Step 1: Understanding the Fundamentals of a Geothermal Heat Pump
This project explores the design and construction of an innovative geothermal heat exchanger aimed at effectively cooling a garage environment. The system operates by extracting cool water from a shallow well, which is then channeled through a heat exchanger installed inside the garage. A strategically positioned fan attached to the heat exchanger disperses the cooled air into the space, while the heat exchanger absorbs and transfers heat from the interior. The heated water is subsequently expelled via an exhaust pipe, completing the cycle. This system leverages the steady temperature found just a few feet below the earth’s surface, a principle that underpins geothermal energy technology. The installation involves excavating a shallow well with a post auger, connecting a water pump and pressure tank to the well pipe, and laying a one-inch polyethylene pipe within a trench to facilitate cold water flow from the well to the garage.
Step 2: Excavating a Shallow Well Using a Post Auger
The shallow well serves as the primary source of the cool, consistent underground water essential for this geothermal system. Its construction begins with the use of a post auger to bore a hole until reaching the water table. A 3-foot well point is securely attached to a 10-foot, three-quarter inch pipe using a durable drive coupling, allowing effective water extraction. The auger is driven into the earth until the water table is encountered. Once reached, the well point is attached and driven an additional two to three feet into the ground to ensure it is submerged below the water table, thereby maintaining reliable access to cool underground water year-round.
Step 3: Digging the Trench and Connecting the Well Pipe
To transport the cold water from the well to the garage efficiently, a trench is meticulously excavated, typically two to three feet deep, depending on property layout. The depth is crucial as it ensures the pipe remains within the zone of relatively constant soil temperature. A one-inch polyethylene pipe is then connected to the well pipe via a barbed coupling, enabling secure and leak-proof water transfer. This pipe is buried within the trench, which helps insulate the water and maintain its cool temperature. Digging to at least two feet deep into the hardpan clay layer ensures the pipe remains in a zone of stable temperature, optimizing the system’s efficiency.
Step 4: Installing the Jet Pump Outside the Garage
The opposite end of the polyethylene pipe from the trench connects to a 1/2 HP Flotec Shallow Well Jet Pump. This pump plays a vital role in moving the cooled underground water from the well into the garage’s heat exchanger. Notably, the Flotec jet pump is designed to operate efficiently with a solar power source, making the system environmentally sustainable. To maximize cooling efficiency and prevent heat interference, it is recommended to install the pump outside the garage, preferably in a shaded area, as the pump generates significant heat during operation. Placing it outdoors helps preserve the cooling capacity and maintains system performance.
Step 5: Installing a Water Pressure Tank for System Stability
The output from the pump is connected via a three-quarter-inch copper pipe inside the garage to a water pressure tank, which functions as a crucial component for maintaining consistent water flow. A brass tee and union facilitate connection, while a relief valve is installed to prevent excessive pressure buildup by allowing excess water to be safely released. The pressure tank acts both as a buffer to prevent pump failure and as a storage reservoir that ensures steady water flow. This configuration enhances the longevity of the pump and increases overall system efficiency by reducing cycling and pressure fluctuations.
Step 6: Connecting the Heat Exchanger and Facilitating Air Circulation
From the pressure tank, the system branches at a brass tee, which divides the flow into two paths: one leading to an outdoor faucet for auxiliary uses, and the other connecting to the heat exchanger—a radiator equipped with finned coils. The heat exchanger is the core component responsible for capturing heat from the ambient air inside the garage. Cold water circulates through the finned coils, absorbing heat from the surrounding hot air, and thereby cooling the environment. To ensure continuous water flow, flexible hoses connect the pressure tank to the radiator inlet and outlet to an exhaust pipe. A box fan positioned in front of the radiator blows cooled air into the garage, enhancing air circulation. Powered by solar panels, the fan operates efficiently, creating a sustainable cooling solution. As water circulates through the radiator, the fan disperses the cooled air, maintaining a comfortable environment year-round. This entire setup offers an eco-friendly, cost-effective method for garage cooling, utilizing renewable energy sources and minimizing electrical consumption.