AIVC - Air Infiltration and Ventilation Centre

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The outdoor air ventilation rate in high-rise residences employing room air conditioners

This paper reports mainly on field studies were indoor overnight CO2 levels are monitored along with outdoor ventilation rates in bedrooms where room air conditioners are employed.The results of laboratory experiments using two typical RACs (room air conditioners) are also reported and discussed.

Changing microbial concentrations are associated with ventilation performance in Taiwan's air-conditioned office buildings

In this study, serial environmental measurements in 12 large buildings in Taiwan have been made to control the air exchange efficiency on the indoor microbial contamination. High levels of airborne microbes seem to be more easily observed in buildings equipped with fan coil unit system than with air handling unit system.
Adequate filtration of fresh air intake should be imperative to control effectively microbial contaminations of outdoor origin.

A global approach of indoor environment in an air-conditioned office room

In this paper the authors in order to reach the objective of a global approach of comfort by a spatial statistical study of the various discomforts, apply a multi-criteria analysis based on ELECTRE II method adapted to the comfort of air-conditioned indoor environment.

Optimization of Hybrid Air-conditioning System with Natural Ventilation by Genetic Algorithm and Computational Fluid Dynamics

In order to clarify whether a combination of designs is optimal, design elements are divided intodesign variables and random variables in the inquiry process for the optimal design. Design variablesrelated to the model are selected by a genetic algorithm, and random variables related to outdoor condition are selected by the moment method. The whole process of optimization consisted of a two-step procedure to reduce the calculation loads for finding the optimal solution. This study carried out a simple analysis using a coarse mesh considering the calculation loads in the first step.

Sampling of aerosols in a hotel’s air-conditioning systems

We conducted an on-site test of air-conditioning systems in a hotel in Changsha, Hunan, China in the summer of 2003. And indoor particulate matters, bioaerosols were the main pollutants sampled from indoor spaces and three air-conditioning systems, one of which serves the lobby of the hotel, with the other two supply fresh air to the cook room and dinning-rooms. Short-term and long-term sampling of deposited particles in the air-conditioning systems was carried out and their size distribution was tested by Optical Particle Counters (OPCs).

Floor-Supply Air-Conditioning System in a Theater Hall

Floor-supply air-conditioning system with Coanda effect is introduced to a theater hall. This system supplies air from floor diffusers set beneath the seat backrest in front of occupants. Supplied air moves upward along the backrest board inducing the circumambient air resulted in airflow temperature difference reduction. Thermal environment was measured under various heat load conditions in the theater hall. Supply air flow along and radiation effect from the seat backrest in front were confirmed using the floor-supply system.

Sleeping thermal environment and bedroom air conditioning in residential buildings in subtropical areas

This paper presents the results of a study on strategies for bedroom air conditioning in HongKong, a typical subtropical city. It reports firstly on a questionnaire survey on the current situations ofsleeping thermal environment and bedroom air conditioning in residential buildings in Hong Kong. This is followed by reporting results of field monitoring of overnight indoor air temperature, relative humidity and indoor CO2 levels in bedrooms in high-rise residences.

Risk-Based Modelling of Air-Conditioning Systems in Hungary

The selection and design of air conditioning systems in Hungary are based on a determined modelling state. In the last decade this was a safe enough basis for the management of systems. As a result of the changes in the macroclimate, however, there has been a major increase in summer temperatures. Taking into account this fact and the need to develop the earlier deterministic modelling techniques we chose to focus on risk-based modelling.

Estimation of Inhaled Air Quality for Personal Air Conditioning by Means of Age and Residual Lifetime of Air Distributions with Newly Developed Calculation Method

A detailed study using Computational Fluid Dynamics (CFD) was conducted on the influenceof the difference in the effective diameters of air supply outlets (wind velocity, assuming the airflow rate to be constant) when using personal air conditioning with isothermal air currents. A method to analyze the new age of air (SVE3*) and the residual lifetime of air (SVE6*) was proposed and studied focusing on the individual supply openings and exhasut openings in a room with multiple supply openings and exhasut openings when using personal air conditioning.

The Effect of Isothermal Task Unit on Thermal Comfort

Task conditioning system is expected to reduce energy consumption in buildings and also toimprove thermal comfort of occupants. In this paper, an isothermal task unit was developed and its impact on subjective feeling was invesigated. Laboratory and field surveys were carried out. The airflow characteristic of the unit and usage of the unit in an actual office are described. Preferred airflow and seating condition of the workers using the unit were observed. Most of the workers preferred the airflow from the unit. Task unit was most effective immediately after a worker took their seat.