Use of Phase Change Material in a Building Wall Assembly: A Case Study of Technical Potential in Two Climates

Conference · Sun Jan 01 04:00:00 EST 2012

OSTI ID:1047024

Childs, Kenneth W ^[1]; Stovall, Therese K ^[1]

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1. ORNL

Phase change material (PCM), placed in an exterior wall, alters the temperature profile within the wall and thus influences the heat transport through the wall. This may reduce the net energy transport through the wall via interactions with diurnal temperature swings in the external environment or reduce the electricity needed to meet the net load through the wall by shifting the time of the peak load to a time when the cooling system operates more efficiently. This study covers a broad range of parameters that can influence the effectiveness of such a merged thermal storage-thermal insulation system. These parameters included climate, PCM location within the wall, amount of PCM, midpoint of the PCM melting and freezing range relative to the indoor setpoint temperature, temperature range over which phase change occurs, and the wall orientation. Two climates are investigated using finite difference and optimization analyses: Phoenix and Baltimore, with two utility rate schedules. Although potential savings for a PCM with optimized properties were greater when the PCM was concentrated near the inside wall surface, other considerations described here lead to a recommendation for a full-thickness application. An examination of the temperature distribution within the walls also revealed the potential for this system to reduce the amount of energy transported through the wall framing. Finally, economic benefits can exceed energy savings when time-of-day utility rates are in effect, reflecting the value of peak load reductions for the utility grid.

• Research Organization: Oak Ridge National Laboratory (ORNL); Building Technologies Research and Integration Center
• Sponsoring Organization: EE USDOE - Office of Energy Efficiency and Renewable Energy (EE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1047024
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CLIMATES
COOLING SYSTEMS
ECONOMICS
ELECTRICITY
FREEZING
INDOORS
MELTING
NET ENERGY
OPTIMIZATION
ORIENTATION
PEAK LOAD
PERFORMANCE
PHASE CHANGE MATERIALS
RECOMMENDATIONS
SCHEDULES
TEMPERATURE DISTRIBUTION
TRANSPORT