APPROACH TEMPERATURE
ENERGY TRANSFER
Figure 2-... Energy/temperature diagram of the triple pressure HR$G.
The compressor train is driven by themotorjgenerator， which has a pair of clutches that enable it to act as a motor when the compressed airis being generated for storage in thecavern， declutches it from the expandertrain， and connects it to the compressor train. The compressor train consists of a three-section compressor each section having an intercooler to cool thecompressed air before it enters the other section， thus reducing the overall compressor power requirements.
The power train consists of an HP and LP expander arranged in series that drives themotorjgenerator， which in this mode is declutched from the compressor train and is connected by clutch to the HP and LP expander train. The HP expander receives air from the cavern that is regenerativelyheated in a recuperator utili.ing exhaust gas from the LP expander， and then further combusted in combustors before entering the HP expander. The
Figure 2-.4. $chematic of a compressed air energy storage plant. (A$ME Tech-nical Paper 2000-GT-0595).
expanded air from the HP expander exhaust is reheated in combustors before entering the LP expander. Can-type combustors of similar designare employed in both the HP and LP expanders. The HP expander， whichproduces about 25% of the power， utili.es two combustors while the LPexpander， producing 75% of the power， has eight. The plant is designed to operate with either natural gas or No. 2 distillate oil fuels and operates over a range of 10-110 MW.
The generator is operated as a motor during the compression mode. The system is designed to operate on aweeklycycle， which includes power generationfive days perweek， with cavern recharging during weekday nights and weekends.
.o.er Augmentation
The augmentation of power in a gas turbine is achieved by manydifferent techniques. ln thissection， we are looking at techniques， whichcould be achieved on existing gas turbines.Thus， techniques such as add-itional combustors are not considered as being practical on an existingturbine. ln other words， the concentration in this section is on practical solutions. Practical power augmentation can be divided into two main categories. They range from the cooling of theinlet， to injection of steam or water into the turbine.
Inlet Cooling
. Evaporative methods-Either conventional evaporative coolers or direct water fogging
. Refrigerated inlet cooling systems-.tili.ing absorption or mechan-ical refrigeration
. Combination of evaporative and refrigerated inlet systems-The use of evaporative coolers to assist the chiller system to attain lower temperatures of the inlet air.
. Thermal Energy Storage Systems-These are intermittent use systems where the cold is produced off-peak and then used to chill the inlet air during the hot hours of the day.
Injection of CompressedAir，Steam， or Water
. lnjection of humidified and heated compressed air-Compressed air from a separate compressor is heated and humidified to about 60% relative humidity by the use of an HRSGand then injected into the compressor discharge.
. Steam lnjection-lnjection of the steam， obtained from the use of alow-pressure single stageHRSG， at the compressor discharge andjor injection in the combustor.
. Water lnjection-Mid-compressor flashing is used to cool the com-pressed air and add mass flow to the system. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：燃气涡轮工程手册 Gas Turbine Engineering Handbook 1(38)
