Studies on buildings have shown that airtightness and insulation increased in family buildings and detached houses too, due to new thermal regulations. In the same time, studies concerning health and indoor air quality have shown that the need of fresh air will increase too.

This paper describes the results of a collaboration study between ENTPE-LASH and LEPTAB within the framework of the IEA Annex 35 “Hybrid Ventilation in New and Retrofitted Buildings”. The aim of the work is to carry out a cross-simulation study and identi

Ventilation is one of the most important measures to dilute indoor air pollutants. In order to maintain a clean indoor air environment, not only the total ventilation rate of the building but also the distribution of outdoor air to each area must be taken into consideration. A performance evaluation of the combined system of air supply from the crawl space and hybrid exhaust ventilation with a small fan and damper has been investigated. This investigation was undertaken over a heating season using a full-scale test house.

To evaluate the impact of the natural ventilation of the air cavity in the prototype of the glazing system being studied in the frame of the project SOLVENT, funded in part by the Commission of the European Union, a prototype of a reversible naturally ventilated glazing system. The system consists of a double (clear and tinted) glazing. In the summer position the tinted glazing is in the outer position and the cavity is open to the outside air at both top and bottom extremes.

In the present communication, a psychometric model has been presented to evaluate the performance of rotary desiccant wheels based on different kind of desiccants e.g. silica gel and LiCl. The developed psychometric model is based on simple correlations between the relative humidity and enthalpy of supply and regeneration air streams. The model is used to predict the performance of three type of desiccant rotors (Type-I, II and III). The model is tested corresponding to a wide range of measurement data.

The combination of an open wet cooling tower with chilled ceilings is a CFC free, cheap and low energy cooling solution. The efficiency of this alternative to mechanical cooling is very dependent on climate. There is a need for specific tools to help designers to size the system and to estimate its energy and water consumption. A building simulation tool, called ConsoClim, has been used to predict the performance of this system for different French climatic locations, thermal inertia, internal loads and solar gains.

To evaluate innovations and efficiency as regards air-conditioning, it is necessary to know for how long and in which conditions the equipment functions, an indication related with the COOLING LOAD and which is their effectiveness - EER - on average (or Seasonal) known as SEER. We extended the concept of SEER to include all sources of electricity consumption, namely the secondary equipment, and we called this extended concept the SYSTEM SEER.

This paper presents the results of a field study on five HVAC duct systems in France. The principal objectives of this work were a) to evaluate the extent of duct leakage in those systems; b) to compare design and actual fan flow rates; c) to evaluate the thermal energy losses in the air ducts. The ductwork airtightness, measured by fan pressurisation method, was found to be in general well above the leakiest EUROVENT 2/2 class (class A), yielding unacceptable uncontrolled airflows. Fan airflow rates were measured with the constant injection tracer gas method.

In order to save energy for building cooling during hot days in regions with cool nights, air circulation throughout the interior of the building has been envisaged as a means to lower the temperature of the building structural mass. In this way, energy required for cooling the building interior is reduced, due to lowered temperature of the wall, ceiling and other structural elements mass, and a greater storage of heat resulting from various heat gains the following day when air-conditioning is on.

In this paper, a literature survey on rectangular and round ventilation ducts is presented. The comparison is based on two important aspects: pressure drop and noise radiation. The pressure losses in the ductwork should be kept as low as possible without jeopardizing proper control of the flow rates in the system. Pressure loss through a rectangular duct is significant higher than a volumetrically equal round one. The higher the aspect ratio, the higher-pressure loss in the rectangular system.