Smart Building Blog

Do you have several rooftop units (RTUs) with nothing more than a thermostat to control them? 75F provides a simple way to get remote control and group your RTUs at a lower cost. Imagine having the capabilities of a building automation system at the cost of a WiFi thermostat. 

Retrofit existing or spec new build rooftop units with 75F to increase energy efficiency and enjoy remote control and diagnostics at a fraction of the competition. Advanced economizer controls, including Demand Control Ventilation (DCV) and comparative enthalpy economy, from 75F improve efficiency by up to 30%, while improving occupant comfort and indoor air quality. An easy installation and a lower cost, as well as payback in as little as one year, makes this an easy decision.

An HVAC system that incorporates variable frequency drive (VFD) with scheduling control can deliver significant energy savings, especially when deployed at scale along with a building intelligence solution offering predictive and proactive controls for incremental adjustments for variable loads.

In many states and cities, VFDs are required by building code on rooftop units (RTU) and air handling units (AHU) of nine tons or greater. HVAC systems are designed to cater to the peak design load of a building. However, most of the days the building experiences partial loads, either because of milder weather or lower than maximum occupancy load. VFDs offer higher efficiency during partial HVAC load scenarios. VFDs also help reduce inrush current at startup, plus lowered mechanical stress.

In AHU's with variable loading capacities, the 75F CCU will continuously adjust both the chilled water supply as well as fan speed to accommodate the building load. Such equipment can take advantage of the small granular control in capacity between 0-100% that the 75F system can offer.  

However, 75F is often deployed with simpler HVAC equipment with only 1 or 2-stages of cooling or heating. In such a case, we follow an approach that modulates the fan speed based on 3 primary positions for 2-stage RTUs.