Laserfiche WebLink
<br /> <br />15 <br />4.2.3. GEOTHERMAL EXCHANGE WITH IN-GROUND HEAT EXCHANGERS <br />In-ground heat exchangers are a groundwater-based solution for <br />heating and cooling buildings. The in-ground heat exchanger taps <br />into the thermal capacity of groundwater and takes advantage of <br />consistent groundwater temperatures. These systems provide <br />significantly more energy per unit of space compared to traditional <br />closed-loop geothermal wellfields. The system utilizes a heat <br />exchanger and pump installed in a standard, purpose-built well. The <br />groundwater remains underground, while the district energy system <br />circulates potable water, in a closed loop, through the underground <br />heat exchanger. This design ensures that groundwater remains <br />undisturbed, mitigating any potential impacts on TGRS and the <br />groundwater remediation efforts. <br />The number of in-ground heat exchangers can be scaled to meet <br />specific heating and cooling demands; each well has a potential <br />capacity of 600+ MBH (50 tons) of heating and 100 tons of cooling. <br />This approach reduces the geothermal system's footprint by 95%, <br />making it ideal for space-constrained sites, minimizing disruption, <br />installation time, and construction costs. Each in-ground heat <br />exchanger is estimated to cost $500,000, which equates to $5,000 <br />per ton of cooling and $830,000 per MMBtu/hr of heating. The in- <br />ground heat exchangers do not need to be installed in a central <br />location or close to one another. They can be spread out along the <br />district energy system distribution network, increasing system <br />resiliency, redundancy, and potentially reducing the distribution system pipe diameter size. <br />4.2.4. AQUIFER THERMAL ENERGY STORAGE <br />Aquifer thermal energy storage (ATES) is another ground source-based technology that uses the thermal <br />properties of underground water-bearing rock formations to store and retrieve thermal energy for heating <br />and cooling applications. ATES relies on a series of wells and piping systems that can move heat between <br />buildings and the local aquifer. The process works by pumping water from the aquifer to a heat exchanger, <br />where heat is either extracted or rejected to the aquifer water. The aquifer water is then returned to the <br />aquifer through another well. In the summer, cool water is pumped from the aquifer to cool buildings, while <br />in the winter, warmer water is pumped to provide heating. This system allows for efficient use of energy as <br />the temperature of the aquifer remains relatively constant over the course of a year. The ATES process for a <br />typical year is shown in Figure 8. <br />Figure 7. In-ground heat <br />exchanger style heat transfer <br />