The solar volume method determines the maximum possible volume that can be built on a certain site (location) and not cause substantial shadowing of the neighbouring land or buildings. With the help of solar volume we can determine volume or check the existing urban tissue. This way of approach is very important in designing solar urban quarters. It can be easier applied in rural or suburban areas with lower urban densities. In densely built urban centres a shift from the basic ground level could be a sensible solution bearing in mind that ground-floor is usually designed for public or commercial spaces (Fig.1).

The peak of the pyramid is the top of the vertical pole. The north angles of the pyramid are determined on the basis of the shadow cast by the pole, when the sun has the minimum

chosen elevation (in the morning and in the afternoon at the winter solstice). Azimuth can be determined from the solar chart for the chosen latitude. The south edge of the pyramid is determined by the parallel projection of the north edge through the base of the pole. In our case the starting points were two: the15 ° elevation on the 21st of December and the legally required duration of solar exposure.

The first solar autonomous desiccant cooling system in Germany was proofed to be technical feasible. It is important to reduce the system costs by simple solar systems. A desiccant system with solar air collectors and no buffer storage can cope with the comfort needs of buildings used mainly during day time with a high glazing fraction in the facade.

The users of the chamber of commerce in Freiburg, Germany are satisfied with the comfort conditions in the two conditioned rooms. The approach of accepting some hours of exceeding the criteria of the German standard DIN 1946 part 2 to be able to realise a solar autonomous and economically viable system has been proofed positively.

The detailed analysis of measured data pointed out, that in further projects the amount of regeneration energy given by the collector should be controllable. This means to install devices which allow to reduce an exceed supply of collector gains for avoiding unfavourable heat transfer to the inlet air stream. This could be realised by mixing the heated air with ambient air or by using only part of the collector field if necessary.

The COP of the system is strongly depending on the plant design, the operation constellation and the ambient air conditions. Therefore one has to be careful in comparing this system with other systems.

The direction of rotation is influencing the quality of heat transfer. For the cooling case, the wheels should rotate in opposite directions. For the heating case they should rotate in the same direction. This was not known by the installation company. The direction of rotation will be changed before the next cooling season starts and the effect will be evaluated.

Lichtblau Florian, Lichtblau Architects BDA

Competition in 1994: Complex task — parish centre in the heterogenous outskirts of a town. Building design defined in dialogue with the Alpine backdrop.

Planning from 1998: Without access barriers, located in a predominantly natural setting, modular, flexible, pre-fabricated in wood and glass. Immediacy of the structure, materials, artistic design.

Energy, ecology: "Passive" efficiency due to the optimised envelope (heating balance, daylight, airtightness). "Active" technology solely with regenerative energy sources (ground heat source/sink, sunlight, biomass).

Synergetic balance: Maximal comfort for minimal energy (2/3 from environment, 1/3 from wood). Solid wooden construction + regenerative energy = positive CO2 balance for standard costs!

The eco house project has been prepared for the architectural competition “Bio-climatic Dwellings” in Tenerife, Canary Islands. The eco house is an ecologically designed cubic dwelling that is 120 m2 and has two stories and a basement. Cubic dimensions of the building optimize heat load because of less surface to build. Building has simple modular plan having axes of (3.20m+1.60m+3.20m). That enables of designer flexibility to set services; kitchen, toilet, bath and circulation in-group as of 1.60m quarter multiples etc. and living dining 3.20m+0.80m multiples.

Entrance, living, dining, kitchen and 2 bedrooms are located to access of South East wind. Greenhouse serves as a tampon area in summer conditions or to collect heat when needed. Greenhouse is at the center of building. Its design eases to conduct desired air to other spaces via direct openings plus special details for conduction. That is living and bedrooms adjacent to greenhouse heat is collected and stored adjacently to the thermally linked spaces.

