It has been estimated that 15% of the energy used for building services in the United Kingdom is consumed in industrial buildings. A large proportion of this is thought to relate to infiltration and ventilation. There has been very little information produced concerning infiltration rates in industrial buildings because of the difficulty in making accurate measurements. During the past three years, British Gas has made ventilation and building leakage measurements in a number of industrial and other large buildings in the UK.
A study has been made, both experimentally and analytically, on the characteristics of thermal performance of high-rise buildings using a simulated model building with five floors and a number of exterior openings under various temperature distributions. The effect of the temperature variation on the location of the neutral pressure level (NPL) was of particular interest of the present study.
A six channel, computer controlled, tracer gas detection system for the measurement of infiltration rates and air movement in large single-cell industrial buildings has been designed, constructed and calibrated. This has been used for over 50 sets of tracer decay measurements in five single-cell buildings ranging in size from 4000 to 31000 m³, The buildings included a sports hall, a vehicle maintenance depot, two factory workshops and an aircraft hanger. Infiltration rates and interzonal flows were derived from the tracer decay curves using methods based on multizone theory.
Ventilation has a considerable influence on both the indoor air quality and energy consumption of buildings. Three parameters can be identified which are of key importance in the assessment of ventilation behaviour: air change rate, interzonal air flows, air leakage characteristics. This paper describes measurement techniques which enable these parameters to be evaluated. The listof techniques presented is not exhaustive and the descriptions given are not particularly detailed.
For more than four years air infiltration measurements have been made on two nearly identical side-by-side test houses in Gaithersburg, Maryland, USA. This testing of the complete seasonal weather influence on air infiltration has, in the past two years, included constant concentration tracer gas measurements (CCTG). These multizone air infiltration measurements have added further detail on the response of air infiltration into the house to weather changes and the variation of air infiltration between different house locations.
The construction and performance of a dynamic wall house are described. It is suggested that such houses function much like the traditional houses with leaky walls and active chimneys. Only here ventilation is controlled while a significant part of the energy required to heat the ventilation be lost. A model is proposed to explain how much walls function at relatively low ventilation rates. The approach promises to improve indoor air quality and thermal envelope performance at reduced construction and energy costs.
A simplified model of air infiltration has been developed at Lawrence Berkeley Laboratory, in order to expand the use of air flow calculation techniques outside the field of research. The validity of the programme must be checked. Benefit has been gained from work dedicated to the same problem in the field of building thermal analysis. Following this idea, a detailed validation methodology is proposed. Progression in the complexity of the modelled structures, use of high accuracy data are sine qua non to this task.
A simplified pocket calculator model has been developed which can simulate the air flow distribution in multizone structures. The model is based on lumped parameters and includes several assumptions to simplify the description of air flow due to wind and stack effect and their superimposition. This paper gives a brief overview of the model and describes several applications. Results obtained from a mainframe based research tool. The examples show that the simplified method can be used to predict air mass flows within reasonable accuracy for different types of buildings.
Sections include: measuring procedure air tightness of facades; evaluation of measuring air tightness in practice; infrared thermography; thermographical research in air tightness, ability to detect air tightness deficiencies with thermography; ability to quantify air leakage; architectural analysis of airtightness deficiencies; recommendations.
Air change rates are measured by an IR-gas-analyser coupled with a microcomputer which is programmed to control measurements as well as data acquisition and evaluation. The implemented programs provide an instant access to results. The experimental equipment is installed in compact form on mobile units. Measurements have been taken in a university laboratory by using the decay- and constant-emission-method to examine air change rates under various conditions. Typical results are presented and show where each of the two methods is more appropriate.
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