Hi, Enertec greets all members with a querry on Thermally Aided Compression

[enertec]

Hi this is Enertec. We are into dealing with HVAC and energy equipments, and HVAC project execution. I have just joined the forum today and have a question to begin right away.

I have been wondering on the fundamentals of gases, whether Charles Law, pressure and temperature being related, can be practically applied to refrigeration compressors.

In refrigeration compressors, you compress the ref. gas, which simultaneously gets heated up. Work is done by the compressor for elevating the pressure of the ref. gas. Can we have it the other way round, i.e., we increase the temperature of the ref. gas by an externally available heat source, thereby increasing the inlet gas pressure to the compressor. Logically this help reduce the load on the compressor.

I request members' thoughts and experience sharing on the subject, lets call it TAC (Thermally Aided Compression). What are the possible constraints / limitations in this method and how can they be overcome. Is this method practical ? Why, if not ?

[guapo]

Hi,

yes it is possible. but what available heat source you can get to put refrigerant in high pressure high tempereture in order to condense it to put back in liquid phase?

Guapo

[enertec]

Hi Quapo,

Thanks for your prompt reply. I am more into Absorption refrigeration, hence this querry. If you say it is possible to have TAC, tell me what level of heating you want. Heat source is dry air available at 500 Deg.C. Would that be sufficient to heat the ref. to the desired level. If not to the desired level, can this not be utilised to partially heat-up (& pressurise) the refrigerant, thereby saving the load on the compressor. Your views !

Enertec

[Josip]

Hi, Enertec

maybe you are thinking about this

Stirling Cycle Refrigeration

something more you have here:

http://archive.greenpeace.org/ozone/excuse/7excuse.html

then you can google "heat pipe" maybe to start here:

http://www.heatpipe.com/heatpipes.htm

this all seem as our near future, but....

I believe we will run compressors by electricity for a long time and of course absorbtion machines with waste heat, like in your case.

Maybe I am wrong, but other guys will come with their thoughts.

Hope this is of some help

Best regards,

Josip

[guapo]

Hi enertec,
You have to look the basic principle or purpose of the compressor, not only heating up the refrigerant but at the same time suck the refrigerant from the eveporator as much as possible untill you get the desired pressure in the evaporator.

Your Idea comes to my mind already when I started learning refrigeration, you have to look at inial cost of the system, operating cost, efficiency, etc.

Josip is right we will used compressor for a long time, but I know you can do something for your 500C.

Guapo

[kevin090972]

hi enertec,

I'm new to this forum and it's my great pleasure to be able to speak to alot more well qualified and experienced professionals in this field. I've noticed some manufacturers like Daikin insulating the compressers using fiberglass. Probably its for the pupose of increasing the temperature as you mentioned or it may be for sound insulation or both. One thing to take note is that as we attempt to increase the temp of the compressor, we mustn't overheat it. Most compressor oil couldn't take temp above 150'C. Also, above 250'C, R22 disintegrates and acid will be formed. In conclusion, I do believe some manufacturer's are "adding" heat to the compressors.