The draft of the European prestandard 17 52, entitled "Ventilation for buildings – Design criteria for the indoor environment" is intended to be a flexible tool for assisting the designer in providing a proper indoor environment for people in ventilated buildings. It specifies how the quality of the indoor environment, comprising the thermal environment, the air quality and the acoustic environment can be expressed.
This paper reports the analysis of the thermal performance of building envelopes of high-rise commercial buildings in the subtropical climate and their interactions with cooling system. Building constructions of commercial buildings in Hong Kong have been investigated and categorized. Their thermal performance and the resulting chiller load is studied with the building energy simulation tool DOE-2. lD. The characteristics of subtropical climate, coupled to high internal gains of commercial buildings, are discussed.
This study presents a new method of interior air motion assessment using artificial neural networks. The air motion inside a building depends not only on the external wind velocity, but also to a great extent on most of architectural parameters such as position and orientation of building, size and configuration of windows, roof geometry, whether the building is stilted or not, etc ..
This paper presents a study of the dynamics of the turbulent mixing of a hot or cold air stream with the air in the interior of a building zone. Observations and CFO results of transient temperature behaviour in a fully developed jet flow field are presented. A simple model for the characteristic time-constant of the mixing process in a room is derived. The mixing of a turbulent jet, as a function of position inside the room, is also discussed. This mixing time-constant plays an important role in total system dynamic behaviour and stability.
Knowledge of the authority of control dampers in HVAC systems may be used for diagnostic purposes or to enhance control performance. In this paper, a method of estimating damper authority in air distribution systems is described. The method only requires measurements that are normally available in modem HV AC systems with digital controls. The method is based on a technique that allows the static pressure drop across a branch to be regulated even if that pressure is not measured. Experimental results on a Variable Air Volume (VA V) air handling unit demonstrate the efficacy of the method.
Dynamic simulation of a seawater-cooled chilling system is performed by using the dynamic models of centrifugal chillers, heat exchangers, seawater and chilled water networks, cooling coil, actuator, sensor, variable-speed pump and DDC controller ofBEMS. The on-line control strategies for the central chilling system are tested and evaluated by using them to control the living chilling system under different AHU dynamic loads in four seasons.
Many houses in Japan have crawl space between the lowest floor and the earth ground which is about 50 cm in height. This is considered as protection against corrosion of wood materials in the floor. Japanese building codes recommend ventilation with outdoor air in this space. In our field research, we found condensation in the crawl space in summer. This is due to low temperature of the ground and high humidity of the outdoor air which is typical of the Asian climate.
Login