modelling

Describes a model that predicts air infiltration from both wind and temperature influence to within 20%. Compares the predicted value and measured infiltration from a full-scale test structure, revealing an average discrepancy of less than 10 m3/hr (out of an average of approx 150 m3/hr). Presents direct measurements of the wind velocity and pressure coefficients induced by the wind on the full-scale test structure.

Develops a model apartment building based upon existing surveys of such buildings and computer simulations carried out to determine the independent effects of climate and size on its energy consumption. The Meriwether Energy System Analysis program used has previously been calibrated by simulating four existing buildings of known energy consumption. From these results, develops data which enables a norm to be derived from the energy consumption of any high rise apartment building at any location in Canada.

Evaluates results from constant concentration tracer gas measurements and fan pressurization measurements in three houses and predicts ventilation rates for longer time periods using the LBL model. Test results show that the best way of both supplying adequate ventilation and conserving energy is to make sure that the building envelope is sufficiently tight and then install a mechanical ventilation system. Shows that it is possible to correlate fan pressurization measurements and infiltration rates.

A number of studies have reported comparisons of building energy simulations to measured building performance. This paper summarizes results of studies of occupied buildings in which monitoring varied from very detailed tonon-existent, the comparison interval from hourly to yearly and the number of buildings from one to 200 plus. These results are briefly compared to results from unoccupied buildings and preliminary conclusions are presented about the use of building energy models for different types of field application.

Uses the building energy program DOE 2.1A with the objective of validating it for use with single-family dwellings. Carries out four studies, each with a different set of conditions. The first involves a single-story house with full basement, while the second involves a single-story house on a slab. Runsblower door tests to estimate infiltration. On a bimonthly basis, simulated heating energy differs from the measured value by up to 11%. The third study, using 75 similar houses with electrical resistance heating, shows an agreement of within 5% between simulated and actual measurements.

Commercial building energy analyses may be used for new building design, energy end use forecasting and energy audit calculations. Many building simulation programs, such as DOE 2.1A or BLAST, are quite complex and must berun by specialists on main frame computers. A simplified method of commercial building energy analysis has been developed and utilises a database of previous DOE 2.1A simulations to predict the outcome of other simulations. Applies this method to an office building in one climate region and finds that it predicts heating, cooling, and total energy use very accurately.

The model of moisture concentrations in a building cavity containing hygroscopic material presented in earlier works is extended to allow for evaporating surfaces within the cavity (eg soil, water tanks) and fluctuating external climatic conditions. Linearized coupled differential equations are solved for three cases - 1. Steady state 2. Step function 3. Periodic climate driving forces. The third case gives formulae predicting the cavity moisture contents at any time of day or year, and shows that the steady state approximation is adequate for all but the tightest cavities.

Discusses the mechanisms available for "single-sided" ventilation - ie when ventilation is achieved by the exchange of air through windows on one side of a space rather than by cross-ventilation. Describes a simple approach to its prediction based upon a combination of theoretical modelling, wind tunnel testing and tracer gas measurements made in full-scale buildings. Describes wind tunnel and full scale measurements which show the effect of degree of opening, window type and combinations of windows on the magnitude of ventilation rate.

Assesses energy saving as a function of window air tightness, and transforms value into a corresponding U-value. Uses a single-cell infiltration model, and shows that using the U-value is a convenient way of comparing different energy saving methods. As an example, computes the U-value for the windows in a detached single-family house in an urban area and for Gothenburg weather conditions.

Presents a review of work carried out by SCBR concerned with airtightness of buildings and ventilation up to January 1982. Describes important features of building systems and mechanics, ventilation systems and immediate surroundings of importance to ventilation process. Assesses the building physics aspects of ventilation systems for various building categories. Discusses a number of ventilation case studies for detached houses and apartment buildings, and presents existing computer programs for single-cell and multi-cell models.