AN INVESTIGATION OF DIFFERENT STRATEGIES FOR SOLVING COUPLED THERMAL AIRFLOWS BY MULTI-ZONE NETWORK METHOD

Published

February 15, 2018

Author(s)

Ali Katal, Liangzhu Wang, William Stuart Dols, Brian Polidoro

Abstract

Natural ventilation (NV) is a method of allowing fresh outdoor air into indoor living spaces by natural means without the use of air conditioning units and other types of mechanically driven devices. Therefore NV of buildings is a cooling strategy that requires minimum energy use and has received more attention in recent decades. Multi-zone airflow network models provide a simple method for simulation of NV in buildings. In NV problems airflow and energy are highly coupled and building engineers and architects need simulation programs that are capable of simultaneous simulation of building airflows and thermal performance. Three different strategies are available for coupling the thermal and airflow models, fully-simultaneous, semi-simultaneous and segregated strategies. All three methods are demonstrated for different steady state problems including an analytical case, a three-zone case and a light well case. It is shown that the fully and semi-simultaneous methods can present non-convergent solutions with fluctuations in internal and/or external loops due to the ill-conditioned matrix equations. While, for segregated solver, matrix equations are well-conditioned and this solver provides convergent solutions in all cases tested. Study of parametric equations and corresponding curves of semi- and fully-simultaneous methods show that these curves are nearly parallel in all cases which correspond to an ill-conditioned system of equations.

Proceedings Title

COBEE 2018 Conference

Conference Dates

February 5-9, 2018

Conference Location

Mebourne, AU

Pub Type

Conferences

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Citation

Katal, A. , Wang, L. , Dols, W. and Polidoro, B. (2018), AN INVESTIGATION OF DIFFERENT STRATEGIES FOR SOLVING COUPLED THERMAL AIRFLOWS BY MULTI-ZONE NETWORK METHOD, COBEE 2018 Conference, Mebourne, AU, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=924032 (Accessed October 7, 2025)