Ecological renovation of the building stock is one of the important problems together with construction of ecological new sites. In this part of the world, which has stabilized population, it should even be more emphasized than the new constructions. It is impossible to separate energy related elements from architectural elements. Spatial organization and architectural form are firmly interconnected with such factors as solar control, ventilation, insulation, location of (thermal) walls, surface properties and color. For ecological renovation these considerations are reference points;

I — The aim of the study is to show exemplary renovation of a social housing unit to be an ecological house in Batikent-Turkey. A financial model will support implication and comparative analysis on energy, water, and urban agriculture.

II — Batikent’ site is the biggest (third in the world) housing project implied in Turkey. Between 1981-1990, 50.000 houses were built in Batikent. Aspects ofecological design principles are applied in some district implications. But holistic approaches were not managed. After 18 years of living in the area, buildings needed renovation. “Ozgur Cooperative" is one of the most interesting district settlement projects in the area. It consists of 306 triplex units. Highlights of passive solar energy design and vernacular architecture approaches used in design.

III — Architect of the project in Batikent, with an expert team, plans to revise his own house as an experimental transformation to Eco-house. Objectives of the study are;

The Eco renovated house is an ecologically renovated dwelling that is 150 m2 and has two stories and a basement. Cubic dimensions of the building optimize heat load. Entrance, living, dining, kitchen and 2 bedrooms are located to access of Southeast wind. With addition of 2 greenhouses a tampon area in summer conditions created, to collect heat when needed. Greenhouse is at the centre of building. Its design eases to conduct desired air to other spaces via direct opening plus special details for conduction. That is living and bedrooms adjacent to greenhouse heat is collected and stored adjacently to the thermally linked spaces. Day to night closing and opening of shutters for windows, greenhouse is used to provide appropriate thermal comfort conditions.

Technical Aspects

■ To revise water system to separate grey water from sewage and collect rainwater.

■ On balconies and the garden there has been edible landscape and it will be revised.

■ Greenhouse will be constructed to connect inner spaces as a heat transferor.

■ Convert materials, finishing and appliances to be healthy, safe and economical ones.

■ Re examines insulation ofwalls, windows. Shutters will also be insulated.

■ Install heat collectors for heating, cooling and domestic heat water systems.

■ Earth pipes will be installed to supplement this above-mentioned system.

■ PV’s will be installed to supply electricity for domestic consumption.

Wind speed and the direction are appropriate to overcome the overheating problems during hot seasons while the solar energy is more than enough to supply the very small amount of space heating requirement during winter using direct gain windows. Ordinary flat plate photo thermal converter needs can easily supply domestic hot water.

The system sizing for the stand-alone PV installation is done by the procedure outlined in the book written by Green. The load is as follows: Solar radiation value for Ankara is 4 MJ/m2 — day; Total daily requirement of electricity is obtained to be around 2175 Wh/day.

The number of modules is calculated as 24. The inclination angle of modules is calculated to be min 15 Degrees. (Latitude 15 Degrees). The reserve capacity of the batteries is assumed to be 10 days, which is quite reasonable for sunny and arid regions. This calculation gives 18 batteries. Efficiency of lead-acid batteries is 80% nickel-cadmium batteries 70%. The cost for the solar panels; The modules $ 7200+Bateries $ 4000+Maintenance $ 2000=Total $ 13200. South and/or east facing direct gain windows can easily supply heating requirements during winter months.

Greenhouses attached to both south and north facades. Heating by thermal mass and cooling, edible landscape, creation of additional space and recreation are the aims of additional structures. Greenhouse shutters will be added for both summer-winter; day — night insulation. Green house will completely moved and become a garden in summer.

Insulation: Existing 2 cm insulation material is adjusted to be 5cm and sandwich brick wall. Roof insulated with 8cm Styrofoam. Existing single glazing is improved to be double, using the old wooden frame. Shutters repaired and inner faces are insulated by film. Existing thermal mass for some of the rooms might be effective in solving insignificant requirements of cool nights and hot afternoons.

Main structure was made out of concrete, the materials for renovation have been selected with aspect to renewable resources and re-used materials are mainly brick, wood and natural insulation materials such as prelate. Structures and attachments will be made with screws or studs, not nails, so that may be easily demented and parts used elsewhere. Lime mortar has been used to make it easy to take down the wall and to clean the bricks. First floor, windows and roof are made out of wood. All parts of the external walls and the roof are accessible for replacement of materials has aged.

