modelling

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.

Describes a detailed simulation program for estimating heat loads and room air temperatures of a residential building. Sets out the algorithms and the example simulation of a house by the program. As room surface temperaures and natural ventilation are important factors in considering the thermal environment and the heat load of the room, they are treated more rigorously than in a previously developed program.

The Fanger Comfort Equation is coupled to a building simulation model. Discusses some factors related to thermal comfort. Incorporates variables influencing comfort as subroutines in the main thermal analysis program. If the temperature calculated is significantly different from the prevailing air temperature, amelioration measures such as changes in the rate of ventilation (natural or mechanical) or conditioning of air are determined by thesubroutine CONAIR.

Investigates the efficiency of models describing infiltration and natural ventilation in buildings. Considers 8 different models. The parameters of the models are determined by fit to data from 6 different ventilation experiments in residential buildings. The number of parameters in each model is varied and the effect of this on the model efficiency is evaluated. The effect of simple corrections of the models for a dependence on the wind direction is considered.