It is well known that the turbulence anisotropyhas a remarkable influence on the flow of threedimensional wall jets. So the accuratesimulation of room airflows with air suppliesmounted just below the ceiling requires a highlevelturbulence closure.Therefore in this paper the potential for theimprovement of room airflow prediction byusing different Reynolds stress models and anew nonlinear eddy viscosity turbulence modelare discussed.
A push-pull fume cupboard is a device to capture chemical vapors in a laboratory or a factory. It utilizes a push flow from the bottom of the sash and a pull flow behind the doorsill to form an air curtain and capturepollutants inside the cupboard. The effects ofarms and walk-by on the capture flow in thepush-pull fume cupboard are not clear. Hence,this study is aimed on evaluation of theinfluences of arms and walk-by on the fumecupboard using a numerical model for turbulentflow. In terms of predicted results, thepush-pull fume cupboard is not affected byarms.
People who become too warm or too cool willadjust their clothing or reset building controls(windows, blinds, fans, thermostats) with theainz of restoring comfort or reducingdiscomfort, if they are free to do so. However,the trigger-temperatures for warm and colddiscomfort depend on (among other things)the clothing and the ,fan setting. The trigger temperaturesdiffer from person to person andfrom time to time. If several controls areavailable, people will first use those that areuser-friendly, effective and withoutundesirable consequences.
A new innovative design concept for the indoorair conditioning systems is proposed. Thisconcept uses passive control and modularly airdiffusion devices and aims complying with boththernial conifort and energy efficiencyobjectives. Passive control aspect is studiedthrough the comparison between a circularreference jet and a lobed jet having the sameexit area and initial flow rate. It is shown that across-shaped lobed orifice allows a consequentincrease of the entrainment within a large rageof initial Reynolds numbers. Moreover the jet'sthrow is conserved despite its strong initialinduction.
Buildings are a man-made environment built innature. The relation between the indoorenvironment and outdoor nature has becomestrained since much energy was consumed inorder to create a comfortable and safe indoorclimate in the 20th century.It seems that as the indoor climate becomessafer and more comfortable, the more pollutedthe outdoor environment becomes, resulting in akind of structural dilemma in our society. Inother words, the separation of indoor andoutdoor space was expedited as air conditioningtechnology became prevalent.
In this work the problem of the estimation of achange in the dynamics and time-varyingthermal parameters for a wall from experimentaldata is solved in several ways. The problem isfirstly solved by the application of a classicalsteady-state method. This method gives goodresults with time series long enough, but showsno predictive power. Secondly, linear timeinvariant(LTI) dynamic statistical models intransfer function form are applied. Theyestimate the thermal parameters and also offerpredictive power. Finally, linear and timevarying(LTV) continuous time stochasticmodelling is applied.
The holistic aim of this study is to make clearthe possibility of passive cooling systems usingnatural cool sources produced by cyclic weatherchanges. Here in this study, we focused on apossible use of rainwater for cooling. First, weset up two rooms in an experimental apartmentbuilding: one has radiative cooling panels andexternal shading; and the other internal shadingalone. The panel surface temperature of theradiative cooling was controlled atapproximately 24 C and the water to besupplied in the panel was produced by a heatpump system.
This paper discusses whether there is thermalcognition acquired through daily experience inthe built environment during summer seasons.For this purpose, we analysed the results of asubjective experiment to reveal the relationshipbetween subjective responses andenvironniental quantities obtained from twoexperimental small wooden buildings: one has aradiative cooling system on the ceiling and theother has a conventional convective coolingsystem.
In the past various experimental investigationsabout room airflows were published. But mostinvestigations are limited regardingmeasurement positions (restricted flow pattern)and the availability of turbulent quantities(Reynolds-Stresses, entrainment, macroscopicinstabilities etc.). Based on the availableexperimental data a targeted improvement ofturbulence models is difficult. Therefore twodifferent room airflow situations wereinvestigated with three-dimensional ParticleImage Velocimetry. Detailed information of theflow, the Reynolds-stress distribution and theentrainment are presented.
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