Java Zen:Thinking Out Loud Tuesday, 2019.02.19
A mathematician, a doctor, and an engineer are walking on the beach and observe a team of lifeguards pumping the stomach of a drowned woman. As they watch, water, sand, snails and such come out of the pump.

The doctor watches for a while and says: "Keep pumping, men, you may yet save her!!" 

The mathematician does some calculations and says: "According to my understanding of the size of that pump, you have already pumped more water from her body than could be contained in a cylinder 4 feet in diameter and 6 feet high."

The engineer says: "I think she's sitting in a puddle."

2007.06.11

Cool On Top

As in Cool Roofs:

Over 90% of the roofs in the United States are dark-colored. These low-reflectance surfaces reach temperatures of 150 to 190°F (66 to 88°C) and contribute to:

  • Increased cooling energy use and higher utility bills;
  • Higher peak electricity demand, raised electricity production costs, and a potentially overburdened power grid;
  • Reduced indoor comfort;
  • Increased air pollution due to the intensification of the “heat island effect”; and
  • Accelerated deterioration of roofing materials, increased roof maintenance costs, and high levels of roofing waste sent to landfills.


In contrast, cool roof systems with high reflectance and emittance stay up to 70°F (39°C) cooler than traditional materials during peak summer weather. Benefits of cool roofs include reduced building heat-gain and saving on summertime air conditioning expenditures. By minimizing energy use, cool roofs do more than save money – they reduce the demand for electric power and resulting air pollution and greenhouse gas emissions.

Unfortunately, there are tens of thousands of Home Owner Association fiefdoms in the way of making something like this happen. There really are many, many simple solutions to the problem, but how do you whip up a fearful frenzy about white roofs? It’s much more satisfying to smack down a Hummer driver or gloat over that shiny new Prius in the driveway.