indicates the first tei threshold tei_lim 1 dashed line and the second tei threshold tei_lim 2 dotted line e g as used in steps 206 212 and 218 of the method in fig2 in this example the first tei threshold is 90 u00b0 c min while the second tei threshold is 70 u00b0 c min as can be seen the temperature error integral tei goes down when the supply air temperature is below setpoint and rises again when the supply air temperature is above setpoint as soon as the temperature error integral exceeds the second tei threshold tei_lim 2 then in fig2 test 218 is no and 220 is yes and the compressor will be switched on after the minimum off time for the compressor step 214 has elapsed graph 305 illustrates the state either being on or off of the compressor full line as a function of time the graphs 301 303 305 show a regular cycle pattern of the compressor and related variables the graphs in fig4 show an irregular cycle pattern the irregular cycle of fig4 is designed to avoid and or reduce ice formation in the cooling space of the refrigerated transport container as have been explained.