Preface

During the conference these case studies will be presented and discussed within individual sessions during the next three days when the responsible planners and engineers of the individual building projects will present detailed information. The main objective will then be the assessment procedures and their corresponding results and needs for further development and activities.
Since the conference attendants will hardly be able to join each of the parallel sessions, this summary will give a brief overview of what they can expect during the case studies sessions.

The case study sessions always group two or three countries for presenting their projects. Selection and configuration of the groups is primarily related to the climatic, cultural and geographic situation of the countries.

Besides the case studies projects, attention should also be paid on the numerous and high quality poster projects presented separately during the conference. These buildings also represent and will complete the scope of the national levels regarding environmental and energy conscious design. Although the buildings shown in this valuable collection have not been analyzed by the Green Building Assessment Tool, they offer comparable architectural and environmental high quality design solutions.

The high-lighting of selected building projects is intended to provide cross information and assistance in pre-selecting the audience`s interest in individual case study sessions.

Main Building of Obayashi Corporation, Japan. This building was completed in 1982 and represents 98 energy conservation techniques including double skin, solar heating and cooling, different thermal storage systems, daylighting strategies, photovoltaic panels and rainwater utilization. Building cost are about 20% higher whereas the operating energy is only 27% compared to a common reference building design in this country.

 Top  Overview

Regarding the overview is worth while:
Fourteen countries representing 3 continents with different cultures, building traditions, different climatic conditions and resulting requirements for building design have collected a remarkable set of building projects.

This collection is an exemplary reflection of the contemporary state-of-the-art considering environment-oriented and energy-conscious design in the different countries.
In other words: the case studies illustrate the national approaches towards sustainable building design, how it can be realized at time and what the future intentions could be.

On the other hand, we should also be aware that this scope of exemplary designs does not represent the common design and building practice in these countries. It is almost quite the opposite: compared to ordinary architectural design in many countries th case studies shown at this conference are still highlighting representatives of "green philosophies" in the countries they come from.

And it is true that more than 95% of the building volume that is been built all over the world will still never get in touch with this scope of environmental and energy-related issues focused in the GBC`98 program and during the next few days at the conference.

	FOCUS building, Switzerland Multi-Residential Swiss Contribution An example which is ample evidence for a successful environmental and cost-efficient building design: Without any extra cost for sustainability, the clear architectural design reduces 50% of the operating energy consump tion and the operating cost by 42%.

 Top  Building Category, Size and Type

Building categories are represented by different building volumes. The smallest project is a residential retrofit building "Mutschellenstrasse" in Switzerland, the largest, "US Environmental Protection Agency Research Facility" represents an office and laboratory building development under construction containing more than 100,000 m² of usable area.

GBC`98 Case Studies Categories vs. Size and Type

Building Size (m²)	1 - 4.000	4 - 10.000	>10.000	Total	Type of Building
Building Category	SMALL	MEDIUM	LARGE		NEW	RETROFIT	DESIGN
OFFICE	6	5	4	15	11	2	2
RESIDENTIAL	7	3	2	14	7	3	4
SCHOOL	1	2	2	5	4	0	1
TOTAL	15	10	8	34	22	5	7

22 of the case studies are new projects and 7 projects are still under design or under construction respectively. 5 refurbishment examples have been assessed as well. Most of the new buildings have recently been built during the last few years and provide better conditions and a more innovative potential for assessment results, documentation and promotion.

Nevertheless, future building refurbishment will gain importance at least in most European countries and for densely populated areas to revitalize urban locations and neighbourhoods.

Future focus will be drawn on the huge number of buildings erected during the building periods after World War II and during the sixties and seventies. These buildings are almost too young to be demolished but too poor in energy and environmental building performance and quality.

	WAT low energy office building, Karlsruhe, Germany Sustainability and innovative building energy design approaches within restricted cost limitations.

Characteristics of 34 international GBC`98 case studies according to building categories
(x) characterizes the building as a project under design or under construction, * characterizes the project as (part of) retrofit design

