Headline in Spokane News:
Possible ammonia leak at the Ice Ribbon, Haz Mat Full Response to 700 West Spokane Falls Blvd.
Industrial ice uses either ammonia or CO2. Ammonia is NASTY stuff. One whiff can ruin your sense of smell permanently, and a larger sniff can kill you. CO2 is nice stuff. It feeds plants. You produce CO2 every time you breathe, so it’s not a foreign contaminant.
Zero guesses as to why the Spokane ice rink chose ammonia instead of CO2. The question was answered by absolute zealous religious force before any heretic could think of imagining it. If the choice was Plutonium Cyanide vs CO2, Spokane would happily choose the benign wonderful nutritious Plutonium Cyanide. Nothing in the universe can possibly be more toxic and deadly than CO2 for our ruling alien lunatics. The Carbon Cultists already forced household refrigerators and AC to use the FACTUALLY TOXIC Halon instead of the FACTUALLY HARMLESS Freon, because Goddess Gaia commanded us to avoid Freon**.
Toxic chemicals are a rational choice in an industrial facility where a small number of workers are aware of the danger and trained to be alert for signs of leakage. Toxic chemicals make no sense in a giant arena where thousands of ordinary people don’t know the danger and don’t know how to handle it.
Most of the commenters don’t know that ammonia is the most common refrigerant in industrial-scale coolers like ice plants and ice rinks. They’re asking “why would the ice rink have an ammonia tank?” I covered the ice industry two years ago, with an explanation of the two choices.
= = = = =Time for a reprint.
Most industrial systems used ammonia, which is stinky and poisonous but requires low pressure to complete the cycle. Low pressure means less power to the compressor and less chance of leaks. CO2 is harmless, but requires much higher pressure and thus more electricity to the compressor.
This compressor has a double-acting cylinder, with valves at each end. One of the output pipes was always sucking and the other was always blowing.
The compressor sucks in gaseous ammonia at maximum heat and expansion (red arrow). The piston reduces the volume and increases the temperature of the gas. The output of the compressor flows into the cooling tower (orange arrow), in gaseous form at high pressure. The tower takes away enough of the heat to change the phase into liquid form. The liquid ammonia then flows (blue arrow) into the coils in the coldroom, where it is allowed to expand and re-gasify, absorbing heat from the surroundings. In this case the surrounding material is a pool of brine, which we’ll see in the next step.
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Evaporation and condensation (sweat, dew) are instantly familiar in Nature. The other parts of the cycle are not intuitive. Our lungs are compressors and evaporators, but the temperature change at the nose is not obvious. The full picture of Boyle’s Law wasn’t grasped until inventors began developing steam engines and hot-air balloons.
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How did the ice plant make its portable blocks of coldness? The method was unexpectedly complicated.
Here’s the coldroom, where the compressed and relatively cool ammonia is allowed to relieve its pressure and absorb heat from the water that will become ice.
What’s going on inside? We have a grid in the floor, over a pool of cold brine kept at -10 degrees by the evaporation coils. The brine is also agitated by a stirrer, not shown here. Polistra is filling one of the cans with water.
I’ve shown only one filled row for simplicity. All rows in the grid were occupied by cans, immersed in the cold and moving brine. The movement insured that each can was cooled equally, and also helped to shake out the air in the cans. Clear ice was considered a mark of quality.
These are the smallest available cans, 8 x 8 x 32, holding 50 pounds of ice. Most systems used larger cans. Each can has a graspable edge on top, which is the key to the mass production process.
Picking up and handling the cans was difficult. Not necessarily from the weight, since a typical workman could handle 50 pounds. The problem was getting out onto the floating grid and grabbing the slippery can. Machines like this air-driven hoist did the grabbing job, and workmen handled the cans after they were on solid ground. The hoist has spring-loaded tongs designed to snap onto the top edge of the can, and mechanisms to lift the tongs and slide the carrier horizontally.
After taking the can out of the grid, the ice had to be pulled out. This machine, known as the Thawing Apparatus, did the job. A box holds the can tightly while warm water sprays on the surface.
After the can expands, the Thawing Apparatus can be tilted to let the ice slide out of the can. Then the can is dropped back into the grid and refilled for the next load.
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** The even nastier reality is that Halon replaced Freon because DuPont’s patent on Freon expired. From Wikipedia:
In 1978 the United States banned the use of CFCs such as Freon in aerosol cans, the beginning of a long series of regulatory actions against their use. The critical DuPont manufacturing patent for Freon (“Process for Fluorinating Halohydrocarbons”, U.S. Patent #3258500) was set to expire in 1979. In conjunction with other industrial peers DuPont formed a lobbying group, the “Alliance for Responsible CFC Policy”, to combat regulations of ozone-depleting compounds. In 1986 DuPont, with new patents in hand, reversed its previous stance and publicly condemned CFCs. DuPont representatives appeared before the Montreal Protocol urging that CFCs be banned worldwide and stated that their new HCFCs would meet the worldwide demand for refrigerants.
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Environmentalism is corporate greed, nothing else. All the idiot enviro activists are serving the same corporate masters they stupidly believe they’re opposing. I used to be one of those idiots, so the betrayal is especially aggravating.
Polistra's Mill 