How the Geo-HEP High-Performance Energy Pile Works
Absorbing heat,
buffering
thermal loads, and exchanging energy with the ground.
Operating Principle of the Geo-HEP High-Performance Energy Pile
The Geo-HEP system utilizes the relatively constant year-round temperatures of the ground for cooling and heating. At the same time, it combines heat exchange with the ground with thermal buffering within the high-performance energy piles.
A Geo-HEP system is always designed on a project-specific basis. Depending on energy requirements, application, and site conditions, it may consist of one or more high-performance energy piles, along with the associated system, pump, measurement, control, and regulation technology.
The System Principle at a Glance
Heat exchange with the ground using a large integrated thermal storage mass.
01
Absorb heat
A heat transfer medium absorbs excess heat from a building, a machine, or an industrial process and transports it in a closed loop to the high-performance energy pile.
02
Buffering Thermal Loads
In the high-performance energy pile, thermal energy is first absorbed by the integrated storage mass. Preferably, approximately 43 m³ of water is available for this purpose, which can buffer short-term load peaks within the system.
03
Transfer heat to the ground
The heat absorbed is transferred to the surrounding ground via the pile's large surface area and is then conducted further.
04
Return the cooled medium
The heat transfer fluid, which has been cooled in the Geo-HEP system, flows back to the application, where it can absorb heat again. This creates a continuous, closed-loop cooling cycle.
The high-performance energy pile thus performs two closely related functions:
- Absorbing and buffering thermal loads within the pile
- extensive heat exchange with the surrounding ground
Important
The body of water serves as a short-term thermal buffer. It is not a long-term seasonal storage reservoir.
Passive cooling without a continuously operating refrigeration unit
Passive cooling is a key application of the Geo-HEP system. Under suitable conditions, the heat extracted from the building or process can be transported directly to the Geo-HEP system via the heat transfer circuit and dissipated into the ground.
A continuously operating conventional refrigeration machine or compressor is therefore not required. Electrical energy is primarily needed for circulation pumps and for measurement, control, and regulation systems.
The heat transfer fluid cooled in the Geo-HEP system is then returned to the application, where it can absorb heat once again.
How efficiently this operation functions depends, among other things, on the required temperatures, the load profile, and the geological and hydrogeological conditions at the site.
Heating with the Geo-HEP System
The high-performance energy pile can be used for more than just cooling.
In heating mode, the Geo-HEP system serves as a heat source for a heat pump. The heat pump raises the available heat to the temperature level required for the building or the respective technical process.
In doing so, the heat pump benefits from the relatively constant temperatures of the subsurface throughout the year. This allows the same geothermal infrastructure to be integrated into both cooling and heating systems.
Combining Cooling and Heating in an Integrated Geothermal System
In applications with both cooling and heating demands, both operating modes can be combined within a single integrated system. In cooling mode, heat is transferred to the ground; in heating mode, the ground can serve as a heat source for a heat pump.
The integrated water mass of the high-performance energy pile continues to serve primarily as a short-term buffer for thermal loads. For targeted long-term or seasonal storage of heat and cooling, Geo-HEP Systems is developing the standalone Geo-HEP seasonal storage system.
The mountains or the subsurface as part of the thermal system
The subsurface is an essential component of the overall thermal system. What
matters is not a specific type of soil or rock, but rather the subsurface’s ability to absorb, conduct, and release heat.
The following factors, among others, are considered in the design:
- The structure and stratification of the subsoil
- Thermal conductivity and thermal storage capacity
- Strength and drillability
- Permissible drilling depth and spatial constraints
Groundwater can aid in heat transfer
Existing groundwater—especially moving groundwater—can transport heat introduced into the subsurface, thereby improving the thermal conditions around the high-performance energy piles.
The Geo-HEP system itself functions as a closed heat exchange system. Groundwater is neither extracted nor integrated into the system’s circulation loop.
Each Geo-HEP system is designed individually
The performance of a Geo-HEP system cannot be described using a single, general parameter. For the design, three areas in particular are considered together:
Needs
Heating and cooling capacity, operating hours, load profiles, and required temperature levels.
Location
Geology, hydrogeology, available land, and technical and local conditions.
System Design
This data is used to determine the appropriate system configuration and the required number of high-performance energy piles.
Is the Geo-HEP system suitable for your project?
Whether Geo-HEP is suitable for a new facility, a retrofit, or specific cooling and heating needs is assessed on a case-by-case basis based on the technical requirements and site conditions.
Have the potential applications for your project evaluated.