South region of the Tenerife island is a place, with sunny and arid climate, having large amount of solar energy all the months and with very small temperature swings between the seasons and also between the day and night. Ordinary flat plate photo thermal converters needs can easily supply domestic hot water. The energy for the appliances and lighting for a self-sufficient house can be produced by a stand-alone solar cell modules and battery system. The climate of this region of the island is so suitable that the amount of reserve capacity for the batteries is relatively small as the region being sunny and arid (Green, 1982) and the efficiency decrease due to temperature increase of the Pv cells is also small because of the moderate temperatures and low temperature swings. Temperature increase of the cells can further be reduced by a proper installation taking into account the direction ofthe wind.

Monthly-average solar energy values on horizontal surface are estimated using a quadratic relation between the solar radiation and bright sunshine hours. The universality of this relation was verified by using the measured data of 100 locations all over the world (Akinoglu, and Ecevit, 1990). Diffuse component is calculated using Page’s correlation (Page, 1964).

Solar radiation values on tilted surface are estimated using the procedure outlined in Duffie and Beckman (Duffie, and Beckman, 1991) for the three different tilt angles. Calculations are carried out for all seasons (tilt=latitude), winter (tilt=latitude+12) and summer (tilt=latitude-12) applications and the results showed that the winter application is relatively better for designing the systems, with a minimum value of around 18 MJ/m2 days for the summer months. However, the differences between the monthly radiation values for the all seasons and winter applications are very small. Note that the calculations are carried out for 6 m2 installation and more that the sun according to the year 1995’s conditions can supply 80 % of the load.

Total daily requirement of electricity is obtained to be around 3100 W-hr/day. The reserve capacity of the batteries is assumed to be 3 days, which is quite reasonable for sunny and arid regions having very short rainy and cloudy periods. This gives around 12 lead-acid batteries of 260 A-hr capacity (Roberts, 1991).

The climate of the south region of the Tenerife Island is excellent to build a self-sufficient house. A wise insulation and may be the use of thermal mass walls for some of the rooms might be effective in solving insignificant requirements of cool nights and hot afternoons. According to estimations the total cost of the building is $ 80.500,00 for the year 1995. The materials have been selected with aspect to renewable resources and re-used; materials are mainly brick, wood, volcanic stone and natural insulation.

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. A specially designed toilet leads urine separately collecting pipe system to be stored in the basement and sold in the market. Pipe equipment set leads gray waters to basement and ponds in the garden to be clarified, re-used and at the end for watering. Detergents waters are used in the same washing cycle. Separated detergent sold to be re-fabricated and re-used. Rainwater collecting from roof, surface waters and well supplies go directly to pond.

For gray water treatment and mix, it is recycled in basement, emerges in cascades into one of the two ponds. Total 400m2 area of garden and greenhouse is supported by homebred fertilizer and water supports %80 of annual consumption of the vegetable, fruit
and white meat of the family. Edible landscape is designed according to their light, water irrigation requirements, aesthetic and creative demands of the people living in the house.

Biogas collection produced by composting process and house unit wind energy is researched for gas production for kitchen and alternative electricity supplement. Wind speed of 5-7 m/s can be used to supply up to 1 kW of energy with a wind turbine having a diameter of 1.5-2.5 m (Randell, Ed., 1988). A rotor type windmill can be installed in the vicinity of the building, which may be attracting due to its easy construction and noise-free operation.

Conclusions

SHAPE * MERGEFORMAT

SHAPE * MERGEFORMAT

Figure 1. Ecolagically considered buildings

ECO-HOUSE

Figure 2. Ecological projects

Since 2002, a number of different studies have been carried out at the Daylighting Laboratory, ranging from site planning to single indoorenvironments ordaylighting components analysis.

Most studies carried out in the facility refer to one of the following categories:

— comparison of environmental performances of different daylighting systems (openings, glazed surfaces, shading devices)

— optimisation, during the design stage, of a specific daylighting system.

The different goals of the studies belonging to the two categories imply different procedures in the use of the scanning sky simulator and artificial sun.

