modelling

Describes a field study carried out to evaluate the effectiveness of the air leakage sealing techniques employed by Ener-Corp Management Ltd. for reducing air infiltration in houses. Performs presealing and postsealing air leakage tests on 82 single detached houses, located in Winnipeg or southern Manitoba. The sample group consisted of 56 conventionally-constructed houses of varying size, style, occupancy and airtightness, and 26 nonstandard structures of smaller but identical size and age. This latter group was part of the Flora Place Project.

Discusses the extension of an infiltration predicting technique to the prediction of inter-room air movements. Air flow through openings is computed from the ASHRAE crack method together with a mass balance in each room. Verifies technique by comparison to published experimental results. Results indicate that the simple model provides reasonable results for complex 2 way flows through openings. The model is as accurate as the available data, about+-20%.

Describes some new theoretical and experimental techniques developed by British Gas to investigate the ventilation of buildings. These include:< 1. The multi-cell model "vent" for predicting ventilation rates< 2. "Autovent", the multi-cell constant concentration tracer gas technique used for measuring ventilation patterns in buildings.< 3. Pressurization techniques for measuring air leakage in buildings.< Gives a selection of results from applications of these techniques to show their scope.

Presents a model for computing the infiltration and air flow between rooms of a multi-room building in terms of basic principles of fluid mechanics. Incorporates model into a comprehensive loads-predicting computer program, and calculates air flows, room temperatures and heating loads for a typical townhouse. When the inter-room openings of a low-rise structure are large compared to the envelope openings, the infiltration and total load can be accurately and more quickly computed by assuming no resistance to air flow between rooms.

Compares LBL infiltration model predictions with air infiltration and weather data collected by MITU. Examines 4 simplifying assumptions in the model:1. The flow through cracks in the building shell can be approximated by orifice flow 2. ""Wind-induced and stack-induced infiltration can be added in quadrature 3. Wind-induced infiltration can be represented by averaging the values for 3 typical aspect ratios 4.

Develops and tests a low-cost computer-assisted diagnostic package to supply the architect and engineer with key information and understanding of the energy use, balance and resulting saving potential of existing and new buildings. The energy balance is shown in a standard graph. Heat losses are calculated in oil equivalent. The program has its own database for typical thermal performance values of different building types and meteorological data of 26 sites within Switzerland.

Uses a validated multi-cell mathematical model of air infiltration to analyse the influence of various ventilation strategies on air distribution and energy demands. Assesses the performance of both natural and mechanical systems for two sets of climatic conditions and for two levels of airtightness. Shows that natural ventilation rates are highly dependent on climate. Additionally, air movement is a function of wind direction and stack effect.

Describes the Energy Performance Design System (EPDS) which is a simplified procedure for energy analysis based on extensive field testing, laboratory experiments and computer modelling. Provides a simple procedure for designing and evaluating the performance of energy-efficient homes. Describes thedevelopment of the simplified air infiltration model used in EPDS. The starting point for model development was a series of field studies on air infiltration conducted 1978-1981.

Describes a computer program developed for the analysis of residential building thermal loads and space heating and cooling energy use. It is capable of modelling the simultaneous heat balances on multiple spaces, building air flows by infiltration and natural and forced ventilation, including thermostatically controlled through the house ventilation, detailed solar gain, part load performance of central and unitary heating and cooling systems, and thermostat droop and cycling characteristics.

Proposes a new experimental technique for investigating the natural ventilation potential of new building designs. The method tests scale models of ventilated buildings outdoors in the natural wind. Results from this method agree closely with data from a similar full-scale building. Discusses use of this method by building designers.