modelling

Uses model buildings to study external distribution of wind pressure and internal air flow. Compares air flow data with computed values derived from the pressure distribution data. Collects the pressure data obtained in a comprehensive study of wind loads on low-rise buildings and rearranges it in a form more suited to the computation of internal flows. Presents and discusses the methods emloyed in the reformulation and the results obtained. Briefly describes the development of design aids from which flow estimates could be made by simple hand calculations.

Performs tracer gas measurements and fan pressurization experiments on an 8-storied student residential building in order to determine the influence of wind as well as of stack effect upon air infiltration. Compares pressure and tracer gas distributions with those from a predictive infiltration computer model for high rise buildings.

Determines ventilation rates and intercell flow rates in naturally ventilated office building using multiple tracer gases. Subdivides the building into 3zones and seeds each zone individually with a different tracer gas. Monitors the time histories of the concentrations of all gases in each zone using non-dispersive infra red gas analysers. Calculates air flow rates from experimental data.

States that methods used by Swiss energy consultants in calculating air change rates are often inaccurate. Most consultants use the "observation method" utilising smoke pencils etc. and mistakes are made in calculating conditions causing air infiltration. Describes a new graphic method for estimating mean air change rates, which needs data on construction, pressurization values and window opening.

Reviews the published data on component air leakage, and from this compiles a set of component leakage figures for use in estimating leakage areas and their distribution in buildings. These calculations are compared with measurements of leakage areas in 36 houses in different locations in the US. The model predicts leakage area accurately for the average of the 36 houses, while for individual houses the standard deviation is about 20%. Discusses the assumptions and methods to convert other types of component leakage data to component leakage area.

Reviews air infiltration studies in New Zealand. Tighter houses have evolved over the years through changes in building methods and materials. Some of the tighter houses can have condensation problems. Investigates the airtightness of 40 houses together with the leakage resistances of a range of building components and bulk sheathing materials. A comparison with houses in other countries shows that comparatively tight houses can arise from simple construction methods not employing vapour barriers. Gives air infiltration rates as a function of windspeed for 4 of the 40 houses.

The estimation of the average wind pressures on buildings can be made via wind tunnel measurements. Carries out measurements on 5 models of buildings under various conditions. With the aid of these results and some interpolation, makes a prediction of the average wind pressure for a large number of buildings. Includes studies of the effects on the pressure caused by another building upwind.

A wind-tunnel model study of the experimental building at Aylesbury, England has been conducted at scales of of 1:25, 1:50 and 1:100. Compares model results with those obtained in other wind-tunnel studies and with full-scale values obtained by the Building Research Establishment at Aylesbury.

Discusses MEPA (Microcomputer Energy Programs for Architects) which has been developed in Sweden to supply energy analysis information during the early stages of design of residential and small commercial buildings, and is used inSweden, Kuwait and the US. It is designed especially for architects using microcomputers.

Describes the Computerized Instrumental Residential Audit (CIRA), a collection of programs for energy analysis and energy auditing of residential buildings. Air infiltration is modelled using the LBL infiltration model based on effective leakage. For a given budget, CIRA can also develop an optimally sequenced list of retrofits with the highest combined savings. Energy calculations compare well with those of DOE-2.1 and with measured energy consumptions from a sample of monitored houses.