air curtain

Infiltration of unconditioned air through access openings and entrance doors with high recurrence can cause detrimental impacts to the energy performance, air quality and thermal comfort of buildings. Air curtains are of strategic importance to attenuate these negative impacts. In addition, air curtains are relevant in specialized HVAC applications for which the impediment of infiltration is also essential (e.g., reduction of smoke propagation in fire events, decrease of contamination hazard in clean rooms, preservation of refrigeration properties in cold rooms).

Heat and mass flow between cold and warm environments due to the pressure difference between both sides. This exchange causes a loss of energy and human comfort in the buildings. The indoor air quality (IAQ) also reduces because of the passage of dust, odour, insects and bacteria along with the fluid across a doorway. To minimise this heat and mass flux and to maintain IAQ, an air curtain is often used as an artificial separation barrier in public and industrial buildings.

Air curtain assisted range hoods are very customary in large industrial kitchens. They allow to increase the capture efficiency of the range hood while lowering the net exhaust flow rate. For applications in residential settings, there is a lack of data on the performance of air curtain assisted range hoods, as well as a lack of information on the required settings and boundary conditions to come to the successful application of air curtain assisted range hoods.

Air curtains are used to eliminate airflows through doorways (doorway tightness). In this paper the impacts of air circulation, jet discharge momentum flux and nozzle design parameters on the tightness of an upwards blowing air curtain are presented. The tightness values were measured using a tracer gas decay method in the laboratory hall. Measurements were undertaken for two nozzle widths, 30 mm and 120 mm, and for two different discharge angles, 10° and 30°.

In the present paper, the influence of the initial inclination angle of the jet on the efficiency ofa vertical downward air curtain is analysed. The air curtain device was mounted over anoverture, in the wall between two equal contiguous rooms, with the typical dimensions of adoor.

The paper presents a numerical study on the airflow within a single-sided heated room with a large vertical opening, with and without interaction of an air curtain. The influence of temperature differences between the heated wall and the exterior on the inflow has been investigated. Also how an air curtain, with different inlet velocities and widths, affect the flow and thermal patterns in the room have been examined. The RNG k-e turbulence model is used for capturing the fluid flow and heat transfer in the building and through the opening.

The influence of wind velocity, jet width, jet angle and heat input on the efficiency of doorway air curtains in small air-conditioned spaces was investigated usical numerical simulation. Results show that proper design and installation of air curtain reduce air exchange between indoor and outdoor up to 90%. Optimum performance is obtained when the curtain air just reaches the floor. The corresponding critical air curtain velocity increases with external wind velocity normal to the doorway and with temperature difference between indoors and outdoors.

This theoretical paper studies of the interaction between air curtains system and purging dilution systems in a real urban underground railway station in order to find the best design to reduce concentration of polluting gas toward adjoining environments. Numerical computations are carried out with NIST package Fire Dynamics Simulator (FDS). The use of an approximate form of the Navier-Stokes equations for low Mach number application is appropriate. Polluted gasses flow towards safe space can be reduced of the 26-53% by operating air curtain systems.

The aim for the design of the ventilation was to achieve the best possible air quality in the non-smoking zones and for the employees in a combined bar/restaurant. Air curtains are used to separate the zones. The experiment proved that the air curtain is vulnerable to temperature differences between the curtain air and the room air but stable conditions have been achieved.. Nicotine concentrations have been measured too. Tests showed that smoking in the non-smoking zones leads to nicotine concentrations above the target levels.

This paper deals with the use of an Air Curtain Device in a typical HVAC application where there is a need to provide aerodynamic sealing between a comfortable human enclosure and a warmer neighbour space.Three different complementary experiments were used in this work : tracer gas method (N2O), Flow field mapping and Infrared thermo-graphic visualizations.The used experimental methods revealed adequate and complementary to understand the flow topology of the studied case