Potty Talk and Marine Refrigeration
In my kitchen at home we use cooking pots and pans made from a variety of metals, and I thought it would be an interesting project to delve into the pros and cons of each material and then go on to see how that works with refrigerator evaporators.
After all, cooking pots and fridge evaporators both utilize metal surfaces to transfer heat, so many similarities exist.
When cooking on the stove, we're conducting heat from an external source (the burners), through the material of the pot or pan to the contents in the interior.
Simple enough you'd think, but different metals have different characteristics, and work in different ways. The ability of a material to transfer heat is known as its Thermal Conductivity. This is quoted in various units, but here we'll use good old fashioned BTU's per hour per foot per degree Fahrenheit (Btu/hr-ft-F).
Listed below are some of the common metals used for cooking pots and pans together with their Thermal Conductivity rating, starting with the most conductive and ending with the least. Basically, the higher the number, the more heat the material will conduct through it
How Beer Warms Ice
"Icing Down the Beer" vs "Beering Up the Ice"
Here's a fact: Heat travels in one direction only; from warm to cold. So if a temperature difference exists between two items, the warmer item will lose heat to the cooler item; so the warmer item gets colder, the colder item gets warmer.
Simply put, when we put warm beers into a cooler of ice, we don't actually cool down the beer as much as warm up the ice! When heat leaves the beer for the ice, the beer gets colder as a result, and soon the contents are all at a wonderfully refreshing 32F temperature. And thanks to the laws of science and beerology, everything will stay that way until all the ice has melted and the beer has been consumed.
But what about your refrigerated ice box? Isn't it always being kept cold?
How to Kill a Battery
We spend considerable time and effort trying to help boat operators understand how to look after their batteries, but we still hear of way too many premature deaths. So in an effort to get the message across from a different angle, we offer the following advice on how to inflict serious harm and punishment on expensive batteries without really trying.
Simply put, there are three main types of abuse you can employ to kill or maim your batteries:
- Excessive heat
- Physical damage (including vibration), and
- Poor charging routines
The first two I hope to be self explanatory, but the third requires some detailed explanation.
Flooded lead acid batteries, including AGM's, don't like being left for extended periods in a partially charged state. Doing so allows some of the lead sulfate crystals that form naturally on the negative plate during the discharge process to harden to the point where they can't then be dissolved the next time the battery is charged. This is known as sulfation which leads to an increasing loss of useable capacity as more and more crystals harden.