Section 2, Engineering Guidelines - Power Dissipation Considerations61186003L1-1D 2-9Configuration Guidelines for the MX2820 SystemMX2820 systems can be actively cooled with fans or passively cooled by appropriately spacingshelves and incorporating baffles into the bay design. For maximum density, fans are recom-mended for the MX2820 system.The following recommendations apply to 19-inch shelves:• Actively cooled (multiple shelf cooling):– Working from the bottom of the bay, install heat baffle and filter assembly (P/N1182005L1 and 1182971L1).– Directly above heat baffle, install up to three MX2820 Chassis (P/N 1186001L1).– Directly above the shelves, add a heat baffle, Fan Module, and filter assembly (P/N1182005L1, 1182006L1, and 1182971L1).– Repeat these steps for additional shelves for up to three shelves between Fan Modules.The filter is unnecessary on the heat baffle above the top MX2820 shelf in the rack.– Figure 2-1 provides an example.• Passively cooled:– Working from the bottom of the bay, leave a 1U space between the bottom of the rackand the first shelf. Install a MX2820 Chassis (P/N 1186001L1).– Leave a 1U space. Install a 1U passive heat baffle (Newton P/N 0040780114).– Leave an additional 2U space, (4U total between shelves), and install another MX2820shelf.– Repeat these steps to fill the bay leaving a 2U space above the top-most shelf.– Figure 2-2 provides an example.• Actively cooled (one-to-one pusher fan):– Locate at least 3U space in a rack for each MX2820 chassis installation. Install a FanModule Assembly (P/N 1184507L1) at the bottom of the 3U space.– Directly above the fan, install a MX2820 Chassis (P/N 1186001L1).– Figure 2-3 provides an example.The following recommendations apply to 23-inch shelves:• Actively cooled (multiple shelf cooling):– Working from the bottom of the bay, install heat baffle and filter (P/N 1181003L1 and1181971L1).– Directly above heat baffle, install up to three MX2820 shelves (P/N 1186001L2).– Directly above the shelves, add a heat baffle, Fan Module, and filter (P/N 1181003L1,1181006L1, and 1181971L1).– Repeat these steps for additional shelves for up to three shelves between Fan Modules.The filter is unnecessary on the heat baffle above the top MX2820 shelf in the rack.– Figure 2-1 provides an example.
