English

As a result of the "Sick Building Syndrome" (SBS) the confidence of operators of office buildings into HVAC technologies has suffered a considerable drop. One of the most urgent questions before reconstructing or renovating old office buildings is, therefore, whether the air conditioning system to be installed will lead to increasing complaints on behalf of the occupants and how to prevent them. As for indoor air flows, one possibility is given by full scale model experiments leading to results which are very much like the future effective values.

The ventilation of a Swedish single family house is investigated by means of tracer gas and pressurization techniques. The ventilation flow plays an important role in this house as it enters through a dynamic loft insulation and exits via the crawl space. This design is said to give preheated and clean supply air, warm floors and good energy efficiency. But to meet these promises, it is essential that the air really flows in the intended paths. A single tracer gas technique is used to determine the air flow rates.

The main goals for this design tool are: - A powerful, but simple to use, technical and economic tool for selecting a ventilation plant. - Guide and control the consultants in accordance with the owner's economic preferences. - The long run extra cost, if one is forced not to follow the guidelines of the method is calculated in order to get the economic backgrounds for a decision. - Creating a key-value for the cost of ventilation that can be understood by engineers and people with economic education. The three most important parts of the selection of this design tool are: 1.

Simulation is proving more and more important in building physics. Programs of different levels of complexity are today available for researchers and designers to model and plan buildings. But the accuracy of the output is not usually provided as a common result. This paper is a short summary of a dissertation [1] focused on the accuracy of the simulation outputs as a function of the accuracy of the input parameters.

A study has been undertaken to (1) evaluate airtightness in recent construction dwellings in New York State, (2) evaluate the effectiveness of various strategies in providing adequate ventilation, and (3) study the use of various ventilation options by residential builders and heating, ventilation and air-conditioning (HVAC) contractors.

The work was concerned with measuring natural convection through a large horizontal opening of different sizes and shapes located between two rooms in a building. Airflow rates between the two rooms were measured using a tracer-gas decay technique. Room 1 was heated to various temperatures in the range 18°C to 33°C using thermostatically controlled heaters; room 2 was unheated. A multi-point sampling unit was used to collect tracer-gas samples from each room. The concentration of SF6 tracer was measured using an infra-red gas analyser.

The monitoring of the performance of domestic ventilation systems is quite a complex exercise. A wide variety of parameters must be taken into account in order that a suitable assessment of performance may be made - in many cases, insufficient data is collected. Even when the data has been collected, it is often the case that comparison of results from different studies is made very difficult due to variations in the treatment and presentation of the data.

As proposed in IEA Annex 20, a two dimensional case, for which detailed experimental data are available, has been specified by Nielsen to test different CFD codes. This report presents the results computed by the FLUENT code and he comparison between the computed results of thisreport and Chen and between measured results presented by Nielsen.

This report presents the computational results for the two-dimensional benchmark test case described in research item 1.45. The code used is EXACT3, standing for explicit time marching algorithm for continuous thermal fluid flow. It is a three-dimensional finite difference code for simulating buoyant turbulent airflows within buildings.