Development of an ode model featuring a three level bleed control and an off-loading sequence for standing column wells

A 2D axisymmetric ODE model that couples heat transfer and groundwater flow in and around a stand-ing column well system was developed by the means of a thermal resistance and capacity network. In this work, the real transient behaviour of the groundwa-ter velocity field and well drawdown is considered by applying the spatial and temporal superposition of the so-called Theis equation, resulting from the time vary-ing bleed flow. The temperature field is obtained by integrating an ODE system. The heat pumps are in-tegrated in the model, thereby allowing the effect of its entering water temperature (EWT) on its capac-ity and coefficient of performance to be accounted for. A three level bleed control and an off-loading se-quence are included in the model. Results demonstrate that the ODE model developed in this paper shows good agreement with the reference solution and that both bleed and off-loading sequence played a key role in maintaining the EWT within a desired operational range. Combined with spatial and temporal superposi-tion techniques, this approach easily allows the evalu-ation of the thermal and hydraulic interaction of a field of several SCWs.