Technologies

The technologies that comprise the installation package include a novel supervisory controller to provide systemwide optimization and reduce electricity consumption across numerous building subsystems, including lighting, refrigeration and heating, ventilation and air-conditioning (HVAC). This will enable site electricity savings of >20%.

 

Internet-of-things (IoT) platform

All energy efficiency upgrades and technologies will be tied back to Locbit’s cloud-based control system accessible through authorized local, remote and mobile devices. The control system will monitor all connected building systems and detect energy waste, equipment malfunctions and other operational problems using a fault detection and diagnostics engine.

 

Lighting upgrade

The store’s existing fluorescent lighting fixtures will be retrofitted to DC-ready light-emitting diodes (LEDs) manufactured by i2 Systems. This lighting product uses a hybrid approach with an LED driver that automatically detects whether incoming power is 277 VAC or 380 VDC and switches to drive the LED based on the incoming current. This approach allows for a retrofit solution that can be broadly implemented with minimal changes to existing electrical distribution wiring in Walmart’s stores, while maintaining future compatibility with DC based electrical distribution systems that could be installed with Solar PV and/or Energy Storage Systems. Additionally, since LEDs are solid state light sources, they are resistant to vibration and offer significantly longer operating lifetimes than most other sources. Fixtures and retrofit kits will be carefully chosen with high color rendering index values for better color consistency and with efficient diffused lenses for reduced glare. The lighting upgrades will also improve visual acuity by providing higher perceived brightness throughout the space.

 

HVAC and refrigeration smart motor system

Turntide’s Smart Motor System will replace the existing supply fan motors across 28 rooftop units. Additionally, the six refrigeration condensers serving the medium and low-temperature refrigeration systems will be retrofitted with 24 smart motors. Beyond the energy savings from the smart motors’ high-efficiency operation, a control platform will enable variable speed operation for both the HVAC and refrigeration applications, as well as an improved HVAC economizer strategy to provide additional energy savings. It will also provide remote oversight for each motor's operation as well as the surrounding systems, enabling fault detection and diagnostics. Third-party field studies have shown the Smart Motor System can reduce annual HVAC energy usage by 50-57% for rooftop units1 and annual refrigeration condenser fan energy usage by 71% when the smart motor replaces the existing floating head pressure control with variable head pressure control2.

 

Direct and indirect evaporative cooling

Using a combination of direct-evaporative cooling to treat roof-top-unit (RTU) condenser inlet air and indirect evaporative cooling to treat incoming outdoor air, Integrated Comfort's DualCool system will reduce RTU compressor electricity use by approximately 20%. The precommercial aspect of this study is the integration with both a whole-building level controller and specifically for DualCool, use of SAYA's water management system to optimize the tradeoffs between increased water use and reductions in electricity consumption.

 

Water management system

By providing continuous commissioning and process optimization, not only will SAYA's system lead to reduced site water consumption, but by integrating their system with the DualCool unit and OptiNergy platform, SAYA will demonstrate the ability to assess and optimize the amount of water used by the DualCool system and ensure reliable operation of the evaporative cooling components.

 
  1. Southern California Edison, "Software-Controlled Switch Reluctance Motors", Emerging Technologies Coordinating Council, 2018.

  2. Wheeler, G., & Deru, M. "Direct Comparison of High Rotor Pole Switched Reluctance Motors as Condenser Fans in a Commercial Refrigeration System".