Performance of passive ventilation systems in a two-storey house.

Air change rates were measured in one two-storey detached house with five basic types of passive ventilation systems: an intake vent in the basement wall, an outdoor air supply ducted to the existing forced air heating system, an exhaust stack extending from the basement to the roof, and two combinations of the supply systems and the exhaust stack. An expression was developed for estimating house air change rate from house airtightness, neutral pressure level and indoor-outdoor air temperature difference.

Air leakage or controlled ventilation?

This paper compares the conventional exhaust system with a supply-exhaust system with regard to the possible degree of control of the air exchange in the individual rooms. Ventilation efficiency and air exchange efficiency are defined and some examples show the local concentration, mean ventilation efficiency and mean air exchange efficiency for some simple ventilation schemes. Exhaust systems require a very tight building with small make up air openings. The ability of the different systems to avoid leakage out from the building of indoor air is also compared.

Residential ventilation systems. Boligventilationssystemer. Teori og erfaringer.

A survey of literature on the theory and practice of residential ventilation. The three main topics are ventilation needs, air movement in buildings, and the properties of ventilation systems. The ventilation need under winter conditions is estimated at 0.35 l/s m2 or, for a dwelling with kitchen and bath, 35 l/s. In fact, ventilation requirements are not constant but it is difficult to find a formula covering the various considerations.

Air infiltration. Where we stand today. Outlook. Zusammenfassung. Wo stehen wir heute. Ausblick.

Briefly notes the significance of ventilation heat losses for energy consumption. Notes the main sources of air pollutants in indoor air and the recommended fresh air rates per person for housing, for smokers and non-smokers. Notes the need for a well-sealed facade with mechanical ventilation and for judicious facade leakiness in the absence of mechanical ventilation. Notes the long-term need is for improved control of air infiltration. Notes briefly the AIC publication "Air infiltration control in housing".

Ventilation systems in residential buildings. Energy effects of ventilation systems in residential buildings. Luftungssysteme im Wohnungsbau. Energetische Auswirkungen von Luftungssystemen im Wohnungsbau.

A comparison of various ventilation strategies and their effect on air infiltration using a pair of experimental single family size houses. Discusses natural ventilation with and without ventilation grilles in the windows, centralized and decentralized mechanical ventilation. Concludes that mechanical ventilation is not economic at present energy prices.

Predicting thermal comfort of people in naturally ventilated buildings

Describes a new procedure for predicting the thermal comfort of people in naturally ventilated buildings. The procedure starts by obtaining, for each important wind direction, velocity ratios between points of interest inside the proposed bu

Moisture control by attic ventilation - an in-situ study.

Moisture enters an attic both from the house and from the ventilation air. It has been assumed that when the roof sheathing temperature cools below the attic air dew point, condensation occurs on the roof sheathing. If this were true, then increased attic insulation levels would require increased attic ventilation rates. Results from an experimental study are presented which show that in fact the roof sheathing is in dynamic equilibrium with moisture in the attic air, and that several hundred pounds of water can be stored in the attic wood without ill effects.

The use of passive solar gains for the pre-heating of ventilation air in housing.

Studies the direct coupling of ventilation heat and solar gains to increase the performance of passive solar systems. Examples of particularly suitable buildings are described. The thermal model FRED, based on a thermal resistance network representing a three-zone building, is modified to include a simple airflow model driven by wind speed and temperature difference. The simulated building is ascribed symmetric permeabilities, then asymmetric permeabilities.

A simple parametric study of ventilation.

A simple study is described which demonstrates the relative importance of the various parameters which determine ventilation, using basically the single-cell version of the British Gas multi-cell model. The graphs presented can be used directly to estimate natural and mechanical ventilation rates under a wide variety of simple conditions. By adopting a non-dimensional approach which introduces the concept of the whole house leakage Reynolds number, the basis is laid for a more general means of estimating ventilation from graphical data sheets.

Theoretical description of pressure and air mass flow distribution in buildings with natural and mechanical ventilation. Beitrag zur theoretischen Beschreibung der Druck- und Luftmassenstromverteilung in naturlich und maschinell gelufteten Gebauden.

Using meteorological and physical data, a model simulating pressure and air mass flow distribution in buildings was produced using the method of non-linear networks. It was used to study wind and buoyancy effects on mechanically ventilated buildings. Calculations were made for a naturally ventilated high rise building for varying permeability distributions and air flow resistances of the building envelope, using data from real buildings and from previous cases described in the literature.