What Facility Managers Need to Know About Load Shifting - Part 2

by Phoenix Energy Technologies on Oct 28, 2019

Buildings heat up excessively when their occupied and unoccupied summer setpoints are set too high, beyond 70-74 degrees Fahrenheit occupied, 74-78 (max) unoccupied. Usually setpoints are set too high because the building manager is trying to save energy. Typically, they set the thermostat to a higher temperature for cooling, such that the system is generally off during these periods.

In Part 1 of this blog series, we explained why this isn't a good idea.

To truly save energy, building managers should understand Adaptive Energy Management (AEM) and how they can use their buildings' thermal mass as a "battery" to store cold energy during the night. This concept is referred to as BaaB — "Building as a Battery."

BaaB_with_border-1 BaaB works best for buildings made from concrete and metal because these materials are great for absorbing and storing heat (or cooling) energy. If your building or facility is made from wood, BaaB won't work as well because wood is an insulator and terrible at absorbing heat energy.

By using AEM, not only do building managers save on energy costs, but they also reduce the wear and tear on their HVAC equipment. This is a result of efficiently changing the working duty cycle of the RTUs (rooftop air conditioning units).

How Does AEM Reduce Wear and Tear on Your Cooling System?

HVAC_system When facility managers allow a building to overheat during the night when the building is unoccupied, cooling systems struggle the next day.

The building cannot compensate for the build-up of heat as it is now in the position of trying to cool hot air coming in from the surroundings AND contend with the stored heat from the night before.

As such, the system struggles to do three things simultaneously:

Cool the air coming from the RTU to achieve the occupied setpoint
Reduce the heat stored in the building's thermal mass
Combat the new heat that is generated when the sun's radiant energy hits the building.

Adaptive Energy Management - How to Use Your Buildings as a Battery

Increased Efficiency

rtu_unit When the HVAC system has to run as described above, it places great stress on the unit.

It causes the system to:

Increase energy usage during the day, when costs and demand have peaked
Increase wear and tear on the actual unit
Increase the frequency of maintenance
Increase instances of unexpected downtime and repairs

None of the above saves energy. None of the above saves money. All of this is the exact opposite of what the building manager was trying to achieve.

AEM_infographic_2

By applying the principles of load shifting and "Building as a Battery," facility managers can help their buildings assume a cooler profile at night. This reduced energy costs while gaining some benefit from "free" outside air cooling. Controlling load shifting allows managers to invest the stored energy into the day-time operations. This results in enhanced comfort and stability for building occupants, less load on the cooling systems, and improved energy savings.

How Does AEM Increase Your Building's Energy-efficiency?

Implementing AEM requires building managers to measure the thermal mass of their buildings continually.

This allows them to:

Determine the impact of the heat from the sun's radiant energy on the outside of the building
Determine the amount of air flowing into the RTU
Assess the temperature needs of the building during unoccupied and occupied periods
Intelligently set, monitor, and adjust the setpoints as all these needs and factors fluctuate

Saving money and energy through AEM would be a somewhat impossible task without a way to effectively measure the above.

The best way to measure is by using a smart building system. The right system allows managers to:

Pairs actionable data with real-time predictive data
Monitoring assets and building analytics
Reduce capital equipment and energy costs

Introducing EnterpriseDX® Energy Management Software

Through real-time measurement of contextual data (such as weather, occupancy, and schedules) as well as verification of energy use and related costs, PhoenixET's EnterpriseDX® Smart Building Platform controls, monitors and manages millions of data points from HVAC systems and IoT devices in your building to help maximize comfort and savings.

One of the most valuable IoT energy management platforms, EDX improves occupants' comfort, reduces energy consumption, and optimizes building performance by automatically sending remote signals to various parts of your building to optimize temperature within your defined parameters.

EDX helps achieve AEM by applying the principle of load shifting and measuring your building's thermal mass to intelligently adjust your setpoints to achieve maximum comfort and energy savings.