English

The paper presents the development of a ventilation scheme for a large bus station and passenger interchange in Bilbao, Spain. The main objective of the design was to ensure that pollution free conditions could be achieved within an enclosed waiting area that opened up on to, and was surrounded by, a semi-enclosed pick-up space, where there could be large number of buses with their engines running. Initial thoughts were to use natural ventilation, architectural and other constraints made this impossible so mechanical ventilation became necessary.

In the framework of a project of the International Energy Agency (IEA) , IEA-Annex XVIII - Demand Controlled Ventilating (DCV) Systems, which started in fall 1987, a review of the state of the art of already existing DCV systems and devices has been undertaken by all participating countries. This paper is concerned with air quality sensors which may be suitable to control air quality on demand. The dominant contaminants are not only variing in different kinds of buildings (dwellings, schools, stores etc.) but also from room to room due to different ways of utilizing the spaces.

The ventilation performance of a proposed naturally-ventilated court-room was predicted and assessed on a statistical basis with regard to the local meteorological conditions. Summertime ventilation was to be provided via an underfloor duct and controllable vents at roof levels, under the action of wind and buoyancy forces. Wind pressure coefficients expected on the external facade of the building were obtained from wind tunnel measurements on a scale model.

The ventilation of a test room (LxWxH = 5.4x3.6x2.4 m) with a wall mounted heat source is investigated for two different air terminal devices. The properties of each air terminal device are described by measuring the velocity decay of the primary wall jet below the ceiling. The velocity distribution in the plume above the heat source has been measured at different heat loads as a function of the distance to the wall and the distance to the heat source.

This paper deals with field experience of airborne moisture transfer problems in houses. Two types of phenomena are discussed in more detail; the infiltration of moist air from crawl spaces and the propagation of moist air produced in kitchens. A modified depressurisation test is described to determine the air tightness of ground floors. A case study is briefly discussed where different remedial measures have been tested to evaluate the moisture removal effectiveness in kitchens.

Air exchange rates in occupied buildings are difficult to assess due to their dependence on a multitude of climatic parameters and inhabitant behaviour. Moreover, the assessment of the influence of the air exchange rate on the radon progeny concentration is hampered by the diurnal and seasonal fluctuations of the indoor radon levels.

Mechanical ventilation systems have been adopted in airtight energy- efficient houses in Canada to provide fresh air, remove moisture and indoor pollutants and provide a comfortable environment for the home-occupants. Homes constructed under the R-2000 Home Program are equipped with mechanical ventilation with heat recovery. Since 1984, the performance of approximately 700 R-2000 Homes has been monitored on an annual basis. This monitoring has included the measurement of indoor levels of formaldehyde and the documentation of ventilation system operation.

Infiltration heat losses due to heating appliances located within the living space are normally evaluated by reducing the conversion efficiency of the boiler, with no consideration for the fluid dynamic interaction between boiler, chimney and building. Purpose of this work is to develop a simplified mathematical model of the overall (building + boiler + chimney) system, suitable to calculate the pressure distribution and air flow rate in the building induced by the simultaneous effect of natural forces and the exhaust system.

The specific value of different flows resulting from air exchanges between rooms or with the outside is not always important. An extensive model is not suitable when only estimations or tendencies have to be drawn (very time consuming). So we developed a simplified infiltration model for predicting airflows in single rooms and between different zones of a building. We integrated this model into a building transient thermal simulation program set up to a micro-computer system. So as to obtain this model, we used simplified assumptions.

An element-assembly formulation of multi-zone contaminant dispersal analysis theory is described. In this approach a flow system is idealized as an assemblage of mass transport elements that model specific instances of contaminant mass transport in the flow system. Equations governing the mass transport phenomena modeled by each element are expressed in terms of contaminant concentration variables, the nodal concentration variables, that approximate the contaminant concentration at discrete points, the system nodes, in the flow system.