A Passive Solar-thermal Aeration System for Rural Pond Aquaculture

Dissolved oxygen is one of the most critical aspects of water quality in a fish culture system. For small-scale aquaculture farmers in resource-constrained communities, aeration systems -- which introduce oxygen to pond water -- are out of reach due to their high capital cost and lack of access to electricity. This thesis presents an alternative, passive, affordable, aerator concept to meet the needs of those farmers. Using a solar-thermal absorber and heat conductor, the device induces convective circulation in the pond, thereby producing an even dissolved oxygen distribution. In order to evaluate this concept, a tool to predict temperature and dissolved oxygen profiles in a water column was developed, along with CFD simulations of the device. Using results from those simulations, prototypes of the device were designed, constructed and tested in Vietnam and Bangladesh. Field trials of those prototypes showed a dissolved oxygen improvement of ~18% near the device.M.A.S