection during winter. It has a planted roof on the first storey roof as well as on a part of the ground floor roof. It has an outer insulation of 8cm and other passive systems like southern openings Trombe wall, a greenhouse and shades that were premeasured.

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Ground floor plan view First floor plan view

Section B-B South view

Figure 2 Detailed designs of a typical two storey dwelling The floor plan�s design was organized in such a way that the daily living spaces be placed on the southern side of the building aiming to achieve the desired internal temperatures (Figure 2). On the other hand limited use spaces, which don�t have high temperature requirements, were placed on the intermediate thermal zone. The rest ancillary spaces were place on the northern side of the building aiming to protect and insulate the rest of the spaces.

Section BB

Ground floor plan view First floor plan view

Figure 3 Detailed designs of a typical ground floor dwelling

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Standard ground floor dwelling: it occupies a total of 56.21 m2. The shape, orientation and placing of the internal spaces followed the same principals as the two storey house. Besides the passive systems placed on the two storey house, on the ground floor dwelling two solar chimneys were added sized 1x0.5x0.5 m for the quicker space ventilation (Figure 3). 4. DIMENSIONING OF PASSIVE SYSTEMS The settlement has been designed for the climatic conditions of Athens. Depending on the average winter outdoor temperature an initial estimation of the ratio between the surface area of the southern glass sun parlor to the heated floor�s area is made. For an average winter temperature +7.2 C, the openings surface area per room surface unit varies from 0.11 to 1.17 m2 [1]. Referring to the ground floor southern openings of a two-storey dwelling: (a) Living room and part of the dinning room: Eplanview=24.96 m2, so opening must range between

0.11x24.96=2.74 m2 and 1.17x24.96=29.21 m2. An opening with 2.3 m height and 1.8 m width is chosen, having a total surface area of 4.14 m2.

(b) Kitchen: Eplanview=13.68 m2; thus, an opening of 1.35 m height and 2 m width is placed having a total surface area of 2.70 m2

(c) Salon and part of the dinning room: Eplanview=26.31 m2; an opening of 2.3 m height and 2.3 m width is placed having a total surface area of 5.29 m2

Referring to the storey southern openings of a two-storey dwelling: (a) Bedroom1, bedroom 2: two openings of 2.3 m height and 1.3 m width are placed each having a

surface area of 2.99 m2. For the southern openings of a ground floor dwelling: (a) Kitchen: Eplanview=12.71 m2; thus, an opening of 1.35 m height and 1,9 m width is placed having

a total surface area of 2.56 m2

(b) Living room and part of the dining room: Eplanview=17.87 m2; an opening of 2.3 m height and 1.6 m width is placed having a total surface area of 3.68 m2

5. PRE-DIMENSIONING OF TROMBE WALL For an average outdoor temperature of 7.2 C during winter, the required wall�s surface area per square meter of space varies from 0.22 to 0.35 m2 [1]. Referring to a two-storey dwelling�s wall: At the southern side of the storey Trombe walls are placed in order to assure bedrooms� heating. Bedroom 1: Eplanview=14.61 m2; hence, Trombe wall�s total surface area should vary between 14.61x0.22=3.21 m2 and 14.61x0.35=5.11 m2. In bedroom�s 1 space, a Trombe wall with a total surface area of 2.5x1.8=4.50 m2 is designed. Bedroom 2: Eplanview=11.37 m2; hence, Trombe wall�s total surface area should vary between 11.37x0.22=2.50 m2 and 11.37x0.35=3.97 m2. In bedroom�s 2 space, a Trombe wall with a total surface area of 2.5x1.5=3.75 m2 is designed. A Trombe wall is likewise dimensioned for a ground floor dwelling. Its total surface area would be 2.5x1.48=3.7 m2 for the kitchen and 2.5x2.0=5.0 m2 for the living room. Trombe walls consist of concrete 25 cm thick so they are going to have a 16.65oC indoor temperature variation and a time lag of 8 [2]. In front of it, at a 6 cm distance, there is a double glass-window 1 cm thick. 6. GREENHOUSE�S PRE-DIMENSIONING For an average outdoor winter temperature of +7.2 C, the total glass sun parlor�s surface area per room�s space unit ranges from 0.33 to 0.53 per m2 [1]. Referring to a two-storey dwelling�s greenhouse: The southern thermal zone has a surface area of 51.27 m2. Consequently, it will vary between: 0.33x51.27=16.91 m2 and 0.53 x 51.27=27.17 m2. A total greenhouse sun parlor of 24.62

