CASE STUDY: Radiation-Solar Comfort Early Analysis in High Density Urban Context

This case study is also available in pdf format. 

SECTOR: Assessment COUNTRY :Belgium 

BACKGROUND
The solar tools presented here are included in the TOWNSCOPE II software developed by the LEMA-ULg.
TOWNSCOPE II is a computer system devoted to support solar access decision-making in a sustainable urban design perspective.
The software consists of three-dimensional urban information system coupled with solar evaluation tools (but also morphological and wind risk analysis tools not quoted here). A special attention has been paid to numerical results interpretation which is all arc, but trivial in complex built environments. As it is a crucial aspect in decision making, especially for current negotiated urban design practices, these visual instruments have been developed in order to unveil the geometrical mechanisms lying , behind the final results.
These tools differ from the existing ones by the attention they pay to the three-dimensional geometry of open spaces. They effectively bring back any urban formal amendment built to the evaluation of its impact on the quality of space in open space. The problem relates then to the representation and the evaluation of the not-built urban form: open spaces.
The preliminary stage before any solar calculation is the construction of a virtual model of the studied site. These models can be produced very quickly because they involve masses and the full-vacuum ratios import more than the architectural details. According to the problem considered, one can modify the models to present various alternatives.

Ground direct radiation Stanislas Place, Nancy, France 

Once the model is completed, the data-processing tools could calculate the direct, diffuse, transmitted and reflected energy radiation on any point or face (frontage, portion of ground, etc) defined by the user.
On the basis of stereographical projections, the masks of shade and thus the sunshine duration can also be evaluated for any specified point.

Frontage direct solar radiation on June 15th Sainte-Margherite, Liege, Belgium 

The broad renewed interest of general public for the city and the quality of life downtown has caused particularly complex passionate debates to emerge. Indeed each one gives, without reserve, his argument and amidst these very firm standpoints it sometimes becomes impossible to defend a point of view.
Broken dialogues, missed urban debates, building sites stopped a thousand times, constructions demolished before they can be exploited, licences to build cancelled, waste lands, etc. are many alarming situations for which these tools try to give a solution. Better management of environmental (natural and urban) resources, better participation of the population and better information of decision makers are the underlying objectives.

Ground total solar radiation on April 15th Sainte-Margherite, Liege, Belgium 

INDICATORS

• Based on stereographical projection for any defined point
• Shade mask and sunshine duration 
• Based on spherical projections or any defined point and surface
• Direct radiation
• Diffused radiation
• Transmitted radiation
• Reflected radiation 

Solar paths on a sterographical projection & numerical output of solar computation (direct and diffused radiation) at on analysis point Ilot Saint-Micel, Liege Belgium

EVALUATION
In 1992, the inhabitants of Pierreuse neighbourhood in Liege complained to the State Council about the supposed consequences of the Law Courts extensions construction, and particularly their fear of being overshadowed by them.
It should be known that, at end of the XIX century, the railroad opening isolated the Pierreuse urban area from the city centre but also gave it, as an another outcome of the important destruction, a natural sunshine and incomparable views.

Law Courts extensions project - Global virtual model Liege, Belgium

The Law Courts extension project proposed to heal this part of the city by recreating missing connections. This large scale project carried by a public initiative posed considerable problems, including the appreciation of the changes the modifications would bring to the environment. As a result of the lodged complaint, during the year, the State Control over Public Buildings asked the LEMA-ULg to carry out a study to analyse the shading effects of the planned building. The impact of shade masks on solar energy received by the neighbourhood was consequently analysed and, compared with the original situation and also with a characteristic local one (Place du Marche, Liege).

Frontage solar radiation - Pierreuse, Liege, Belgium

These results were used during the lawsuit between the residents and the authorities. The judgement concluded that "The harmful effects called upon cannot be regarded as abnormal or exceptional in an old and significant city and, in all cases, they do not seem to seriously compromise the quality of life of the applicants" The lawsuit was closed and although two other complaints were lodged by the residents the question of " Sunlight" was never on the agenda again.

Solar paths on sterographic projections calculated for a point defined at the centre of Pierreuse's place in Liege

Solar paths on sterographic projections calculated for a point defined at the centre of Place du Marche in Liege(benchmark data)
 

Even though this experiment is not particularly positive, it has a lot to teach us (we also have to mention that a part of the project decreased in height during the studies). In fact, it tends to highlight the requirement need to create a common reference frame that will lead to a better comprehension of the situation for the decision-makers and for all the stakeholders. Three great principles of sustainability are in background of this experiment: citizen solidarity (whether one is a high decision maker or simple inhabitants), precaution (to question oneself a priori) and the participation (active of each one rather than an interminable continuation of sterile arguments).
 

BENCHMARK DATA
This experiment put in evidence the significant choice of relevant benchmark data. Indeed, the urban development of a city, cannot be called in question by the existence of an advantageous and exceptional situation concerning only a very limited number of people. The judgement pronounced by the State Council constitutes, in that, an unique case. If the solar needs and requests are obviously different in Lisbon or in Copenhagen for example, the urban development possibilities and the local premises layout must also be taken into account; the conclusions could not be the same in a town Centre of the Middle Ages or in a Seventies suburban zone.

