A renovated 20-yr.-old geothermal HVAC system in the Bottleworks Loft Condominiums building is providing efficient, high-quality indoor air for its residents.
By Jay Egg, Egg Geothermal
By the time construction started on the upgrades to the geothermal heating and cooling system at Bottleworks Loft Condominiums in Cedar Rapids, IA, the Bottleworks Owners Association (BOA) members had about four months left to finish the project before the sunset of the 30% Federal tax credits at the end of 2016. The Bottleworks Owner’s Association (BOA) had a hefty sum allocated to upgrading the historic mixed-use building, and they had every intention of meeting that deadline.
Listen to Editorial Director Gary Parr discuss the renovation at the Bottleworks Loft Condominiums with Jay Egg, president and founder of Egg Geothermal.
The Bottleworks Building, which is listed on the National Registry of Historic Places, started life as the Weaver Witwer Grocery warehouse and Life Beverage Bottleworks. In 1945, plans were unveiled to replace the Monroe Elementary School building, which had been converted to a warehouse some years earlier, for the Weaver Witwer Grocery Co. The “new” building was completed in 1946, and looks much the same today. A big draw to the building in those days was the soft-drink bottling process that took place on the street level of the warehouse. Wide-eyed kids and adults alike were drawn to the fast-paced action going on inside, watching bottles of soda brands such as Life Cola, Red Rock Cola, and the well-known Hires Root Beer fly by on the conveyors.
After Mr. Witwer retired in 1963, his grocery business ended and the Bottleworks building was used for various purposes, including warehousing of groceries for other companies. In 1996, Osada LP, a Cedar Rapids-based low-income apartment-management company, had obtained Federal backing to create 67 low-income apartments in the historic building.
Being a government-funded project, one of the required components was incorporating a highly efficient, long-lasting heating and cooling system. To keep maintenance to a minimum and energy efficiency at a maximum, the Osada project included installation of a distributed geothermal heat-pump system.
In early 2008, the building was targeted for another improvement. This upgrade eventually became known as the Bottleworks Loft Condominiums. Unfortunately, the upgrade was followed just a few months later by the massive 2008 Cedar Rapids flood. This event was the sixth costliest in FEMA history, flooding 10 sq. mi. of the city and displacing more than 18,000 people. Recovery was a slow and costly process for the river town’s residents.
Eventually, the floodwaters receded and, in 2009, Gail Handley was among the first dozen people to move into a Bottleworks condo. She became part of a transition group that moved the condo owners away from the developer and toward a homeowners-association management structure in 2012.
One of the dominant issues the new BOA (Bottleworks Owners Association) had to deal with was the now 20-yr.-old, failing geothermal-based HVAC system. Handley, then HOA president, sent me an email in May 2015, stating that she had concerns about geothermal-system maintenance, particularly a growing number of leaks in the system’s piping.
The system was designed with about 228 ton of heat-pump capacity from 94 geothermal heat pumps (GHPs). Driving the system is a vertical closed-loop geothermal source (loop-field design) located in the grass lot south of the building. The field consists of 150 boreholes, each of them 215 ft. deep.
I was contracted to evaluate the system and make recommendations about its future. What I learned was that the only part of the system that had a future was the geothermal loop system. It had been designed and installed properly, following IGSHPA (International Ground Source Heat Pump Association, Stillwater, OK, igshpa.org) standards and was, with one exception, in prime condition after 20 years and the massive flood. The problem was the mechanicals on the roof and inside the building.
The only problem in the loop field was that the fluid chemistry was not within specifications. That was a relatively easy fix.
Elsewhere, the system needed significant help. The steel piping was springing new leaks regularly; each time the culprit appeared to be rust and corrosion. Several of the common-area GHPs were out of order and/or in varying stages of disrepair. The 100% fresh-air system was all but non-functional, providing the airflow but none of the preconditioning (heating and cooling) needed for the building. All of these elements had an effect on one another in various ways.
The solution involved installing:
• a dedicated outdoor air system (DOAS) with exhaust recovery ventilation
• Aquatherm (Lindon, UT, aquatherm.com) piping to replace the failing steel pipe
• geothermal heat pumps for the common areas
• geothermal circulators with variable-frequency drives
• a control system to modulate the pumps.
The BOA board agreed to move forward with the proposal. Extensive due-diligence and negotiating efforts cut the original estimate in half and maximized Federal government and local utility rebates.
Replacing the DOAS was the first step. The Model ERCH unit, manufactured by Greenheck Fan Corp., Schofield, WI, was also fitted with hundreds of feet of ductwork to channel the conditioned exhaust air through its exhaust-recovery ventilation (ERV) feature. Brecke Mechanical Contractors, Cedar Rapids, IA, made quick work of the installation. Though the system was up and running in short order, adjustments will continue to be made to the DOAS—which monitors everything from outside air conditions to CO2 concentrations inside the building—to optimize its performance, energy efficiency, and air quality.
Once the equipment and supplies started arriving for the upgrades (pipe, GHPs, circulators, and controls), the work inside the building started. That was early September 2016, leaving slightly less than four months to replace most of the mechanical system in the building. Hundreds of thousands of dollars in tax credits were riding on the project being operational by December 31, 2016.
The first stage of the interior work was to replace the piping. Winter was coming and building downtime had to be managed to maintain occupant comfort. That function was handled by BOA president Ron Lower, who acted as on-site construction manager. Because the DOAS was operational at this point, it was possible to maintain temperature control to some degree, even while the common-area and individual condo GHPs were disconnected. Many common and private-unit GHPs were also replaced during this stage.
By November 10, most of the building’s 86 GHPs were on-line and leak checked. Pipe insulation, controls integration, and several other details became the focus. With the piping replaced, circulators and VFDs installed, and most of the GHPs in place, the upgraded building system was fundamentally operational. The next 40 days were spent adjusting and testing the system and its controls. The building-compliance audit was performed in mid-January 2017.
As the building goes through the first year of operation there will be plenty of opportunities to increase energy efficiency by adjusting the building-system controls. Except for the minor tweaks for energy efficiency, the building is ready to serve generations of Bottleworks owners without skipping a beat.
One of the residents answered with a resounding “Yes!” when asked if she would seek out a geothermal building again. Why? Because there was no need for outside equipment such as air-conditioning condensers or a cooling tower, no boiler, and no combustion heating, which means no on-site greenhouse-gas emissions. The only “noise” is from the super quiet GHPs that provide heating and cooling.
Jay Egg, president and founder of Egg Geothermal, Kissimmee, FL, is a consultant and designer of geothermal HVAC systems. In addition, he has authored two books and numerous articles on the subject. He can be reached at email@example.com.