Pit Thermal Energy Storage (PTES)

Energy storage is a key element in securing a stable and cost-effective energy supply in the future creating balance between supply and demand. Pit Thermal Energy Storages (PTES) enables storing of excess energy generated by wind or sun as well as excess heating from the industry for later use in district heating networks increasing the flexibility and efficiency of the heat production.

Aalborg CSP offers supply and installation of key PTES components as well as turnkey PTES solutions customized to fit individual energy needs and requirements for the most efficient and reliable heat production. Aalborg CSP also offers pre-studies and analysis, e.g. feasibility studies, pre-engineering and detailed engineering service for systems and solutions around the PTES.


Cost-efficient and flexible energy storage solution

A PTES system helps ensure on-demand heat supply during peak periods, when there is no or limited energy generation from the sun or other fluctuating renewable energy sources. The storage makes it possible to replace fossil fuels with CO2-neutral energy as it enables utilization of excess heat from solar heating plants or industrial processes as well as excess electricity produced by wind or PV. The excess energy is stored as low-temperature heat and released later, when the demand for heating and hot water is high. A PTES is a cost-efficient way of storing excess thermal energy as water is a cheap storage medium with a high heat capacity.

Integrating a Pit Thermal Energy Storage in the heat supply increases the efficiency of the heat production, adds flexibility to the system and contributes to lower heating bills for the consumers.


Increasing efficiency with patented lid technology

A Pit Thermal Energy storage is a large water reservoir used for storing thermal energy. The reservoir is lined with plastic linings to retain heat and prevent leakages, while the top of the storage is covered by a floating insulating cover used to retain the heat and keep the storage tight from rainwater. The patented lid design prevents the accumulation of moisture and allows vapour to diffuse out from the lid construction rather than accumulate inside the insulation. These unique design features help minimize heat loss thus improving the efficiency and reliability of the storage and lowering energy costs for the district heating plants.

Excess heat and electricity are used to heat up the water in the storage to approx. 80-90 °C. When the heat demand increases, cooled return water from the district heating network is passed into the bottom of the storage. The heated water at the top is thus sent out to the consumers.


Optimized integration with heat exchangers and other systems

For higher efficiency and optimal operation, the PTES can be integrated with other solutions and systems. This may include – but is not limited to - integration with district heating centrals, heat pump systems and solar heating systems. The storage must be charged and discharged in an efficient way with an operational philosophy that ensures safe operation, functionality, long service life and last but not least the performance.

Aalborg CSP is an expert in design, supply, optimization and control of integrated energy systems and heat exchangers and is one of the globally leading companies within the field. The company’s reference list includes commercial scale integrated system projects in Australia and Brønderslev (Denmark) as well as complex heat exchanger and boiler systems for the world’s largest CSP project in Dubai.

In combination with the PTES solutions, Aalborg CSP ensures the integration with other systems with an overall turnkey solution that ensures design, quality, delivery and performance.

Did you know

...that Aalborg CSP has delivered a 11,312m2 flat solar panel field in Denmark to produce 5,568MWh green energy annually?
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