No	Country Sum	OFFICE		MULTI -RESIDENTIAL		SCHOOL
1	Austria     2	0		1 (1)	Comparison of a typical 10 storey multi-unit residential urban block and a suburban luxury development (design)	0
2	Canada    3	1	Modern office building concept addressing multiple -tenant usage and superior indoor environment	1	Sustainable community project for an innovative group of moderate-income environmentalists	1	Replacement High School designed as a next generation school type of Private-Public Partnership (PPP) concept
3	Denmark    1	(1)	Design project to investigate environmental building performance of a common Danish office building	0		0
4	Finland    1	0		1	Suburban project addressing energy efficiency and decrease of operating cost not exceeding average initial cost	0
5	France    2	0		1	High energy efficiency labeled multi-storey public housing project of a national demonstration program	(1)
6	Germany    3	3	Projects selected due to innovative design concepts, cost limitation, size and transferability regarding real market conditions without funding	0	One of the case studies is characterized by mixed use including office, retail, shops, apartments and kindergarden	0	One school building extension and retrofit were presented as a poster project
7	Japan BCS    3	1	Typical 11-storey office tower selected for assessment to provide recommendations for future design projects	1	First environmental-friendly 4-storied multi-family development addressing energy, health and comfort	1	Downtown Boys` Schoolwithin a typical urban Tokyo neighbourhood focussing the improvement of daylight use
	Japan IBEC    2	2	High/low-tech representative buildings using considerably different strategies / systems of environmental design	0		0
8	Netherlands    2	1*	New atrium building extension and retrofit project focusing daylighting natural ventilation and building mass	1*	Pilot project for sustainable and energy efficient urban housing including social aspects and user participation	0
9	Norway    2	1	Environmental and regional adapted architectural design solution for a contaminated site at the harbour of Horten	(1)	Pioneer and reference urban residential project for future housing focusing on overallecological design approach	0
10	Poland    2	0		(2)	Ambitious housing projects developed for improvement and trend-setting for the real residential building market	0
11	Sweden    2	0		1*	3-storied retrofit addressing the preservation of building construction and the use of sustainable material	1	2-storied building also serving for educational purposes by demonstration of the applied environmental strategies
12	Switzerland    2	0		1 (1)	Very successful cost and energy efficient housing project for a co-operative house building society	0
13	U.K.    2	2	Exemplary buildings designed for remarkable reductions in energy consumption and serving for model projects	0		0
14	U.S.A.    5	2* (1)	One large scale new research building and two medium size retrofit office conversions foc. on resource efficiency	1	Infill townhouse and service facilities project focusing on minimum energy and environmental resources	1	Energy and cost-efficient Middle School with specific respect on daylighting and energy saving of 50-60%
	TOTAL 34	15		14		5

 Top  Case Study Selection

The case study presentation will highlight a selection of international buildings according to architectural and economic features that represent examples of the different building categories and types based upon the information about the projects which has been delivered so far.

Obviously not all buildings can be shown during this presentation and the examples in this paper will not be the final selection for the conference slide presentation. It should be mentioned that all case study buildings have their individual quality within the type and category they belong to and of the importance to act as an exemplary building, encouraging and assisting future building design in their particular countries.

Most of the case study buildings have been selected according to the following criteria:

• Scope and efficiency of energy and environmental building concept, strategies and systems
• Magnitude of innovation and exemplarity and typicality of the project
• Availability of building data necessary for the execution of GBA-tool in concert with the readiness of project representatives to participate in the assessment procedures.

The summary building presentation will also give insight to particular design intentions and architectural philosophies the case studies will address and which will also be reflected by the building performance. An attempt for cost and energy considerations, comparisons and compatibility will be done as well.

 Top  Designers` Intention and Approaches

While some of the case studies serve as prototype and / or pioneer and pilot buildings. More or less "exotic" they will remain exceptions dedicated to be monitored and investigated for potential future transferability. However, most of the buildings represent projects which are very close or even meet the corresponding country specific situation of the real estate and tenants market conditions. They show very clearly that the demand for sustainability, energy conscious design and overall environmental approaches is increasing and supported by reasonable cost in comparison to conventional and traditional building design. This is also true for the most of the poster project collection.

BRE Environment Office, Garston, U.K. Highly engineered future role model for environ-mental office design. The building had been pre-assessed by BREEAM with a rating of excellent. The energy and environmental strategies include natural ventilation assisted by wind towers, groundwater-assisted cooling, BMS, electric lighting control and photovoltaics. Attention has also been paid to recycled concrete and brick material from the previous building on the site.

