Recent comments in /f/askscience

celo753 t1_j1b80g1 wrote

Reply to Is accidental transportation of microbes to Mars bad? by Responsible-Maybe912

It depends on who you’re asking. Some people believe we should purposefully colonize other planets with life, in the hopes that someday some of it will thrive. For scientists, it is very bad, since it will make experiments that check for the remnants/presence/building blocks of life possibly return false positives. In the grand scheme of things, taking humans to mars is impossible without contamination of the red planet, and the scientific value of having a human on-site on mars likely outweighs the negatives of contamination.

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bluesam3 t1_j1b6pb7 wrote

Reply to comment by Bunslow in Why do we use phase change refrigerants? by samskiter

It's very climate-dependent - the colder the outside is, the less efficient air-source heat pumps tend to be (partly due to inherent reasons, and partly due to having to do work to defrost the outside unit) - if you're somewhere with relatively mild winters, COPs above 3.0 are very achievable with domestic units. If you live somewhere with extremely cold winters, it's much less achievable.

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RelativisticTowel t1_j1b44mn wrote

Reply to comment by samskiter in Why do we use phase change refrigerants? by samskiter

In many domestic refrigerators we do recycle a bit of heat. The external areas around the door gaskets are colder, and prone to a buildup of condensation if you don't heat them up somehow to match the rest of the exterior. We can and on occasion do put electric heaters there, but the best solution when possible is to simply route the starting section of the condenser (where the gas temperature is pretty high) through those areas. Bad move from a heat pump efficiency perspective since some of that heat leaks back into the cold side, but good for the efficiency of the appliance as a whole.

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