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waste heat recovery

saumya Member Posts: 2

currently I am doing a project in a small scale ammonia plant and want to know if the heat dumped  in the cooling water by means of various exchangers can be utilized. This heat is of low grade with the temperature range 90-120 degree Celsius. Also there is a large volume of flue gases going into the atmosphere with a good amount of heat content(exit to atmosphere at 174 degree Celsius), what is the most efficient technology to make use of this heat available.

Thank you




  • Tom Blackwell_2
    Tom Blackwell_2 Member Posts: 126
    Heat recovery

    There are many ways to recover waste heat from a refrigeration system. Heat exchangers on the hot gas leaving the compressor would be first choice. A heat exchanger on the spray water could be used for low grade heat. All of these are standard devices-not normally used because energy has been too cheap and the first cost usually rules.
  • saumya
    saumya Member Posts: 2
    edited June 2011
    waste heat recovery

    i want to know if there is a method so that the heat which is being dumped in cooling water can be recovered, please help me with a specific answer
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    It depends....

    Are there any hot water heating applications, or process applications requiring energy? If there are, then there is a distinct possibility of waste heat recovery, but if not, then it's most probably not feasible . If it is an extremely loong distance from source to load, then again, it might not be worth while.

    Personally, I think ANY waste heat recovery potential should be utilized, but I am not in a position to tell people how to spend thier money, and in most cases, if they can't see a complete ROI within 5 years, they will not tackle it. Sad but true, and possibly some day the environmental cops will change all of this, but for now, it is predicated by economics.

    If you want specific answers around here, you have to give a specific application. I.E., I have waste heat refrigerants at XXX degrees F, and need to heat potable water to XXX degrees F, what should I use. There ARE some material limitations and issues of compatability.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
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