Proposal of Optimal Control Method in order to reduce Mutual Interference of Air Conditioning Indoor Units

In recent years, many multi-type package air conditioning systems for buildings have become widespread in office buildings in Japan, and there are many cases where one air conditioning space is shared by using several indoor air conditioning units. The advantages of multi-type package air conditioning system are that it is possible to operate and control individually for each indoor unit, and that the user can arbitrarily change the temperature setting of the indoor unit.

Vertical Distribution of Temperature and Contaminant Concentration in a Room with Impinging Jet Ventilation System

The impinging jet ventilation system (hereinafter referred to as IJV) has been proposed as a new air conditioning ventilation system. Properties of indoor environment with this system using impinging jet are complicated. The present paper reports fundamental properties of indoor air with distributed interior heat generation load assuming an office. The experiment was conducted in the climate chamber of which floor area was 27.0 m2, and basic properties of temperature and CO2 distributions were investigated.

Cooling Performance of Air-Conditioning System with Ceiling Suspended Packaged Air Conditioning Unit over Divided-Type Membrane Ceilings in Large Classroom

The mainstream of air-conditioning system for medium and small sized buildings is conditionally air mixing ventilation with ceiling cassette unit of packaged air conditioner (PAC), however, it may bring a high cold-draught risk to occupants, due to the direct drop of the supply air jet. To solve this problem, the air mixing ventilation system can be improved into an air based radiant air-conditioning system by stretching the non-flammable membrane under the ceiling with PAC, thus the cold-draught of PAC could be substantially eliminated and the indoor environment could be improved easily.

Modelling of Supply Air Jet from Diffusers of Four-way packaged Air-conditioner for CFD Analysis on Unsteady

Recently in Japan, many buildings introduce packaged air-conditioner (hereinafter, this is called “PAC”) as an air conditioning equipment. Most of the PACs can change the direction of supply air blown from the unit and the “Swinging Mode” can change airflow direction periodically as one of the airflow direction setting of PAC. Before constructing the building, appropriately predicting the indoor environment (e.g. temperature distribution or air velocity distribution and so on) is important for indoor environment design.

The effects of leakages in roofs with ventilated air layers - a CFD approach

The following paper is focused on hygrothermal behaviour of roofs with ventilated air layers subjected to air leakages in their internal decks (the internal partial construction located below the ventilated air layer). Possibilities of CFD modelling of such constructions are discussed in the first part of the paper including the problem of introduction of water vapour diffusion into calculation. A brief comparison of results from CFD analysis and from calculation based on a technical standard is also included.

Prediction of mass transfer rate on the surface of tested building material using CFD analysis

We developed an airflow control unit for small chambers for uniformly controlling airflow on the surface of tested building material in the small chambers. We will present the mass transfer rate on the surface of tested building materials corresponding to an actual building in order to exactly evaluate the performance of the reduced amount and concentration of released chemical materials with the small chambers. We measured the airflow velocity on the surface of building materials in the small chamber with the developed airflow control unit and the fan speed for airflow control.

CFD Analysis on Capture Efficiency in Commercial Kitchen using Low Radiative Cooking Equipment with Concentrated Exhaust Chimney

In a commercial kitchen, a large ventilation rate is needed and energy consumption can be large because a large amount of effluence of heat and moisture need to be removed. To improve kitchen environment and to save the energy, low radiative cooking equipment with concentrated exhaust chimney was developed. Although a ventilation rate may be decreased by using this equipment, the effluence needs to be captured well. To predict indoor air and thermal environment of commercial kitchen using this equipment, CFD analysis is useful.

Influence of Partition Curtain on Vertical Profile of Temperature and Contaminant Concentration in Sickroom with Displacement Ventilation

For patients, the sickroom is a place where they receive medical treatment and also a living space where they spend most of time in a day. Therefore, good indoor air quality and comfort should be kept in sickroom. We propose to use the displacement ventilation as a means of obtaining high indoor air quality in sickrooms. The purpose of the study is to examine the validity of this system. This paper shows the experiment results and CFD analysis results to examine the effect of partition curtain in the displacement-ventilated room.

Prediction of Plume above Residential Cooking Range by means of CFD analysis

Recently, Island kitchen is installed in many houses in Japan. In the island kitchen, the cooking range is placed on the island unit, and the center hood is located above the cooking flow in the room. In such a kitchen environment, there is a possibility that cross winds or other disturbing flow may reach the cooking zone. For this reason, pollutant fumes from the cooking range may be diffused to residential zone. CFD analysis is an effective measure for comprehending such a diffusion of the thermal plume.

Experimental Investigation and Accuracy Study of CFD Analysis for Airflow around Cross-Ventilated Building

In predicting flow rate of a building ventilated by wind, the orifice equation is usually used. This conventional method cannot work for the building provided with large openings. Therefore, the final goal of this study is to establish a new prediction method of the cross-ventilation rate, which is based on energy balance inside the stream tubes passing through/around a building. In determining stream tubes, it is beneficial to use CFD. In this study, the accuracy of CFD analysis is studied. Three turbulence models are used in the simulation; i.e.