For the approximation of the internal loads of humidity, too high values are often chosen inSwiss low energy houses. Later on in reality, the occupation and the presence in the dwellingsare significantly lower. These leads to high specific air volume rates and consequently to lowhumidity levels. Humidification by vapour generators, humidity recovery and optimized air volume rates are currently applied. Engineers can now calculate the internal humidity loads without humidity storage in walls etc.

This paper describes steady-state energy and exergy analyses on an instantaneous and on adaily basis for dwelling ventilation systems and domestic hot water DHW production systems. The ventilation uses mechanical exhaust with environmental air supply without heat recovery or balanced ventilation with heat recovery. The exhaust ventilation air is used to preheat DHW, using a heat exchanger or a heat pump. Energy and exergy demands in winter days for De bilt, the Netherlands, are presented at the component level, in terms of heat and electricity, for the systems.

Ventilation system is being recommended as an effective tool to improve indoor air quality(IAQ) in apartment houses. Recently, in Korea, apartment house suppliers are required by lawto establish ventilation systems in apartment houses. In this study, improvement of IAQ byestablishing mechanical ventilation system in apartment houses was investigated through mock-up tests. Seven apartment houses were arranged for the test and concentrations of VOCs and Formaldehyde were examined under various conditions of ventilation rates and duct works.

In Finland 12 apartment buildings were investigated as a part of European project HOPE. There were one building with passive stack ventilation with fan assisted exhaust air ventilation, four buildings with mechanical exhaust ventilation only and seven buildings with mechanical supply and exhaust air ventilation system. Altogether 600 questionnaires were returned. Modern passive stack ventilation system with separate exhaust fans in kitchen and bathroom did not assure sufficient ventilation even in March when ventilation rates and CO2-levels were measured.

Improving ventilation performance both for energy and IAQ creates a trend of installing moreheat recovery supply and exhaust systems in new buildings and controlling better the airflows.Many studies have shown the impact of improved ventilation system on achieved performance but information about the market status and the difficulties in installing for instance supply ducts in collective dwellings are still lacking.

Food odor dispersion from residential unit to core is one of problems in high-rise residentialbuilding. In this study, it was analyzed in terms of stack effect, and the method how optimal air inflow of core was estimated and how the location of air in/outlet were decided were suggested to solve it. A combined CFD(Computational Fluid Dynamics) and CONTAMW analysis was used for stack effect of building, dispersion of food odor, optimal air inflow of core, and the location of air in/outlet in the method.

Air pressure conditions in typical Finnish residences are analyzed using data from fieldmeasurements and computer simulations. Field measurements were conducted in a two-storeydetached house and in a five-storey apartment building. The effects of airtightness, ventilationrate, air leakage distributions, and outdoor environmental conditions on air pressure conditions in a detached house were simulated on a multi-zone simulation model using the IDA ICE simulation program.

In this paper we give an overview of the ways occupants use ventilation systems and describe the results of interviews conducted in households equipped with balanced ventilation. An attempt is made to quantify the effects of occupant behaviour on the final energy use of the household for heating. This energy use is studied for several behaviour scenarios, leading to the conclusion that occupant behaviour may easily reduce the predicted savings to zero, or even may increase the energy use when compared to natural ventilation.

This study focuses on the correlation between the airtightness of a building envelope and the average infiltration and energy consumption of a typical modern Finnish detached house. The correlation between tightness and infiltration was determined using an empirically validated dynamic IDA-ICE simulation model of a two-storey detached house. The effect of wind conditions, Finnish climate conditions, balance of ventilation system and leakage distribution on infiltration were studied with the simulation model.

The study aims at quantifying the impact of the retrofit of ventilation systems from the energy, IAQ (Indoor Air Quality) and health perspective. In a first part, the French market has been defined (number of each ventilation system installed in existing building). Both qualitative and quantitative studies of malfunctions noticed on ventilation systems have been made.
In a second hand, the influence of ventilation retrofitting on the building energy performance
has been evaluated. The impact of implementing innovative techniques (i.e. decreasing the fan