Toilet solid wastes, kitchen and garden organic wastes, leaves roots are collected, stored and composed to be fertilizer in the edible landscape in and outside house. Grey water was connected to city sewers, after ecorenovation Bath and WC grey waters are collected in basement to be naturally purified and used in garden. Garden and greenhouse vegetation and trees are planted for household requirements: Edible landscape design according to their light, water irrigation requirements plus aesthetic and creative demands of the people living in the house. Evergreen trees obstruct prevailing wind direction. On south fruit trees planted.

C. Aghemo, A. Pellegrino, V. R.M. Lo Verso

Politecnico di Torino, Dipartimento di Energetica, Faculty ofArchitecture chiara. aghemo@polito. it

Introduction

The use of daylight in non-residential buildings has become an important strategy to improve environmental quality and energy efficiency by minimising artificial lighting consumption, heating and cooling loads. Daylighting design and building design should be inseparably linked to each other, in one only creative process aimed at generating appropriate architectural and technical solutions while reducing building energy consumption1. Nevertheless, daylighting strategies are seldom considered in the earliest stages of a building design: this is often due to the lack of simple tools able to accurately predict the performances of daylighting systems exposed to lighting conditions varying continuously in distribution and intensity, according to seasons, day’s hours and specific climate conditions.

As an alternative to a software based-on approach2,3, an efficient prediction tool for daylighting design is represented by the use of scale models under an artificial sky and sun, purposely designed facilities which enable reproducing daylighting conditions by means of artificial lamps and luminaires.

Scale models are often used by designers to analyse design solutions in a three­dimensional physical representations, hence belonging to design culture and assuring a good adherence with real situations, since even complex spaces can be reproduced; furthermore, the simulation ofopaque and transparent materials’ optical properties is easier in most conditions, thanks to the possibility of using real materials.

Using scale models under an artificial sky and sun makes it possible to simulate the dynamic behaviour of daylight to allow the comparison of the environmental performances of different daylighting systems: it is actually possible to maintain constancy and repeatability of luminance distribution of the sky vault and the apparent movement of the sun, assessing a daylighting system with reference to same daylighting conditions4,5,6.

As we find in the text above, the quantitative part of the solar radiation can be efficiently analysed with ratios of building shadows influencing the surroundings and vice versa. This relation influences:

• building geometry,

• distances between buildings,

• orientation,

• duration of solar radiation

• during the chosen period of

• time,

• layout density

• consequently number of

• residents on site.

Solar rights in Slovenia

In 1988 the Sanitary Inspectorate of the Republic of Slovenia issued an obligatory instruction on minimum sanitary and technical parameters, which have to be considered when assessing the physical planning acts. One of them is minimum duration of solar exposure of living spaces during four reference days in a year that has to reach at least 1 hour on the 21st of December, 3 hours on the 21st of March and the 21st of September and 5 hours on the 21st of June.

Simulation model

The simulations were carried out for a flat site in Ljubljana (latitude 46.03 N).

As a reference a building with the following geometry was simulated:

• length (L) 60 m,

• width (W) 12 m,

• height (H) 6 m (2 floors),

• longer facades facing S and N.

For each type a site layout, consisting of four parallelly positioned buildings was designed. The required site size for four buildings was measured according to shadow contours delineated with boundary lines, marking a rectangular site.

A series of indoor and outdoor tests for temperature and illuminance measurements were done on hourly and daily basis to evaluate the performance of each room. These tests enabled us to obtain an immediate evaluation of the efficiency of the system, to visualize the amount of daylighting redirection, to observe how direct sunrays penetrate the interior space, and to detect the presence of bright areas generated by the prismatic glazing panels. Temperature and illuminance measurements were taken at the height of 70cm~80cm for different interior reference zones

(Fig.3 & Fig.4). A Testo-435 Thermocouple Meter and Minolta T-10 illuminance meter with a data management Software T-A30 was used for data collection.

the maximum ambient temperature was 23.5oC whereas the temperature for reference case was 26.5oC and target case was 29.66 oC (Fig.5).The temperature of target room was 3oC higher than the reference room, and about approx 6oC than the ambient temperature. Prismatic panels directly transmit input solar thermal range radiations into the room, which causes to increase the temperature. This increase in temperature may, sometimes, produce local thermal discomfort in some parts of the room. In order to reduce this effect and for the ventilation purpose, an electric fan was used to circulate the hot air uniformly to produce better thermal

conditions inside the room. Fig.5. Temperature measurement results.

