Total power and BTU are misleading, as the POE endpoint devices are outside the telecom room. For example, 48 POE+ devices, like a 3802 access point, will be dissipating a total of 4910 BTU/h (48 * 30w * 3.41 BTU/h/w) wherever they are out in the building, but not in the telecom room. So of the potential 2200 w (7502 BTU/h) of the two power supplies, 4910 BTU/h of that will be outside the room that I'm interested in specifying cooling for. The remaining worst case 2591 BTU/h is what potentially could be dissipated inside the com room. Some of that heat is from the switch electronics, which is powered from the two 1100w power supplies, and some of that heat is wasted from the inefficiency of the power supplies.
From the technical specifications section of the 3850 Hardware Installation Guide, the 1100w power supply total input power/btu is 1250w/4263BTU/h. The total output power/btu is 1100w/3751BTU/h. So our waste heat is (4263-3751) = 512BTU/h, or 150w for each power supply in the switch.
So we know the waste heat of the power supplies and we know the amount of heat dissipated outside the closet, but we don't know how much heat the switch electronics give off. The data sheet lists power consumption by a standalone switch with no PoE devices connected: At 100% throughput the 3850-48F consumes 132.36w, so produces 451BTU/h. Our total potential com room heat load from the 3850-48F with two 1100w power supplies is 1475 BTU/h.
Someone please show me this is incorrect.
