30 May 2005


Large buildings often have peak cooling loads greater than their peak heating loads. Internal and solar
gains often drive equipment selection in large buildings, even in cold northern climates. The cost of the
equipment and earth loop needed to meet the peak cooling loads can increase the initial cost of a
GeoExchange™ system to the extent that a less costly conventional system is often chosen.
Thermal ice storage systems have been used for many years to reduce installed chiller capacity and
shift peak electrical demand. Traditionally such systems have been installed with a conventional heating
plant to heat the building while the chiller builds ice at night for the following day’s cooling demands.
A distribution system designed to take advantage of the heat removed from the ice, and use an earth
loop as an alternate heat source and heat sink provides benefits, including:
• Elimination of separate equipment to provide space and water heating
• Reduction of equipment capacity needed for space cooling
• Reduction of the size and cost of the earth loop needed
• Doubling the efficiency of a geothermal HVAC system
• Reduction in greenhouse gas emissions