How an industrial facility reached its sustainability goals

In this case study, a hybrid HVAC system was used to achieve energy efficiency goals

By Chris McDaniel and Sven Peulen June 1, 2023
Courtesy: Jordan & Skala Engineers

While the architecture/engineering/construction industry is seeing both a significant and rapid shift toward fully electrified systems, there are still instances where electrified systems are not able to meet the unique needs of a project — but there are several hybrid and custom options that can both meet environmental and project goals if full electrification is not an option. As technology and local municipalities continue to shift toward full electrification, we expect to see more innovation and greater use cases for a fully electrified system.

Over the past 10 years, Jordan & Skala Engineers has worked with a leading international big box retailer to design customized hybrid rooftop units (RTUs) for massive industrial distribution and warehouse facilities, keeping in mind both the specific needs of the owner, as well as the overall impact on the environment.

This major retailer has large distribution centers across the globe, averaging about 5 million square feet per facility. With square footage this significant, it was imperative to the owner to maximize energy usage and use as least amount of energy as possible.

Intelligent thermostats “learn” from historical patterns and “remember” energy requirements from days and weeks prior, allowing the thermostat to adjust which times it runs to reach the desired temperature and deploy temperature setbacks during unoccupied hours. Courtesy: Jordan & Skala Engineers

In the instance of this owner, using fully electrified mechanical systems did not meet the retailer’s goals, therefore the design team worked diligently with their project team to design a custom variable refrigerant flow hybrid system that met their needs while still assisting with energy savings goals and efficiency.

It was imperative to the owner that their mechanical systems included energy recovery for outside air, specifically due to the outside air dampers — which was not possible using a fully electrified system.

The Jordan & Skala Engineers team worked with the owner and manufacturer to create a hybrid, custom system that included direct expansion cooling and heat pump heating for cold climates. When the facilities reached below a specific temperature, the system would switch to full heat pump mode, which was particularly helpful for locations in the north that reached freezing temperatures in the winter months.

At the time of the system’s design, it was cutting-edge technology and therefore, the very first of its kind. Jordan & Skala worked directly with the manufacturer to achieve the owner’s goals; this system is now being manufactured and is included as a part of the vendor’s standard available systems. As a part of the custom heating, ventilation and air conditioning (HVAC) system’s design, Jordan & Skala’s sustainability team ran energy models to calculate the exact energy consumption and  operational loads that each distribution center will be using (as the mechanical system requirements vary from project site to project site).

In addition to the actual design and type of the mechanical system, a robust controls strategy was also key to this retailer’s energy management and savings. As a part of this, learned controlling — with schedules to operate the heat pumps — was implemented into each of the packaged units.

For example, if the system stays on a bit longer than anticipated, it will trigger load shedding. The massive controls system is operated by service stats, meaning that each distribution facility has a remote building operation system, available for virtual adjustment and monitoring 24/7, across all 200+ project sites. This type of remote controls system can be thought of like the smart thermostats that are used in households throughout the U.S., where the device uses machine learning algorithms to determine energy usage peaks and dips.

Smart controls, such as the system implemented by this owner, assist with maintaining a specific custom temperature for employees within the distribution center, keeping the owner in compliance with the Occupational Safety and Health Administration regulations.

Author Bio: Chris McDaniel, PE, LEED AP, is a principal at Jordan & Skala Engineers, where he oversees all Washington, D.C.-area projects for the firm. He has more than 25 years of proficiency in mechanical engineering and project management, as well as 11 years of mechanical system installation experience. Sven Peulen, PE, LEED AP BD+C, is mechanical discipline leader at Jordan & Skala Engineers. He has been with the company for 12 years and has more than 17 years of mechanical engineering experience.