The German national case studies, for example, focus on office buildings including one mixed-used project. The selection criteria included energy and environmental approaches, project size and type (new buildings) in order to get reasonable results by comparing the buildings with each other. Moreover, the case studies should represent typical requirements for contemporary office design such as

• energy and cost efficiency: in two cases defined cost limits had to be achieved
• transferability: the building had to dispense with public funding of building or surplus cost
• typicality: the projects should represent a typical challenge of contemporary design tasks

Planners intentions of the international case study contributions are similar in terms of the targets on energy and environmental building design in each of the building categories.
Aside from specific criteria regarding individual functional requirements the intentions include Scientific and technical approaches such as:

• Pioneer / pilot / prototype building testing innovative building concepts and technical systems
• Transfer of technologies to an other building type or scale
• Moderate refurbishment by far-reaching preservation of existing structures
• Image-related aspects such as
• Competitive reasons for individual or national image promotion
• Image setting and representation by innovation for the client and user

PRISMA, Nuremberg, Germany Urban mixed use development of a new city block providing energy and cost efficient urban functions and services such as offices, flats, retail, shops and kindergarden - a proto-typical commercial property. The heart of the energy concept is a 15,000 m³ atrium space serving as a natural air conditioning system for pre-heating and pre-cooling supply air for the adjacent spaces. Attention has been paid to building material, energy conservation and passive ecological principles.

Promotion and marketing strategies such as:

• Promotion of environmental building qualities towards a selected market potential
• Attempt and execution of new marketing strategies
• Setting future standards by
• Investigation of building performance by monitoring
• Demonstrating that sustainability in building design is compatible with economics needs
• User-related expressions including
• Creation of human living conditions by new future design and sustainability standards
• Supply of highly motivated environmentalists including social, cultural and economic issues
• Distinctive improvement of working place quality by optimization of daylighting
• Improvement of indoor climate conditions and thermal comfort

The building presentations during the case studies sessions will focus on energy and environmental features of building design and performance. Both qualitative descriptions and quantitative hard energy and emission data will be shown which have been the base for the application of the GBA-tool and the assessment results.

		Atrium building concepts provide attractive spatial amenities for occupants and benefit from energy and environmental qualities: below: PRISMA ATRIUM, Germany
EARTH PORT Tokyo Gas, Japan Design philosophy of the Tokyo city gas supply company office building adresses "life cycle energy saving" by energy conservation and by optimizing natural ventilation and daylighting. Remarkable reductions of energy consumption and operating cost have been paid by moderately increasing initial cost.

 Top  Multi-Unit Residential

						Core atrium of WAT serving as an engine for passive ventilation by a glazed blackwall and as a natural light source by daylight optimization including transparent stairs and galeries
Leopoldstadt Vienna Austria	Malmin Helsinki Finland	Waterspin The Hague Netherlands	Kloserenga Oslo Norway	Zawady Warsaw Poland	Focus Uster Switzerland
dark green CASE STUDY - usable-to -gross ratio
green ENERGY CONSUMPTION - Case Study - to-reference-ratio
light green BUILDING COST - Case Study - to-reference-ratio
white OPERATING COST - Case Study - usable-to -gross ratio

 Top  Comparability of the case studies

It is almost impossible to compare buildings which have been built at different countries all over the world and are characterised by different climatic conditions, building practices and traditions, cultural backgrounds, social and economic systems.

Moreover, the different building categories have significantly different user profiles, and new buildings can not be compared to retrofit building projects. While for new buildings cost and energy calculations or determinations can easily be provided, retrofit buildings can not or only hardly be related to reference numbers because refurbishment is a too complex and building specific matter of design. Thus, retrofit case studies are left out of these considerations.

Nevertheless it is worth to analyse environmental-oriented new case study buildings of a particular category versus its national corresponding reference building in terms of:

• area conscious design efficiency by the net-to-gross area ratio
• energy efficiency building concept
• specific (extra) building cost for innovative design technologies and system application and
• reductions of operating cost that have hopefully been achieved by the overall design approach

The reference figures which these ratios are based on have been provided by the individual countries and may have different sources. In some cases a virtual reference building has been created for the specific location of the case study. Most of these determinations represent average statistical numbers which are commonly available through governmental reports or published by other national or federal institutions.
These relations serve as a suitable approach to evaluate the entire success of building in the particular country in terms of:

• economic acceptance of surplus cost for environmental strategies and system applications
• cost-efficiency of initial cost versus operating cost
• reasonability of extra cost versus energy conservation potential
• transferability to other projects within the corresponding category

Usable-to-Gross Area Ratio

The relation between usable and gross area of a building is one indicator for cost efficient design. It describes more or less how much of the overall built volume can be used, rent and/or sold. The higher the ratio the more economic the design.

All building categories have different average or common practice ratios which are important planners targets as a reaction to clients` requirements. Because of the different definition of usable area, these numbers will of course vary among the different countries. However, with regard to this background, buildings within a certain category will give information about individual design qualities in their countries.

