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I came across these two terms and not sure if they could more or less be considered the same thing.

wikipedia defines it as:

Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics.

In that wikipedia there is a section talking about disposal, not sure if that is the same though. It says:

Low temperature heat contains very little capacity to do work (Exergy), so the heat is qualified as waste heat and rejected to the environment. Economically most convenient is the rejection of such heat to water from a sea, lake or river. If sufficient cooling water is not available, the plant can be equipped with a cooling tower or air cooler to reject the waste heat into the atmosphere. In some cases it is possible to use waste heat, for instance in district heating systems.

Wondering if anyone on here has insights into it.

Thanks

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  • $\begingroup$ The article is saying waste heat is any unintensional heat made from doing an operation. Then, because most often that unintended heat isn't of a type capable of being repurposed, it is disposed of. Sort of like how garbage is the unintensional result of our daily operations... and since much of it isn't something we can repurpose, we send it to the landfill. I don't think waste disposal services are any type of heat themselves, they're like garbage disposal... taking the waste that we have that we can't use and getting it out of the way. $\endgroup$
    – JeopardyTempest
    Dec 6, 2021 at 12:51
  • $\begingroup$ The use of "waste disposal services" in the title of this question has nothing to do with the concept of "waste heat". I suspect you meant "waste heat disposal techniques" instead of "waste disposal services" in the title. $\endgroup$
    – David Hammen
    Dec 6, 2021 at 14:56

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The title of the question and the text associated with it do not match.

The title mentions waste disposal services and waste heat, but the text only discusses waste heat.

Waste disposal services are any services that dispose of any waste. A sewage treatment plant is a waste disposal service, as is a land fill facility for any form of rubbish as is a waste incineration plant.

As for the block quotations concerning waste heat in the text, the first quotation simply gives a definition/example of waste. Some examples of this would be the heat generated when metal is being shaped on a lathe. The friction between the cutting tool and the metal item generates heat. To prevent thermal damage to both the item being cut and the cutting tool both needsto be cooled so they are constantly flushed by a cooling liquid during the cutting proces. This heats the liquid which is then transported elsewhere, such as a heat exchanger to be cooled. The heat from the exchanger then releases the heat either to the atmosphere or undergoes another cooling process.

Heat produced by an internal combustion engine is another example. The engine contains voids that are filled with water or water and coolant and the waste heat is ejected to the atmosphere via the radiator.

The second block quotation gives examples of how waste heat can be disposed: into bodies of water such as rivers, lake or the ocean or the atmosphere cooling towers.

In thermal power stations that heat water to produce steam that turns turbines to generate electricity, such a coal, gas or nuclear power stations, once the steam leaves the turbines it needs to be cooled for form water so it can be reused. The way it loses heat is via cooling towers. In colder climates, such as Russia, such heat can be used to provide communal heating for domestic purposes.

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