View Full Version : Help pls: air-to-air heat exchanger and Regenerative heat exchanger?

14-04-2007, 02:32 AM
Hi all,

i'm a student designing a refrigeration system this yr.
i'm trying to find out the latest technology that exist in the market for:

1. air-to-air heat exchanger
2. regenerative heat exchanger/regenerator

ive done some research already for both, however what i found is mostly talking about air conditioning systems and heating buildings.

could they be used the same way for a refrigeration system?

im more confused about what is a regenerator now after reading more about it.
is a regenerator the same as a recuperator?

Could someone kindly please enlighten me....:confused:

where is the place to start to find information on these areas as i find that the research ive done is still not giving me a good enough understanding?

Many thanks.;)

ps. i wasnt sure if this is the right place to put this here...because the HEs im talking about is related to both refrigeration and AC systems.

15-04-2007, 04:55 AM
hi S man
What application is your refrigeration system being designed for, low or medium temperature? I dont quite understand your air to air heat exchanger. Evaporators and condensors are both heat exchangers, vessels within a refrigeration circuit designed to transfer heat either to or from the refrigerant in them, (liquid or vapour).
An example of a recuperator in a refrigeration system may be a 3 way valve on the discharge line of a commercial supermarket refrigeration system which would for example divert the high pressure high temperature refrigerant either to the condensor, eg. a remote rooftop mounted condensor, or on a cold day divert the high temperature high pressure refrigerant to a fan coil unit to heat the air within the supermarket for human comfort. Let me know if that helps, perhaps i can help you further.

15-04-2007, 03:17 PM
Hi penair,

What spiderman needs is an Air to Air heat exchanger for heat recovery system.
Am I right spidernan :confused: ?

I would like to read about them too.:D ANYBODY?

15-04-2007, 07:48 PM
For air to air heat recovery I would imagine something like the Lossnay units but I am not aware of their use in transferring heat within a refrigerant based system.

16-04-2007, 01:58 AM
Air to air heat exchanger is used to reclaim sensible and latent heat from exhaust air.Regenerator is used in heat recovery wheel or dehumidifying wheel to keep the capacity of the wheel. I don't know what your system is.Pls make it clear and let us know more:)


16-04-2007, 05:12 PM
I've also seen plate-type sensible HX's and heat-pipe latent HX's. Lot's of companies make plate-type for residential and commercial heat recovery.

17-04-2007, 05:14 PM
Many thanks for all your replies to this.
there was a bit of confusion to what i wrote previously.

Basically, i want to use a air-to-air heat exchanger that works like a regenerator or recuperator for my refrigeration system.
Initially i used an automotive intercooler (tube and fin aluminium) as a regenerator.
But i read somewhere that there is new technologies available (i.e. High efficiency air-air heat exchangers).
The regenerator is used to control the temperature for a cold storage room.

Could anyone kindly direct me to where is the place to find out these new technologies of air-air heat exchanger?

Once again,
Thank you for reading.:)

18-04-2007, 03:05 PM
Hi there,

I think the confusion still remains:confused: .

The regenerator is used to control the temperature for a cold storage room.

HOW ? :confused:

17-07-2007, 11:47 AM
Basically, i want to use a air-to-Air heat exchanger that works like a regenerator or recuperator for my refrigeration system.
Initially i used an automotive intercooler (tube and fin aluminium) as a regenerator.
But i read somewhere that there is new technologies available (i.e. High efficiency air-Air heat exchangers).
The regenerator is used to Control the temperature for a cold storage room.
If you could sketch out the schematic(what ever way you have used the inter cooler) we will be able to suggest.
Your question is still some what unclear:confused:

mohamed khamis
17-07-2007, 01:31 PM
Hi Spiderman

Ok this is breif information as i remember when i was undergraduate student but i will dig in my material to provide u by the details, give me one more day or two days.

Firstly, u r talkig about air-to-air heat exchanger and its application as i understood. As it is known the air has poor heat transfer coefficent and on the same time has low density of 1.2 kg/m3 therefore the application of using air as a heat transfer meduim must be large in terms of its heat transfer surface area or time of heat transfer occuring. The large heat transfer area u can find it obvoiusly in finned-tube heat exchanger "the fins offest the needing of increasing surface area on the side of air or gas existence" but becuase the air-to-air heat exchnager has a bad luck of existance of two meduims of heat transfer of air so it is blindley expected to have fins in the cold-side and fins in hot-side and this only shape which satifies that is the hot box or honeycomb heat exchnager which is so-called recuperator heat exchanger. The increase of heat tranfser time can be occured by slowing the air passing (without its velocity) through the heat exchnager or another word to be out of confusion to keep the air passing in the heat exchnager for rather long time. this is accomplished by making the heat exchnagers composes one cyclinder divided into partions the hot air passes contunously in the upper and the cold air in the bottom passes continuosly also and on the same time the cylinder or drum is rotated slowley to change the loaction of the hot half cylinder (the material stored the heat content) with the cold half cylinder and thus the cold air is heated by regeneration the heat from the cylider material which stored the heat so this kind of heat exchnager is named Regenerator and it is commonly used in Steam power genertor in component named air preheater heat exchnger.

Secondly the appplication is in air conditioning system only as our fellows mentioned in heat recovery system where the fresh ventilltaed air is cooled or heated on expense of the exhuasted air (takes place 20% of system capcity) and i don not have knowledge to be used in refrigeration system becuase there is no ventilation in refigernation application some refigernation exppert corect me if i am wrong. I wish it could help


mohamed khamis
18-07-2007, 08:07 AM
Hi spiderman

this some materials i have found on my PC.


the second file 6MB gives some analysis and calculation for air-to-air heat exchanger design in different applications


I wish it could help

Best regards:)