English

The purpose of this project was to devise a simple, experimentally validated method for quantifying the energy impacts of exterior envelope air leakage. Four full-size exterior envelope test specimens, two opaque wall systems and two fenestration systems, were built for determining simultaneous conductive and convective heat loss. The two opaque clear wall sections were metal-faced sandwich panel and cold formed steel frame.

In 1995, the U.S. Department of Energy (DOE) began planning for a new generation of building simulation tools. As part of this planning activity, DOE created an inventory of DOE-sponsored tools in early 1996. By mid-1996, this work had evolved into a web-based directory with information on 50 software tools. Today, the directory contains information on more than 125 tools from around the world. To inform the simulation tool planning efforts, DOE sponsored workshops in August 1995 and June 1996, inviting energy simulation developers and users.

This paper outlines the methods and results of a four-year project that measured heat flows through two uninsulated slab-on ground floors on nominally wet soils. One floor was on peat soil, the other on clay, and water table depths were 0.5 m to 1.0 m through most of the year. Heat fluxes were measured over the whole floor using heat flux transducers (HFT) at the concrete floor surface, and temperatures were measured by thermocouple, continuously for four years. The soil conductivities and soil temperatures were measured daily at 11 positions near one edge of the floors.

Air leakage and duct wall conduction in forced air distribution systems often waste 20% to 40% of the energy used to condition residences in hot, humid climates. The simulation of these forced air distribution system leakages, their attendant uncontrolled airflows within the building system, and their consequential energy uses may be achieved by treating building spaces as pressure vessels (nodes) that are interconnected with the forced air distribution system, the outdoors, and each other through the basic laws of pressure and airflow.

Modem, massive building envelope technologies (masonry and concrete systems) are gaining acceptance by builders today. All U.S. thermal building standards, including ASHRAE 90.1and90.2 and the Model Energy Code, are linked to the steady-state clear wall R-value. They also have separate requirements for high mass walls. Very often, only steady-state R-value is used as a measure of the steady-state thermal performance of the wall. This value does not reflect the dynamic thermal performance of massive building envelope systems.

Airflow in buildings is one of the major factors that governs the interaction of the building structure with the mechanical system, climate, and occupants. If the airflow at any point within a building or building assembly can be determined or predicted, the temperature and moisture (hygrothermal or psychometric) conditions can also be determined or predicted. If the hygrothermal conditions of the building or building assembly are known, the performance of materials can also be determined or predicted.