Appraisal of the M Factor and the Role of Building Thermal Mass in Energy Conservation

摘要

A new concept in heat transfer calculations known as the M factor has been introduced to account for thermal storage due to mass in building walls. This report reviews the assumptions behind the development of the M factor. The effect of mass in walls on seasonal or annual energy transmission through walls is examined, as well as the applicability of the M factor as a correction to account for any mass effects. In connection with the effect of mass on seasonal energy consumption, the use of a M factor correction when checking a building for compliance with energy conservation standards such as ASHRAE Standard 90-75 is investigated. The suitability of applying the M factor correction to the peak load determined by a steady-state calculation for equipment sizing is also explored. In addition, the relationship of thermal mass to other parameters that determine loads and energy consumption is investigated, and the role of thermal mass in energy conservation is discussed. (ERA citation 05:029221)