The only change is that the school will be saving an estimated $52,000 a year on the North Building’s heating, ventilation and cooling (HVAC) system according to local newspaper reports.
Over the summer, St. Clair Community College has been installing a horizontal geothermal field under an existing parking lot near the North Building.
A geothermal or ground source heat pump system uses the Earth as a heat source in cooler months or as a heat sink in warm weather. The systems use the Earth’s ability to maintain a fairly constant temperature under the surface to fuel a system that operates much more efficiently than traditional HVAC systems.
The loops under the ground extract heat from the ground when needed. When outdoor temperatures rise and it’s time to crank up the air conditioner, the system extracts heat from the building and distributes it to the ground.
In a closed loop horizontal system, like that of St. Clair County Community College, a slinky (or coiled) loop field has hundreds or thousands of feet of pipe that overlay each other. The loops are laid out along the bottom of open trenches and are connected to each other through headers. In a closed system, water is mixed with antifreeze and then circulated. The antifreeze and water mixture circulates through the internal heat exchanger and the loops underneath the ground.
Because the systems need to last a long time and be leak free, the best solution for geothermal loop systems is high-density polyethylene (HPDE) pipe. Most geothermal systems of this nature are rated for a 50-year service life.
The more than 30 miles of piping needed for St. Clair’s geothermal project gave McElroy distributor Etna Supply an opportunity to service the customer with in-house fabrication and an arsenal of fusion machine options.
One of the main tools used on site was the new Socket Tooling Kit, designed for common geothermal piping sizes. Watson Brothers, a local contractor hired for the geothermal installation, ordered the Socket Tooling Kit to replace another socket fusion system that only allowed the heater to warm to a predetermined temperature. The new Socket Tooling Kits feature the MultiMc™ Heater with microprocessor control and a dial thermometer to monitor the heater temperature. Also included in the Socket Tooling Kits are heater adapters and tools specific to often used pipe size ranges. All of the components fit in a custom-designed toolbox.
“Our guys like having the ability to dictate what the temperature of the heater is,” said David Dahnke, project manager for Watson Brothers. “The other socket tooling equipment didn’t afford us that luxury.”
Within the depths of the open parking lot, the socket tooling is used to connect the large 1-inch IPS coils to 4-inch headers. The headers used along the sides of the loop fields were fabricated at Etna Supply’s shop in Wixom, Michigan by McElroy Master Mechanic Troy Taylor.
Taylor spent plenty of time with a McElroy Sidewinder, fusing 198 4-by-1-inch and 240 3-by-1-inch sidewall tees for the job. The tees were fused onto the headers and trucked to the site throughout the construction process. Taylor even took time to show his productivity through a time-lapse video.
Online viral videos played a role on the project, with Taylor directing Watson Brothers’ fabricators to a video showing the best way to package the 1-inch pipe coils for delivery on the site, saving immense amounts of time. The coils were unwrapped from their initial shipping form by Watson Brothers, and then rerounded on a plywood board with markings at a given distance. The markings worked as a guideline for the overlaps within the coil, so that when rolled out on site, the coil would be uniform and organized up and down the line. Once zip-tied into form, the coils roll up into balls that fit six to a truck. On site, the coiled pipe is easily unrolled in place and then fused into the system.
