English

A new facility for the study of ventilation in buildings has been recently developed at the University of Basilicata (Potenza, Italy). This facility consists in a Controlled Ventilation Chamber (CVC), with an overall size of 2.4*2.4*3.0 m (the length may be extended to 4.2 m) . The CVC is divisible in two parts with a connecting door and is equipped with four grilles from which air can be immitted or extracted. A variable speed fan can adjust a flow rate of 0 to 10 ach.

The use of computers for data acquisition and analysis in air exchange measurements with tracer gases has become state of the art for the researcher. However, for air exchange measurements in the field, reliable operation of the equipment and the proper reporting of the results are still points of concern. Here, the computer can assist the user in the correct handling of the tracer gas equipment, in dealing with unfavourable measurement conditions, and in the production of a readable report.

This paper describes tests of thermal and ventilation performance of two relatively new occupant-controlled localized thermal distribution (also called task ventilation) systems. The first is a raised-floor distribution system providing air through grilles in the floor panels, and the second is a desk-mounted unit supplying conditioned air at desktop level. These systems have been tested in a mockup of a typical partitioned open-plan office, and the resulting temperature and air velocity distributions are reported for a variety of system and locally controlled conditions.

This paper treats the structure of models for predicting interzonal airflow and contaminant dispersal in buildings. It will discuss the mathematical structure of such models, the use of modem data structures, the application of structured program techniques and the use of object-oriented structures for the development of users interfaces and building description processes.

A new turbinemeter is developed to be used as a ventilating rate sensor in livestock buildings. Starting from a previous sensor, which we introduced in 1983, several improvements were done tobecome a low cost air flow rate sensor with an acceptable accuracy of 60 m3/h in a range from 200 to 5000 m3/h and this for pressure differences from 0 to 120 Pa. This sensor can beintegrated in the climate control equipment of livestock buildings to improve process control.

In order to reduce the convective flow which is the principal responsible for the high indoor 222Rn concentrations, several mitigation technics have been developed and used in many countries. Since they don't always respond as expected, there is a need of instruments helping in their design and their evaluation. This paper suggests the use of a numerical code, based on the finite difference method, for the evaluation of 222Rn mitigation strategies in dwellings, It is supposed that 222Rn transport from soil into a dwelling occurs mainly by pressure-driven air-flow.

The performance of ventilation provision in subfloor cavities is relevant to the fields of energy efficiency, condensation risk, and air quality. Thorough programs of site measurements of ventilation rates by means of tracer gas tests are in general protracted and expensive, and it is quite clear that would be highly desirable to be able to predict ventilation rates given details of building design, ventilation provision, and d.egree of exposure.

This paper describes the use of tracer-gas techniques to measure airflow in a rectangular duct and a HVAC system. Experimental procedures are discussed for the application of the constant injection, pulse injection and decay techniques using N2O andSF6 as tracer gases. This paper also describes a new tracer-gas system with variable sampling speed which was used to measure the decay of tracer-gas concentration. A comparison is presented between tracer-gas measurements and those made with a pitot tube and a hot wire anemometer.

This paper presents some of the early theoretical work conducted within the framework of a research program aimed at analysing the interaction between gas-fired domestic appliances and the indoor environment in terms of energy consumption, indoor air quality and operational safety. A simplified multizone mathematical model has been developed, which is capable of analysing the thermo-fluid dynamics behaviour of the building + appliance + chimney system.

With respect to architecture and building materials, this reorientation process has led to advanced technological developments designed to achieve a reduction in the consumption of resources for heating purposes. There is a general trend to reduce the heat loss caused by a transmission through walls and windows. Today, triple glazing and well-insulated walls are used to cut the heating energy demand. On a medium-term basis, the transmission loss might be reduced by approx. 70% so that anaverage energy consumption of 50 kWh per m squared and year might possibly be attained in the future.