Induction cooktop proves most efficient
John Eisenberg’s letter in the Oct. 5 Town Crier (“Do reach codes kick can down road?”) is correct that burning gas is almost 100% efficient, but in the case of a gas stove, there is another important effect. What fraction of the heat from a gas flame actually heats the food?
When we remodeled our kitchen a few years ago, we did some research on how quickly we could boil water to cook spaghetti.
From the BTU rating of a gas stove, I calculated the time it should take to bring a quantity of water to a boil. With a thermometer and stopwatch, I compared several cooktops. A gas cooktop took about three times longer to boil water than my prediction.
Even though the gas flame is efficient, most of the heat goes up past the pot, just heating the kitchen. The quickest and most efficient cooktop turned out to be an electric induction cooktop, which directly heats the magnetic metal of the saucepan.
Eisenberg deserves our thanks for raising the larger question of how much natural resources we are using to support our lifestyle.
Mark G. Leonard
Los Altos
Pipe owners decide which trees removed
Consider the power in a 90-inch transmission main, and the damage from a leak or rupture. We have seen flow from ruptured hydrants on 6-inch pipes that serve our residential neighborhoods.
How much more water can a 12-inch pipe deliver than a 6-inch? Twice as much? A good geometry student would predict four times as much, since a 12-inch pipe has four times the area.
Good thinking, but that’s not the whole answer. The bigger pipe enjoys another advantage, called the “wetted perimeter.” It would deliver over six times as much.
Now consider the damage a leak in a 90-inch pipe would cause, and ponder why the Los Altos City Council should spend any time at all discussing the removal of trees over that pipe. The pipe owner should make the decisions.
Enjoy the walk and be thankful you have access.
Jerry Clements
Los Altos
(Worked on the design of the East Bay Aqueduct)
