Thursday, March 21, 2019

Carroll Saves Money Using Geothermal Heating and Cooling Systems

When voters passed the $208 million dollar bond in May 2017, one of the items included in the proposition was a new geothermal heating and cooling system for Old Union Elementary, Johnson Elementary and Carroll Elementary. Work on these facilities began early in the 2018-2019 school year and continues currently with a projected completion of August 2019. The new Carroll ISD Music Center will also feature a geothermal system when construction begins later this spring.

Geothermal Diagram

Before the Bond election was called, Carroll ISD formed a Capital Needs Planning Committee (CNPC) to research the needs of the district moving forward. One of the major goals of the CNPC was to research ways to create solutions that move operational expenses to debt service in an effort to avoid paying a premium under the school finance system nicknamed “Robin Hood.” The installation of geothermal systems on campuses is one of the projects that will help with this specific goal.

As part of the 2009 Bond Program, CISD installed geothermal systems at Carroll Middle School and Walnut Grove Elementary School. The savings, according to school officials, have been remarkable.

A geothermal heat pump (GHP) is essentially a thermal battery for the heating and cooling of a building. GHPs are electrically-powered systems that tap the energy stored deep in the earth’s surface. These systems use the earth’s relatively constant temperature to provide heating, cooling, and hot water for homes and commercial buildings. During the warmer months, a GHP will cycle heat from your facility and store that heat in the ground while cooling the facility. That stored heat will be used during the cooler months to heat the facility. 

Geothermal Field at Carroll Elementary

With the additional systems being added at Old Union, Johnson, Carroll Elementary Schools and the new Music Center, Carroll ISD will have six geothermal systems working toward more efficient uses of energy.

One of the main advantages of geothermal heat pumps is their low energy consumption levels, whereas they consume 20-50% less energy than conventional heating or cooling systems. Lower energy consumption results in lower utility bills for the district.

According to Don Penn, Mechanical Engineer for IEG, the average savings per year on a GHP user’s utility bill is between $0.75 and $1 per square foot. Carroll ISD’s elementary schools are approximately 100,000 square feet on average, so that equates to a potential savings of $100,000 per year on each facility’s utility bill. When you account for each facility currently running a GHP system or installing a GHP system, the district could be looking at an estimated $750,000 total annual savings on the energy bill.

Given that Carroll ISD is a Robin Hood district, the district would have to collect approximately $1.2 million dollars in taxes in order to cover the $750,000 in utility costs out of the operational budget. Geothermal is both an efficient use of energy and efficient use of funds that will save funds that can be used in other areas supporting the students and staff of CISD.

Carroll Bond Builder Safiy Islam, a seventh grader at Carroll Middle School, had an opportunity to research and learn more about GHPs; Check out his video below.


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