This paper summarizes key results of ASHRAE Research project RP-1137, which sought to quantify the benefits and longevity of the recommissioning process on variable air volume (VAV) systems that incorporate direct digital control (DDC). Field testing was completed in three diverse facilities over a period of up to two years, generating three data trends. General performance indicators were compared using the data collected prior to commissioning, immediately after commissioning, and long after commissioning was completed (a minimum of six months later).

For the characterization of PM (particulate matter) indoor/outdoor relationships for wind induced naturally ventilated residences in taiwan region, a simple size-dependent indoor air quality model was applied in association with measured outdoors PM profiles and potential loss mechanisms.

For that study, measurements were carried out in an office-type experimental room to investigate the distribution of airflow velocity and air temperature. Inside that experimental room equipped with a fan-powered floor air unit (FAU) calculations of turbulence intensity and draught rate distributions were made too. Results are presented.

The aim of that study is to model and evaluate the performance of several ventilation methods in pollutant removal from indoor environments. 3 different ventilation methods are examined : a displacement ventilation and two mixing systems. Experimental data are obtained to validate the airflow model. The simulation results show that different ventilation methods affect the pollutant distribution inside the room. The computer model could help in selecting appropriate ventilation systems to maximize indoor air quality for occupants.

Using the same system for natural ventilation and smoke control is the examined possibility of that study. In that aim a prototype building is proposed : it is an eight-storey building with a solar chimney located on top of the atrium. In parallel reduced scale model experiments and CFD analysis are conducted. It appears that in case of fire breaking out in the atrium, the neutral pressure plane of the smoke layer remains inside the chimney.

To study the microenvironment around human body with personalized ventilation system, a seated computational thermal manikin is used. Interaction between thermal plume around human body and personalized airflow is analyzed in detail, the mechanism of inhalation process becomes clearer.The results from CFD and experiment are compared : the improvement of CFD simulation accuracy is recommended.

A numerical simulation with a validated CFD model of several types of buildings was used to investigate the difference between mixing (MV) and displacement ventilation (DV) under different boundary conditions.The second part of that study deals with indoor air quality.The comparison shows that DV may provide a better IAQ in the occupied zone.

In order to investigate the difference between mixing (MV) and displacement ventilation (DV) under different boundary conditions, a numerical simulation with a validated CFD model of several types of buildings was used. The comparison shows that DV can maintain a thermally comfortable environment under a very high cooling load .

In this paper, three methods of recovering sensible heat during heating and ventilation process of heat pump have been studied experimentally. For the experiment an air-source heat pump system with none, single and double heat recovery facilities has been built and tested in two constant-temperature and constant humidity thermal chambers.

For that study a field survey on indoor environment in 10 office buildings with displacement ventilation was performed. The responses of 227 occupants were collected and analysed. It appears that combined local discomfort because of draught and vertical temperature difference is not a serious problem in rooms with displacement ventilation.