Important oversizing factors are observed for room air-conditioners leading to important energy wastes and costly summer peak demands for utilities. This article intends to show that sizing decisions should be based on dynamic simulation results and include an assessment of the air conditioner part-load performance. The sizing methodology established is applied to evaluate different oversizing levels for different types of buildings, climates and systems. This enables to compare our methodology to typical rules of the thumbs applied in France.

A promising approach to reduce the primary energy demand of office-buildings without violatingthermal comfort is passive cooling by thermo-active building systems (TABS). The presented studyintroduces two low-energy office buildings within the framework of the German programme ENOBwhich are conditioned by TABS mainly supplied by geothermal energy.

A method for controlling the temperature of the occupancy zone in a room equipped with a fan coil ispresented. The heterogeneity of the air velocity field and the temperature distribution is considered. As it leads to a system with a great number of differential equations, the Proper OrthogonalDecomposition is applied to build a low order model. Moreover, the value given by a sensor oftemperature enables the estimation of the temperature in the occupancy zone with a state estimator.The performances of the model are shown through the first results of simulation.

Responsive Building Elements (RBE), as defined in International Energy Agency - Annex 44,are building construction components which are actively used for transfer and storage ofheat, light, water and air. These construction elements (like floors, walls, roofs, foundationetc.) are logically and rationally combined and integrated with building service functions suchas heating, cooling, ventilation and lighting.

Although unanimously acknowledged by the experts for its performances as regards energyeffectiveness and indoor air quality optimisation, humidity sensitive ventilation still too often suffersfrom a lack of knowledge inherent in its singularities. The matter of this article is thus to bring a newlighting on the humidity sensitive ventilation determining airflow rates in the calculations of ductworksdimensioning and in the energy impact related to the air renewal.

Detailed mathematical models of VAV equipment and subsystems have been developed and used tocompose larger DCV systems with a large degree of detail. The models and systems take intoaccount both flow/pressure distribution and thermal/contaminant dynamics. The models have beenvalidated against measurements. A number of detailed simulation cases have been conducted. Theresults show that energy usage depends strongly depends on occupancy, flow rates, chosen setpoints as well as the outdoor temperature.

Demand-controlled ventilation (DCV) has largely been documented in the literature through fielddemonstration projects and computer simulation studies. However, in France and in the majority ofEuropean countries, the use of this technique is still quite limited.

The absolute necessity of air renewal to maintain indoor air quality and thermal comfort in buildingsfaces the major issue of energy consumption reduction and optimisation in building sector. Manystudies carried out so far point out the performances improved thanks to the recourse to ventilationstrategies and control algorithms in the aim of optimising the energy consumption of air renewal, butvery few of them could assess the performances in the particular case of large buildings despite thepotential energy gains it represents considering the great volume and huge air flow rates induced.

This paper presents results of an evaluation of workplace occupant satisfaction in 16 state ofthe art office buildings of a variety of sizes and energy concepts in Germany. Some of thebuildings feature very low total energy consumption as well as passive cooling strategies. In thequestionnaire, all relevant aspects concerning occupant satisfaction of indoor environments areaddressed.

Analytic models and static approaches as the case of Fanger, Deval, Sherman, Gagge, and Stolwijkmodels cannot completely predict indoor thermal comfort. Building designers could take advantage of adaptive approach of thermal comfort which can account for the complex interaction betweenoccupants and their environment that could affect their comfort.We had carried a field study in two office buildings on March 2005. It has included physicalmeasurements and questionnaires on thermal perception and appreciation.