Week 8- mechanical systems

What stood out first was how much of our energy still comes from fuels that run out. The slides showed that oil is used in about 99% of vehicles and makes up roughly 40% of the energy we use in the U.S., and that 42% of our electricity comes from coal while only about 13% comes from renewable sources.

The second half of the unit moved into HVAC, which is all about human comfort. We compared heating systems like hydronic, forced air, electric radiant, and wood, and cooling systems like heat pumps, split systems, and through-wall units. What I hadn’t thought about before is how much of this lands on the interior designer. Ducts, registers, and returns have to be planned together with light fixtures, sprinkler heads, smoke detectors, and ceiling details, or the design intent never actually gets built. It made me realize that a mechanical system isn’t just something the engineers handle, it decides what a designer is allowed to do with a ceiling or a wall.

For my research I picked geothermal. I had always pictured geothermal as a power plant in a place with geysers, but the diagram showed horizontal coils, vertical bore holes, and open loops all connected to a regular house. The word itself comes from the Greek for heat from the Earth, and it can be used two ways: deep wells bring up steam or hot water to spin turbines. Since the ground stays at a fairly steady temperature, the second use works in far more places than I expected, and it connected the fuel section of the unit directly to the heating and cooling section.

I spent some time on the Department of Energy and a few other sources to see how it compares to everything else. Geothermal power plants run more than 90% of the time, compared to about 75% for coal, and unlike solar and wind they don’t depend on the weather. Geothermal heat pumps are up to 65% more efficient than traditional HVAC units. Iceland gets more than half of its primary energy from geothermal, but in the U.S. it only makes up about 0.4% of our electricity, with most plants in the western states and Hawaii. That gap is what surprised me most, since it is clean and constant but still barely used.

Seeing it all together made the tradeoff clear. A geothermal system saves energy for years, but the client has to be willing to pay more at the start, and the loops are buried, so they need to be planned before anything else is built. That is the same lesson from the HVAC section, just at a bigger scale. The mechanical decisions come first and the design has to work around them. For a designer, that means knowing about options like this early enough to bring them up with the client and the rest of the team.