/ 6 kW electricity ı 9,5 kW electricity ı. 45 kWataa0c MAKALE / ARTICLE 175 kW natura! gas --+ ■ . . 45 kW at 1000 °c . Liquiddesicant system ·---·• - . :/�?, m;� 1 ■ 1 �ı,;o 1 improvements. lts remote location makes it difficult and costlyto provide steam and chilled waterfrom campus sources, so heating and cooling are provided atthe building site. The faur-story building was built with two cooling zones, handled by separate air 140 kW (40 tonnes) of cooling Figure 1. Schematic of the planı serving Zone 1 This advanced technology integration requires a new application of existing technical expertise and cooperation between government, academia and industry. Through the lntegrated Energy Systems Test Center at University of Maryland; the DOE, Oak Ridge National Laboratory (ORNL), equipment manufacturers and utilities are learning to work together to integrate distributed energy systems into a commercial building's existing energy architecture more effectively, testthose systems, andtransferthe new expertise to industry, the engineering community, the government, building owners and educators. The Test Center is experimenting with systems that have been engineered in the fıeld, right outside the building. The DOE and the University of Maryland co-found the Test Center, and ORNL provides technical management. Phil Fairchild, Program Manager far Cooling, Heating, and Powerfar ORNL, explains, 'What we are trying to do here is to put together different pieces ofequipment, use recoverable energy, and in doing so, understand the science of integration so that we can betler advise manufacturers how to integrate equipment in the future. lf we reach our goals, manufacturers will have a betler incentive, in terms ofeffıciency gains, to offer packaged or modular systems to the commercial building sector'. THE INTEGRATION TEST CENTER The Test Center is located in College Park, Maryland, where winters tend to be mild and summers fairly hat and humid, and is housed in the Chesapeake Building at the edge ofthe University of Maryland campus. The administration building is an ideal test site because it represents a typical commercial building. At 5000 m2 , the building qualifıes asa mediumsized office building, a group comprising 23% of US buildings. Builtin 1991 and powered by electricity, the Chesapeake Building alsa has signifıcant room far energy effıciency '� handlers. Fortuitously, this design gives Test Center personnel the opportunity to test two different CHP systems. However, because the top two floors have larger cooling loads due to sunlight and rising heat, direct comparison ofthe performance of different systems is not possible. The building's original design included an air conditioning variable air volume (VAV) system served by two 90 tons direct expansion (DX) electric rooftop units (RTUs). Electric reheat coils in the VAV boxes are used far heating. Each RTU serves one of two zones, each consisting oftwofloors. The CHP componentsfarthe TestCenterwere integrated into his original system and are described below. The existing RTUs are stili used, but a greatly reduced rate. To assess how much improvement in the energy efficiency, emissions and indoor air quality the building has achieved, ORNL and the University of Maryland characterized the Chesapeake Building's baseline energy use in late 1999. This characterization included an examination of load profıles, energy distribution, HVAC controls, and mechanical equipment design. Two natural gas-powered, engine-driven Goettl airconditioners (EDACs), an existing 90 tons rooftop air conditioning unit, anda Kathabar desiccant dehumidifier cool and dry air in Zone 1 (see Figure 1 ). Waste heat from the EDAC, normally discarded, powersthe dehumidifier, reducing the need farexternal power. The dehumidifıer supplements the cooling load on the EDAC and RTU by drying supply air, a function typically done by the mechanical cooling of the EDAC and RTU alone. Together, these interactive components cool Zone 1. A Capstone 60 kW microturbine, an existing 90 tons rooftop air conditioning unit, an ATS desiccant dehumidifıer, and a Broad absorption ehiller supplement electrical powerfarthe building and cool and dry air in Zone 2 (see Figure 2). The microturbine generates 60 kW of electrical powerfarthe building. Waste heat from the microturbine exhaust provides the driving heat tor the absorption ehiller and the reactivation heatfarthe dehumidifıer. The absorption ehiller assists the TRU in providing air conditioningfarZone 2. The dehumidifıer dries the supply air far the building, a function normally done by the RTU. Together, these components interact to efficiently supply air conditioning far Zone 2 and reduce the grid electric demand ofthe entire building. Controls and communications hardware and software programs enable CHP and building energy equipmentto work in concert, facilitating integration ofthe individual components. The equipment room in the Chesapeake Building was converted into the IES Controls and Communications Center. Monitoring and control tools are housed at this center, including software developed by the University of Maryland. ENERJi & KOJENERASYON DÜNYASI 59
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