Geothermal technologies are based on the steady supply of heat that radiates from the core of the planet to the surface. Due to underground temperatures being cooler than above ground temperatures on the hottest of summer days, yet warmer than on the coolest of winter nights, geothermal systems allow the user to keep their building at a consistently comfortable temperature with greater efficiency than many other types of systems.
There are two basic types of geothermal systems: open and closed loop. Open-loop systems pump ground water from a well or pond through a loop and into a heat pump, extracting heat for cooling or heating. Although open-loop systems are generally cheaper to install, closed-loop systems are considered easier to maintain, in that the supply of water from wells can be unreliable. Here’s how a closed-loop system works:
- A closed-loop system consists of buried pipes, circulating a liquid similar to antifreeze which helps to transfer heat to a heat pump and from there to the building.
- There are differing patterns for closed-loop systems, but vertical installations are the most common, because they take the least amount of space.
- Some closed-loop systems may also utilize a variation of this operation known as “direct exchange.” This process does not use a heat exchanger but rather moves refrigerant through buried copper tubing and requires a larger compressor as well as consistently moist soil.
Benefits of a closed-loop system: Geothermal heat pump systems consistently deliver more energy per unit consumed than most conventional systems. Furthermore, geothermal heat pumps can be joined together with a “desuperheater.” This device can heat water in the summer for free by taking it from the house as well as reducing water heating costs by half during the winter months.
Our goal is to help educate our customers in Detroit, Michigan about energy and home comfort issues (specific to HVAC systems). For more information about geothermal and other HVAC topics, download our free Home Comfort Resource guide.
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