Forthe comparative evaluation ofdifferent daylighting systems, models reproducing sample environments are used. Besides, reference conditions are assumed, both forsky conditions and sun positions, and repeated in orderto compare environmental performances due to

assessed systems. At present, for this category, most studies have been carried out to evaluate the performances ofdifferent shading systems (overhangs, vertical fins, Venetian blinds, light-shelves, PVC, wood or aluminium louvered screens) for both residential and non-residential environments (e. g. attics, offices, classrooms, etc.)19,20,21.

The optimisation of a specific daylighting system is carried out during the building design stage and it is related to the distributive and photometric characteristics ofthe space for which the system has been conceived. At present, forthis category, most studies have been carried out to optimise the design of shading systems such as mobile or fixed, matt or specular, continuous or micro-perforated louver shades. Aim of the studies has been concerned with maximising the amount of admitted daylight while screening direct sun­light, hence controlling glare and overheating phenomena and meeting at the same time the Daylight Factorstandard requirements. In these cases, quantitative (illuminance and Daylight Factor levels) and qualitative (images taken inside the scale model) data were collected fordifferent louver tilt angles and for maximum and minimum daylight availability during the year (clear and overcast skies, June and December, morning and noon)22,23.

The "sun-on-ground” module of the programme SENCE calculates the shape of the building shadow in a chosen moment. With a sequence of calculated shadows we can exactly see how the shadow "travels” over the building site. In the paper we calculated minimum recommended duration of building shadows at four reference days. The required duration of solar radiation upon the living room window is: 1 hour at December 21, 3 hours at March 21 and 5 hours at June 21. In the research the time around noon was taken into account. The shadows-on-ground were calculated for each hour during the required number of hours at the reference days (11.30-12.30 at 21st Dec., 10.30-13.30 at 21st Mar. and 9.30-14.30 at 21st Jun.). Then the shadows were overlaid. A pattern of shadowing during the selected time was obtained (Fig 4).

Iso-shadow

The "Iso-shadow" module of the programme "SENCE" (Fig. 5) calculates the duration of the solar radiation on horizontal surface. It is quantified as thermal flow received on a site.

Iso-shadows are the ratio of the received solar irradiation on a given site to unobstructed solar irradiation received on the same site, expressed as a percentage. ‘ of iso-shadow chart. The chart consists of iso-shadow contours, marking the areas, which receive the same percentage of solar radiation. The quantity of incident radiation is divided into 10% steps, from 0% to 100%, during the optionally selected period of time: day, month or year. In this way it is possible to determine the exact extent and duration of solar radiation on the basis of which the evaluation of the chosen site layout can be made.

In our case the 80% yearly iso-line on a given site was chosen as the minimum satisfactory value. The area arround the 80% iso-shadow line comprises the long morning and evening shadows with low incidence angles. This area has high fraction of received solar irradiation and can be used for neighbouring buildings.

The traditional design methods has producted, in recent times, buildings that:

• are built with materials characterized by high contents of embodied energy;

• use high amounts of nonrenewable energy sources;

• produce notable quantities of polluting substances;

• set the problem of disposal of material and/or recycling in maintenance, renovation and dismantling phases of buildings.

Environmental considerations related to traditional design methods of buildings urgently need a different approach.

New ‘sustainability oriented’ design criteria have to be set, in addition to new materials, building components, building techniques and technologies.

A meaningful goal may be the design of buildings that require less energy without loss of comfort. That means reducing building services powered from nonrenewable energy sources. Therefore, design and realisation of natural ventilation systems constitute an important subject in the research field on the ability of buildings to respond to climatic conditions.

The ‘passive-type based’ solutions characterized by using components or parts traditionally already existing in buildings seem particularly interesting. This approach avoids the introduction of additional components in the building fabric and, above all, it allows the selected solutions to be inserted in existing buildings.

This study aims to evaluate how the stairwell can be an essential element of natural ventilation systems in low-rise buildings.

