After a brief treatment of the ideas and aspects that play a role in ventilation, gives a general outline of chosen investigation methods, with a concise review of apparatus and calculation models used. Presents a review of the ventilation investigations carried out by IMG-TNO during the last 10 years in factories, labs, hospitals, auction halls etc.
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.
A short treatment of the concepts and aspects that play a role in ventilation is followed by a brief description of the investigation methods employed. Gives a concise survey of the equipment and mathematical models used. Reviews the ventilation research carried out by the IMG-TNO. Covers factories, laboratories, hospitals, auction halls and similar buildings.
Presents results of an investigation aimed at working out thr design principles for natural ventilation conduits. Discusses results obtained in an aerodynamic wind tunnel.
Reviews methods of energy conservation in factories. States that excessive infiltration is unlikely to be the cause of high energy consumption, but that the most significant loads imposed by infiltration probably occur through open loading bays. Suggests the installment of double door lobbies to overcome this. Says the ideal factory heating system would include mechanical ventilation, with outside air mixed with warm "roof level" air. Describes potential sources of energy wastage and ways of rectifying this situation.
Air velocities, air temperatures and dust and fluoride concentrations were measured in a burning shop of a pellet plant. The results show that there is a clear relationship between the air velocities, air temperatures and airpollution concentrations. The air flow pattern consists of an air current which rises above the burning machine as a result of convection and escapes through roof grates. Air is supplied through facade grates. The transport of air and polluting substances, especially in the cross direction of the hallindicates the influence of the wind.
Compares annual fuel consumptions of seven large factories against calculated requirements to illustrate seasonal thermal efficiencies of 7.7 to 49.7%. Shows that ineffective and uncontrolled ventilation is by far the most significant factor in excess fuel consumption. Illustrates savings of 38 to 80% in fuel which have been achieved. Shows that fuel savings of 20 to80% are possible in the factories studied, with 35 to 95% savings possible when heat recovery is provided in addition to other improvements.
Proposes a method for measuring the rate of air change in factories using ammonia as a tracer gas and measuring its rate of decay by a colorimetric method. The advantage is that extremely small quantities can be detected. The method is cheap, easy to use, reasonably accurate and unobjectionable to the occupants.
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.
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