The influence of air infiltration and window opening on the indoor air quality in Austrian residential buildings was investigated. During the heating season, air infiltration plays a major role in securing hygienic conditions of indoor air and acts as basic ventilation. Air tight windows in new or renovated buildings do not provide this basic ventilation and can give rise to poor indoor air quality unless acceptable fittings for permanent ventilation are provided. Window opening can not replace the effect of permanent ventilation but plays a role as comfort ventilation.
Roof space ventilation is important in warm weather to dry out moisture that may have accumulated in the roof space. It is important to reduce the movement of moisture from the living areas to the roof space and to ventilate the latter by means of vents distributed between the upper and lower parts of theroof to take advantage of both wind action and stack action.
Presents four short articles treating aspects of building ventilation: 1) Achieving a balance - the work of the AIC, 2) House full of horrors - indoor air pollution and progress in eradicating hazards, 3) Letting off steam - test houses with ventilation system for condensation control, and 4) High and dry - condensation in the roof, eaves to eaves ridge ventilation.
A large proportion of heated rooms depend primarily on natural convection for the distribution of heat within the occupied zone. A method of predicting air temperature variations with height is presented. Using the heat and mass flow rates of the driving convection plume, along with the corresponding parameters of downward flowing air streams at cool surfaces, an estimation of the maximum (upper) temperature and the minimum (lower) temperature can be made. Incoming air entry points can also be taken into account.
Describes use of water tanks to simulate two- and three-dimensional natural ventilation air flows through open doors and windows. Density differences are produced by dissolved salt. The technique is inexpensive and visualisation of flows through complicated patterns of doors and passageways, and even separate floors can be easily set up.
Attic ventilation is compared with other means of ceiling heat flux reduction in low cost housing. A simple steady state mathematical model has been run with climatic data for a summer day of Porto Alegre, Brazil. The increase inceiling thermal resistance has proved to be the best improvement, but it is expensive. The greatest proportion in ceiling heat flux reduction is in the natural ventilation range and forced ventilation adds little to it. As natural ventilation does not imply extra cost, it is very important in low cost housing and should be optimised.
This paper reports the findings from tests undertaken in an untight, two-storey, brick-built detached test house. Different ventilation schemes were in use: natural ventilation and mechanical ventilation (both extract and balanced ventilation).
This paper outlines the living conditions that can occur in the proximity of buildings and the significance of the wind velocities that can be established, for example for shopping centres when these include high-rise buildings or for patio schools when these are to be suitable for education in the open air. It also illustrates how natural ventilation in the building occurs and describes the influence of the wind on mechanical ventilation systems.
Describes four ventilation options for a 3-4 person dwelling of 100-140 m2 living area. These are: a simple transverse system conforming to State (Land) building regulations, a shaft system conforming to Standard DIN 18017 (old design), a central heat recovery based system conforming to Standard VDI 2088, and a central heat recovery/heat pump system. Presents the energy balances of the four systems with the aid of energy flow diagrams.
The determining parameters for the formation of condensation are 1) the surface temperature of the building section and 2) the dew point temperature of the air in the room. Thermal bridges in intensively insulated outside walls and decreased ventilation due to tighter windows both increase the risk of condensation. Mechanical ventilation reduces the risk, but natural ventilation is dependent on occupant behaviour.
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