SVL News

Accubloc: Efficient Energy Recovery in Cold Climates

In this Coffee Break, we discuss how Innovent has reinvented the (enthalpy) wheel

Since enthalpy wheels were invented in the 1970s, they’ve become a standard energy recovery device in many HVAC systems. But for all their success, enthalpy wheels present problems as well. They require regular maintenance, are prone to lost capacity from frost control, and feature multiple moving parts and air seals.

In this Coffee Break, Dave Milligan and Jake Saewart from Innovent, a Minneapolis manufacturer of custom HVAC equipment, introduce us to Accubloc, an ultra-efficient heat exchange technology meant to improve on the deficiencies of enthalpy wheels.

How is Accubloc heat recovery technology different from an enthalpy wheel?

Innnovent AccublocAccubloc utilizes two banks of vertical heat exchange media. These are tightly packed aluminum sheets, up to 24” deep, available with or without a desiccant coating.

It looks like an enthalpy wheel but with a few key differences. The most evident is that the heat exchange media in Accubloc is fixed in place. A set of industrial-grade, fast-acting aluminum dampers control the airflow in and out of the device.

How does Accubloc transfer energy?

The heat exchange media is split in half with no airflow exchanged between the two sides. The outdoor air gains heat as it travels through the media, while the return air relinquishes its heat energy on the other side of the media before exiting as exhaust air.

After a 20-second charging interval, the dampers flip positions. Now, the outdoor airstream gains energy from the side of the heat exchange media that was charged by the return airstream during the previous interval.

Is there any cross-contamination of the two airstreams?

Innovent has verified that it is roughly the same as with an enthalpy wheel. The 2-3% of cross-contamination happens when the dampers are flipped, and the small amount of return air inside the exchange media is forced back into the supply airstream.

Accubloc is designed for applications that could utilize an enthalpy wheel for heat exchange. It is not intended for applications that require a flat-plate heat exchanger that guarantees no mixing of airstreams.

How does Accubloc perform?

Accubloc achieves 90-95% effectiveness in winter and 75-80% in summer with a desiccant coating. It can accomplish these efficiencies because of the physics of heat transfer. The device features a large surface area for heat transfer — 20” or 24” deep — and it’s given a comparatively long interval during which to transfer that energy.

The other significant advantage of Accubloc is that it can be run in cold climates with no preheating required. By continually reversing the airflows through the heat exchanger, there’s no chance for frost to build up on the media. The only time it becomes a problem is when ambient temperatures creep below -50 °F, frost can potentially start to build up on that side of the unit.

A secondary benefit of Accubloc is that it’s highly efficient at retaining moisture in a space. The relative humidity maintains itself. Any moisture from the return air will build up during the 20-second interval and be immediately introduced back into the supply airstream when the dampers reverse.

Contact Us


    Reason for Contacting

    Get in TouchBillingEventsTraining/SeminarLiterature/Graphics/LogosEngineering ProjectsOther

    Please prove you are human by selecting the car.

    This will close in 0 seconds

    Parts Inquiry


      Please prove you are human by selecting the truck.

      This will close in 0 seconds

      Equipment Inquiry


        Please prove you are human by selecting the flag.

        This will close in 0 seconds

        Shipping Date/IOM Manuals/Wiring Diagrams Request


          Please prove you are human by selecting the key.

          Please prove you are human by selecting the car.

          This will close in 0 seconds

          Question for Sales Engineers


            Please prove you are human by selecting the heart.

            This will close in 0 seconds

            Service Contact


              Please prove you are human by selecting the heart.

              This will close in 0 seconds

              Aftermarket Parts


                Please prove you are human by selecting the heart.

                This will close in 0 seconds

                General Job Application


                  Please prove you are human by selecting the cup.


                  This will close in 0 seconds

                  Hydronics Contact Form


                    Please prove you are human by selecting the flag.

                    This will close in 0 seconds

                    Viral Mitigation Contact Form


                      Please prove you are human by selecting the car.

                      This will close in 0 seconds

                      Jim Lubratt

                      President & Chief Executive Officer

                      Jim Lubratt has been president of SVL since 2006. He first joined the company as a sales engineer in 1992 and was made a partner in 2000. He holds a Bachelor of Science in mechanical engineering from Southern Methodist University and first entered the HVAC industry as a marketing engineer for a heat pump manufacturer in Texas.

                      In addition to his role at SVL, Jim is vice president of AQC Industries, LLC, a manufacturer of specialized underground ductwork systems. He is also an investor and board member for Hydromx, Inc., a manufacturer of heat transfer nanofluids, and Crotega, Inc., creators of personal and building security solutions.

                      Jim and his wife, Tracy, met in college and married in 1993. They have three children, two of whom have graduated college in Texas, while their youngest is attending Grand Canyon University in Arizona.

                      Outside of work, Jim places a priority on his faith, family, friends, and fitness. He enjoys helping people-supporting charities, time with his wife and kids, road-biking with friends and efforts to stay physically fit.

