2016 ASHRAE Winter Conference

Ambient particulate matter (PM) air pollution is critical to human health and well-being given the association of urban air pollution with increased respiratory and cardiovascular mortality. For urban office buildings in big cities, use of economizers has dramatically increased recently for energy saving and ventilation purposes. The objective of this paper is to examine outdoor-indoor transports of ozone and PM_2.5 (particles < 2.5 micron in diameter) for urban office buildings considering economizer operating modes. This study employs multi-zone contaminant transport model for prediction of outdoor-indoor pollutant dynamics in two cities: Los Angeles and Beijing. The model simulates an infiltration of ambient ozone, PM2.5 (< 2.5 micron), into a DOE reference building (medium office) based on outdoor climate condition, outdoor intake and filtration efficiency. Seasonal variations are also considered to capture the influences of high ozone levels during the summer in LA and elevated particle concentrations during the spring season in Beijing.

Exposure to ambient fine particles (PM_2.5: particles < 2.5 μm in diameter) and ultrafine particles (UFPs: particles < 100 nm in diameter) has adverse effects on human health. Residential buildings greatly impact human exposure to outdoor particles because people spend more than 90% of their time indoors (and much of that time at home) and outdoor particles can infiltrate through building envelopes and mechanical ventilation systems with varying efficiencies. This paper will model the impact of various combinations of central forced air HVAC filtration and mechanical ventilation systems on indoor concentrations of fine and ultrafine particles of outdoor origin in three types of residential buildings (i.e., older, existing and new homes).

Exposure to airborne particulate matter is connected with adverse human health effects. The majority of human exposure to airborne particles occurs inside buildings. In order to improve indoor air quality by reducing indoor particle concentrations, high efficiency particle filters installed in central forced air heating, ventilating and air-conditioning (HVAC) systems are being used. ASHRAE Standard 52.2 relies on a method of laboratory testing to measure the performance of general ventilation air-cleaning devices to assist end-users in their selection of appropriate air filtration products to increase living or working environmental quality. In this project, an in-situ test method is used to measure the particle removal efficiency of a wide range of commercially available filters in 28 particle size ranges from 0.01-10 µm in diameter.

Membrane-based energy recovery ventilators (ERV) are an effective means of reducing energy cost and allow for scaling down HVAC equipment. Owing to their compact geometry and rough surfaces of the porous membrane substrate, ERV exchanger cores can be fouled by airborne particulate matter. In this study, the influence of particulate fouling on the membrane-based ERVs was investigated via accelerated material- and core-level fouling experiments.  The core-level experiments, inside an aerosol wind tunnel (AWT), investigated the effect of dust accumulation on the performance of cross-flow cores (including sensible and latent effectiveness, and pressure drop) through comparing pre- and post-fouling performance tests of two core samples. The influence of the membrane surface exposed to particle-laden air, and working airflow rates were considered during AWT tests.