134A not less efficient than R12, was RE: HVAC diagram

[Dave Pisciotta]

The following was clipped from www.griffiths.com  I have found it to be a
good resource.

"Is R134a less efficient than R12 ?
R134a is NOT less efficient than R12. Actually R134a is more efficient.
Pound for pound R134a is a more efficient refrigerant than R12. Whether
R134a performs as well as R12 in any given a/c system depends upon system
components and the amount of R134a used. Given two identical vehicles, each
with the same weighted amount of refrigerant, the vehicle with the R134a has
the "capability" to remove more heat (measured in btu's) from the vehicle
than the same type of vehicle using the same amount of R12. The most common
influences which effect the capability of R134a to perform well are the
condenser, the superheat setting of the expansion valve or the amount of
R134a. Condensers designed to release greater amounts of heat help evacuate
the greater amount of heat which R134a removes from the car's interior. And
by "matching" the correct amount of R134a to use in a given vehicle,
correcting the superheat of the expansion valve, you can in the same manner
balance or match the amount of heat drawn out by the evaporator and released
by the condenser. These efforts to "balance" the system can not be realized
if there are problems within the a/c system, such as: poor performing
compressor, dirty condenser or poor air flow through the condenser,
malfunctioning expansion valve, water or air in the system, improperly
operating fresh air or heat input in the climate-air mixing system. "

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