Bruno Peuportier

Life cycle assessment applied to the comparative evaluation of single family houses in the French context

A life cycle simulation tool has been developed and linked with thermal simulation. Inventories given in the Oekoinventare database or collected in the European REGENER project are considered to evaluate the environmental impacts of material fabrication and other processes (energy, transport, etc.). An application of this tool is presented here concerning the comparison of three houses: the present construction standard in France (reference), a solar and a wooden frame house. The results of this exercise are presented and its limits are discussed. It seems still difficult to apply life cycle assessment (LCA) to the selection of materials and components. Rather, LCA can be used for the improvement of technical solutions (e.g. increasing the roof insulation in the solar house).

Simulation tool with its expert interface for the thermal design of multizone buildings

A simplified simulation module has been developed to calculate the thermal performances of multizone buildings, using modal analysis. This technique reduces the computation time and therefore allows architects to perform accurate simulations using a low cost micro computer (type AT for instance). The thermal calculations are based upon a data structure in which the building is decomposed into elements (thermal zones, walls, windows, materials, ...). Each building element has been modeled as a computer object. Components of higher complexity are linked to simple components via pointers. Thus, if a component is modified, the modification is automatically transmitted through the whole structure. This environment is particularly adapted to connect the thermal calculation module (COMFIE) to an expert interface. At the moment, no expert system or inference engine is implemented, but simple algorithms which work in the following way. The user inputs a project and several characteristics (heat losses, solar gains, ...) are studied by the expert tool, which then proposes alternative designs. The user may test these modifications by repeating the simulation. This tandem simulation/expert interface takes into account the specificity of the project and its climate when applying the expert knowledge. A few expert rules are proposed, in order to enhance the energy savings and the thermal comfort. New expert rules may also be generated and/or validated. This design tool not only provides the user with fast and accurate simulations, but also offers him an opportunity to include the thermal aspects in his design approach with the help of expert rules, and this constitutes a real computer aided design.

Evaluation of the environmental quality of buildings towards a more environmentally conscious design

Appropriate design and construction can reduce the environmental impact of buildings over their entire life cycle. Such a prevention strategy can be supported by an evaluation tool. Our approach consists of applying life cycle analysis to the building sector. The use of computers is preferred for an easier comparison of alternative designs and to test possible improvements of a project. We adopted an object oriented approach in order to link models with professional practice. A data structure has been defined, in which a building is decomposed into objects. The corresponding classes include both data (inventories of basic materials and processes) and methods (accounting for fabrication, recycling, etc.). The result of such an evaluation is an environmental profile, constituted from various indicators on natural resources used, environmental effects and waste produced. First sensitivity analysis were performed showing the importance of the utilisation phase with its associated energy, water and waste fluxes. The environmental performance of a building is a result of a sequence of decisions like the choice of the building site, design choices, occupants behaviour, etc. The potential applications of this research are to inform the various actors about the consequences of their choices, to assess the environmental interest of innovative technologies (e.g. solar components) and to develop new tools for practitioners.

Comparative analysis of active and passive solar heating systems with transparent insulation

Abstract The objective of this research is to achieve a high solar fraction in social housing, for which investment costs are strictly limited. Six houses have been built in the east of France: two with active (solar collectors) and four with passive (Trombe walls) solar heating systems. Two types of transparent covers are compared: a capillary structure and a simpler polycarbonate plate. The project was monitored during 1 year. Experimental measurements as well as simulation results are presented in this article. The use of simulation allowed a comparison of the various systems on a common basis, i.e., minimizing the effect of different occupants behaviour. Compared to the less expensive cover, transparent insulation increased the productivity of the air collectors 25% and doubled the gain of the Trombe wall. Thanks to passive or active controls, the thermal comfort was not reduced by the solar systems in summer nor in mid-season.

