Dedicated outdoor air systems (DOAS) integrated with ceiling radiant cooling panels as a parallel sensible cooling system are being considered as an alternative to conventional variable air volume (VAV) systems for commercial buildings because of their energy conservation, first and operating costs, and indoor air quality advantages. A pilot DOAS/radiant panel cooling system is being constructed on a university campus to investigate its advantages over alternative cooling systems in

Recently indoor air quality (IAQ) became an important issue and as a result researchers have developed a large number of different air quality indicators. This study focuses on air exchange efficiency (ea) and contaminant removal effectiveness (e) as suitable indicators for use in design and on-site measurements. These two IAQ indicators were numerically studied and compared for five typical indoor spaces with different ventilation strategies and contaminant sources. Overall,

Based on the algorithms of the stereoscopic particle image velocimetry (SPIV) we have developed, two digital cameras in an angular oriented configuration were used to simultaneously record two images of the same space of interest in a full-scale room. The room was seeded with helium-filled soap bubbles of neutral buoyancy. The 5.5 3.7 2.4 m (W D H) test room, which is used to simulate and monitor indoor air environment, was constructed within a large air-conditioned room

This paper presents the study of a local exhaust ventilation system with plain (unflanged) and flanged hoods. Centerline velocity and velocity contours in front of exhaust hood openingswere measured and compared to other previously reported results. Centerline velocity correlations are derived for a full range of hood axes. The effect of turbulence intensity and surrounding equipment on the velocity contours is also analyzed. Capture velocity for three different types of contaminant particles (saw dust, wheat flour, and sand) was determined.

This investigation uses three subgrid-scale models of large eddy simulation (LES) to study airflows in and around buildings. They are the Smagorinsky model, a filtered dynamic subgrid-scale model, and a stimulated small-scale subgridscale model. For outdoor airflow that is highly turbulent, the simple Smagorinsky model is sufficient. For indoor airflow where laminar flow can be as important as turbulent flow, the filtered dynamic subgrid-scale model and the stimulated small-scale subgrid-scale model are recommended.

This paper provides a summary of the methods and results of performance testing for a coupled Indoor/Outdoor Environmental Simulator (C-I/O-ES). The simulator consists of an IEQ chamber, a climate chamber, and a replaceable separation/test wall assembly. Both chambers have stainless steel interior surfaces and are equipped with independent heating, ventilating, and air-conditioning (HVAC) systems for simulating indoor and outdoor thermal and air quality conditions, respectively.

Reducing the airflow and heat input rates of a furnace that is connected to a duct system in thermal contact with unconditioned spaces can significantly reduce thermal distribution efficiency. This is a straightforward theoretical calculation based on the increased residence time of the air in the duct at

The airflow rate in heating and cooling equipment has major implications for the performance of the system. Improper flow across air conditioner and heat pump coils degrades the capacity of the coil, low flow across the heat exchanger in furnaces can cause the system to cycle on the high-temperature limit switch, and the flow rate has major implications for the efficiency of the duct system. The primary method for measuring the airflow through an air handler uses the change in temperature between the return and supply side of the air handler.

Many energy codes require that ductwork installed outside of the conditioned space be sealed. Prescriptive codes have no performance standard for what constitutes an acceptable level of duct sealing. Testing and anecdotal evidence indicate that many new homes have extensive leaks on both the supply and return sides of the heating system. A field study of 29 recently built homes was conducted in the Spokane, Washington, area. Systems were visually inspected; all defects were

The purpose of continuous fan operation is to bring in fresh outdoor air to the conditioned space in order to maintain acceptable indoor air quality. Ventilation not only uses more energy, but it also impacts air distribution system efficiency.This is partially due to various system interactions. The objective of this paper is to quantify the impact of continuous fan operation on energy use and distribution efficiency by introducingtwo new parameters: energy use ratio (EUR) and distribution efficiency ratio (DER).