Innovative hybrid gas/electric chiller cogeneration
January Progress--A kick-off meeting was held in San Diego with Alturdyne on January 21st. The proposed hybrid gas/electric chiller/cogenerator design concept was discussed in detail. The requirements and functionality of the key component, a variable speed, constant frequency motor/generator was presented. Variations of the proposed design were also discussed based on their technical feasibility, cost and market potential. The discussion is documented in a Trip Report. February Progress--After significant GRI/Alturdyne discussion regarding alternative product design concepts, the team made a decision to continue with the proposed product design, a hybrid chiller capable of also providing emergency power. The primary benefits are: (a) the flexibility and operating cost savings associated with the product's dual fuel capability and (b) the emergency power feature. A variable speed, constant frequency motor/generator would significantly increase the cost of the product while providing marginal benefit. (The variable speed, constant frequency motor generator is estimated to cost $25,000 versus $4,000 for a constant speed version). In addition, the interconnection requirements to the electric grid would significantly limit market penetration of the product. We will proceed with a motor/generator design capable of serving as the electric prime mover for the compressor as well as the generator for emergency power needs. This component design is being discussed with two motor manufacturers. The first generation motor/generator will not be a variable speed, constant frequency design. The variable speed, constant frequency capability can be an advancement that is included at a later time. The induction motor/synchronous generator starts as a wound rotor motor with a brushless exciter and control electronics to switch between induction mode and synchronous mode. The exciter is a three-phase exciter with three phase rotating diode assembly. In the induction motor mode, the field windings are shorted out by SCRs located across the field. In the synchronous mode, a small ct on one of the exciter leads would power the rotating exciter electronics. Upon sensing exciter current, the electronics would automatically open the SCRs allowing synchronous operation. Quotes will be obtained from American Motor and Reuland, two motor/generator vendors. March Progress--A product layout was completed. The width is reduced significantly from the original hybrid design because the evaporator and condenser tube in shell heat exchangers are located below the engine/motor/compressor drive-line. Alturdyne is searching for a consultant to perform a drive-line torsional analysis. This analysis is necessary to ensure that the drive-line is not subject to undue vibrations operating through its entire speed range. Much effort was directed toward motor/generator selection. A decision was made to use Reuland Electric. A motor with double-end shafts will be purchased. The design effort which will be completed at Alturdyne will involve the modification of the wound rotor motor to also provide synchronous power. Work has been completed on developing the new controller which will be utilized for the original hybrid product as well as this advanced product. Work continues toward developing a manufacturing cost estimate. A detailed bill of material will be developed for the product. Key components include the engine, compressor and motor/generator.
- Research Organization:
- Federal Energy Technology Center Morgantown (FETC-MGN), Morgantown, WV (United States); Federal Energy Technology Center Pittsburgh (FETC-PGH), Pittsburgh, PA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- FC26-99FT40641
- OSTI ID:
- 774502
- Report Number(s):
- DE-FC26-99FT40641-01; TRN: AH200109%%3
- Resource Relation:
- Other Information: PBD: 1 Apr 2000
- Country of Publication:
- United States
- Language:
- English
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Innovative hybrid gas/electric chiller cogeneration. Quarterly technical progress report, April--June, 2000