If you make the air composition exactly like the Baehr environment conditions (it differs from the standard air composition and p = 1.01325 bar in your case) then you can see that the exergy flow in source 1 is only 0.01 kW, which may be a round-off error, as it should be 0 kW. In sink/source 2 the temperature is increased by 5 K. As a consequence the exergy flow to the system is 0.04 kW.

In source 7 the pressure and temperature of the flue gasses are 2 bar and 250 C and the composition differs from the environment composition, which introduces both a thermo-mechanic and chemical exergy flow to the system.