This white paper from Coolcentric discusses CAPEX and OPEX costs of cooling a data center. The paper compares the traditional CRAH air cooling method utilizing chilled water to passive Rear Door Heat Exchanger (RDHx) solutions. Our study concludes that in terms of CAPEX, the RDHx cooling is roughly equivalent to CRAH cooling at approximately 5kW per rack power dissipation. However, OPEX for RDHx cooling, is better at reducing today’s energy costs. As we look to the future and the expectation that energy costs will continue to rise, OPEX savings from an RDHx cooling solution are likely to be even more significant.