They both have a similar working principle , but the assembly of the refrigerator is slightly different. In the Refrigerator,  the condenser is incorporated with it in the same confined space, thereby, rejecting the heat back to the room rather than cooling it.  While, in the case of the Air-conditioner, the condenser is placed outside the room.. in that way, the generated heat is rejected outside and the room is cooled. 

In the case of the refrigerator, Increasing the load means, increasing the heat absorbed by the evaporator being sent to the condenser and the heat gotten from the work done in the compressor as well. This lead to more heat in the room. 

If you want to make the Refrigerator to function as the air-conditioner, ensure to evacuate the condenser from the room and install a proper circulatory system in the refrigerator as well. 

Hope this help.