1.2. Illuminance Results

The measured results show that the reference room is full of glare due to direct sun patches (Fig.10). These sun patches changed their position throughout the day with respect to changes in altitude angles of the sun. The illuminance levels were measured over 150Lux~ 6kLux (Table.2) at a distance of 1m, 2m, 3m, and 3.5m from the window and the daylight factor (%) was calculated over 1~15.6 (for illuminance data collected) for ten different zones. Here the daylight factor means, ” The ratio of interior illuminance at a given point on a given plane (workplace) to the exterior illuminance (reference) under the same sky conditions”. i. e. Daylight Factor= Interior illuminance x100 / Exterior illuminance. The result comparison at morning, solar noon, and evening timing of the day, under clear sky conditions, shows that the distribution of work place illuminance along the centerline of the room (south facing wall) was not uniform (Fig.6, Fig.7 & Fig.8). The illuminance was varied up to 6kLux at a distance of 2m from the window, and daylight factor varies up to
15.6 (at solar noon Fig.9) which produced an uncomfortable glare. Moreover, there was no reasonable uniform drop-off in light levels with respect to distance increase from the window of the south-facing wall. Changes in azimuth and altitude angles of the sun throughout the day affect the depth of penetration and distribution of daylight in the room. The simple glass on the entrance of the reference room transmitted about 90% sunrays and was not able to control the directly penetrating sunrays into the room, which brightened some part of room while the rest of the room was in shadows.

Measured results of prismatic glazing system (target room) indicate that for solar azimuth angle у < +33°. The prismatic model achieved work place luminance level of over 400Lux near the south-facing wall. The illuminance levels were achieved > 100Lux at a distance of 3.5m from the window even in the evening times. The distribution of work place illumination along the centerline of the space from the window is fairly high and uniform through out the day, as expected (Figs.6, Fig.7 & Fig.8). Also the daylight factor ranged from 0.5 to 2.1 for ten different zones is fairly high and uniform (Fig.9).

There was no appearance of direct sun patches on work plan area in the target room (Fig.11.). The main reason for the uniform illuminance inside the target room is that the prismatic panels control the sunlight by reflecting, refracting, and diffracting the rays.

The transmittance of light rays through prismatic panels depends upon the incident angle. These panels accommodate a wide range of solar altitudes to produce uniform illuminance and to obtain maximum penetration without creating descending rays of sunlight that create glare.

Fig.11. The target room with PSHC (solar noon).

2. Conclusion

The results of illuminance measurement revealed that the target room showed uniform illuminance with respect to the position of sun while the reference room showed non­uniform high illumiance creating a glare inside the room. The daylight factor ranged from 0.5 to 2.1 also confirmed the illuminance uniformity for target room while the daylight factor ranged from 1 to 15.6 showed the nonuniformity in the illuminance levels for reference room. The prismatic solar hybrid collector unit was achieved better thermal conditions and significant redistribution of ambient sunlight within the target room, redirecting the incident light towards the ceiling where it was reflected onto the working area below. This drastically reduced the need for artificial light. The system with prismatic glazing unit has represented an efficient approach to exploit natural light for glarefree and uniform illumination of working spaces. Low luminance levels of back zones could be improved by improving the reflection properties of ceiling. According to the CIE guide on electric lighting of interior (CIE-1986), an illuminance of 20Lux is regarded as the minimum level for non working interiors and the recommended for normal working space is 200Lux, which validate the results of illuminance for target room (with PSHC). The overall results clearly proved that the prismatic solar hybrid collector could be successfully used to enhance the thermal and visual comforts preventing glare by solar radiation. For further optimization of

the light guiding properties, we plan to model the daylighting system with prismatic glazing unit with ray-tracing methods and Monte — Carlo simulation.

