2017 ASHRAE Annual Conference

Mechanical ventilation accounts for a significant portion of the total energy consumption in large office buildings. The air needs to be transported over large distances through ducts, it requires filtration and needs heating and cooling to condition the ventilated space. Most offices in North America have closed windows, and manually opening these windows for natural airflow is discouraged as this can interfere with the operation of the building’s HVAC system. The recent drive for energy efficiency has created renewed interest in using natural ventilation to reduce energy consumption. This paper suggests a new approach to natural ventilation by using motorized windows controlled by the Building Automation System (BAS) in existing buildings. This paper presents a detailed breakdown and analysis of the simulation results, including an economic feasibility analysis of the application of BAS-controlled motorized windows.

The purpose of this research is to elucidate the influence of overhang of an exhaust hood on the capture and containment of the exhaust hood. The capture and containment performance depends on capturing and containing the thermal plume from cooking appliances. Larger exhaust hood openings seem more able to capture thermal plumes even if they expand due to air disturbance. However, provided that the ventilation rate is the same, the face velocity of exhaust hoods is low of the larger exhaust hood openings. This may prevent containment of the thermal plume from cooking appliances. We prepared an electric fryer and an electric noodle cooker. These devices are typical cooking appliances whose thermal plumes are weak and strong, respectively. The capture efficiencies of exhaust hoods were revealed, including the parameters of overhang length of exhaust hood and ventilation rate.

The K-12 education system is the largest public enterprise in the United States. Public K-12 schools employ approximately three million staff and enroll more than fifty million students. Public schools have an expenditure that includes funds for salaries, benefits, transportation, materials and energy use. Of these expenditures, energy use is often targeted for reduction, which sometimes results in reduced ventilation. While saving energy is desirable, it must be achieved without compromising student health. Lack of proper ventilation can result in a decrease of students’ attention and can cause health-related issues. This paper evaluates how the type of heating, ventilation, and air conditioning (HVAC) systems installed in schools and HVAC operation conditions affect temporal and spatial distributions of carbon dioxide (CO₂) concentration in classrooms.

This paper discusses a systematic experimental study of the effects of operating conditions (i.e. relative humidity and temperature of working air streams) on the transport of water vapor and CO2 (as a major indoor air contaminant) through a series of standard polymeric materials suitable for membrane media used in ERVs’. Results are reported for the permeation experiments of binary mixtures of water vapor and CO2 in five commercial polymers of two major types (glassy and rubber). The selectivity of water vapor over CO2 was also evaluated from permeation experiments. In general, the permeability results suggest that ERV exchangers using polymer membranes can achieve high latent effectiveness (i.e. very high water vapor permeability) over a wide range of operating temperature and relative humidity while maintaining very low CO2 permeability and very low EATR crossover rates (<1%) accordingly.