English

This paper presents helical heat exchangers for geothermal use. The differences with more widespread geothermal exchangers are given, and a complete thermal model for the underground such as for the exchanger is developed, including the local freezing of water contained in the underground when temperatures are lower than 0◦C. This model is com-pared with published data and with experimental re-sults. In a second part, the model is applied to the heating and the cooling of buildings.

Moisture transfer in porous construction materials car-ries many causes for their degradation: mould devel-opment and freeze-thaw damage are favoured by the accumulation of water, and chemicals such as chlo-ride ions and carbon dioxide may accelerate the frac-turing of cementitious composites. Over time, mi-croscopic and macroscopic cracks progressively de-velop under the effects of mechanical loading and sorption/desorption cycles: their influence is to be ac-counted for in long-term hygrothermal performance assessments of the building envelope.

This paper proposes to apply the celebrated Proper Or-thogonal Decomposition (POD) approach in order to obtain a short-term control model for the temperature dynamics of the borehole system. The main idea be-hind POD-based modeling is the extraction of a set of optimal basis functions containing the main char-acteristics of the system from snapshots of the system dynamics at various time instants. This way, POD al-lows an accurate description of the heat diffusion pro-cess where the POD modes can be used as states of the control model.

This investigation proposed a two-step model to inversely identify release location and temporal rate profile of an indoor pollutant source in an arbitrary release form. The first step is to run inverse solution of the release rate profiles based on Tikhonov regularization for all possible source locations with concentration information provided by one sensor. The second step is to interpret occurrence probability of each solution obtained in the first step according to the Bayesian probability model, by matching the concentration at the other sensor.

In the frame of a research project, the energy production for a residential unit including its mobility by micro-CHP was simulated in detail. Several variations of energetic building standards, of types of energy generation and of energy carriers were inves-tigated. They were compared to reference scenarios in respect of primary energy consumption and envi-ronmental impact. For the building use, standard data published in Swiss standards were used.

Thermal coupling between a heat pump and a hybrid photovoltaic thermal (PV-T) collector is efficient for two reasons. First the heat produced by the PV-T collector raises the temperature of the cold source of the heat pump, increasing its coefficient of performance. Secondly the PV collector can be cooled in a more efficient manner than in usual cases, which increases its efficiency.  
The aim of the paper is to describe the work that has been done to evaluate by simulation the performance of such a system installed in a demonstration building. 

Hygrothermal properties (such as thermal conductivity, sorption isotherm, moisture diffusivity…) are required for all Heat, Air and Moisture transfer (HAM) models. The objective of this work is to study the effect of different parameters of HAM model and simulation conditions on the prediction of temperature and relative humidity in a room made of hemp concrete which is known to have a low environmental impact. After presenting its physical properties, we present equations of the HAM model with variable coefficients for a simple layer wall and for a building.

In order to find an effective method to keep indoor air quality good through the year in real houses, a simulation program: Fresh was reformed to integrate several important factors in Japanese detached houses and named “Fresh2010”. The factors are infiltration from the concealed spaces, behaviour of window openings, the kind of ventilation systems and a concentration control systems. The present dwellers’ habits of opening windows may be one of the factors in causing indoor air pollution.

This paper investigates the effectiveness of multiple external shading devices and identifies the most effective fixed external shading configurations for commercial building types in hot climates. Daylight contribution is also analysed in detail in order to monitor the daylighting factor reduction including uniformity for each shading configuration. Existing dynamic thermal modeling software is used to completing analysis on a theoretical open office plan building.