Armstrong Fluid Technology has launched an automated control solution designed to drive additional energy savings from chiller plant.
Interfacing seamlessly with the existing building automation system, the Armstrong Opti-Visor controls the key energy-using components of the chiller plant, providing the optimal operating settings for equipment such as water-cooled, variable-flow chillers, compressors, cooling towers and condenser water pumps.
By controlling the chiller plant ‘holistically’, Opti-Visor harnesses valuable energy savings - even where equipment is recently installed. Armstrong Fluid Technology estimates that energy savings of between 15% and 30% can be expected from the chiller plant, meaning a payback period of less than a year. The first live installation of Opti-Visor in the UK, however, provided immediate savings of 42% , indicating that, depending on the application, the potential benefits could be even higher than the company’s quoted estimates.
Armstrong Opti-Visor is an ultra-efficient relational control solution for operation of all-variable-speed chiller plant. It is ideal for retrofit in buildings with chiller plant less than five years old, but is also suitable for new construction applications involving variable primary flow chiller plants and advanced building automation systems (BAS). It is ideal for chiller plants with greater than 3 million ton-hrs of operation per year (1,000 tons at 3,000 run hours per year).
Opti-Visor is connected to the BAS/BMS through the BMS communication. Here it learns about building conditions, building load and plant conditions from the BMS data. Using its advanced patented control methodology (Hartman Loop) it then integrates the variable speed devices to optimize energy efficiency, determining the optimal operating parameters. This information is communicated back to the BMS for the BMS plant automation module to implement.
The Opti-Visor control technique can improve the annual average power consumption rate to better than 0.5 kW per ton, or COP greater than 7.0. This is made possible because the Hartman Loop technology of the Opti-Visor maximises the variable speed potential of the site’s chiller equipment. The majority of chiller plants use technology developed during the analogue era, and operate using three independent control loops with PID feedback control. In contrast, the Hartman Loop technology is a digital era technology that operates the plant as one integrated solution. This digital approach enables faster response, better stability, the introduction of VFDs on the CW pump, the optimization of thermodynamic effects at the equipment level, and lower risk of equipment failure through cycling stress. Compared to typical BMS offerings, the Opti-Visor provides more in-depth analysis and tuning of the plant s operations. It monitors and adjusts component operation to achieve peak efficiency and also adjusts for changes as individual components age.
The Opti-Visor offers touchscreen control and intuitive menus for easy operation and review of key performance and systems indicators including:
User access is also available through web-enabled control and performance monitoring.
- BMS / BAS compliance
- Plant performance (YTD, 30 day, actual)
- Plant status
- BMS communication
- Chilled water plant schematic with equipment status
- Plant operating load (capacity and kW)
- 30 day plant performance trend charts (efficiency, load, and chiller efficiency)
- Alarm history screen
- Default screen showing; plant efficiency, plant efficiency chart, CHWST, ECWT
- Component efficiency levels (pumps, fans)
Opti-Visor offers ‘plug and play installation’, requiring only minor modification to the existing BAS plant automation module to ensure that the BAS recognizes the control signals from the Opti-Visor and will make available the input data points necessary. The Opti-Visor ‘bolts on’ to the existing chiller plant, simply requiring a VFD on each condenser water pump, a new serial communication connection to the condenser pump VFDs, and a new power cable from the MCC to the condenser water pump VFD and the the VFD to the pump. It requires no maintenance.
Picture: Armstrong OPTI-VISORTM (Image: Armstrong Fluid Technology)