Refrigeration-veggies up close

Control System Strategies Save Money by Miguel L. Purdy, P.E.

How much do you spend each month or year to keep your perishables fresh?   From meats to dairy and frozen foods, to fresh produce and floral, it has been estimated to that between 30% and 50% of the electricity used in food retail is consumed by the refrigeration system.  Ambient conditions that differ from the original design and equipment selection conditions adversely affect the energy used in refrigeration.  Then, other inefficiencies creep in over time, such as dirty coils, burned up fan motors, etc., all the while driving up energy costs.  Systems that were put in as the state of the art systems a few years ago must be refined, tweaked, managed, updated and replaced on a regular basis because of newer, more efficient control schemes that were not available at the time of installation.

Reset First

What is the first step to improving your refrigeration system efficiency?  Well, it is not upgrading or replacing the control system.  The first step is system recommissioning.  Over time, with service calls and owners keeping the system in operation, your systems drift away from the original specifications and set points.  Recommissioning resets all of this and gives you some level ground to work from when looking at the controls system.

Establish Control Strategies

The next step is where monitor and control systems including energy management system come into play.  There are many new technologies that help automate refrigeration control, monitoring and maintenance scheduling.

Floating Suction Pressure Control

Adjusting and maintaining suction pressures allows the system pressure to float above established set points and maintain case or walk-in temperatures.  This is called Floating Suction Pressure Control (FSPC).  For each 1 PSI increase in suction pressure, it is possible to save 2% in compressor power.  The control systems read the systems temperatures and pressures then adjust the set points to ensure that the refrigerant leaving the coils reach the superheat design parameters.

Floating Head Pressure Control

An additional control strategy is reducing the compressor discharge pressure or head pressure.  This strategy is known as Floating Head Pressure Control (FHPC).  By allowing the control system to reduce the head pressure, the system could save as much as 0.5% per PSI reduction.  At least one study found 14% savings of combined compressor and condenser energy consumption for floating head pressure controls with variable frequency drives.

Load Shredding

Control systems do a great job of making the system operate more efficiently, but it can also perform other cost saving measures for your store.  This is where load shedding comes into play.  Suppose there are some functions that are not required to operate during a peak load time of day, such as anti-sweat door heaters, these loads can be turned off for that period of time.  That will not only save some energy, but more importantly, it will reduce the electrical consumption at higher rate times.  Control systems also can coordinate different aspects of the refrigeration system so some large loads do not operate at the same time, if possible, thus reducing the increased demand charges.

Unified Systems

Selecting the right energy management and control system can also unify other systems besides refrigeration, such as lighting and HVAC.  A unified energy management and control system allows the building HVAC management system and the refrigeration control system to work together to keep the systems from fighting over the temperature and humidity conditions in the space.  It can control the lighting within the store to conserve energy when spaces are unoccupied and when the store is closed, or there is less traffic.

Approach to Control System Upgrades

The key to a successful upgrade of any refrigeration system comes from a thorough, front-end engineered approach.  The methodology for the upgrade can be in the form of 1) a phased migration, 2) complete system replacement, or 3) a system upgrade. An important point to remember is that any new user interface must communicate with any existing controllers on a continuous basis.

A phased migration is often the best approach to large scale systems such as large grocery stores.  This approach eliminates risk of system failures or inoperable systems for any period of time, while providing a fallback position with the existing control system, should a failure occur.  While phased migration does have its drawbacks in terms of cost and time, the offsetting benefits include reduced risk and less downtime.

The approach of control system upgrades or complete replacement offers benefits which include: 1) increased asset protection, 2) increased reliability, 3) improved efficiency, 4) faster information access, 5) better interface functionality, 6) improved component communication, 7) reduced service and implementation costs, and 8) lower component costs over legacy systems.

Significant savings are possible

Some controls manufacturers have stated that controls systems can save at least 15% on the electric bill due to better capacity control, set point shifting, scheduling, load shedding and enterprise wide energy management.  The payback for such systems can be 1½ years through energy savings alone, not to mention the reduction in unplanned maintenance calls.

Could your facility use an extra $35,000[1] added to the bottom line each year?

One study found in one of the largest supermarket chains, a survey of 50 stores showed the majority had control systems but that the control strategies were not implemented correctly.   These misgivings provide an opportunity for savings of up to 335,000 kWh annually per site. This opportunity to save money was hidden because the building operators believed they already had the full benefits of controls.[2]

Control systems have come a long way over the last few years.  Is your system doing all that it can for you?  Are you missing out on significant operational savings due to your current control system, or maybe just from the control scheme?  A small investment could allow you to reap large paybacks to the bottom line.

