modelling

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.

Uses wind tunnel model studies of houses to determine how best to reduce the surface pressure variations from wind and the associated air infiltration emphasizing the correct placement of suitably modelled coniferous trees. Finds that tree crowns convert the directed kinetic energy of approaching wind into random turbulent energy, which reduces pressure gradients on the windward walls, a prime region for air infiltration.

Presents a review of the main methods used for the study of air movement. Includes sections on physical modelling (wind tunnel modelling etc), analogue (water and electrical) models of air movement, mathematical models and digital computer analogues, and full scale investigations including pressurization andtracer gas techniques.

A model that relates fan pressurization results to infiltration values during the heating season is the basis for infiltration estimates in several different audit programs. Describes the model and presents validation results. Uses the model in 3 different audit strategies. The first is an energy audit to determine economically optimal retrofits for residential buildings, based on actual, on-site measurements of key indices of the house. Analyses measurements on a micro-processor and determines retrofit combinations compatible with minimum life-cycle cost and occupant preferences.

Discusses principle that the position of supply air devices has a considerable influence on the ventilation efficiency that can be achieved. Considers factors affecting ventilation efficiency and different ventilation models. Illustrates different air supply systems.

Compares measured hourly data on indoor humidity with data obtained by calculative values for NBS Houston test houses and for the high mass test building in an environmental chamber. Measured values are usually very different from the calculated values if no considerations are given to moisture absorption and desorption phenomena that take place at the interior surfaces. Introduces the Tsuchiya model that permits the evaluation of room surface moisture absorption capability.

Uses a two-zone model to describe the concept of and to define the effectiveness of ventilation. Deals with multiroom aspects and procedures for measuring ventilation effectiveness. The simple two-zone model predicts generally high effectiveness for ventilating systems using the displacement principle, taking advantage of stratification. Reviews tests using thisprinciple in an office room for 1-3 people (28 sq.m., 2.8m ceiling height).

Investigates the reliability of the single-room infiltration model used in the computer program ENCORE. Compares calculated air change rates with tracer gas (N2O) measurements in 25 identical one and a half storey detached houses. Describes the infiltration model, the parameters and some results. Thecomparison shows good correlation at low wind speeds (< 3m/sec) but the model's values at higher wind speeds are too high.