This research evaluates how parts of buildings can act as an indoor microclimate control system. Computational Fluid Dynamics (CFD) codes [3] were used in order to design/verify the behaviour of the building components as a natural ventilation system.

This study focuses on building types that are very common, such as the blocks of in-line houses (three — to five-storey with a single stairwell and with two apartments on each floor). The natural ventilation system studied is characterized by easy implementation in energy retrofitting of buildings and by inexpensive installation and management, furthermore, the related operation is quite easy.

In the energy retrofitting of buildings, the finalization of systems with the aforesaid characteristics would allow their implementation on a significant percentage of the building stock in the followings sectors:

— indoor air quality, when the system is designed for only natural ventilation;

— energy savings when the system deals with passive cooling.

In this study, in fact, the main innovation is the different architectural and functional conception of traditional building components, such as the stairwell. In addition, the stairwell is not only used as a chimney in order to increase the air-change rate in the cold season, but it can be used also as a wind-catcher in summer.

The main results of CFD simulations concern the design of the stairwell openings (location, size, aerodynamic characteristics) and the design of an aerodynamics control system.

The behaviour of the examined natural ventilation system is governed by a very large number of parameters. The results shown concern only a certain number of the typical boundary conditions. However, these results can be useful for the designing of other similar natural ventilation systems.

Future research projects will concern the evaluation of different boundary conditions. The further aim is the definition of the most relevant parameters for the designing of similar systems.

The high energy consumption of the existing building stock will give us headaches for decades to come. To prevent the new buildings of today from becoming the inherited burdens of tomorrow, the Protestant parish of Waltenhofen in Allgau built its new Parish Centre according to an integrated ecological and energy-conscious concept. The Church as an institution aimed to give a signal concerning responsible building according to the current state of the art.

Kirchplatz

Erdg«choss mit Aussenanlagen

Floor plan of the complete property

Ecological construction

As well as meeting the operating energy demand with solar energy, the energy associated with the construction itself and the materials cycles were also optimised. To compensate for the CO2 emission associated with the production of glass and concrete, solid wood was used as a construction material. Compound materials were avoided, the roof was covered with plants and the rainwater is used. The choice of regional building companies and re-use of the excavated earth and rocks in the landscaped grounds minimised the energy needed for transport.

Construction detail

Tommy Kleiven, SINTEF / Civil and Environmental Engineering Anne Grete Hestnes, NTNU / Faculty of Architecture and Fine Art

Natural ventilation in buildings relies on wind and thermal buoyancy as driving forces. Humankind has used these driving forces throughout history to create the desired thermal environment and to transport away undesired contaminants. The technique we take advantage of to control and adjust our indoor climate has grown ever more sophisticated. This technique has in the 20th century been dominated by mechanical ventilation and air conditioning. These technologies have developed into systems of great complexity with an increasing number of components, need for space, and use of energy. Despite this, many of the mechanical systems do not manage to deliver the desired indoor climate. Because of this contradiction, the focus has again been put on simpler, more robust, and less energy consuming solutions.

The driving pressures derived from wind and thermal buoyancy are low compared to those produced by fans in mechanical ventilation systems. It is therefore necessary to minimise the resistance in the airflow path through the building. Thus, the building itself, with its envelope, rooms, corridors, and stairways, rather than the ducts familiar from mechanical ventilation systems, is used as air path. A natural ventilation concept is therefore highly integrated in the building body and will consequently have influence on building design and architecture.

This paper examines the relationship between building design and the utilisation of natural ventilation in office and school buildings in Northern Europe. The main objectives of the work have been to identify and investigate the architectural consequences and the architectural possibilities of natural ventilation. Case studies and interviews with architects and HVAC consultants have been the most central “research instruments” in achieving this. The case buildings studied are the GSW Headquarters in Germany (solar chimney/double facade), the B&O Headquarters in Denmark and the Media Primary School in Norway (sunspace). The most important findings are that:

— Utilisation of natural ventilation in buildings has architectural consequences as well as possibilities.