Investigating the ability of various buildings in handling load shiftings

In modern constructions of residential buildings, several energy saving technologies exist. Therefore, when such buildings are renovated, various investments can be considered. The contribution of this article is a method for evaluating the ability of several renovating configurations to keep the inhabitants in a comfortable situation during load shifting periods. This question is of importance in the relationship, and then in the price setting, between the users (inhabitants) and the energy provider who uses these load shifting periods to optimize his production on a regional or national scale.

Using Dynamic Programming Optimization to Maintain Comfort in Building during Summer Periods

Being increasingly insulated, new buildings are more and more sensitive to variations of solar and internal gains. Controlling solar protections and ventilation is therefore becoming essential. In this publication, we study the possibility to maintain comfort in the building by controlling either mechanical ventilation for night cooling or solar protections or both of them during hot periods. The proposed energy management is a predictive set of optimal commands issued from a dynamic programming optimization knowing in advance the weather, occupation and internal gains for the next 24 hours. This method is tested on a bioclimatic house situated in Chambery, France with an annual heating demand of 26 kWh/m².

Empirical validation of different internal superficial heat transfer models on a full-scale passive house

Being highly insulated, low-energy buildings are very sensitive to variable solar and internal gains. In this context, some modelling assumptions frequently used in simplified building energy simulation tools might be called into question. While higher insulation levels reduce the influence of heat transmission through opaque walls, absorption of solar and internal gains at inner wall surfaces, and indoor superficial heat transfers, become concerning. The convective and long-wave radiative heat transfer models are investigated in COMFIE, a dynamic energy simulation platform. More detailed internal heat transfer models are developed by decoupling convective and long-wave radiative heat transfers and using time-dependent coefficients. Furthermore, an empirical validation process on both simplified and detailed models is carried out using measurements from a full-scale experimental concrete passive house, addressing the model uncertainty vs. complexity issue.

Derivation of simplified control rules from an optimal strategy for electric heating in a residential building

In France, 40% of buildings are heated with electrical devices causing high peak load in winter. In this context, advanced control systems could improve buildings energy management. More specifically, optimal strategies have been developed using a dynamic programming method in order to shift heating load, taking advantage of the building thermal mass. However, this optimization method is computationally intensive and can hardly be applied to real-time control. Statistical techniques can be used to derive near-optimal laws from the optimal control results. These rule extraction techniques model the relationship between explanatory variables and a response variable. This paper investigates the use of Beta regression model. This regression-based strategy was able to mimic the general characteristics of the optimization results with a small mean bias error (−6%) and greatly reduce computational effort (150 times faster). Given its simple mathematical formulation, it could be implemented in real-time building systems control.

Eco-design of Buildings and Infrastructure

The Chair on Ecodesign for buildings and infrastructures was created by ParisTech in partnership with VINCI with the aim of developing evaluation and simulation tools that integrate all ecodesign aspects (e.g. greenhouse gas emissions, impact on biodiversity, depletion of resources, etc.) and provide genuine decision-aid instruments, based on a scientific approach, to all those involved in the urban environment (i.e. designers, builders and users). The present book takes stock of five years of research under the Chair. It starts by presenting some methodological bases of ecodesign, life cycle assessments, impact studies, and methods for planning and transport. Several specific subjects are then covered, i.e. public transport, parking, road traffic, the environmental profile of building materials, building retrofits, energy management, and biodiversity. The last part of the book sets out how the knowledge and tools developed under the Chair were applied to a case study: Cite Descartes in Marne la Vallee (Ile de France). This work is aimed at urban planners, local authorities, contracting clients, architects, engineering firms, contractors, building managers, research lecturers, and anyone interested in the environmental quality of the places we live in.

Eco-design for Buildings and Neighbourhoods

A growing number of urban inhabitants are aware of pressing environmental concerns. This book aims to provide information about relevant environmental quality criteria in urban construction settings, before methods are proposed for assessing these criteria. These will be extremely helpful to eco-building designs, commencing from the very early stages of a project (site selection, program, architectural designs) to the detailed design, construction and management of buildings. The book covers eco-technologies in the field of energy and water conservation, renewable energy, waste management and environmentally-friendly materials, but does not lose sight of comfort and health aspects.