Pit Thermal Energy Storage lids

Besides turnkey delivery of customized Pit Thermal Energy Storage (PTES) systems, Aalborg CSP also offers supply and installation of key PTES components including lid solutions for existing systems. For PTES systems, Aalborg CSP uses a unique patented lid design, which enables dewatering and vapor diffusion. These unique design features ensure lower heat loss in the PTES contributing to higher efficiency and reliability of the complete energy system.

The lid design from Aalborg CSP addresses some of the key issues observed and experienced during previous deployment of PTES projects. This includes issues related to water ponding, moisture and air accumulation and thermal expansion.


Diffusion-open top cover construction minimizes heat loss

A Pit Thermal Energy storage is a large water reservoir used for storing thermal energy. The reservoir is lined with plastic linings, while the top of the storage is covered by a floating insulating lid. The lid is used to retain the heat and keep the storage tight from rainwater.

The lid design used by Aalborg CSP is based on a reversed roof principle and designed as a diffusion-open top cover construction. The diffusion-open construction allows for vapor to diffuse through the upper liner above the insulation rather than accumulating inside the construction. This improves the insulation ability of the PTES and reduces the heat loss inside the storage thereby improvingthe efficiency.


Lid divided into sections for improved rainfall handling and scalability

The lid is furthermore divided into sections. The lid sectioning has several advantages as it addresses and solves issues with water ponding, air accumulation, and thermal expansion.  Each section is designed with an inward fall towards the center, which results in a very efficient handling of rainwater. In the center of each section, a pump well ensures the removal of water. This system makes it possible to drain the surface of the lid safely and automatically with no maintenance. 

The inward fall on each section furthermore allows for air pockets, that would otherwise develop underneath the lid construction, to be led away. In addition, dividing the lid into sections also enables scalability.

These unique design features ensure lower heat loss in the PTES resulting in higher performance and efficiency of the overall energy system as well as a lower price per delivered MWth.

Did you know

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