— Natural ventilation primarily affects the facades, the roof/silhouette, and the layout and organisation of the interior spaces.

— The ventilation principle applied (single-sided, cross — or stack ventilation) together with the nature of the supply and extract paths, i. e. whether they are local or central, are of key importance for the architectural consequences and possibilities.

— Designing a naturally ventilated building is more difficult than designing a similar but mechanically ventilated building. An interdisciplinary approach from the initial stages of design is mandatory for achieving successful natural ventilation concepts.

As an example ofapplication ofexperimental researches carried out by means ofscale models under artificial sky and sun, a specific case-study, concerning the assessment of environmental performances ofsimple shading devices, is presented. Tested shades were conceived and designed to be applied to educational buildings located in Turin. To analyse daylighting conditions inside high-school classrooms, a scale model was achieved so as to reproduce a sample classroom, representative oftypical real environments with regard to sizes, exposure, optical and chromatic internal surface properties and daylighting system typologies (unilateral side-lighting through vertical windows). For artificial sky and sun experimental activities purpose, the achieved model was 1:10 scale, featuring (figure 2):

•

sizes: reproduced classroom is 9 m long, 6 m wide and 3 m height, determined according architectural design handbook. These sizes are representative of typical real classrooms

• 2 windows in the south wall, each of them 3 m wide and 2 m height, sill being 0.9 m from floor level; the openings have a clear 6 mm glass and a grey frame similar to the one characterising some real classrooms

• internal surface colours and luminous reflectance values (rl): the ceiling is white painted (n = 0.72), walls have a lower part light blue painted (rl = 0.48) and an upper part with an ivory-coloured finish (rl = 0.61), while the floor is made of red brick (rl = 0.33)

• internal surface optical properties: all materials were assumed as Lambert diffusers. Among all possible solutions, shading devices chosen forthe south-oriented glazed wall consisted of both external and internal screens. Tested configurations are described in table 1. In particular, the performance ofa simple overhang was compared to the one of otherfixed screens (like external light-shelf, internal light-shelf, external-internal light-shelf and horizontal fins). The goal of improving daylight penetration in the rear part of unilateral side-lighted classroom was one ofthe criteria used to define the tested configurations. For this reason, the upper part of internal light shelves, different finishing were tested (matt, semispecular and specular). The same was applied to one of the horizontal fin (finished in both a matt and a semispecular material).

Screens’ size and position were determined in order to assure a comparable shading effect. Forthis reason, assumed configuration were characterised calculating the Shading

Factor value24 (SF) and the final geometry was set so as to have similar SF values (table 1 and figure 3) and an efficient shading effect with respect to Sun’s position during the year. The SF values were determined both for the summer time (referring to June, 21st) and for wintertime (referring to December, 21st), based on monthly average irradiance data measured for the town of Turin25.

As far as experimental activity is concerned, two sets of measurement were carried out for each shading configuration.

The former involved the use of the artificial sky, aimed at quantitatively assessing the illuminance and Daylight Factors values in correspondence of 16 points on the classroom’s work plane (positioned at a height of 0,8 m from the floor).

Measurements were repeated referring to different sky conditions and different daylight availability: both a CIE Clear Sky and a CIE Overcast Sky were assumed as reference standard sky conditions, while to take daylight variation during the year into account both a winter condition (identified in December, 21st, at noon) and a summer condition (June, 21st, at noon) were simulated.

The latter experimental set involved the use of the artificial sun, aimed at qualitatively evaluating the dynamic penetration ofthe Sun into the classroom fordifferent periods of the year and within a single day. The analysis was carried out for two “extreme” sun-light conditions: a winter day (December, 21st) and a summer day (June, 21st), respectively characterised by lowest and highest Sun’s elevation angles with respect to the annual solar dynamic behaviour. For both days, sun-light penetration was assessed at different hours: 9 a. m., noon and 4 p. m.