Fifteen air cleaners, representing different technologies and types of devices, were tested with a mixture of 16 representative VOCs (17 VOCs in tests for products associated with ozone generation) in a full-scale stainless steel chamber by using a pull-down test method. Their initial performancewas evaluated in terms of single-pass efficiency (?) and the clean air delivery rate (CADR). technologies evaluated include sorption filtration, ultraviolet-photocatalytic oxidation (UV-PCO), ozone oxidation, air ionization (plasma decomposition), and botanical air cleaning.

Current models and test methods for determining filter efficiency ignore filter bypass, the air that circumvents filter media because of gaps around the filter or filter housing. In this paper, we develop a general model to estimate the size-resolved particle removal efficiency, including bypass, of HVAC filters. The model applies the measured pressure drop of the filter to determine the airflow through the bypass cracks and accounts for particle loss in the bypass cracks. We consider a particle

This paper presents a comprehensive discussion about past, present and future research focused on air curtain performance optimization. The past reserach mostly relies on simplified analytical solutions for jets. The present approach takes a more comprehensive step toward understanding and quantification of all major parameters that affect the air curtain flow field by utilization of modern analytical/computational and experimental techniques. The goal of future work is a systematic approach to map optimum air curtain performance as a function of the major design parameters.

A research project is being conducted at the National Research Council of Canada (NRC) to evaluate the effectiveness of current emergency ventilation strategies to control smoke spread in the event of a fire in two road tunnels. The research study includes numerical and experimental phases. The numerical phase uses computational fluid dynamics (CFD) models to study smoke ventilation in the tunnels. The experimental phase is used to calibrate and to partially validate
the chosen CFD models and to provide the necessary initial and boundary conditions.

This paper compares CFD models and field-measured data from four large enclosed locomotive facilities. For each facility, CFD models were built using two computational fluid dynamics programs. These included a commercially available software package using a revised Reynolds Averaged Navier-Stokes (RANS) k-epsilon model and a public domain large eddy simulation model. This paper discusses the development of the models, compares their predictions with field measurements,

This paper summarizes the results of field measurements that were conducted in four operating diesel locomotive shops. The physical geometry and ventilation system design are documentedfor each shop, and their usage is described. Measurements taken over a four-day period at each location are discussed, and typical data are presented. When possible, average contaminant concentrations for similar operating events are also analyzed together to provide a more completeassessment of ventilation system operation.

The air performance effects expected due to inlet velocity distortion for axial fans is predicted based on basic airfoil data. This expectation is compared with the test data gathered in RP-1010. Sound data for various inlet configurations are also presented to help understand the test data.

The experimental study determined the degradation in performance of large axial fans caused by close inlet walls. Three fans with hub to tip ratios of 0.30, 0.49 and 0.74 were each tested at four blade angles and over the flow rate range of wide open to near shutoff. The closest walls, 0.5.D front clearane and OD side clearance, caused only modest loss in flow rate, up to 3,5 % and less than a 5 % loss of efficiency in the O.49 H/T fan. The other two fans had only minor decreases in flow rate and in efficiency for the closest walls.

Fan energy use in variable-air-volume (VAV) systems can be reduced by resetting the supply duct pressure. The standard way to reset duct pressure is by controlling the most open terminaldamper to a nearly open position. This strategy is rarely used because of a variety of issues including sensing limitations, network bandwidth, and stability. This paper describes the development of a new method of determining the critical supply duct pressure for VAV systems.

Air-to-air energy recovery can be used to reduce ventilation loads for small commercial buildings. Enthalpy exchangers are one approach to energy recovery that is commonly employed. An alternative technology involves the use of a heat pump that operates between the ventilation and exhaust streams. In this paper, the performance of a ventilation heat pump heat recovery unit was studied through simulation. A model of the heat pump was developed and validated using