duct

The quantitative knowledge gained from the assessment of particle deposition in ducts is importantto study, for example, the elimination of air leakage from duct systems with aerosolized sealant particles or to implement strategies of cleanliness of air ventilation systems. The study of particle deposition on the components of ventilation systems contributes also significantly to a better understanding of human exposure to particulate pollution. In this work we investigate deposition of aerosol particles in bifurcating ducts with a curved inlet segment.

The aim of that study was to evaluate the effect of compression on pressure drop in flexible, spiral wire helix core ducts used in residential and light commercial applications. Tests on ducts of 6, 8, 10 in. nominal diameters were conduted under different compression configurations following ANSI/ASHRAE standard 120-1999. That study suggests potential improvements to that standard and gives new data for duct design.

Microperforated sound absorbers have been successfully implemented in suspended ceilings, transparent panel absorbers or other applications. That principle of microperforation has been introduced to further engineering areas such as duct systems where the air flows through the micorperforation. So along with the ventilation aspects, the sound absorption effects need to be taken into account. In that aim, the theory of a microperforated absorber was extended by the effects due to airflow through the microperforation.

Our commitment to improve both air quality and energy savings in existing dwellings involves scopemeasurements campaigns. Constraints linked to the use of measurements material in these conditions, the keeping of their reliability all project long and their costs prompted industry to develop special devices for this kind of application. It is the case of this high accuracy manometer required for the wide demonstration project called HR-VENT (Nangis- France).

The Delta-Q duct leakage test has been developed over the past several years as an improvement to existing duct pressurization tests. It focuses on measuring the air leakage flows to outside at operating conditions that are required for energy loss calculations for duct systems, and infiltration impacts. The Delta-Q test builds on the standard envelope tightness measurement technique of a blower door by repeating the tests with the system air handler off and on. This study uses detailed

Duct leakage in forced-air distribution systems has been recognized for years as a major source of energy losses in residential buildings. Unfortunately, the distribution of leakage across homes is far from uniform, and measuring duct leakage under normal operating conditions has proven to be difficult.

Detailed measurements of the thermal characteristics of one one-row and one four-row ducted, hydronic air heating coil have been performed. The measurements were made in a carefully designed and produced laboratory setup, capable of creating almost perfect step changes of both water flow rate and supply temperature. The heaters steady-state characteristics were first modeled. The model was then calibrated with a set of measurements by means of parameter estimation. Then a couple of dynamic models, based on the calibrated steadystate models, were tested.

The search for top quality is the requirement of the professionals of "hygienisation". A description of desinfection with its methodology applied to ducts is presented : dust removal, cleaning of the surfaces before their disinfection.

A kind of protocol for the desinfection of air-handling ducts is presented in this paper with its different steps : relationship with the customer, available techniques, prerequisites for the desinfection, choice of the products and the desinfection itself.
The limits of the system are presented too along with possibilities to develop.

In Norway and Sweden's schools, hybrid or natural ventilation with ground-coupled fresh air intake ducts (or culverts) is the popular way of conditioning air.The ground-coupled ducts are normally made of concrete and easily accessible for inspection and cleaning; they can be divided into two parts: the air-intake culvert and the air-distribution culvert. Measurements show that the use of ground-coupled ducts along with a suitable airflow regulation is a guarantee that the supply air is colder than room air.