NEW TYPE OF COMPRESSOR. 2

[Leffe]

I am an mechanical engineer and have just started tests of a new type of compressor I have invented. I have made a prototype to produce compressed air (10 bar) and it is performing very well. My question here is to try to form an opinion wether this new compressor would be suitable to use for cooling. What pressures are used in cooling systems? What pressure would be the optimal? What types of compressors are used in different systems and why? Before I approach anyone in these matters i need to get some basic information and undestanding abote cooling. Iwould very much appreciate if someone here could help me out.
Thankyou
Leffe

 

[quark]

Generally the discharge pressure of a chilling compressor depends upon the type of refrigerant and the condensing temperatures. Generally it is between 150 PSI to 275 PSI and can go maximum to 300 PSI in worst conditions.

The main criterion for a chilling compressor is that it should take care of part load conditions. I mean there should be some built in capacity control. In normal air compressors, you operate them at full load at all conditions and use a receiver as buffer. But chilling compressors are recirculating type and you should move only that quantity which is required for optimum power consumption.

There are reciprocating, screw and centrifugal compressors for bigger applications (and also scrolls for small units). The main difference is the capacity (tonnage)in the same order and their response to load variation.

If I can ask, what type of compressor is yours? Don't worry if you don't want to say.

Finally what about my royalty?

I wish you success in your invention.

Best Regards,

 

[Leffe]

Thankyou for your reply. Now I know that we are talking aboute 10 - 20 bar pressure. I also didn't know that centrifugal compressors was used in cooling units. You can think of the compressor I have made as a rotor compressor similar to a lysholm screw only "mine" has less internal leakage and can operate efficient over a wide range of speeds.
Aboute what size do one prefer a screw before reciprocating and why? Screwcompressors for air uses oil for cooling but also to reduce internal leakage. How is this done in screwcompressors for cooling?
Right now all my money goes in to the prototype so for your royalty,,,,sorry.

Leffe

 

[quark]

Centrifugal compressor is used for low pressure applications. R123 is a refrigerant which has condenses at ambient temperature at even 90 psi. A thumb rule for type of compressor and capacity is like this.

Upto 100TR - Reciprocating compressor
100TR to 300TR - Screw compressor
200TR and above - Centrifugal compressor
1 TR = 12000 BTU/Hr = 3024 kCal/Hr(approx)

Basically it is because of effciency at low load conditions. Centrifugals have very good efficiency at low loads with combined guide vane control and variable speed arrangement. Recips are not good above 100 TR. It is not that there are no smaller screws. I saw screw chillers of 50TR capacity also.

Yes, cooling is done by oil. The capacity control is done by a solenoid type plunger which controls refrigerant flow into the compressor based on the temperature of the chilled fluid. I have a personal dislike to screws because of their metallic noise. If you do something in this regard, that would be much better. The oil you are using shuld be compatible with the refrigerant.

I am not sure, if varying the speed of positive displacement compressors decrease power consumption or not. Basically I am at the user end and though I actively participate in overhauling of compressors, never been through the manufacturing details.

York and Mcquay are two good manufacturers. Physically check their machines for good understanding. If you want to learn about refrigeration, a good book is
Principles of Refrigeration by Roy J Dossat

Americal Refrigeration Institute (ARI) has procedures for testing chiller equipment.

I will be happy to help you.

Best Regards,