AIVC - Air Infiltration and Ventilation Centre

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mathematical modelling

Crack flow: a power law estimation technique.

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.

An experiment for airflow determination by quadratic programming.

In buildings with mechanical ventilation there are spaces with substantial pressure differences, which bring exfiltration, infiltration and transferred air between the rooms. For such buildings we have converted a multiple cell theory to a quadratic programming problem, and developed a computer programme, MCSPID for airflow identification. Today MCSPID is inpractical use to simultaneously determine flow rates for airsupply, exhaust air, transferred air, infiltration and exfiltration with a single tracer gas.

An approach to the simulation of coupled heat and mass flow in buildings.

This paper describes the techniques used within the ESP system to represent and solve the heat and mass conservation equations relating to combined building and plant systems. In particular, it describes the equation-sets used to represent inter-zonal (building) and inter-component (plant) fluid flow and the method used for the integration of the non-linear heat and mass flow equations. By means of a case study, the application in a realdesign context is demonstrated.

The main trends in energy saving in buildings - theory and practice in the USSR.

The paper reviews some problems of theory and practice of energy conservation in buildings. The necessity for a policy of energy

System identification theory of the thermal network model and an application for multi-chamber airflow measurement.

A comprehensive theory of multi-chamber air infiltration measurement using a single tracer gas is introduced from the general stand point of system identification. The thermal network model can be applied not only to the temperature transfer and diffusion system but also to the tracer gas transfer system. This model is formulated mathematically in a stale equation. The coefficents in the state equation represent airflow rates of infiltration. Two theories for estimating these coefficients are deduced from the least square.