English

Mechanical systems which use common ducts for combined heating and ventilating functions are becoming popular in the Pacific Northwest (U.S.). These systems range from simple fresh-air inlets ducted to the return side of a forced air heating s stem to more complex heat recovery ventilation systems utilizing the K eating ducts for air distribution. Typical integrated systems do not have heat recovery capability.

The basis of this study are experimental results obtained on a real scale cell in controlled climatic conditions which are used to show the potential influence of radiative participation of inside air on natural convection in a room. In a second part, a numerical analysis of flow patterns and heat transfer in a twodimensional thermally driven cavity containing a participating fluid is presented.

Application of hot wirelfilm ariemometry in room air flows presents difficulties because: (1) the effect of natural convection due to the heated wire beconies significant for low air velocity measurements; (2) the angle sensitivity of a hot wire becomes small at low air velocities, which makes it difficult to resolve the direction of each velocity component. This study aimed at quantifying the uncertainty of tlie hot wire anernornetry and examining the angle sensitivity of a hot wire in low air velocity measurements.

Inter-zone convection affects the general movements of air in a building and must be evaluated for accurate thermal zones heat and mass balance. The paper presents results of an experimental study of convective heat transfers caused by temperature difference between two zones connected by an opening of height 2. 05 m and varying width. Experiments were carried out in a full scale calorimetric chamber (5.5 m x 2.5 m x 2.5 m). Temperature differences were maintained by two active vertical walls locatedon either side of the doorway.

Both infiltration and exfiltration has a predominant influence on the space heating requirements in cold climates. Good predictive design methods are required to estimate the air leakage component in buildings. This predictive methods will be useful in implementing the air leakage control strategies for reducing the problems associated with air infiltration in both new and existing high-rise buildings.

Due to the limitations of computer storage and time the flow boundary conditions at an air inlet device have to be specified for numerical simulations of air flow patterns in rooms. With regard to this the present work gives velocity measurements near an industrial air inlet using a Laser-Doppler-Anemometer. From the stochastic velocity data the time-averaged velocity components, standard deviation and turbulent kinetic energy are evaluated.

A set of diagrams for estimating flow coefficients and exponents in the power law flow equation for cracks are presented. The diagrams are primarily intended for those who perform infiltration calculations by hand or by using a computer program for single and multi-zone infiltration and ventilation calculations. The error introduced by the estimation technique is compensated for by means of a correction coefficient with aspecific value in different pressure difference intervals. A computer program performing the calculations behind the diagrams is available for public use.

This paper is concerned with the application of air flow simulation in design. It describes the real world application - and the results of this with respect to building design improvement - of a building energy modelling system, ESP (RT) , which supports the analysis of coupled heat and fluid flow as encountered in a building andlor plant environment. The use of the system, and the design benefits to accrue, are demonstrated by elaborating two real world case studies.

This paper extends the integral mass balance approach to the remaining constant concentration technique. An integral formulation of the constant concentration problem is presented that accounts for the possibility of variation of tracer concentration. This approach leads, in principle, to data reduction strategies that may be expected to improve the accuracy of the constant concentration technique and that may be used to isolate those portions of a given constant concentration data set that are likely to be most reliable.

The evaluation of a code can be done by investigating two items: solving the correct equations and solving equations correctly and eficiently. An indoor airflow code VentAirI has been developed and is evaluated here. An evaluating procedure is suggested. The code is characterized by the standard high-Reynolds-number k-E model with wall function, the two-band radiation model and the SIMPLE algorithm. Test examples are: 1. A three-dimensional forced convection problem (Re=5000), 2. A natural convection problem (Ra=5 *10^10), 3.