The ventilation and leakage characteristics of suspended floors are not well documented. As part of a larger study of air flows in housing, the air flow through a suspended floor has been investigated under a number of conditions and methods of ventilation. The leakage of the suspended floor and the space beneath it has been measured and is compared with the house leakage.
In Sweden, the energy crisis in the early seventies resulted in attempts to lower the air change rate in buildings to reduce energy consumption. For many building categories, this lead to a deterioration of the indoor climate or problems with moisture and mould growth, Today, many residents demand higher ventilation rates, often the motivation is concerns about health and comfort. In this paper is presented results of measured air change rates in Swedish dwellings during the period 1974-88.
The air exfiltration part of ventilation is often difficult to determine and its part of the energy balance is therefore usually determined as a remainder or given a constant value. This paper examines ventilation systems in six different modern houses. The constant concentration tracer gas technique tended to underestimate the total ventilation. A simplified theoretical one-zone model made accurate estimations of the air exfiltration. For detailed information on air flows a multi-zone network model was useful.
Rising moisture from the ground has caused quite a lot of damage on foundations of Swedish buildings. It is in some constructions possible to prevent this by mechanical ventilation below the floor or below the concrete slab. This paper will present a model for coupled air flow and heat conduction for mechanically ventilated foundations. The presented model uses analytical expressions for the air flow in an air-permeable layer below a rectangular building. Analytical double-periodic functions of elliptic type are used.
VAV - air conditioning system makes it possible to control indoor conditions even when the heat loads are changing. But this is possible only when each part of the system works as it is intended to work. When the air flow varies in a large range, it can cause situations, where pressure loss of some flow dampers are out of their operating range. This is possible especially whenthe system is large and the velocities are high. This means that the air flow is not correct. Also increasing noise levels may appear.
In the "Stockholm Project", different blocks of multifamily buildings have been extensively monitored for about three years. Temperatures, airflows and electricity use have been registrated each hour. As an additional base to this examination, ten fan units in the buildings have been intensively studied. The results show that the specific use of power for transportation of ventilati n air varies between approximately 1 and 4 kW per m³ and second. The results from the measurements indicate a notably low level of installation efficiency.
France is one of the European countries where ventilation has the most advanced regulation. Vertical ducts have been used for a very long time, making easier the transfer from passive to mechanical ventilation ( which covers now 90 % of the blocs of flats and 70 % of the individual housing) . 1969 regulation has been based on a continuous air exhaust from the service rooms and air replacement through inlets in the habitable rooms. This has never been changed since then and is a part of french regulation's features.
Login