English

This paper demonstrates the technical considerations that are important to understanding the energy-saving potential of encouraging the use of brushless direct current (BDC) motors in residential air handlers. Energy savings estimates are provided, and the regulations that are already in place are explained. Some misperceptions about the testing and operation of residential furnaces and air conditioners are also covered. Using one set of parameters that assume typical cyclic

The life-cycle assessment (LCA) methodology is used in this paper to assess the environmental effects of air-handling units (AHU) over a 20-year life cycle. This assessment is based on quantifying the consumption of resources (energy and materials), the harmful emissions into the environment (air, water, and soil), and the potential changes in the environment (climate change, acidification, and ozone production).

This paper shows how air-to-air heat and energy system design problems can be formulated for a simple HVAC configuration and solved for the least life-cycle cost system while still retaining a small payback period. Mathematical expressions and design tables are presented to facilitate the design process. The design process is illustrated for the city of Chicago where both large heating and cooling loads occur in HVAC applications. The example design problem presented shows that

This paper presents an integrated IAQ/HVAC simulation environment that can model the impact of contaminant-based demand-controlled ventilation (DCV) strategies on both indoor air quality and HVAC system energy use for multizone buildings. The predictions of the integrated IAQ/HVAC simulation environment are first validated against experimental data obtained from laboratory testing. Then the simulation environment is used to investigate the performance of three ventilation control strategies, namely: one conventional control using fixed-position for outside air damper and two

This paper examines thermal mixing of outdoor and return airstreams in typical air-handling units equipped with parallel blade dampers. The mixing of the two airstreams in rectangular and square mixing chambers is studied for eight different dampers and blade orientations. Testing is conducted at a total supply air of 16000 CFM with outdoor flow percentages of 15% and 30%. The temperature differential between the outdoor and return airflows is kept at 40F. Damper blades with chords of 4 and 6 inches are tested.

Field tests of stairwell and vestibule pressurization systems were performed in a 32-story high-rise building. Pressure differences in the stairwell, and vestibule and average air velocity were tested under various conditions. Test results indicate that indirect pressurization through a stairwell is feasible. Ignoring stack effect, the worst door-opening condition is that the fire doors of the top or bottom three adjoining floors of the building are open simultaneously. Pressurization systems in

A wind tunnel dispersion modeling study was conducted to investigate exhaust contamination of hidden versus visible air intakes. A hidden intake is typically on a building sidewall or on the sidewall of a roof obstruction opposite the exhaust source. A visible intake is at roof level or on top of
an obstruction, directly above the hidden intake. Overall, the study has shown what designers suspected: placing air intakes on building sidewalls is beneficial when the stacks are on the

This paper summarizes efforts to identify economically viable strategies to reduce HVAC-related energy use while improving the indoor air quality for a public zoo facility that houses primates and large cats. The primary focus of energy conservation strategies for the facility centered on use of airto-air energy recovery devices. Computer simulations, validated with experimental data from the facility, were used to estimate energy savings for alternative energy conservation strategies.

Particle diffusion with gravitational sedimentation in displacement and mixing ventilated rooms is investigated numerically. The drift flux model, which considers the settling of particles under the effect of gravitational sedimentation, is adopted to simulate particle diffusion, while the simplified
model for solving the continuous fluid flow is combined. Since the PM 2.5 and PM 10 particles are mostly concerned in indoor environment, passive contaminant and 2.5-20 micron particles are investigated in this paper. The numerical results show that in a mixing ventilated room, the

One challenge in indoor air quality studies is the measurement of three-dimensional air velocity profiles in an airspace so that the nature of airflow can be better understood and appropriate ventilation systems can be designed. There is much dispute over a variety of computational fluid dynamics (CFD) models, primarily due to a lack of credible data to validate those models. This study aimed to develop a stereoscopic particle imaging velocimetry (SPIV) system suitable for easurement of full-scale room three-dimensional airflow.