Experimental study of ventilation performance and contaminant distribution of underfloor ventilation systems vs. traditional ceiling-based ventilation system

This study shows the possiblity of improving indoor air quality thanks to underfloor ventilation systems. The top-return configuration and the floor-return one are tested and compared to a traditional ceililng based mixing system.

Best practices for underfloor air systems

The number of Underfloor air systems (UFAD) has incresed 40 % between 1995 and 2002, thanks to the benefits it offers : lower churn costs, improved IAQ, lower energy costs, potential to reduce floor-to-ceiling heights. But knowledge of how to apply the technology is not widespread.
Design phases, construction and commissioning phases of the UFAD project are presented along with a paragraph on the importance of educating building occupants on UFAD.

A study on the control methods for the radiant floor heating and cooling system in residential building

When applying the radiant floor cooling system using Ondol - the Korean traditional radiant floor heating system - it is important to select a precise control method to maintain a stable room temperature and floor surface temperature and prevent surface condensation. Therefore, it is necessary to systematize various control methods and to conduct a comparative study of the respective control methods so as to be able to control the radiant floor heating and cooling system efficiently.

A case study on the application of underfloor air conditioning and ventilation system in a school assembly hall

Floor return (FR) type underfloor ventilation system was installed in the assembly hall of aprimary school in Hong Kong. Experimental investigations on the airflow and temperaturecharacteristics were conducted. Pollutant distributions were also measured with different freshair supply rates. Results reveal that the use of low momentum floor supply panels reduced therisk of draught discomfort and created a more significant temperature stratifications comparedto those with fan boosted type floor air terminals. Ventilation of polluted air was localized upto the occupants breathing level.

What real-world experience says about the UFAD alternative

This article aims at providing an overview of recent field experience, as reported in the literature, about underfloor air distribution systems (UFAD) as an alternative to conventional air distribution.

Experimental comparison of characteristics between ceiling-based system and floor-based system using CAV HVAC system in cooling period

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.

Thermal stratification performance of underfloor air distribution (UFAD) systems

Tests were operated to analyse thermal stratification with undefloor air distribution systems supplying air at different rates and temperatures.

IAQ, energy, and cost implications of underfloor air distribution systems

Literature was reviewed about underfloor systems and engineers having experienced these systems on completed projects were interviewed. Underfloor air distribution systems improve thermal comfort , indoor air quality and user satisfaction.

A study of thermal comfort in an office environment with floor return type underfloor ventilation system

Thermal comfort (PMV and PPD indices) of a floor return underfloor ventilation system was evaluated through experiments with different supply air temperatures and internal heat loads. Results are shown and analysed.

Indoor air quality and thermal comfort studies of an under-floor air-conditioning system in the tropics.

Gives a report on thermal comfort and IAQ studies of an under-floor air-conditioning (UFAC) system in a hot and humid climate. In order to predict the airflow pattern of the supply air jet and to determine the occurrence of thermal stratification in the office room, thermal comfort parameters were measured at predetermined grid points within an imaginary plane. The authors also used Fanger's thermal comfort index to detect the occupants' thermal sensation, and measurements were made of the concentration levels of dust and carbon dioxide.