Crack flow equations and scale effect

Reconsiders semi-empirical equations derived from earlier laboratory investigation of flow through cracks. Proposes revised method of application. States equations offer improved technique for estimating open areas of room components. Presents supportive experimental results. Demonstrates implications of the equations regarding scale effect for full-scale and model-scale situations. Presents some results of ventilation rate measurements at model scale to illustrate effects of scale and wind turbulence, flow characteristics of scale model windows and of simple circular holes.

The effect of wind on energy consumption in buildings.

Treats 4 mechanisms of building heat exchange with the environment and their effect on overall energy consumption: 1) air infiltration and exfiltration, pressure distributions and gradients and resulting mass transfer at building surfaces; 2) influence on surface heat transmission of turbulent mixing of air close to building surface and mechanisms causing this mixing; 3) how air circulation around buildings strongly affects air conditioning cooling towers and how incorrect location of ventilation inlets and exhausts can reduce thermal efficiencies of cooling equipment and increase fan power

Calculation method for the natural ventilation of buildings.

Reviews mechanism of natural ventilation. Provides mathematical expressions for wind pressure distribution, stack effect, and air flows. Treats air leakage component's characteristics, both individually and connected in series or parallel. Employs model simplification to 1 and 2 Junctions. Illustrates a 1-Junction model calculation. Finds calculated and measured values agreed well for a large factory hall.

Ventilation heat losses through factory shed entrances. Zum Problem der Luftungswarmeverluste an Hallentoren.

Argues that heat losses and ingress of cold air through factory doors are best reduced by the use of air locks and air curtains. Derives equations defining heat losses through unprotected doors. Illustrates air balance of an industrial shed. Diagrammatically illustrates in a graph relation of heat losses to size of entrance. Treats methods and effectiveness of reducing heat losses by air curtains and air locks respectively. Recommends unheated air locks except for circumstances dictating use of air curtains.

Characterisation of building infiltration by the tracer-dilution method.

Notes importance of air infiltration for total energy budget of a structure and indoor-outdoor pollution. Treats briefly significant energy savings which can be achieved by reducing infiltration rates in buildings. Describes in detail tracer dilution method of determining infiltration rates, which entails measurement of the logarithmic dilution rate of a tracer gas concentration with respect to time.

Field studies of dependence of air infiltration on outside temperature and wind.

Expresses air infiltration rate measured using tracer gas in 2 similar town houses in terms of wind speed, wind direction, indoor-outdoor temperature difference, average rate of boiler firing and fraction of time that doors are open. Method yielded reproducible rates of air infiltration within 0.1 air exchanges per hour in any single one-week run once outside temperature, wind speed and wind direction were allowed for. States results partly reveal set of physical principles determining house air exchange rates which are so far poorly understood.

The effect of wind speed upon heat requirements and internal temperature.

Sets out simplified analysis of thermal load imposed by infiltration of cold outside air into interior of heated building as function of prevailing wind speed and difference between internal and external temperatures. Treats infiltration loss, structure loss, effect of wind speed on loss. Summarises these values in tables. Concludes incidence of wind speeds in excess of those used for calculation of heat losses at design condition can have a significant effect on internal temperatures. Notes implications for non-attainment of design temperatures in intermittently heated buildings.

Behavioural approaches to residential energy conservation.

Outlines some research by social psychologists to induce people to reduce residential energy consumption. Results indicate that summer electricity consumption could be predicted from energy-related attitudes. Personal comfort and health concerns were the best predictors of consumption. Treats experimental examination in 3 separate studies of psychologically derived techniques to reduce summer electricity consumption. Gives results and conclusions.

Multi-chamber theory of air infiltration

Estimates of air infiltration in houses based on tracer gas measurements have usually assumed house is a single perfect mixing chamber with incoming air instantaneously and uniformly diffused to all parts of the interior. Points out that in reality some parts of the house - basement or rooms with doors closed - exchange air only very slowly with other parts so that actual mixing is far from instantaneous. Presents theory and mathematics necessary to apply tracer gas method to buildings of many chambers.

Wind, temperature and natural ventilation - theoretical considerations.

Discusses in theoretical terms complexity of interactions of weather-driven air infiltration by 1) wind and 2) convection induced by indoor/outdoor temperature difference. Notes implications for practice of this complexity such as near impossibility of achieving accurate computer models. Treats flow through a single crack. Illustrates diagrammatically and discusses nature of the interaction of the 2 effects for several idealised examples. In an appendix proves mathematically the subadditivity of the effects for a wide class of situations.