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m2 is chosen, which conforms to the above surface areas. Referring to a ground floor dwelling�s greenhouse, the southern thermal zone has a surface area of 17.87 m2. Consequently, it will vary between: 0.33x17.87=5.89 m2 and 0.53x17.87=9.47 m2. A total greenhouse sun parlor of 9.25 m2 is chosen, which conforms to the above surface areas. In this case, the pre-dimensioning is not made per room as with the Trombe wall, because a uniform space with free airflow is dealt with. The greenhouse has triple glass and is considered that there is free airflow during the summertime, since the greenhouse�s glass parlor is removed. This happens in order to avoid thermal discomfort due to greenhouse during summer. 7. PLANTED ROOFTOP A planted rooftop was installed which is a complex thermal system that has considerable heat insulation properties both for winter and summer time. The planted rooftop offers considerable noise protection, contributes to rational rain water management and creates an aesthetically pleasant, healthy and functional area [3]. 8. CALCULATING SHADING OF SOUTHERN OPENING The goal is to keep the southern openings totally shaded during June and July. The angle the sun makes at 12 pm at July 21st is 63 degrees. The height, h, of the model house storey is 3 m. So, for h=3 m and =63o, the required sunshield length should be x=1.52 m.

Figure 4 Schematic representation of the sun�s course relatively to the building and shading

appearing on it on June 21 at 3 pm (left) and on December 21 (right) for a two storey building.

Figure 5 Schematic representation of the sun�s course relatively to the building and shading

appearing on it on June 21 at 3 pm (left) and on December 21 (right) for a ground floor building.

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The sun�s course is schematically presented in figures 4 and 5 for different dates and daytimes using the Ecotect analysis for two-storey and ground floor dwellings, respectively. Sunshields are selected to be installed in the standard house only, with a 1.5 m length for both the ground floor and the two storey house. 9. SETTLEMENT�S DWELLINGS ENERGY ANALYSIS For the thermal analysis of the buildings and the calculation of shading of the settlement using the Ecotect software, it is imperative to enter the climate data of the study area. The climate data on which the present analysis is based are those of Athens and come from the Energy Plus Version 2.1.0. software. For greater calculation precision, from the (local terrain) menu urban was selected which affects thermal analysis and natural airflow.

Table 1 Indicative element values used in thermal analysis

U-Value AdmittanceSolar

AbsorptionThermal

Decrement Thermal

Lag (W /

m2(W /

m2(0 - 1) (hrs) (hrs)

External Walls Trombe Walls Rooftop Planted Rooftop Greenhouse Windows

Prior to the thermal analysis, the temperature with which dwellers will feel comfortable must be set. According to the Greek building energy performance regulation, the thermal comfort zone margin is 20o to 26o Celsius. That means that when temperature drops below 20o Celsius the tenants activate heating and when temperature rises above 26o Celsius the tenants activate cooling systems. For the cooling of shower and WC spaces, natural ventilation will be provided. A comparison of heating and cooling burdens has been made and the results are shown in Table 2 and Table 3 for a two storey and a ground floor dwelling respectively.