The first step to improve your operational costs is to contract with a commissioning agent or firm to conduct a systems commissioning, then work with an experienced controls engineer to develop the controls system strategy that is configured to best serve your system needs.


Miguel Purdy, P.E. is a licensed mechanical Engineer who has over 25 years of refrigeration system engineering design expertise.  Miguel serves as the Program Manager for Refrigeration at HFA can be reached at or 479-273-7780.


1 Based on 335,000 kWh x $0.1045/kWh = $35,007.  National average electricity cost = $0.1045/kWh

[2] Supermarket Controls and Commissioning: Uncovering Hidden Opportunities, Diane Levin and Lawrence Paulsen, Portland Energy Conservation, Inc., 2006 ACEEE Summer Study on Energy Efficiency in Buildings.

Engineering a Meaningful Place

We sat down with A/E Firm HFA to ask about the importance of integrating engineering into a good architectural design.

Q: What is the role of engineering when designing a new space?

A: The architect creates the space with the needs of the client in mind, while it’s the challenge of the engineer to make the space functional, comfortable and safe. One of the engineer’s main goals is to design the most optimal use of the space.

“Successful design integrates architecture and engineering into a holistic space.”


Q: What’s the biggest advantage of HFA being an integrated A/E Firm?

A: Communication. The HFA design team all work in the communication to stimulate creative design solutions. Truly integrating an A/E firm is like designing a good space, you have to understand how the disciplines work together to create the holistic experience for the end-user. In this scenario, our clients are the end-user.


Q: How does that integration help in creating meaningful places?

A: Any designer can create a space, but great spaces happen when architects and engineers are working together to optimize it for the human experience. That’s the end goal of any project. Good space design is about the way it makes you feel when you experience it, and we want to create a meaningful place for all to enjoy!

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HFA Ranked Top 5 by Architectural Record

Arch Record List

Architectural Record has ranked HFA the 5th top design firm in the nation for the Retail Market.

As a full service architecture and engineering firm, HFA continues to be a leader in Retail Store design across the United States.


Designing for the Customer Experience

We were interviewed about the impact of design on retail. Here’s what we had to say:

Q: Retail brands work tireless hours defining their image, how do you encompass their image into the space you’re creating?

A: For us it’s about a deep connection with the client. We first try to understand their business philosophy. We want to know why they’re in business. Then we immerse ourselves into their brand, so we can become the customer. The goal is to design a space that works for the end-user — their customer.



Q: Creative Solutions, Meaningful Place.. What does that mean? And why did you choose it as your mission?

“The goal is to design a space that works for the end-user”

A: It means we aren’t just in business to design buildings. We want to create spaces that touch your heart and to experience the space in a meaningful way. We chose it because that’s how we want our team members to design and feel.

Q: Retail brands these days like to roll-out full remodels, how do you manage those projects?

A: The key is understanding the client and their customers. Once we fully understand their program, we use the techniques learned in our 25 years of retail to efficiently design every store, whether it’s 5 stores or 500.

View HFA website

Here’s the original article as published in Commercial Construction & Renovation Magazine:


HFA Architects and Engineers Celebrate 25 Years

Identifies 25 Ways to Impact the World Through Design


The architectural and engineering firm based in Bentonville, Arkansas reached a major milestone unachieved by most firms, 25 years in business. In recognition, the staff developed ideas of ways to impact the world through design.

Founded by architect Harrison French, the one person firm has grown to over 170 employees serving nationally recognized clients throughout the United States and is positioned to begin working internationally. The fully integrated, multi-disciplined firm has been recognized among the fastest growing firms for the past six years, by Zweig Group, a national architectural and engineering industry consulting firm.  Based upon the number of licensed professionals, HFA was recently recognized as the largest architectural and engineering firm in Arkansas. The growing Bentonville firm has an office in Houston, Texas and staff in Dallas, Texas.

“This anniversary would not have been possible without the hard work of a lot of talented professionals and great clients.” said Harrison French, AIA, Principal / CEO,  “I’m even more excited about our future as we continue to challenge ourselves and develop our skills even further.”

In celebration of their achievement, HFA hosted an event on May 7th in their newly renovated headquarters office which was transformed from a vacant home improvement retail store. The beautifully designed studio was awarded LEED CI Gold certification for its utilization of sustainable design and energy saving systems.

In recognition of their 25 year achievement, the HFA staff launched 25 Ways to Impact the World Through Design initiative.  This thought provoking initiative asked our staff members to identify a design idea that can be used in our daily lives and the impact that design can have upon the world.  There were 89 entries submitted by our staff of which the 25 where chosen by the staff to represent our 25 years in business.  At our May 7th anniversary celebration, the top three design ideas were selected by a vote of the attending guests.

