Ground loop (electricity)

Abstract: The ability to predict both the long-term and short-term behavior of ground loop heat exchangers is critical to the design and energy analysis of ground source heat pump systems. A numerical model for the simulation of transient heat transfer in vertical ground loop heat exchangers is presented. The model is based on a two-dimensional fully implicit finite volume formulation. Numerical grids have been generated for different pipe sizes, shank spacing and borehole sizes using an automated parametric grid generation algorithm. The numerical method and grid generation techniques have been validated against an analytical model. The model has been developed with two main purposes in mind. The first application is used in a parameter estimation technique used to find the borehole thermal properties from short time scale test data. The second application is the calculation of nondimensional temperature response factors for short time scales that can be used in annual energy simulation.

Abstract: Source line bias is an error introduced by a non-zero resistance in the ground loop of the read/write circuits. During sensing the control gate voltage of a memory cell is erroneously biased by a voltage drop across the resistance. This error is minimized when the current flowing though the ground loop is reduced. A method for reducing source line bias is accomplished by read/write circuits with features and techniques for multi-pass sensing. When a page of memory cells are being sensed in parallel, each pass helps to identify and shut down the memory cells with conduction current higher than a given demarcation current value. In this way, sensing in subsequent passes will be less affected by source line bias since the total amount of current flow is significantly reduced by eliminating contributions from the higher current cells.

Abstract: In this paper, five inductive couplings that exist in filters are analyzed using theory and experiments. Based on this analysis, methods for improving filter performance are described. The resonance in the system ground loop is then identified and analyzed; its effects are discussed and methods for its reduction are proposed. Finally, the inductive coupling between the common mode (CM) filter output loop and the converters is pointed out, and its effects are evaluated by analysis and experiments.

Abstract: A loop-type ground antenna formed by connecting a capacitor between two ground points is described. The resonant frequency of the ground loop is conveniently controlled by changing the capacitance. The proposed loop-type radiator is excited by conventional shorting line loop feeding that may include an inductor. A loop type ground antenna is designed for Bluetooth and Wi-Fi applications.