Table 2 Heating � Cooling demanding burden comparison for a two storey building Heating-Cooling demanding burden

Standard two-storey dwelling Bioclimatic two-storey dwelling

HEATING COOLING TOTAL HEATING COOLING TOTAL MONTH (Wh / m2) (Wh / m2) (Wh / m2) (Wh / m2) (Wh / m2) (Wh / m2) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec TOTAL

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From Table 2, it is obvious that the house with the passive solar systems (bioclimatic house) needs less energy to achieve thermal comfort conditions. It requires less energy than a typical house both during winter and summer. The smaller cooling burdens are due to the sunshields and the planted roof, while the smaller heating burdens are due to the greenhouse, the Trombe wall, and the planted roof. From Table 3, it is obvious that the house with the passive solar systems (bioclimatic house) needs less energy to achieve thermal comfort conditions. It requires less energy than a typical house both during winter and summer. Cooling burdens are smaller due to the sunshields and the planted roof, while the smaller heating burdens are due to the greenhouse, the Trombe wall, and the planted roof.

Table 3 Heating � Cooling demanding burden comparison for a typical ground floor building Heating-Cooling demanding burden

Standard ground floor dwelling Bioclimatic ground floor dwelling

HEATING COOLING TOTAL HEATING COOLING TOTAL MONTH (Wh / m2) (Wh / m2) (Wh / m2) (Wh / m2) (Wh / m2) (Wh / m2) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec TOTAL

10. CONCLUSIONS Using the Ecotect Analysis software it has been confirmed that passive solar systems save energy by utilizing solar radiation. The thermal analysis results have shown that during the whole year the required heating and cooling burdens needed to achieve thermal comfort were reduced in buildings with greenhouse, Trombe walls, sunshields and planted rooftop. The total thermal burden reduction is 18.23% [(12,585.94 heating burden of a typical house � 10,292.64 heating burden of a bioclimatic house) / 12,585.94 thermal burden of a typical house = 0.1823] and the cooling burden reduction is approximately 7% [(21,000.96 cooling burden of a typical house � 19,543.24 cooling burden of a bioclimatic house) / 21,000.96 cooling burden of a typical house = 0.069] for the two storey building. There is a cumulative total burden reduction [(33,586.9 total typical building burden � 29,835.88 total bioclimatic building burden) / 33,586.90 total typical building burden = 0.12] of 12%. For the ground floor building a 16.25% thermal burden reduction was calculated [(23,408.41 heating burden of a typical house � 19,605.59 heating burden of a bioclimatic house ) / 23,408.41 heating burden of a typical house = 0.1625] and 11.9% cooling burden reduction[(35,551.09 cooling burden of a typical house � 31,559.72 cooling burden of a bioclimatic house) / 35,551.09 cooling burden of a typical house = 0.1119] . There is a cumulative total burden reduction of 13.2%

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[(58,906.14 total typical building burden� 51,165.31 cooling burden of a bioclimatic house) / 58,906.14 total typical building burden = 0.132] 13.2%. Using the Ecotect Analysis there is no way to represent the microclimate improvement achieved by using planted roofs, the proper surrounding space shaping with the use of trees and the improvement in comfort conditions from the airflow created by solar chimneys and holes on Trombe walls. Trombe walls can increase energy savings during winter. The method that ecotect uses underestimates considerably their influence. Even with passive solar systems and efficient sunshields, even with planted rooftops as those used in the present implementation, there cannot be 100% energy autonomy during the whole year. In such a case, it is suggested that renewable energy sources should be used in order to fulfill the extra energy requirements. References 1. Andreadaki, E. (2006) Bioclimatic Design, Environment, and Viability. University Studio Press

Editions, Thessaloniki. 2. Perdios, S. (2007) Energy Saving Interventions in Buildings - Sport Centers � Industries �

Transportation. SELKA 4M Editions. 3. Vrahopoulos, M.G., Filios, A.E. and Kotsiovelos, G.T. (2002). Energy Saving in Buildings

Having a Planted Rooftop. Proceedings 7th Conference on Sun Technology, Patra, Greece, pp. 253-259.