hi frind the unit of cooling capacity is ton of refrigeration so u havve to cinvert 150watt in to ton of refrigeration

You do not calculate the cooling capacity by the wattage, as all fators , such as typre of refrigerant apply

Input power in watts is electrical energy and refrigeration capacity can too be be given in watts both being forms of energy ( in kj).However directly relating of input power to watts thermal is not correct as the properties of refrigerant, type of compressor and it's performance and matching of the rest of the system components , design evaporation temperature(SST), air flow through evaporator etc will play a part.The mass flow rate (kg/s) of the refrigerant ( which is a function of the compressor performance ) and the thermal properties of the refrigerant in question will give you an idea of the thearetical capacity. But compresor details such as displacement are hard to come by . Best compare in put power to input power with catalogue data of any simillar (but may be even different brand ) refrigerator to check capacity! .