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Thermal Energy Networks (TENs) Terminology

Thermal Energy is an abundant source of renewable energy all around us that is measured in temperature. Wastewater systems, energy-intensive buildings, bodies of water, and even the ground beneath our feet generate heat that can be transferred in and out of buildings to provide heating and cooling. Like wind and solar energy, thermal energy can be harnessed to create an emissions-free built environment.

Thermal Energy Networks: heating and/or cooling systems where two or more buildings share thermal energy via ambient water pipes and use a non-combusting, non-emitting energy source such as geothermal or waste heat for baseload thermal energy (i.e. the annual continuous heating and cooling load, generally over 80% of the energy use of most districts). In a thermal energy network, every building on the network will need a ground source heat pump. Thermal energy networks are designed opportunistically to use the resources of the location.

Clean Thermal Energy Networks (CTENs) is a thermal network without combustion. District energy systems that pipe steam can be considered “clean” if the steam is created by heating water with renewable energy such as deep geothermal or highly efficient electric equipment such as heat pumps, but not if combustible fuels (e.g. a gas power plant) are used to create the steam.

Utility Thermal Energy Networks (UTENs) are networks built by utilities (gas, electric, or water)

District Energy Systems provide heating and cooling generated in a centralized location and distributed through underground piping to residential and commercial consumers. The heat is often obtained from a cogeneration plant burning fossil fuels. More recently, the central plant energy source comes from renewable energy such as geothermal.

District energy systems have been around for over 100 years, and have evolved over time and are described as having 5 generations with each new generation improving efficiency. The first generation systems were steam based and fueled by coal. Over time efficiency was improved by decreasing the temperature of the water and emissions were reduced by changing the energy source. The most recent or fifth generation district heating and cooling networks (5GDHC) have similar characteristics to thermal energy networks including the addition of heat pumps in every building on the network to extract and reject heat to an ambient temperature water loop.

Other terms for Thermal Energy Networks: district thermal, community heat pumps networks, community thermal networks, heat networks, heating and cooling networks

Other terms used for Geothermal Networks:  networked geothermal, networked ground-source heat pumps, geothermal micro districts, GeoMicroDistricts, community-style heat pump systems, community heat pumps, CommunityGeo, GSHP communities, geo-exchange systems