Buildings with Geo-HEP
Cooling and heating buildings using geothermal heat pumps in a
pendulum cycle
Buildings often require both cooling and heating energy throughout the year.
The Geo-HEP high-performance energy pile can meet both of these needs using the same geothermal infrastructure.
The System Principle at a Glance
How the Shuttle Service Works
This seasonal alternation between passive cooling and active heating in conjunction with a heat pump is referred to as swing mode.
Passive Cooling
In cooling mode, excess heat is transported from the building to the HEP. There, it is first transferred to the water inside the high-performance energy pile and then dissipated into the surrounding mountains via the pile’s outer surfaces.
Under suitable conditions, this cooling can occur passively.
Heating with a Heat Pump
In heating mode, the direction of heat exchange is reversed. The HEP absorbs thermal energy from the surrounding mountains and makes it available as a geothermal heat source for a heat pump. The heat pump then actively raises the temperature to the level required for the building.
43 m³ of water for heat transfer and buffering
Each high-performance energy pile has a total water volume of 43 m³.
Within the HEP, the water mass serves as a thermal storage, buffering, and transfer medium. It facilitates the absorption and distribution of thermal energy and can buffer short-term load fluctuations.
In cooling mode, heat is absorbed by the water mass and then transferred to the rock. In heating mode, heat exchange occurs in the opposite direction.
Cyclic Operation: The
Same HEP Infrastructure for Cooling and Heating
A particular strength of the HEP lies in its ability to operate in a pendulum mode. This allows the same HEP infrastructure to be used for passive cooling and active heating depending on seasonal demand.
Cooling period
During the cooling season, excess heat is transferred from the building to the surrounding mountains.
Heating season
During the heating season, the HEP absorbs thermal energy from the mountains and makes it available to a heat pump as a heat source.
Thermal Interaction with the Mountain Range
At the HEP, the direction of heat exchange with the surrounding rock mass changes during pendulum operation.
In cooling mode, heat is transferred to the rock mass. In heating mode, thermal energy is extracted from the rock mass.
How these alternating operating states affect the thermal conditions at the site depends, among other things, on the ratio of heating to cooling demand, the operating times, and the geological and hydrogeological conditions.
These factors are taken into account in the project-specific design.
The seasonal storage system can also operate in pendulum mode
In addition to the HEP, the Geo-HEP seasonal storage system can also be integrated into pendulum mode—depending on the system configuration.
However, its operating principle must be clearly distinguished from that of the HEP.
The seasonal storage facility is located in the mountains or underground; however, it does not use the natural ambient temperature of the mountains as an energy source or heat sink.
Instead, the storage field is specifically managed thermally. Thermal energy is introduced from outside, stored, and later extracted.
Depending on the system design, part of the seasonal storage field can also be used as a cold storage facility. This allows both heat and cold to be stored and made available at a later time as part of a coordinated energy strategy.
HEP Swing Mode and Seasonal Storage Swing Mode
Both components can thus be used in shuttle mode, but they operate according to different thermal principles.
HEP Shuttle Service:
The HEP utilizes the natural thermal conditions of the mountains. In cooling mode, heat is transferred to the mountains; in heating mode, heat is drawn from the mountains and supplied to a heat pump.
Seasonal Storage Pendulum Operation:
The storage array is specifically charged and discharged with thermal energy. Depending on the system design, part of the storage array can be used as a cold storage facility. The natural ambient temperature of the mountain range does not serve as an energy source or heat sink in this process.
For which buildings is shuttle operation an option?
Cycle operation is particularly suitable for projects that have both cooling and heating needs throughout the year.
These may include, for example:
- Residential complexes and larger residential buildings
- Commercial buildings
- Administrative buildings
- Manufacturing facilities
- Buildings with seasonally varying heating and cooling demands
The appropriate system configuration is determined based on heating and cooling requirements, temperature levels, load profiles, building systems, and site conditions.