                      A message from Jim on the achievements of SVL

                      SVL started in February 1967 by Charlie Schwab and Craig Vollhaber. Schwab-Vollhaber, Inc. (as it was named at the time) steadily grew and, in 1985, welcomed Paul Lubratt as another partner, becoming Schwab-Vollhaber-Lubratt, Inc. SVL’s founders had the determination to build the most talented, customer-focused HVAC representative in the Midwest. Our original drive and passion still shape the company and culture to this day. The achievements of an organization are the results of the combined efforts of every individual. From humble beginnings, SVL founders paved the way to industry success with hard work and determination. “Today, SVL is strongly organized with great people to lead our industry forward as we are challenged with fast-paced changes to reduce our environmental impact,” says Jim. Now, 55+ years later, SVL is under the leadership of two new principals who share the same vision and drive that has propelled SVL throughout the years. Built on a foundation of integrity, Jim Lubratt, and Charlie Vollhaber strive to ensure opportunities for personal growth, improved work environment, and shared life enrichment. The achievements of our organization are the results of the combined efforts of every individual.

                      This will close in 0 seconds

                      Charlie Vollhaber

                      Executive Vice President & Officer

                      Charlie Vollhaber is a third-generation employee at SVL, as a grandson of company co-founder Craig Vollhaber and son of former CEO Todd Vollhaber. Charlie holds a Bachelor of Science in mechanical engineering and an MBA, both from the University of Minnesota. He became an outside salesman for SVL in 2013, was made a partner in 2019, and then executive vice president and officer in 2022.

                      He grew up playing sports, including football, basketball, golf, and track, and enjoys the competitive nature of the HVAC industry. “I like that no two days are ever the same as there are always questions to answer and problems to solve,” he says. “Most of all, I enjoy working with great people and coordinating together on challenging projects to achieve positive results together.”

                      Outside of work, Charlie enjoys spending time with his wife, Lesley, and their three boys. He’s also fond of golfing, traveling, and attending concerts and sporting events. One of his favorite quotes is from the book of Philippians: “Do nothing from selfish ambition or conceit, but in humility count other more significant than yourselves. Let each of you look not only to his own interests, but also to the interests of others.” Because HVAC and construction is such a team effort, he says, “this mindset helps to create positive results in a vast majority of situations.”

                      A message from Charlie on the culture of SVL

                      “At SVL, we strive to cultivate a unique culture that revolves around finding and empowering exceptional individuals. We believe in equipping our team members with the right tools and resources to succeed.

                      As we’ve grown the business, we have deliberately maintained a small firm culture, fostering an environment where collaboration thrives. We encourage open dialogue and promote a sense of comfort among our employees, allowing anyone to ask questions and seek guidance from anyone else, regardless of their level within the organization.

                      We foster a workshop-like atmosphere where everyone’s contribution is valued. Presenting your work to another individual or a group of teammates provides a platform for collaboration, where ideas are shared, dissected, and improved collectively. We firmly believe in the power of mentoring and provide various avenues for both formal and informal guidance. Whether it’s through structured training programs or casual conversations, we encourage team members to discuss a wide range of topics, from work-related successes or issues to everyday personal life topics.

                      In summary, our culture is built on the foundation of attracting exceptional individuals, empowering them with the necessary tools, and fostering a collaborative environment where mentorship and growth thrive. We are committed to creating an atmosphere where every team member feels supported, valued, and encouraged to reach their fullest potential.”

                      This will close in 0 seconds

                      Al Gramse

                      Vice President of SVL Service Corporation

                      Al Gramse has been in the HVAC industry for over 30 years. He began as a service technician.  Then over his career worked in technical support, building automation, then service manager prior to his current role.

                      How did Al end up in the HVAC industry?  “After high school, I took a couple years to figure out what I wanted to do.   Where I was working at the time, a grumpy old coworker, who I didn’t get along with, walked up to me and said ‘What are you doing here?  Go back to school.’”  I said, “For what?”  He said “There’s a tech school down the street.  Go down there and pick something that interests you”. Then he walked away.  That weird interaction, with someone I didn’t get along with, sent me down a 30-year path in the HVAC industry.   Never underestimate the potential of a little encouragement.   Even if it is from a strange source.

                      Al has been with SVL for 15 years and is the head of our SVL Service division. “The people here are some of the best in the industry,” Al says. “A bunch of team-oriented, knowledgeable, go-getters.” His personal mantra is “figure it out,” “Do a little fact-finding on your own. Use your own brain before you use someone else’s. But know when to ask for help.” he prescribes. “It’s amazing what you can accomplish on your own if you dig in a little bit.”

                      Outside of work, Al has lots of outdoor hobbies, including hunting, fishing, and motorcycling, though his favorite pastime is simply hanging out with family.

                      This will close in 0 seconds

                      Jennifer Roach

                      Director of Marketing, Events & Administration

                      More than just a creative director, Jen brings 30 years of marketing and leadership magic to SVL. Her journey began in the trenches of graphic design, quickly evolving into crafting eye-catching campaigns for iconic brands like Target, Gabberts, Gander Mountain and Camping World. As a seasoned director and agency veteran, she honed her skills with recreational vehicle giant Parts Unlimited before leading creative teams at HOM Furniture and, ultimately, landing at SVL during a crucial growth phase.

                      Jen thrives on "servant-leadership," empowering her team and fostering a culture of trust and mutual respect. "It unlocks their potential, fuels creativity, and leads to work we're all proud of," she says. "I want my team to care, collaborate, and push boundaries together."

                      When not shaping impactful campaigns, Jen enjoys weekend adventures with her husband, Scott, and son, Crew. Their lives are a tapestry of shared passions, from bike rides and baking experiments to cheering on Simley High School wrestlers. And with her recently built forever home in Cottage Grove, her free time now includes a new, thrilling chapter: weekend renovation warrior!

                      This will close in 0 seconds

                      Mike Ruff

                      Vice President of Information Technology

                      Mike Ruff, th