Large-scale HVAC & Refrigeration
Several patent and accident investigations have been conducted in the field of Heating Ventilation and Air Conditioning (HVAC), and also in the closely related field of mechanical refrigeration. These control systems are used to regulate refrigerant compressors, air handlers, and auxiliary equipment used for air conditioning, refrigeration, and freezer applications.
The installations have ranged from HVAC systems on large buildings to turbine generator air inlet coolers having condensers the size of a football field. The control systems relate to HVAC load demand as well as equipment optimization to reduce electrical consumption. They are implemented with stand-alone controllers, industrial computers, and PLC-based control systems.
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Product Performance: a control system anomaly resulted in a ruptured heat exchanger water line in a large scale refrigeration system. The industrial process cooled turbine inlet air a power plant. The resulting mixture of ammonia and water in the closed loop system damaged large sections of the copper cooling coils.
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Patents: several patents for HVAC and refrigeration system control based on the "Hartman Loop" and other energy optimization technologies. These patents involved several varieties of single loop and bypass chilled water loops. The HVAC optimization was based on the "natural curve" and other techniques using variable speed motors driven by variable frequency drives (VDF). The systems optimize cooling while minimizing electrical costs for individual subsystems as well as the overall HVAC system.
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The optimization affected the chilled water loop(s), compressor loading, condenser water loop, and cooling tower fan control. The systems can be installed as add-on optimizers that interact with existing building automation systems (BAS) using Modbus and other protocols. The systems can also be installed as complete stand-alone systems that include the optimization processor, variable frequency drives, pumps and motors, and the various system sensors required to perform optimized control.
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