Assured capacity of heat storage tanks using CFD
Guaranteed thermal capacity is possible by using CFD in the design of your heat storage tanks. Obtain an efficient and cost-effective solution with undisturbed thermal layers during operation.
From waste to sourceStoring surplus heat from industrial processes is a challenge that when attained, creates economic benefits both for industrial process plants and combined heat and power plants. Moreover, the environmental benefits for society due to reduced over-production and thus minimized waste is substantial. This is where heat storage tanks, also known as thermal energy storage units, make a difference.
For industrial processes, thermal energy storage allows saving waste energy, for later re-introduction into the system when needed. This reduces the need for auxiliary equipment to re-generate energy that has already been produced at an earlier stage. For combined heat and power plants, thermal storage allows closing the time-gap between demand of district heating and electricity. Heat generated at specific hours of the day, as by-product of electricity production, can be stored and used later when district heating demand rises.
Meeting the designed capacity of the heat storage tank
Proper functioning of a stratified water heat storage tank is directly related to its ability to meet the designed thermal capacity, as well as to preserve high temperatures inside the tank.
To control the latter, special attention must be paid to the thermocline layer, which is the layer that naturally separates cold water at the tank’s bottom from hot water at the top. A good design implies a thin thermocline layer, meaning that there is only little mixing between hot and cold water.
How to minimise the thermocline layer
Hot and cold water enters and leaves the tank during charging and discharging. This process induces turbulence and mixing inside the tank, disturbing the thermocline layer thus increasing its thickness. Such disturbance creates permanent thermal losses and reduced tank capacity, which cannot be recovered. This leads to continuous economic losses for the end user.
In order to preserve an undisturbed thermocline layer, reduce thermal losses, and maintain a high thermal capacity, water must enter and leave the tank through diffusers that create as little turbulence and mixing as possible.
Using CFD to guarantee high thermal capacity and minimum thermocline layer
We use CFD to design and validate stratified water heat storage tanks that operate optimally. Our services cover design and optimisation of internal piping systems and diffusers, ensuring optimal functioning from a flow and mechanical perspective.
Our CFD design procedure ensures:
- High thermal capacity
- Thin thermocline layer
- Minimum thermal losses by reducing turbulence, mixing effects and optimal design of flow in pipes
- Reduction of diffusers size and weight compared to conventional design methods
- Design flexibility, upon feedback from construction teams.
Through CFD, we are able to predict flow behaviour inside the tank. This is crucial for its proper functioning. Such detailed overview provides valuable information that would otherwise only be available once the heat storage tank is constructed and tested. Since we simulate the process inside the entire tank, we can guarantee the tank’s performance, heat output and thermocline thickness, prior to its construction.