What is the relation between cfm and tr in a/c system?

Answer 1

Assume you mean a DX system, the answer is between 300 and 400 cfm per 1 TR (12000 Btu/hr). Which end is better is a heat load capacity versus energy efficiency tradeoff. The tradeoff factors going from 300 to 400 cfm/TR may be:

(1) Compressor power goes up by 5 to 10%.

(2) Evaporator superheat goes up a geat deal if load in high but may surprisingly goes down a bit when load is minimal (that is too low suction pressure causing all refrigerant to be held back is a diminishing-return condition to avoid).

(3) Energy efficient ratio (ERR) goes down, assuming the compressor is correctly sized, so that the marginal efficiency goes up with higher heat pump load.

(4) And refrigerant discharge pressure of course goes up.

Good luck.

Answer 2

in ac systems cfm is used to indicate capacity of the air handling units(AHU). cfm stands for "cubic feet per minute" which means that the AHU can deliver xxx cubic feet(volume) of air per minute.( similar to cubic metre per minute)
tr indicates the cooling capacity of the ac/ref unit. for example 1.5 tr window ac etc. tr stands for ton rating.
the relation between them comes handy when designing big ac systems.
the cfm and tr rating should match for the air conditioning to be effective and of optimum design.