A customer is building a new data center. They want to implement a free cooling strategy in order
to reduce their Computer Room Air Handling (CRAH) costs, while increasing their rack density.
Which free cooling methods meet the customer requirements? (Select two.)

A.
Water-side economization

B.
Air-side economization

C.
Cold-aisle containment

D.
Closed-loop containment

E.
Hot-aisle containment

Explanation:
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c02507744/c02507744.pdfp4, topic
“free cooling strategies”