Geothermal HVAC Monitoring System with Single Wire

The concept of this single wire geothermal HVAC monitoring system revolves around the use of a single pair of wires that can be used to transmit power and data between a set of cooperating network components.

Installing a bunch of analog temperature sensors is the conventional monitoring approach which are wired to individual analog-input channels on a centralized or distributed, PC-based monitoring system. The 1-wire is achieved by utilizing low-power devices that can extract enough power from the data-line during the “1” state of the line. An inexpensive serial port adapter plugged into the PC is used to read the temperature sensors.

Initially, the temporary monitoring and logging station was built which is an old Windows PC running the HVAC program. The program is built using the Active Control Suite (ACS) software written for controlling underwater Remotely Operated Vehicles (ROVs). The PC logs all the system values into a text file once a minute which can be imported into Excel for analysis.

The original PC screen shot shows the local live display where the geothermal ground loop is shown by the graphic as well as the domestic hot water circuit, etc.

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