The Digi-RTU® is an innovative add-on control to improve the energy efficiency of DX rooftop units (RTUs).
By intercepting heating and cooling calls, this unique control varies the speed of the fan and compressor to match loads while maintaining space conditions.
The Digi-RTU® technology is approved for energy efficiency incentives in Connecticut by both Eversource and the United Illuminating Company; in Massachusetts by Eversource, National Grid, Cape Light Compact; and in Rhode Island by National Grid.
In 2011, the American Public Power Association selected the Digi-RTU® for their DEEDS Energy Innovator Award.
What The Digi-RTU® Does
Controls supply fan speed (VAV)
Controls compressor speed and capacity (VRF)
Integrates air-side economizers
Manages Demand Controlled Ventilation (DCV)
Enables Demand Response signals
Communicates with Building Management Systems or Thermostats
Enables remote monitoring and control
Enables fault detection and diagnostics (FDD)
Digi-RTU® Case Studies
Digi-RTU® controls have been installed throughout the country with outstanding results. Click on the titles below to see larger images.
The Digi-RTU® control can be applied to various mechanical systems, including:
Packaged Rooftop Units (RTUs)
Water and Air Source Heat Pumps
RTUs from 4 to 50 Tons
Up to 4 stages of cooling and 2 stages of heating
Scroll and reciprocating compressors
Any OEM RTUs
Any BMS or thermostat interfaces
Other Digi Products
Digi-Sft is the software platform that owners use to remotely communicate with Digi-RTUs®. The Digi-Sft package enables users to access all data available from their Digi-RTUs.
Using a gateway, the Digi-Sft program can communicate through any BACnet or Modbus system, including our Smart Building Manager (SBM).
Digi-ACC® is a variable speed controller for air-cooled chillers. It controls chiller and compressor sequencing, compressor speed, pump staging and speed, and resets the chilled water setpoint based on measured building load.
The Digi-ACC® can reduce chiller energy consumption by 10% to 40%, pump energy by 30% to 70%, and can reduce peak demand.
Digi-CRAC® is similar to the Digi-RTU but is specifically designed to control computer room air conditioners (CRACs). It is equipped with an automatic emergency bypass to restore original operation and offers an open communication interface for centralized monitoring and control.
The Digi-CRAC® improves energy efficiency by 30% to 60%, reduces peak demand up to 50%, enables fan power savings up to 60%, and is available for demand response applications.
The Digi-SBM® is a dedicated front end for the Digi-Sft communication software. In addition to providing access to all of the connected Digi-RTU modules the SBM provides additional diagnostics and system-level metrics for the end user.
Digi-VAV® is a controller for VAV boxes on any air handling system. It measures the "freshness" of the supply air andresets the minimum airflow of each box, controls the minimum OA at the unit, and resets the system static pressure.
The Digi-VAV® can decrease heating energy by 30% to 90%, cooling energy by 10% to 25%, and fan energy by 30% to 50%.
Digi-VFS® is a fan and pump flow station for our virtual Digi fan and pump controllers.
Our virtual meters calculate accurate fan and pump flow and efficiency and do not require the usual straight duct or pipe for installation. The Digi fan controller dynamically resets the static pressure based on actual load. The Digi pump controller dynamically resets the system loop pressure based on load and optimizes pump staging in multi-pump applications.
Want to Know More?
If you would like to know more about the Digi-RTU® or any of our other energy saving products, please contact us.