Standard on Underground Thermal Energy Storage Design
Canada Approves Standard on Underground Thermal Energy Storage Design and Installation of Earth Energy Systems (Canadian Standards Association 448)
Canada has adopted a national standard that will encourage the use of underground thermal energy storage for earth energy systems (Part 3 of CSA 448 on “Design and Installation of Underground Thermal Energy Storage (UTES) for Commercial and Institutional Buildings”). UTES stores available energy within the subsurface of the earth ground or groundwater) for heating and cooling applications. Projects are operating in a number of countries and are the subject of an international collaboration under the Energy Conservation Through Energy Storage Implementing Agreement of the International Energy Agency. This collaboration has provided the technical basis for the new Canadian standard.
The standard applies to the intentional storage of energy in the earth for use later in the year. Recognized energy sources include winter ambient air, heat pump reject heat (summer), heat pump reject cold (winter), solar energy, and process heat. Applications for UTES include space heating and cooling of all building types, agricultural and industrial process cooling. UTES may be used to meet all or a portion of the heating or cooling requirements of the building or process.
UTES has been used to store large quantities of thermal energy to supply process cooling, space cooling, space heating, and ventilation air preheating, and can be used with or without heat pumps. Underground thermal energy storage is used as an energy sink and source when supply and demand for energy do not coincide. UTES may be used on a short-term or long-term basis; as the sole source of energy or as a partial storage; at a temperature useful for direct application or needing upgrade or in combination with a dehumidification system such as desiccant cooling.
UTES has significant potential for increasing energy efficiency and reducing greenhouse gas emissions from the use of conventional energy sources. Three federal government departments collaborated with the Earth Energy industry to develop the standard – Natural Resources Canada, Public Works and Government Services Canada, and Environment Canada.