IJV11

To study the thermal effects on airflow in a street canyon under real heating conditions (due to diurnal solar radiation), a one-way static approach combining an urban canopy model and CFD is proposed in this paper. An urban canopy model was developed to calculate the individual temperatures of surfaces in the street canyon. The calculated surface temperature may be used as a thermal boundary for CFD simulation. The reliability of this model was validated against a field experiment in Harbin, China.

This study presents an optimization method of sensor layout to improve identification accuracy of indoor contaminant sources. The method integrates an index, the performance of sensor layout (PSL), with a two-step screening procedure to determine sensor layouts that have potential to achieve relatively high levels of accuracy in source identification. Using the PSL, the performance of each possible sensor layout can be predicted and evaluated, and therefore the optimization method can be performed without running a source identification model.

This paper focuses on the performance of a new air curtain ventilation system. Particle Image Velocimetry (PIV) is used to visualize and investigate the airflow characteristic of an air curtain in an enclosure and the airflow pattern and temperature fields are measured and analyzed in detail. The air supply velocity and the slot inlet location were varied during the experimental process. The current results show that with the increase of air supply velocity the cooling effect in the occupied zone is further strengthened.

Based on the theoretical and experimental studies of natural ventilation, the performance of natural ventilators has been analysed. Four types of natural window ventilators and three types of wall ventilators were studied. Experimental results show that the natural ventilators have a greater ventilation effect whilst meeting national and local standards of ventilation for residential buildings in heating or cooling seasons.  The installation of such devices can be a compromise between ventilation and energy loss.

In order to get more effective natural ventilation into a room with a single sided opening or large depth, two new window types have been developed in the laboratory. These are based on three new patent developments. The first window is defined as a dual level ‘up-down folio’ window which consists of two pairs of openable sashes with one pair placed directly above the other.  The second is a multi-sash mid-pivoted window with vertical deflectors.

This paper presents a method for predicting occupants’ indoor thermal sensation in naturally-ventilated environments, based on real thermal sensation samples, using a GA-BP neural network model. This method improves the traditional back propagation neural network by incorporating an integrated genetic algorithm into the BP neutral network which aims to optimise the connection weight or threshold of the parameters in the input layer of the GA-BP neutral network model, which represent the factors affecting adaptive thermal comfort.

Both critical and optimistic claims have been made regarding the performance of heat recovery ventilation systems (HRVS) in dwellings. Such arguments are raised partly because two key aspects are not fully clarified, i.e. the performance criteria and the influence of uncertainties. In the current paper, an assessment method for HRVS considering the influence of uncertainties is described. This includes  adequate assessment criteria, the method of identifying the uncertainties, and the method of addressing the influence of such uncertainties.

The control strategy for mechanical ventilation systems has significant impact on the performance of the system, in terms of energy consumption and correct air distribution. This paper presents a static pressure reset control system employing a new type of flow damper with lower pressure loss for use in low pressure ventilation systems. The flow damper has a droplet shape that minimizes turbulence generation and the resulting pressure loss. The performance of the damper was examined by making measurements of pressure loss and airflow.

In a world where energy conservation in buildings is an important target, natural ventilation is an important field in which carbon footprint reductions can be achieved. This paper investigates the possibility of creating horizontal channels to deliver natural cross ventilation passively in deep-plan buildings that otherwise would suffer from a lack of fresh air ventilation. The research objective has been to find a new system in which the depth of buildings is no longer an issue when it comes to natural ventilation.

Heating Ventilating and Air Conditioning (HVAC) systems are primarily designed for ensuring good indoor air quality and thermal comfort. However, building energy requirements tend to put demand on reducing air change rates. Passive control of jet flows in order to enhance mixing and entrainment may be a solution to this problem.