District Energy Systems, also known as Thermal Energy Networks or TENs, have the ability to connect multiple buildings for the purpose of moving heat to or from other buildings and to or from heat sources/sinks like ground heat exchangers. Ground source (geothermal) heat pumps and other mechanical systems are typically connected to these systems to take advantage of the load diversity of such systems (e.g. one building or zone is in cooling while another building or zone is in heating, simply moving heat from one area to another). Therefore, mixed use developments, higher education campuses, healthcare campuses, and other applications with load diversification benefit from a district energy system.
IGSHPA’s Position on District Systems
IGSHPA supports the use of District Energy Systems and embraces this technology when projects are evaluated through a comprehensive and disciplined planning process. Such evaluations should include a thorough analysis of connected load diversification, available land area, the suitability of ground heat exchanger configurations, and overall economic feasibility. Economic considerations may include factors such as whether streets or other infrastructure must be excavated or whether the project is part of new construction.
Even when a government agency, real estate development, or institutional owner’s technical consultant has produced a strong economic summary and technical study—including a detailed energy profile—that indicates a project “pencils out” on paper as an excellent opportunity, additional considerations must be addressed early in the pre-development phase. These include determining the level of community buy-in and willingness to participate, clearly defining who will pay for the system, and identifying how the project will be funded.
Because a district energy system (often referred to as a thermal energy network, or TENs) will likely function more as a utility than as a traditional building project, governance, ownership, financing, and long-term operational responsibility must be carefully evaluated. The system must be durable, efficient, and capable of expanding over time while minimizing total life-cycle cost. Capital will often need to be deployed in unpredictable stages rather than all at once, and systems should be designed with the expectation that what is built on day one will not represent the final state.
Accordingly, district energy systems should be deployed incrementally, in step with real estate development as it unfolds—matching capacity to expected demand as buildings and loads come online—while also making prudent, no-regret, future‑proof investments along the way. While individual development projects have defined start and end points, district energy systems represent long-term partnerships that can span decades.
While district systems offer many advantages, IGSHPA recognizes that certain applications may be better served by individual ground heat exchangers—one per building—depending on site conditions, phasing, ownership structure, or long-term operational considerations. Therefore, all viable system configurations should be objectively evaluated during the initial investigation to ensure the most appropriate, cost-effective, and technically sound solution is selected.
Workforce Development and Training Programs for District Systems
Although district systems may appear to be new technology, they are a proven technology, much like ground source heat pumps and have been applied for many years. Fortunately, there are resources available (see below), including comprehensive training programs. In essence, a district system still requires “the basics” for design and installation, such as building load calculations, GHX (Ground Heat Exchanger) design/layout, pump(s) selection, distribution piping design, selection of heat pumps and hydronic specialities, and creation of system specifications and drawings, followed by commissioning and inspection/verification.
IGSHPA has a full complement of CSA/ANSI/IGSHPA C448:25 Standard based training and certification programs to provide design and installation guidance for practitioners, developers, and other stakeholders. For more information on training and certification, review IGSHPA’s Training pages.
Available Resources
ASHRAE District Heating Guide (2013)
ASHRAE District Cooling Guide (2019)
IGSHPA helpful links, NLR (formerly NREL), DOE, Oak Ridge and other reports
Policy / Statistics / Presentations
U.S. Job Growth Predictions Relevant to District Systems / Thermal Energy Networks (TENs)