“This has been a very fun design challenge and we were excited to see that there were so many innovative ideas created by our staff.   The design ideas really tell the story that our staff is not only very creative, but that they are truly caring people who really want to help the world become a better and more meaningful place to enjoy.” said Larry Lott, AIA, President and COO.

About HFA (Harrison French & Associates, LTD) is a multi-disciplinary design firm providing Architecture, Interior Design, MEP Engineering, Fire Protection, Structural Engineering, Civil Engineering, and Landscape design services to the retail, commercial and assisted living markets throughout the U.S. and holds professional licenses in all 50 states; and the District of Columbia. Please visit us at

Press Release: HFA named as the largest A/E Firm in Arkansas

BENTONVILLE, Ark. (Feb. 16, 2015) – HFA has been named as the largest A&E (Architecture and Engineering) firm in the state of Arkansas. The Northwest Arkansas Business Journal recently released a list ranking firms by the number of employees working in Arkansas. With 150 staff members in January 2015, HFA was the largest firm on the list.

Additionally, The Arkansas Business Journal recently released their list of the largest architectural and engineering firms in the state, ranking firms by the number of licensed architects and engineers working in Arkansas.  With sixteen licensed architects and fourteen licensed engineers, HFA was named the third largest architectural firm and the ninth largest engineering firm.

“We are excited by our recent growth as we continue to follow and further develop our strategic growth plan.  We are actively seeking more talented individuals to join our team, and have added ten staff members since the time of the ranking.” said Larry Lott, president/COO.

Overall, HFA has been the largest employer of A&E staff working in the state of Arkansas over the past three years.

Press Release: HFA Awarded an Arkansas American Planning Association Award

National Design Firm, HFA, was given an award by the City of Bentonville for the work HFA did for the 2004 Downtown Bentonville Master Plan.  The City of Bentonville received an Achievement in Plan Implementation award from the Arkansas Chapter of the American Planning Association and wanted to recognize HFA’s contribution to that project.  The award was presented to HFA on Tuesday, February 10, 2015 during the Bentonville City Council meeting.

APA Award

HFA’s work in the Downtown Bentonville Master Plan project consisted of an analysis of different building types that could be used as models for future development.  Renderings were produced that the city used to promote their vision of the urban fabric and scale of downtown Bentonville.  Since the master plan was implemented, Bentonville has seen successful private development occur that is consistent with the model developed.


HFA Headquarters Office Awarded LEED-CI Gold Certification.


HFA, a Bentonville based A/E design firm with a national reach was awarded LEED-CI Gold Certification on, December 17, 2014.

HFA took a former National Home Center building of 45,000 square feet and transformed the retail big-box space into an office of tomorrow. It’s a successful adaptive re-use. The office features an open layout for a collaborative work environment and new south exterior windows provide natural light into the studio space.


Some key points:

• The space was designed using energy-efficient lighting and HVAC, water efficient fixtures and landscaping, as well as eco-friendly materials and furnishings.

• The design team excelled in the Innovation In Design Category including Exemplary Performance Credits.

• Careful equipment and appliance selection eared a few extra points.

• HFA diverted 83% of our construction waste by separating and recycling or reusing on site.

Although the addition of the south exterior windows achieved 1 point in the certification process, the daylight and views it provides to an adjacent park are worth much more than that to employees. It’s created a great work environment.


Larry Lott, President & COO stated, “It has been a long road from the first day that we established one of our major design goals for our new office was to not only have an attractive office, but to seek LEED Silver as well. It was fantastic to hear that we not only achieved our original goal of Silver (which requires 50 points) but exceeded it with the approval of 65 points which put it over the required 60 points for LEED-CI (commercial interiors) Gold. It’s a credit to our staff’s abilities to fully utilize their sustainable design creativity and expertise resulting in a meaningful office environment for us to enjoy each day.”


HFA would like to thank all of our staff who contributed to the successful design for our winning project (from design, to construction, to operation, to applying for LEED certification); and also thank the contractors and product vendors on the project for contributing and exceeding their LEED requirements as well.

What Questions?

Chris Horton

By Chris Horton, Vice President & CFO

In my last article, I wrote about the integrated Architect/Engineer team and the benefits of finding and hiring the right one. This article will act as a guide for the questions you should be asking when performing your search.

The American Institute of Architects website ( has several suggestions of questions to ask during your interview of potential candidates. Working on an integrated A/E team comes with a set of unique challenges and opportunities that an engineer or architect would not necessarily face when only performing the tasks related to their discipline and then passing the project along. It is important to ask candidates about their experience with integrated projects as well as other kinds of teams they may have worked on. Design philosophy, who will be the main point of contact at a partner firm, and experience level are just a few of the factors that need to be taken into consideration, but these simple questions should help you narrow down your choices.

