Commercial Architecture April 2017 - 19

FEATURE

geothermal hvac

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, obtained Federal backing to create 67 low-income apartments in the historic
building.
Being a government-funded project, one of the requirements was to incorporate 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 had to deal with was the now
20-yr.-old, failing geothermal-based HVAC system. Handley, then BOA
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.
WHAT HAPPENED?

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-func-

Top. The residence of former BOA president Gail Handley features a bottle-cap theme in
keeping with the building's history.
Middle. The lobby and common areas on each of the five floors are served by 14 geothermal
heat pumps.
Right. The ceiling height of second-floor condominiums is high enough to allow those
owners to have second-story loft spaces. This residence is a corner unit.

commercialarchitecturemagazine.com

APRIL 2017

COMMERCI A L A RCHI T EC T URE

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Table of Contents for the Digital Edition of Commercial Architecture April 2017