English

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,

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.

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

This paper evaluates the operating cost savings and overall economics associated with these two different ventilation load reduction technologies : demand-controlled ventilation (DCV) and enthalpy exchangers. A specialized simulation tool was developed and used to perform the evaluations. For both technologies, the savings potential and economic payback are better in more extreme climates., particularly in cold climates because the ventilation load is a larger portion of the overall load.

With sponsorship from the US Department of Energy, a research project has designed, fabricated, and tested improvements to an air conditioner’s outdoor unit fan system. The primary objective was to improve condenser fan performance while reducing motor po

This paper presents the effects of façade design on crossventilation for Taiwanese elementary schools that are typically naturally ventilated. A prototype classroom that serves 30 students with divided upper and lower windows was used. Numerical simulatio

A quantitative relationship between a room’s pressurization ratio and its leakage airflows has been established in recent ASHRAE research. With this engineered approach, design of multistage pressurizations in cleanrooms and laboratories can be more predi

A stereoscopic particle image velocimetry (SPIV) system was used to measure airflow characteristics in an irregularly shaped test room. These measurements were compared with air velocity measurements obtained by a sonic anemometer instrument, hot-wire instrument, and draft instrument. All of the measurements were taken at five measurement locations along the center plane of the test room. For each measuement location, numerous pairs of SPIV, sonic, hot-wire, and draft data were collected and averaged to determine the average velocity.