The present study analyses the dynamics of distributed thermals. The buoyancy is injected into a quiescent water medium by perturbing the temperature field. Subsequent temperature and velocity field evolution is obtained through numerical simulations using the Boussinesq-Fourier model for incompressible water flow. It is observed that the system evolves from one form of thermal non-equilibrium state to another form of thermal non-equilibrium state. A thermodynamic analysis is also conducted to unveil the evolution dynamics of distributed thermals. The analysis uncovers a fundamental aspect postulated here as the "circulation shaft-work hypothesis." The swirling strengthbased quantification of circulations finds particular relevance in this hypothesis. Subsequently, the connection between the swirling strength and velocity fluctuations is unveiled, uncovering an inherent length scale that signifies the extent of the circulation regions. The present study believes that the thermodynamics-based analysis, taking swirling strength into account, can open up a new paradigm for understanding the evolution of thermals.