The aim of this part is to discuss advantages of energy efficient building design in high-rise buildings by a project designed for Istanbul Municipality Headquarters. The building has 42 storeys and oriented to south. The proposed project is ecologically, economically and aesthetically considered.

It is based on natural energy use for heating and cooling systems as a main part of ecological architecture approach. In a high-rise office building one of the biggest energy consumption is cooling load. Energy cost can be reduced by intelligent design: e. g. correct orientation and location, use of solar energy collected in attached greenhouses, intelligent facades etc.

In this study, orientation difference for main surface and greenhouse effect for heat gain are analyzed by SUNCODE program, which is personal computer version of SERI/RES thermal analysis program. The analysis is realized for four different cases, which are, attached greenhouse, without greenhouse, oriented to south and west. For these cases solar gains and heat losses are analyzed and the results are discussed.

The program calculates heat losses and solar gains from building and different building elements for each indoor space for different periods (hourly, daily, monthly, seasonal, yearly etc.) according to user preference.

In addition, heating and ventilating equipments loads and heat losses and solar gains from windows are calculated by mathematical simulation techniques. The program needs building data like materials and dimensions, orientation, area, shading and climatic data for estimating heat loss to outdoor and earth, total thermal capacity, solar radiation (direct, normal, total horizontal, direct horizontal, diffuse horizontal), outdoor temperature (average, minimum and maximum), wind speed (average, minimum and maximum), average indoor temperature, humidity, earth temperature, heating and cooling degree days.

Annual heating need of the building is 2207.999 GJ for south oriented building while it is 2336.397 GJ for west oriented building. It means 6% gains from total heat load of the building.

Three parts for attached greenhouse analysis divide the building. Zone 2 and zone 3 are estimated as attached greenhouse and without greenhouse. The annual heating need of the building is 5818.370 GJ for the tower without greenhouse while it is 5407.940 GJ for the towers are estimated with attached greenhouses. It means 7% gains from total heat load of the building.

Different types of artificial skies have been realised in the past: mirrorskies, dome skies, spotlight sky simulators or scanning skies, each characterised by different advantages and disadvantages7,8,9,10,11,12.

Comparing the potentialities and limits of each type of artificial sky, at the Daylighting Laboratory ofthe Politecnico di Torino it was decided to design and achieve a scanning artificial sky, able to reproduce the diffuse skylight component, supplemented by an artificial sun, able to reproduce direct sun-light component13,14. The facility was conceived not only for research purpose, but also and especially as a tool for designers (architects, engineers, lighting designers) to predict which way daylight characterises outdoor and indoorenvironments, since it allows both determining daylight levels (illuminance and daylight factor values, spatial distribution of daylight over an indoor room) and reproducing how a daylighted environment appears as well as what is the dynamic behaviour of sun penetration.

The “sky” reproduces one sixth of the vault, consisting of 25 individually dimmable luminaires (figure 1), based on the model ofsubdivision ofthe sky hemisphere proposed by Tregenza for sky luminance measurements and assumed by the CIE in the IDMP (International Daylighting Measurement Program)15,16. In orderto reproduce the entire sky dome, the model’s stand produces a six-step scan rotation, modifying foreach scan the luminance distribution. Global photometric quantities and pictures are therefore obtained adding the partial values and images. Different sky conditions are reproducible according to both standard models and real luminance values recorded at IDMP measuring stations. The “Sun” is in a fixed position, so the model’s stand is rotated an tilted to suitably reproduce the relative Sun-Earth position, according to solar geometry equations.

In short, main advantages as tool for daylighting design may be summarised as follows17:

• good adherence with real situations

• possibility of simulating different sky conditions, referring to both standardised daylighting models and real skies, experimentally measured

• possibility of comparing performances of different daylighting systems

• possibility to carry out an objective measurement of photometric data (quantitative evaluation) and a perceptive assessment of the daylighted environment (qualitative evaluation), by taking photographs of the indoorsimulated environment

• possibility of carrying out studies with different aims and on different scales, from site planning to indoor environment to daylighting systems.

Apart from the advantages already listed a scanning artificial sky presents some limits, linked to the finite distance between the model’s stand and the portion of dome: especially when dealing

with large models, an horizon line error and a parallax error (different parts of the considered model receive different quantities ofdaylight and sun-light18) may occur.