When evaluating consultant teams, which typically may contain many professional disciplines, it may be very difficult to tell if a team is truly integrated. This task takes asking a different set of questions all together. Teams are so often setup in silos and very seldom talk to each other face-to-face. Email has become the way of managing and is among the reasons that deadlines are not met, major misses occurs, etc. Ask the following:

How are their teams structured and how they share fees?

What about their philosophy on teamwork, do they sit together or is each discipline segregated?

What consultants do they use (you will usually have some outside consultants) and how they are integrated into the team?

Who will be attending any meetings with you?

It is very important that the key players are involved. If your consultant plans to send a single person, run away! One person cannot have the breadth and depth of knowledge you need to ensure you are getting the product you want.

So we have discussed what questions to ask, but what about you, the owner. What kind of things do you need to bring to the table? Well, you guessed it. That’s for another article!


ElOLC bannereven staff members from HFA made up five teams to create designs for submission in the Little Free Library Competition, a competition to design a buildable permanent installation to house 20 average sized books. The small libraries will be outside by a sidewalk, bike or walking path and must be designed to protect books from rain, high and low temperatures, wind and snow.

This project provides an opportunity to raise awareness about literacy and help more books reach more people, while raising funds for the Ozark Literacy Council (OLC).  OLC is a nonprofit organization that has been providing basic literacy and language services to adults in Northwest Arkansas for 50 years.

The design competition was presented by The OLC, Northwest Arkansas AIA, and the Fay Jones School of Architecture on August 22, 2014.

2nd Place, Pequena Biblioteca, Esteban Ayala and Matt Turner

2nd Place, Pequena Biblioteca, Esteban Ayala and Matt Turner

2nd Place, Pequena Biblioteca, Esteban Ayala and Matt Turner

2nd Place, Pequena Biblioteca, Esteban Ayala and Matt Turner

Jason Boze and Matt Turner, two young emerging leaders at HFA, took charge in organizing the design competition at HFA; from organizing the teams, reviewing final submissions, and setting up times for HFA teams and advisors to collaborate.

Along with Jason and Matt, Esteban Ayala, Steven Baker, Andy De Young, Daniel Gunn, Shay Hawkins, Stephanie Kohlberg, Erica Richter, Phillip Richter, Chet Savage, and Grace Smith all participated on teams and AIA professionals, Dave Wilgus, Lori Filbeck, Jeff Brust, Bo Ebbrecht, and Allen Hart, provided feedback and assistance.

“We were pleasantly surprised by the desire of our staff interested in participating.  This competition offers our staff an opportunity to engage in design outside our corporate client constraints and collaborate across departments.  It’s a great outlet,” said Dave Wilgus, Associate at HFA.

The sense of community, collaboration, and excitement for learning and designing shown on this project were great displays of the culture HFA has continued to develop since relocating to new headquarters in January, 2014.

3rd Place, The Book Shed, Daniel Gunn

3rd Place, The Book Shed, Daniel Gunn

3rd Place, The Book Shed, Daniel Gunn

3rd Place, The Book Shed, Daniel Gunn

All the entries exhibited the type of design thought and forward thinking HFA has come to rely upon from its team members.  HFA staff members, Esteban Ayala and Matt Turner won 2nd place with “Pequeña Bibliotecha” and Daniel Gunn won 3rd place with “The Book Shelf”.  The winners were selected at the 2014 Arkansas State AIA Convention on October 16th.

The Literacy Beacon, by Andy De Young, Stephanie Kohlberg and Grace Smith

The Literacy Beacon, by Andy De Young, Stephanie Kohlberg and Grace Smith

The Literacy Beacon

The Literacy Beacon, by Andy De Young, Stephanie Kohlberg and Grace Smith

Each library chosen for construction by a sponsor will be given $500 for building costs.  The sponsors can choose any submission to be built.  First, second and third place winners received a prize of $300, $200 and $100 respectively.

Detail about this community outreach literacy initiative and design project can be found at:

Plot Twist, Steven Baker and Shay Hawkins

Plot Twist, by Steven Baker and Shay Hawkins

Plot Twist, Steven Baker and Shay Hawkins

Plot Twist, by Steven Baker and Shay Hawkins

The Lantern, Erica Richter, Phillip Richter and Chet Savage

The Lantern, by Erica Richter, Phillip Richter and Chet Savage

The Lantern, Erica Richter, Phillip Richter and Chet Savage

The Lantern, by Erica Richter, Phillip Richter and Chet Savage