DRIVERS
The study was commanded by the Liege's direction of the State Control over Public Buildings following the complaint lodged by the Pierreuse's inhabitants.
Nevertheless, the main driver of this type of research is, in fact, the numerous and complex concrete cases met where the lack of references and rational arguments lead to social, economic and environmentally unfavourable consequences.

LESSONS LEARNT
Today there is a significant renewed interest for the quality of life downtown. Buildings cannot be considered any more from simple technical and economic points of view, the whole economic-social-cultural development has to be considered, a sustainable balance between the exploitation of the existing and the development of new dynamics has to be found, the large notion of accessibility has to be explored deeper, etc...
All these ideas become fortunately come to the forefront of planning but in practical terms the dialogue between all the parties often remains sterile and prevents them taking all these ideas into account. The elaboration of a pertinent content and its representation mode appears then as a priority.

APPLICATION
The tools have been developed to be applicable at any urban site. Of course, the virtual model has to be constructed on the basis of each situation and we emphasis again, the importance of relevant benchmark data to make comparison.
These indicators have already been used to analyse different situations in various European city centres : Lisbon (Portugal), Metz (France), Nancy (France), Arras (France), Compiegne (France), Pec (Hungary),etc

TRANSFERABILITY
See above.
Modifications should be surely brought for typical cities where completely new characteristics are to be taken into account (coastal cities, for instance).

IMPACT ON SUSTAINABlLITY AREAS
Environmental: Medium (natural but also urban resources management)
Social: High (better comprehension, active participation, social cohesion)
Economic: Medium (indirect economic consequences of an harmonious development of the city centre)
Institutional: Medium (force transversal work and participation, state local norms and acceptable values)

PROJECT CONTACT
Veronica Cremasco
Prof. Albert Dupagne LEMA-University of Liege
LEMA-University of Liege Chemin des Chevreuils , 1 (bat 85213)
Chemin des Chevreuils , 1 (bat 85213) 4000 Liege
4000 Liege Belgium
Belgium tel: +32 04 3669367
tel: +32 04 3669394 fax. +32 04 3669562
fax. +32043669562 Veronica. Cremasco@ulg.ac.be
Albert. Dupagne@ulg.ac. be

REFERENCES

• TELLER J., AZAR S., TOWNSCOPE 11- A computer system to support solar access decision-making, to be published in Solar Energy Journal, Elsevier, (1999)
• DUPAGNE A. , TELLER J. , Spherical projections as a communication instrument for morphological decision-making in urban design CE-DG XII, COST -UCE-C4; Internal workshop on "Groupware for Urban planning", Lyon, Feb. 1998
  
• DUPAGNE A., "Energyas an Environmental Criteria for Urban Planning", Proceedings of the Seminar "Energia e Ambiente na EXPO'98", EU-CE.DG Xll-programme THERMIE, Lisboa, Dec.1995, pp14-15
  
• DUPAGNE A., LECLERCQ P .' La climatologie comme facteur modifiant du pro jet urbain I Actes du 8eme Colloque International de Climatologie Publications de I'AIC, Universite de Liege, Paris, 1995
  
• DUPAGNE A., LECLERCQ P .' Etude d'ensoleillement du quartier Pierreuse a Uege, rapport public, Ministere des Communications et des Entreprises publiques, Regie des B8timents, Direction de Liege, LEMA-ULg, Liege, 1992. 

LEMA-ULg: Laboratory of Architectural Methodology -University of Liege
http ://www.lema.ulg.ac.be/tools/townscope/

Ecology		Economy		Social aspects
Are emissions to air, water and soil within the restrictions set locally and internationally? Are the emissions decreasing?		Is the cost/effectiveness and/or cost/benefits of the system reasonable compared to other systems? Compared to other needs in the city and to political goals?		Has the planning and decision-making for the infrasystem been done in a democratic and participative way?
Solar energy management		Cost of a preliminary study negligible		the purpose of the case: development of a participative method to help the decision making process.
Is the use of natural resources reasonable compared to other comparable systems? Is the use decreasing? (e.g. fossil fuels, water, phosphorus, potassium)		Are the citizens willing to pay for the services offered? Are the services affordable to all citizens?		Is the function and the consequences of the system transparent to and accepted by the citizens? Is the system promoting a responsible behaviour by the Citizens?
Method benefit: preliminary studies don’t use any natural resources but could avoid a non suitable construction.		Should be easily affordable to all citizens (public service)		The methods is free of access, everyone could obtain details.
Is the system allowing a reasonable bio-diversity with regard to the kind of area studied? Is the bio-diversity increasing?		Is the organisation(s) that finance, maintain and operates the system effective?		Is the system safe to use for the citizens? (hazards, health, well-being)
Not really directly concerned.		The cost should not be prohibitive for public finances		Computer simulation.
Is the system more or less sustainable than a conventional system regarding ecology?		Is the system more or less sustainable than a conventional system regarding economy?		Is the system more or less sustainable than a conventional system regarding social aspects?