English

Conventional calculations of heating (and cooling) loads for buildings assume that conduction heat loss (or gain) through walls is independent of air infiltration heat loss (or gain). During passage through the building envelope, infiltrating air substantially exchanges heat wall insulation leading to partial recovery of heat conducted through the wall. The Infiltration Heat Recovery (IHR) factor was introduced to quantify the heat recovery and correct the conventional calculations.

Currently, houses do not perform optimally or even as many codes and forecasts predict, largely because they are field assembled and there is no consistent process to identify deficiencies or to correct them. Solving this problem requires field performance evaluations using appropriate and agreed upon procedures in the form of a new process called residential commissioning. The purpose of this project is to develop and document these procedures and to demonstrate the value that applying them could provide in both new and existing California houses.

In residential and light commercial construction in the United States, heating and cooling ducts are often located outside the thermal or pressure boundary of the conditioned space. This location is selected for aesthetic and space requirement reasons. Typical duct locations include attics, above dropped ceilings, crawlspaces, and attached garages. A wide body of literature has found that distribution system conduction and air leakage can cause 30-40% energy losses before cooling and heating air reaches the conditioned space.

This field study concentrated on measurement of duct leakage to outside the conditioned space because this is most useful in energy calculations, e.g., proposed ASHRAE Standard 152P (ASHRAE 1997). For room by room load/comfort requirements, the total duct leakage (including leaks to conditioned space) is more appropriate, particularly for additional comfort considerations. The objective of this field study is to help to identify major sources of uncertainty and to quantify the trade-offs between different test methods.

Performance of radon mitigation systems, including active sub-slab ventilation, basement over-pressurization and crawlspace isolation and ventilation, was monitored in 12 houses in the USA during 10 years. Results are given showing the radon concentrations measured quarterly or annually. Results of the inspection of the mitigation systems and the needed maintenance and modifications of the systems to maintain and improve their performance are also reported.

This report summarizes the results of two high temperature longevity tests conducted by the Energy Performance of Building Group (EPB). The first test involved the aging of common “core-to-collar joints” of flexible duct to sheet metal collars, and sheet metal “collar-to-plenum joints” exposed to continuous 200°F (93°C) circulating air. The second test consisted of baking duct tape specimens in a constant 212°F (100°C) oven following the UL 181B-FX “Temperature Test” (Underwriters Laboratory 1995) requirements.

The initial solid-phase concentration of volatile organic compounds (VOCs) is a key parameter influencing the emission characteristics of many indoor materials. Solid-phase measurements are typically made using solvent extraction or thermal headspace analysis. The high temperatures and chemical solvents associated with these methods can modify the physical structure of polymeric materials and consequently affect mass transfer characteristics.

LBNL - Proceedings of Indoor Air 2002 (9th International Conference on Indoor Air Quality and Climate) - June 30 - July 5, 2002 - Monterey, California - vol 1, pp 521-526, 3 figs, 10 refs","This paper presents a model for particle deposition on fin-and-tube heat exchangers, that takes into account mechanisms such as impaction, diffusion, gravitational settling and turbulence. Models results are presented and analysed. They agree with experimental data.

A physically based diffusion model is used to evaluate the sink effect of diffusion-controlled indoor materials and to predict the transient contaminant concentration in indoor air in response to several time-varying contaminant sources. For simplicity, it is assumed that the predominant indoor material is a homogeneous slab, initially free of contaminant, and that the air within the room is well mixed.

Age of air is a technique for evaluating ventilation that has been actively used for over 20 years. Age of air quantifies the time it takes for an elemental volume of outdoor air to reach a particular location or zone within the indoor environment. Age of air is often also used to quantify the ventilation effectiveness with respect to indoor air quality. In a purely single zone situation this use of age of air is straightforward, but application of age of air techniques in the general multizone environment has not been fully developed.