Читать книгу Maintaining Mission Critical Systems in a 24/7 Environment - Peter M. Curtis - Страница 63

Combined Cooling, Heat & Power (CCHP), also known as cogeneration, is an ideal strategy for improving data center energy efficiency. This is accomplished by using some form of power generation equipment that also produces thermal energy as a by‐product. Since data centers typically require 24x7 cooling, the recovered thermal energy can be used to activate absorption chillers that turn the waste heat into free cooling.

There are two types of power generating equipment that can be easily integrated with a DC distribution system. One is a fuel cell. The fuel cell is an electrochemical device that produces DC electricity, much like a battery. Only a voltage regulator is needed to match the DC voltage of the fuel cell to the DC distribution voltage or an inverter to create AC power that can be synced to a building’s electrical supply or used independently. Since the chemical reaction within the fuel cell produces heat, this thermal energy can be recovered and used to drive an absorption chiller.

Figure 3.7 Absorption Chiller

(Courtesy of Yazaki Energy Systems, Inc.)

Figure 3.8 Typical Fuel Cell

(Courtesy UTC Power)

The microturbine is another prime mover that can produce DC power. Microturbines operate on the Brayton cycle to rotate a small permanent magnet alternator at very high rpm to generate high‐frequency AC, which is rectified to DC. A voltage regulator can be used to match this DC to the DC distribution voltage, or an inverter can convert the DC power to 60hz AC. The turbine exhaust can be run through a heat recovery absorption chiller to make chilled water.

Figure 3.9 Microturbine CCHP System

(Courtesy UTC Power)