Shows the results of a study of the effects of turbulence upon ventilation. Controlled fluctuating air flows were directed upon openings in the side of acube simulating a building. The relationship between the turbulent characteristics of the air flow and the ventilation rate in the building modeare examined. Mean windspeed and the turbulent velocity and intensity of the air flow were measured with a thermocoupled anemometer. Resulting ventilation rates were measured by means of tracer gas decay, using CO2 as the tracer and an infra red analyser to monitor the decrease in concentration.
A livestock building for 30 cows in loose housing was constructed in 1982. In the cow stable natural ventilation is provided through openings along the eaves. New types of inlets and outllets have been designed for natural ventilation systems. The regulation system for the air flow rate is a modified P-type regulator. Using timesharing of the regulation function, the inlet areas can be regulated in groups by means of four different temperature sensors in the building.
Considers a building with an arbitrary number of point and line heat sources at the floor. Fresh air flows in the room through windows, warm air leaves through roof louvres. To model the complicated flow field, the building issubdivided into several regions. Mass, momentum and energy balances are set up for each region. Well-known results are used for turbulent plumes and wall boundary layers due to natural convection. Pressure drops across entrance and exit openings have to be compensated by buoyancy forces.
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.
Natural ventilation can be used to reduce cooling loads and increase human comforts in buildings in hot humid climates. Airflow rates are determined by the wind pressure on the faces of the building and the amount of open area. Describes wind pressure coefficient measurements made on 2 buildings at theKaneohe Marine Corps Air Station on the island of Oahu, Hawaii during summer 1982. These full scale measurements will be compared to reduced-scale measurements made of the boundary-layer wind tunnel at the Naval Civil Engineering Laboratory.
Describes an analytical model for the prediction of ventilation rates and internal temperatures as influenced by the combined effects of heat dissipation inside industrial buildings and natural wind action. Applies this to a two span low building equipped with a natural ventilation system. Results emphasize the relative importance of thermal and dynamic variables including wind incidence, terrain roughness, and the role of the opening in the internal partition wall.
Develops a calculation procedure to predict the room air temperature and heat load of Japanese housing. Includes the process to calculate natural ventilation precisely. Predicts the room air temperatures of 2 experimental houses using this method. Finds that the prediction agrees well with actual measurements.
Parts 2 and 3 of a series of articles. Describes office buildings with natural and mechanical ventilation systems mentioned in part one, where the mechanical ventilation plus humidification and cooling is used only during the coldest parts of the winter and hottest parts of the summer. Provides comparative cost analysis for the building. Discusses design criteria to take account of fullor part time natural ventilation. Treats maximum room depths, window types,external and internal doors, furniture, room layouts.
Reports conclusions from projects investigating the tightness of buildings sponsored by the Ministry of Trade and Industry. Describes factors influencing ventilation such as size and shape of building, location, distribution of leakage points, interior air flow paths and the design and control of ventilation. Wind condition and temperature difference are the only driving forces in natural ventilation, in mechanical ventilation the temperature has only a limited influence but the wind may cause considerable draught in an untight building.