Measures to reduce energy consumption: a simulation study for mushroom houses.

The purpose of this study is to provide a model to facilitate the simulated evaluation of theenergy consumption for different mushroom house and climate set point configurations.Climate management in this application is complex, including control of: oxygen, carbondioxide, and water vapour, temperature, evaporation rate, air cleanliness, and indoor-outdoorpressure differential. Climate set points vary according to the stage of crop growth and need tobe maintained regardless of weather conditions.

Comparison of zonal and CFD modelling of natural ventilation in a thermally stratified building.

This paper compares two well-known modelling approaches for natural ventilation in a multi-zone building with thermal stratification and large openings. The zonal approach in this paper assumes a fully mixed condition in each zone, and considers the bi-directional flows through all large openings. The zonal model is integrated into a thermal analysis code to provide simultaneous prediction of both ventilation flow rates and air temperatures in each zone. The CFD approach uses a finite-volume method for turbulent flows.

Contamination control by unidirectional flow ventilation in a refuse disposal facility.

A series of CFD and model experiments were carried out in order to find the most effective ventilation system in a separated refuse disposal facility. The ventilation system needed in the facility protects the working space from dust and odors generated by handling refuse. The desired ventilation system is to introduce the outdoor air from the one side of the working area and to exhausts the contaminated air through the opposite side of the refuse stock yard, so-called the unidirectional airflow ventilation.

Effect of data logging frequency on tracer gas measurement.

A data acquisition system which uses a computer provides a more useful analysis system. Since the processing speed of computer is continuously increasing, the information than it is possible using conventional data acquisition systems. However, the raw measurements also include the signal noise which may lead to difficulty when the signal is analyzed. This work assesses an algorithm for removing possible signal noise, usually with high-frequency, from the measurement of tracer gas concentration.

Upward flows in a multi zone building with subfloor plenums and solar chimneys.

Solar chimneys are often used to extract air from a building by thermal stacks, while subfloor plenums are used to passively cool air before it is supplied to a building. This paper examines the overall flow pattern in buildings with both solar chimneys and subfloor plenums. For a multi-zone flow system in which each zone has only two effective openings, an analytical solution is derived. A sufficient condition for upward flows to occur is derived from the analytical solution.

CFD modelling and experimental validation of air flow between spaces.

Studies of airflow between two adjacent spaces of building were carried out using CFD simulation. The results of CFD simulation were validated against test data set obtained from full-scale experimental tests. The agreement and discrepancy between the prediction and measurement results were discussed. Further numerical exercises were carried out to study under the conditions that were difficult to achieve by experiments and the results obtained were supplemented to the understanding of convective heat transfer between adjacent rooms.

Effect of interior partitions on the air movement and air quality in a room with mixing ventilation.

Working spaces in modem buildings are easily formed by interior partitions because these buildings have been designed and constructed as open spaces for flexibility. This could lead to an indoor environment which might be different from the intended design. In this study, the effect of partition on the indoor air quality in a model room has been investigated with different configurations such as the height of' partition and the gap between partition and floor.

Prediction of air flow distribution in rooms and associated pollutant transfers by the systemic approach.

The general strategy adopted in the development of a computational tool performing the identification of parametric models based on the Residence Times Distribution (Rm) theory is exposed. Two main aspects of the modelling procedure are presented: the structural discrimination of the various solution schemes, and the parameters estimation step. The structural model determination is solved by a stochastic procedure based on a Simulated Annealing algorithm, while the parametric identification is solved by a nonlinear deterministic procedure.

The comparison between air change efficiency and contaminant removal effectiveness under some typical air flow conditions in the room ventilated mechanically.

There are many indices to evaluate the ventilation characteristics of the ventilated rooms. These indices are classified into air change efficiency and contaminant removal effectiveness. In order to know how to use many indjces for a good understanding of the characteristics of the concerned ventilation system, the values of various efficiencies under some typical air flow conditions with isothermal condition are compared. The local mean age distributions and local contaminant concentrations are measured with tracer gas technique in a scaled model of the room ventilated mechanically.