During part- load operation, the evaporator temperature rises and the condenser temperature
falls, effectively increasing the COP. But at the same time, deviation from the design
operation point and the fact that mechanical losses form a greater proportion of the total
power negate the effect of improved COP, resulting in lower part- load efficiency.

iread the above ^^^ in a book,the thing is i do not understand this.

How would operating at part load increase the COP( change the evaporator and condensor temperature respectively)
from what i noe of refrigeration:
COP=te/tc-te
where te= is the temperature of the refrigerant in the evaporator
tc= the condensing temperature of the refrigerant

By part load they mean when the refrigerator is not full( say with food in a domestic one)
please explain ?
thnks in advance