Based on your question about using flue gases, this is what I understand you to ask for. As the flue gases exit from a combustion chamber, some devices run it past a heat exchanger to heat up another substance. The corrosive affect of the flue gas condensate is always a concern. One advantage is that you can control the condition (i.e. temperature) of the exiting gases. I do not know of a specific company that manufactures something called a Heat Recuperator, but this is the basics of the application.
Heat Recuperators are air-to-air heat recovery units that effectively reclaim heat from furnaces, incinerators and such high temp. applications.
There are two types of Heat Recuperators, viz: Tubular Heat Recuperator and High Temp. Insulated Heat Recuperator.
Now I want to know, How Heat Recuperator actually works? i.e. the Source will be Flue Gases but what will be the Sink and how it can be used for reclaiming the heat?
I am not familiar with the details of how to make heat recuperators, but I understand the concept. The "sink" is the air or liquid that you want to heat up. This has to be done in a heat exchanger (i.e. shell and tube). The two types you mentioned sound the same except for efficiencies (one may be insulated to reduce heat lost to surroundings). Not knowing your reason for asking, let me add that it does no good to reclaim the heat unless you have something specific to heat up. For example, if you are using blowers for cooling in a glass furnace application, you may want to temper the source air to keep the glass stress level to a minimum. In this case, the blowers would direct air through a shell and tube heat exhanger with the flue gasses from the furnace being the other fluid. Probably the main reason to use something like a heat recuperator would be to heat a fluid up initially so it takes less energy to get it up to the temperature you desire to use it at.
Heat Recuperators are waste heat recovery heat exchangers. In a combustion process it preheats combustion air with heat from the waste flue gases. Use of this preheated combustion air results in fuel savings, savings percentage depending on the level of air preheat vis-a-vis flue inlet temperature.
The basic function is to reduce the final flue outlet temperature from the combustion process / furnace.
Besides combustion air, it is also used for preheating other gases and mediums like air for drying, combustion air for another process, low C.V. Gases, Nitrogen and other inert gases or gaseous mixtures for protective atmosphere furnaces, etc.
Recuperators are commercially classified in many manners -
1. Depending on the principle methods of heat transfer used - Radiation, Convection, Combination, etc.
2. Depending the material of construction, like Ceramic, Metallic, etc.
and many other names.
It is also used as pure hot air generators or Indirect fired Air Preheaters.
Please mail sanghi@cal2.vsnl.net.in if you need any further clarifications. We are the leaders in Recuperators and Air preheaters in India.
