MAKALE / ARTICLE 6 kW eleetrirty l 20 kW heat loss in duet 10 kW net loss in duet at 107 C ·• 40 kW 0exhaust [il] • f dry air • · - ı1oom 3 /h Lessons learned about equipment and system performance will provide manufacturers with the knowledge to build the next generation of packaged, integrated energy systems for commercial buildings. 215 kW natura! � 150 kW ex!Ja ust at 315 C Absorptionehill er 6,5 kW to absorption ehiller Figure 2. Sehematie of the plant serving Zone 2 3 kW ( 1 8 tonnes) hilled water 8 kW to solid desieeant system ünce all the own equipment is up and running, the engineering team will use a 'whole-building diagnostication' (WBD), developed by Pacifıc Northwest National Laboratory, to identify and diagnose common problems in the HVAC system and equipment. WBD is software that tracks a building's energy use, monitors the performance of air handling units, and detects problems with outside air control. A web-based monitoring and control system has been employed to provide building level data to system integration researches and the public from any site equipped with a computer and internet access. LESSON LEARNED 'The lntegration Test Center and the University of Maryland are seeking to provide essential real world answersto IES integration issues. in the short time ofthe center's existence, we have learned important technical lessons that are being transferred to industry to develop new equipment and integration solutions, such as the need for a properly designed exhaust plenum box that eliminates heat leaks to the microturbine compressor inlet,' notes Phil Fairchild. Figure 3 and 4 show the energy conversion steps when the microturbine and the absorption ehiller work together to produce power and cooling outputs, and compare this systemtotheconventional, grid-based alternative. MT effieieny = 27% Absorption parastie = 6 kW 222 Wv Absorplion COP = O.7 Figure 3. Microturbine-based cooling and power system ENERJi & KOJENERASYON DÜNYASI 60 ■ l The experience gained from the Cheasapeake Building and its IES system can be broadly grouped into four areas of design: design for CHP, energy savings, buildings and maintenance. The lessons from design for CHP pertain to any CHP system and include carefully matching exhausttemperature and mass flow rates between equipment. Unless the components are designed together, or one is designed with the knowledge that it will be packaged with the other, one component will not operate at its design point asa result of the integration, reducing its performance. Additionally, ifthe exhaust heat medium is not matched with the waste heat recovery equipment, then more heat exchange steps will be required, increasing the cost and decreasing the effectiveness of the system. DesignforCHP Design for CHP also involves looking for duplication between the individual items of equipment. Since these components are currently designed in isolation, each will come with its own controller and sensor network and differing electrical voltages. Duplications cost the customer money and introduce more possibilities forfailure into the system. One example isthe possibility ofreducing the numberofsensors when measured parameters can be shared through the centralized controller between the components, or when the number of transformers can be reduced by standardizing to only a few voltages within all components. Last in this category is the effective isolation of components from each otherwhen in not use. Forexample, dampers orvalves may leak, causing waste heat to leak into components that are otherwise shutdown. The Chesapeake Building has seen the effects of heat leakage, either through under-specifıed components or heat pathways unseen at design. When the system was conceived, there were no specifications or standards for this type ofdesign. A book is now being written based on the experiences gained. Grid effieieney = 30% 57 kW Chiller COP = 3.5 Figure 4. Conventional power and cooling system
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