Solar Aeration System for Aquaculture

Aquaculture is a major food source in many low and middle-income countries (LMICs). Improving water quality for aquaculture can increase yields, improve food security, and reduce antibiotic use. In the developed world, aeration is used to significantly improve water quality. However, aeration is the third largest cost in aquaculture, limiting its use in LMICs. In addition, current aeration methods require a secure electrical connection which is not always available.

Our device is a novel method of aeration which does not require electricity, has low maintenance requirements and can be cheaply deployed. The device utilizes the pond’s two-layer structure. The top layer is warm and oxygen rich as the plants in the water generate oxygen during the daytime (above saturation), while the bottom layer is cold and oxygen depleted.

Our device consists of a solar heat collector and a heat transfer pipe which heats a portion of the oxygen-depleted bottom to induce convective water circulation. Calculations have shown this can improve oxygen content by 30%. Following demonstration, we will establish a social enterprise to bring the technology to scale.

Bangladesh

Solar Updraft Aeration System for Aquaculture

Challenges for aquaculture

  • Without aeration the oxygen content is low at low depths
  • Existing aeration systems are energy intensive and expensive

Goal

Increase aquaculture yields by 25% using a low cost aeration system to circulate oxygen to the depths of the pond for enhanced fish production.

Approach

Our design uses passive solar heating to circulate the water and thereby distribute the oxygen throughout the pond’s depth.

The design of the Solar Updraft Aeration (SUpA) has been validated using CFD studies and a bench-top prototype.

aeration-Schematic

Diagram showing design variables and boundary conditions for the SUpA system CFD model

 

aeration-CFD

Streamline plot for the chosen SUpA system dimensions

 

aeration-prototype

Bench-top proof-of-concept model

 

Field-visit

WERL members (left to right: Shakya, Ahmed, Prof. Bilton) visiting Vietnam to perform Field Tests on the solar aeration system (the test site is a pond near Hanoi, Vietnam)