This paper proposes a new personal air-conditioning system, which modifies a common partition used in offices to a partition-type fan-coil unit (PFCU) with inlets and outlets on its surfaces. Chilled water is supplied as the cooling energy, and is delivered to the partitions by pipelines incorporated into the structure. Hence, conventional air conditioning systems using ceiling-based air diffusers for open-plan offices may be dispatched into several small individual systems controlled by the occupants.
This study compares indoor climate, cooling efficiency and energy consumption of an underfloor air distribution system and a ceiling-based system in a test chamber. Floor-based system appears to provide better thermal conditions with lower electricity consumption.
This paper proposes a new mode of ventilation for indoor airflow. Computational results show that with properly designed supplied air velocity and volume, locations of diffusers and exhausts, the proposed system should be able to maintain better thermal comfort with a smaller temperature difference between the head and foot level, and possibly lower energy consumption, if compared with conventional systems. It looks promising that better indoor air quality (IAQ) in the breathing zone could also be achieved but that further work is needed to determine if IAQ benefits are significant.
CFD calculations were used to compare temperature and air velocities in an environmental chamber equipped either with a conventional comfort overhead air supply system or with an underfloor supply system. Results show the advantages of underfloor system to provide adequate temperature, velocities and turbulence in the seated zone.
The purpose of this study is to clarify the usefulness of a displacement ventilation air-conditioning system introduced into a multipurpose hall after CFD simulation and measurement. In the multipurpose hall of Kurume City, a displacement ventilation air-conditioning system equipped with a floor outlet had been adopted. A CFD simulation for the purpose of selecting an air condition system indicated the floor outlet system would be more effective for the design plan of the hall than a ceiling outlet system.
In this article, four turbulence models are studied to capture the flow and temperature behavior of the air close to a low-velocity diffuser for displacement ventilation. Turbulence is modeled by means of one zero-equation model and three different two-equation models, i.e. the LVEL, the RNG, the Standard k-e, and the Chen-Kim model. They are evaluated for their performance in predicting the air flow patterns and temperature profiles close to the diffuser.
For a long time PPD index defined in international ISO7730 standard has been a practical tool for evaluation of measured thermal comfort conditions in existing buildings. However, its usage has not yet been realized in design phase. One of the reasons is that there has not been any practical tool available to estimate average velocity conditions within the occupied zone. A kinetic energy model for calculation of the average room velocity has been presented in earlier paper. Current paper reports additional verification results of the kinetic energy model with different types of diffusers.
The interferometric modeling of temperature fields allows to visualize clearly the distribution of temperatures in typical centres of ventilated and warm air heated spaces and spaces heated using radiators and walls. For the visualization the Mach-Zehnder interferometer is applied and the research is realized on diminished models by means of the similarity theory application.
A zonal model was developed to predict temperatures and moisture in a room taking into account the adsorption/desorption by building materials. Results show how adsorption/desorption influences the moisture field.
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