The performance of three different ventilation systems in cold climate homes is discussed. Comparisons are presented of monitored datasets by contrasting operations of the three ventilation systems, the energy impacts on the overall HVAC systems, and resulting indoor environmental conditions. Whole building simulation results, based on ventilation system models using EnergyGauge and validated in part by the monitored datasets, provide normalized comparisons of HVAC system energy use.

This work presents simulations results exploring the influence of the building air-tightness on the energy consumption of buildings for different hypothesis on the type of ventilation system. It shows that the energy impact is different depending on the ventilation system, and that buildings ventilated with a supply-extract ventilation system, even those without heat exchanger, are much more sensitive to air infiltrations than buildings ventilated with an extract ventilation system.

The hybrid ventilation systems have been widely used for livestock barns to provide optimum indoor climate by controlling the ventilation rate and air flow distribution within the ventilated building structure. The purpose of this paper is to develop models for livestock ventilation systems and indoor environments with a major emphasis on the prediction of indoor horizontal variation of temperature and concentration adapted to the design of appropriate controlling strategy and control systems.

The probabilistic model (PROMO) applied to the problem of air infiltration in low-rise buildings is presented. The PROMO model allows the estimation of the effect of variations of climaticconditions on air exchange in a building. In PROMO, experimental data are used in order to evaluate the parameters and types of the distributions of temperature, wind speed, and wind direction. Those distributions are employed to evaluate the distributions of air change rate caused by air infiltration and can be used to estimate probability of inadequate ventilation.

Studies on air circulation became of great importance in recent years, since are crucial for the energy consumption of buildings, for the pollutant dispersion within cities and for the good comfort conditions for the pedestrians and the habitants. The semi-empirical model developed in this study aims to accurate wind speed computation inside street canyons. In the framework of the Urbvent European Research project, an extended experimental campaign took place in five different urban street canyons in the centre of Athens during the summer of 2001.

The paper presents a study of the indoor climate of a monumental building with periodic high indoor moisture loads. Several scenarios of the past performance and new control classes are simulated and evaluated. The results include the influence of hygric inertia on the indoor climate and (de)humidification quantities of the HVAC system. It is concluded that: (1) The past indoor climate can be classified as ASHRAE control C with expected significant occurrences of dry (RH below 25%) and humid (RH above 80%) conditions; (2) ASHRAE control C is not suitable for the new hall.

High levels of indoor relative humidity are one of the main causes of moisture damage in buildings. That cause can be removed by an appropriate ventilation system. Relative humidity controlled ventilation systems were designed to increase energy performance of buildings without exposing them to moisture damage. The study of the performance of such a system in terms of energy savings and maximum relative humidity is proposed here using numerical simulations with an appropriate whole building heat, air and moisture modelling approach that is developed in the frame of IEA Annex 41.

This paper investigates the sensitivity of indoor humidity models to the numerical description of water vapour buffering in porous materials in the room. Three different numerical models are compared: a lumped capacity model, which lumps the moisture inertia in a single capacity for the room, a two-node model, which differentiates between the room air humidity and the representative humidity of an equivalent humidity buffering material, and finally a room-wall model, which describes the water vapour transfer and storage in the building fabric through a continuum model.

This paper investigates the effectiveness of a Purging System in a high-rise office building in Singapore with the aim of improving indoor air quality. The study initially adopts a continuous monitoring concept to investigate the impact of a daily purging operation on pollutant concentration levels at the low, middle and high floors of the office building. Pollutants investigated include formaldehyde, carbon dioxide, carbon monoxide and total volatile organic compounds (TVOC).

An on-line mathematical approach was used to model the spatio-temporal temperature distribution in an imperfectly mixed forced ventilated room. A second order model proved to be a sufficiently good description of the temperature dynamics (R = 0.929) of the system. Furthermore, it was possible to fully understand the physical meaning of the second order model structure.Using this model, a Model Based Predictive (MBPC) climate controller was developed for a Single Input Single Output (SISO) system.