By means of a case study involving a severe case of coupled heat and sir flow in buildings, this paper aims to quantify the differences resulting from different methods (ping-pong and onion approach) for linking heat and air flow models. The main conclusion is that when used improperly, the onion method will have implications in terms of computing resources, but - more seriously - the ping-pong method may generate substantial errors.
This paper describes a method which aims to generate an overall view of multizone building air flow by integrating methods for bulk air flow analysis, air flow field analysis, and building thermal analysis. This has been achieved by implementing a computational fluid dynamics approach within the ESP-r building energy simulation environment which already incorporated a model air flow network approach. The current state of the method is demonstrated by a case study. The main conclusion from this is that the integrated method is very promising.
In line maintenance hangars, air planes stay about 2 hours, usually at night-time. The coolingdown of the inside air during the opening time of the hangar gates (up to 5 times per night, lasting 15 to 30 minutes each) has a considerable impact on the comfort conditions for the workers, and on the energy required for reheating. The time-dependent air flow rates and associated heat loss rates during the door opening and closing cycles is assessed by simple transient thermal models and CFD (Computational Fluid Dynamics) calculations.
Air flow measurements and simulations were made on a 13-story apartment building to characterize the ventilation rates for the individual apartments. Parametric runs were performed for specific conditions, e.g., height, orientation, outside temperature and wind speed. Our analysis of the air flow simulations suggest that the ventilation to the individual units varies considerably.
A new multizone airflow and contaminant dispersal program CONTAM93 is described. While this program is based on existing theory of network airflow analysis and contaminant dispersal, it employs a unique graphic interface for data input and display. The interface uses a sketchpad to describe the connections between zones and icons to represent zones, openings, ventilation system components, and contaminant sources and sinks. The program, its graphic interface and plans for its further development are described.
Summary report and evaluation of the Roomvent 94 conference in air distribution in rooms. The roomvent conferences are dedicated to problems if aero- and thermo-dynamics of ventilated rooms.
A study of the reliability of systems by considering the ability of different systems to maintain a required air flow rate over time is included in a subtask of IEA Annex 27 "Evaluation and Demonstration of Domestic Ventilation Systems". Measurements were performed to determine the variation in ventilation rates due to variation in climate and variation in performance of the ventilation system. The monitoring was carried out in one-family houses and apartment buildings, which are representative of the Swedish housing stock.
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