Note From The Editor
Greetings,

With more than 25 years experience, K & M Shillingford is enjoying the environmentally conscious public catching on to what the Oklahoma-based company has known for quite sometime – that geothermal heat pump heating, ventilating and air conditioning (HVAC) systems are the way of the future. Their local business is booming with more and more customers following in the footsteps of friends, neighbors, and colleagues that have installed the energy-efficient, cost-saving HVAC systems.

“I’ve been waiting for this day for about 20 years,” said Tom Nowak, a longtime geothermal veteran at K & M Shillingford. “We’ve been waiting for the day that geothermal became popular enough to have a writer knocking on our door wanting to do a story on us.”

Having jumped headfirst into the geothermal movement decades before other companies has given K & M Shillingford the advantage of learning from tricky installations and other mistakes before other organizations. The years of experience have created an unmatched knowledge base.

The geothermal veterans have installed many different types of geothermal HVAC systems locally over the years – open and closed-loop systems, vertical- and horizontal-loop systems, and lake and pond systems. All the systems have one constant. Each system requires high-density polyethylene pipe (HDPE) and HDPE’s inherent qualities to securely transport groundwater or anti-freeze solution to perform the heat extraction critical to the process. HDPE is the pipe material of choice because of the flexibility to move with shifts in the ground, the wide range in operating temperatures, and the ability to resist corrosion from chemicals in the ground. The pipe doesn’t rust either.

The International Ground Source Heat Pump Association (www.igshpa.okstate.edu) is probably the best at explaining how the open and closed loop ground source heat pump systems work. “For closed loop systems, water or antifreeze solution is circulated through plastic pipes buried beneath the earth's surface,” the website states. “During the winter, the fluid collects heat from the earth and carries it through the system and into the building. During the summer, the system reverses itself to cool the building by pulling heat from the building, carrying it through the system and placing it in the ground. This process creates free hot water in the summer and delivers substantial hot-water savings in the winter. Open-loop systems operate on the same principle as closed-loop systems and can be installed where an adequate supply of suitable water is available and open discharge is feasible. Benefits similar to the closed-loop system are obtained.”

Regardless of which system K & M is installing, the pipe sections of the loop are joined through butt fusion. The butt fusion process starts by “facing” or shaving the pipe ends simultaneously so that they can be joined together with heat to create a continuous, sealed pipeline. The welding of the pipes is accomplished by using a hot plate in contact with the pipe ends, which heats the plastic to a molten state. Then, after its removal, the ends are pressed together under a controlled force to form a weld that is stronger than the pipe itself. K & M has the fusion process down to an art – doing most of their fusions indoors at their headquarters, with only one or two fuses required out in the field. Some of the McElroy fusion machines used include the PitBull No. 14, Sidewinder, and Socket Tooling equipment.

K & M’s Tulsa-area projects range from public schools to historical landmarks to apartment buildings to churches. All of the projects benefit from amazing savings. In fact, Nowak is proud of a recent project where a 40,000-square-foot warehouse put in an HVAC system and now has the utility bill of a 10,000-square-foot space. The constant business requires the employment of four crews that fuse pipe and install the systems as part of their everyday duties. During the time the company has been fusing pipe, they’ve relied on McElroy fusion equipment to make proper fusion joints.

Only a few city blocks separate the two Tulsa companies, and more than just fusion equipment has changed hands in the name of business over the years. McElroy founder Art McElroy was approached about a need for a more efficient polyethylene component in K & M’s vertical loop systems. McElroy told K & M to “give him a week, and he would have something.” A week later, McElroy presented them with the U-Bend cross connector. Today, polyethylene pipe manufacturers sell coiled rolls with modern preinstalled U-Bends that are much like the McElroy’s initial invention.
The component is critical in vertical closed-loop systems, where a pair of pipes are joined by the U-Bend and placed in the bottom of a drilled hole, approximately 250 to 500 feet deep, dependent on the characteristics and engineering of the job. Without the U-Bend cross connector, the pair of pipes would require more drilled space to house the thermoplastic pipe or a completely different technology altogether.

As K & M was benefitting from the U-Bend and McElroy fusion equipment, the business partnership became a two-way street, with K & M installing geothermal units on several buildings on the McElroy campus. The benefits of the geothermal heat pumps were tremendous and at one point, one of the McElroy buildings boasted the lowest cost to heat per square foot on the Public Service Company of Oklahoma’s grid.

Polyethylene as a Geothermal Solution

Sincerely,
Tyler Henning
thenning@mcelroy.com