For Hvac scope in India average but try some international standards country like middle East US, And UK etc.

They are leading users for Hvac system design.

For this Hvac system design you can join training center or you can work any MEP Consulting or MEP contracting company you will get some idea about Hvac system design.

Plz check the below link for some idea about Hvac project oriented training center.

Krish Chennai’s answer to Which are best institutes for HVAC course in South India?