In many buildings, for instance tunnels, underground, parking areas and industrial halls, the L/H is so large that the flow pattern induced by a two dimensional supply air jet along the ceiling can be completely different from that in rooms of normal sizes. Earlier model experiments indicate that, in this case, the supply jet will have a limited penetration length (Ire) because the entrainment generates a backward flow in the lower part of the ventilated space which at a given distance will disperse or deflect the jet.

Cooling ceiling systems are controlling only the sensible heat balance of the rooms; they are always combined with a ventilation system foreseen to control indoor humidity and to cover air renewal requirements. Between the types of cooling ceiling in use, the passive chilled beams seem to be the most sensitive to ventilation air influence. Jn most of the cases, the ventilation outlets are located in the ceiling void, and consequently this generates a penalty on the beam cooling power. The work presented aims at estimating this influence, through results issued from experimental studies.

In an air-conditioned office building, the ventilation air is normally mixed with the return air from the room in the air-handling unit. Therefore, the value of the air exchange efficiency defined by age of air is usually about 1.0, which is close to the perfect mixing case. If the fresh air and air-conditioning air are supplied separately, it is possible to increase the value of the air exchange efficiency at the breathing zone if the former is supplied directly to the breathing zone. In this paper, the results of the CFD investigations for the ventilation tower system are described.

This paper proposes a new ductless air supply system with a ceiling plenum chamber using low temperature air as a secondary HY AC system for an ice thermal storage system. The proposed air supply system mixes low temperature air with return air from a room using a mixing fan unit (MFU), pressurizes a plenum chamber with the mixed air and supplies the air to the occupied room from diffusers on the ceiling.

Scale model experiments make it possible to analyse design concepts of ventilation, especially air distribution in large enclosures. The airflow structure similarity is fulfilled when experiment is carried out according to the principles of the approximate scale modelling. Special attention should also be paid to proper simulation of boundary and initial conditions. In a real ventilated object, the air is supplied with standard diffusers equipped with deflecting vanes.

The behaviour of room airflows under fully turbulent conditions is well known both in terms of experiments and numerical calculations by computational fluid dynamics (CFD). For room airflows where turbulence is not fully developed though, i.e. flows at low Reynolds numbers, the existing knowledge is limited. It has been the objective to investigate the behaviour of a plane isothermal wall jet in a full-scale ventilated room at low Reynolds numbers, i.e. when the flow is not fully turbulent. The results are significantly different from known theory for fully turbulent flows.

The keeping of animals in livestock buildings requires the ventilation of these buildings. On the one hand good climatic conditions for the animals in the livestock building have to be provided, on the other hand the emissions have to be kept at a low level. The airflow through the livestock building plays an important role for both opposing requirements. The targeted control of the climate in the livestock building and for the minimization of emissions calls for knowledge about airflow and emission streams.

In this study the instantaneous temperatures and velocities close to a diffuser for displacement ventilation have been recorded by using whole-field measuring techniques. The air temperatures were measured indirectly by the use of a low thermal mass screen in conjunction with infrared thermography. The measuring screen was mounted parallel to the airflow, acting as a target screen. By using the thermal images the size of the near zone was also calculated. To determine air movements a whole field method called particle streak velocimetry (PSV) was used.

Presented in the paper is an efficient and accurate numerical method for simulation of ventilation duct flow. The mathematical method is based on the three-dimensional incompressible RANS equations with isotropic k-w near-wall turbulence closures, written in generalized curvilinear coordinates in strong conservation form. The numerical method presented here is used to calculate the turbulent flow through a bend of rectangular ventilation duct featuring pressure induced secondary motions and rotation effects on turbulence.