EKOPORTEN in Norrköping, Sweden Multi-unit residential retrofit project addressing overall environmental and energy measures including energy, land and water, material and sewage issues. Refurbishment of buildings is characterized by higher energy demands in modt cases because of the increasing comfort level compared to the situation before retrofit. Thus, energy saving in retofit design is a big challenge and has to be paid by significantly higher initial cost for energy and environmental techniques

 Top  Energy Performance

Energy saving potentials are characterized by overall building design, energy conservation techniques and renewable energy utilization. The energy saving potential can be expressed by comparing the case study building to a reference and / or standard common practice building. In many countries this relationship will even categorize for instance low-energy-standards and subsidizes may depend on a certain limiting number.

For case study interpretation attention has to be paid to the data base of energy determinations whether including energy demand or actually monitored consumption, including or excluding electricity, expressing operating energy related to use or prime energy.

 Top  Initial Building Cost

Building cost are commonly expressed in specific numbers related to usable, net or gross area.
As true as for the criteria mentioned above, building cost determinations may also differ within the scope of countries regarding the in/exclusion of design cost and/or taxes which vary extremely from country to country.

 Top  Office Buildings

					Core atrium of DATAPEC building acting as an integral part of the overall ventilation strategy: Pre-conditioned fresh air supply from hollow foundations is transported via the atrium space into the offices.
DATAPEC Gniebel Germany	WAT Karlsruhe Germany	EARTH PORT Yokohama Japan	Obayashi Tokyo Japan	Marine E+S Horten Norway
dark green CASE STUDY - usable-to -gross ratio
green ENERGY CONSUMPTION - Case Study - to-reference-ratio
light green BUILDING COST - Case Study - to-reference-ratio
white OPERATING COST - Case Study - usable-to -gross ratio

 Top  Operating Cost

The increase of operating cost becomes more and more important for building occupants. In most countries commercial spaces are rented on net rent level excluding operating cost which have to paid separately and which differ very much even within the same building depending on individual user profile. Operating cost represent a wide scope of cost elements including energy, water, cleaning and other services, waste and other charges, central technical facilities, services and security, taxes, etc.
Therefore, serious and comparable data even within one country and one particular building category for new buildings and reference projects can hardly be obtained. Those case studies providing numbers for this category including reference values mostly relate to energy cost solely because it is almost impossible to indicate reference figures which cover the whole collection of operating cost elements seriously. This matter of fact clearly shows that more attention should be focused on operating costs which are increasingly important for the overall success of an innovative building concept and the acceptance by occupants and clients.

DATAPEC Office Building, Germany The cylindric building is designed as an efficient organisme using innovative building and climate engineering strategies to dispense with mechanical air conditioning for a building providing high internal loads by extensive screen work. Architectural and technical approaches of daylighting, heating and ventilation concepts have been developed collectively during a consequently multi-disciplinary design process. The client and user of the building benefit from this innovative building in a many-fold way: Reduction of initial building cost, decrease of operating cost, remarkable energy conservation and saving potential and the increase of working place and indoor qualities.

 Top  Conclusion

All building examples which will be shown and discussed during this conference represent their national and individual importance and value for the countries they come from. The projects serve for multiplication and can be transferred to other building designs.

Last but not least attention should also be paid to poster presentation. These building examples have not been analyzed in detailed by GBA-Tool as the case studies.
Nevertheless this collection does not diminish their architectural, energy and environmental quality at all. Most of the projects presented in this collection are real highlights setting future standards within the building category they represent. By this way the poster exhibition is a high quality building documentation and an indispensable enrichment for the discussion and promotion of the necessary change in design and building culture towards future sustainability.

Despite of the enormous effort which has been made for analysis, assessment, evaluation and documentation of the case studies, a great deal of work will remain after this conference.
Both on the international and the national level as well as on regional and local level the experiences of sustainability, environmental design and energy conservation must be promoted and pushed into the field of design professionals.

Besides the already planned products such as print media and CD-ROM documentation material it is recommended to disseminate the results and experiences of the GBC`98 program by direct ways of interactive communication activities including:

• Mobile exhibitions linked to national / regional conferences
• Organization of national. regional and local workshops addressed to clients and developers
• Support and improvement of multi-disciplinary architectural competitions

The objective and main task for all GBC`98 members will now be to develop these future activities in their countries. The presented building projects have shown that sustainability design is compatible with cost-efficiency.
Thus, dissemination and application of information and experiences should address planers including architects and engineers, building authorities and municipalities, and most important: developers and clients as responsible decision makers.

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