58 MAKALE/ ARTICLE Technology Reciprocating Engine Turbine and microturbine Fuel Celi Typically, CHP systems are built by engineers with expertise in broad areas of HVAC technology. Engineers specify equipment from various vendors and suppliers who provide controls, chillers, storage tanks, cooling towers, heat exchangers and electrical Size lnstalled cost ($/kW)' Electricla efficiency (LHV) Overall efficiencf Variable O&M costs ($/kWh) Footprint Emissions (g/kWh unless othe<Wise noted 30 kW-8MW 300-1500 28-42% -80-85% 0,0075-0,02 0,02-0,03 Diesel: NOx: 9,9-11, CO: 0,45-0,9 Natura! Gas: NOx: 0,7-1,7, C0:1,8-2,7 30 kW-20 MW + 350-1500 14-40% -85-90% 0,004-0,01 0,01-0,03 NOx: 3-50 ppm CO: 3-50 ppm 100-3000 kW 2000-5000 40-57% -80-85% 0,002-0,05 0,08 NOx: <0,02 C0:<0,01 Fuels Diesel, natura! gas, gasoline, digester gas, biomass and landfill gas; larger units can use dual fuel (gas/diesel) or heavy fuels Natura! gas, diesel, kerosene, naphta, methanol, ethanol, alcohol, flare gas, digester gas, biomass and landfill gas Natural gas, propane, digester gas, biomass and landfill gas (potentially) connection equipment. Timeconsuming consultations with multiple vendors may be needed to ensure that the equipment will interact in a way that yields optimal performance. Each individual component must be custom engineered into the building's system design. This process is fıne for large systems, but far too costly and complex for systems providing less than 1 MW. 1 Cost values signifıcantly based on siting and interconnection requirements, as well as unit size and confıguration. 2 Assuming CHP Source: Resource Dynamics Corporation, lntergrated Energy Systems (IES) for Buildings: A Market Assessment, August 2002. Table 1. Costs and performance dala for CHP technologies also more efficient and require less fuel than traditional systems. According to the US Department of Energy, CHP systems could reduce annual greenhouse gas emissions by at least 25 million tons ofcarbon ifthe Government's goal to double US installed capacity by 201 O were met. CHP can also improve indoor environmental quality (IEQ). US buildings consume at least 30-50% more energy than necessary to provide adequate IEQ. However, heating, ventilation and air conditioning (HVAC) systems often do not provide sufficient humidity control or meet a building's need for outside air. in combination with a desiccant dehumidifıer, CHP systems can provide betler humidity control then conventional systems, and reduce the potential for mould and bacteria growth. Table 1 summarizes the cost and performance of CHP technologies. While price and performance dala on reciprocating engines and gas turbines are fairly well established, data for fuel cells are based on a limited number ofdemonstration projects. Asa resul!, comparisons of price and performance should be interpreted with some uncertainty. PACKAGED CHP FOR PLUG-AND-PLAY INSTALLATION Despite these potential benefıts, the commercial sector has not invested as heavily in CHP as the industrial sector. Conventional large cogeneration systems in industrial settings are well developed and widely deployed, and use readily available thermal technologies. One prevalent barrier to widespread CHP application in the commercial sector is the lack of pre-packaged, pre-engineered systems that can 'plug and play' into a building's existing energy system as one unit. Ronald Fiskum, Program Managerforthe US DepartmentofEnergy's Office of Distributed Energy and Electric Reliability, notes, 'American manufacturers are very good at developing air conditioners, boilers and power generation as stand-alone pieces of equipment that perform very well. However, we have not considered that, in the real world, these individual contributors do not function efficiently with one another. lntegrating technologies into modular systems that include on-site power generation, heat recovery and thermally activated technologies will achieve synergistic efficiency gains not possible from individual contributors'. ENERJi & KOJENERASYON llONYASI To make CHP systems less expensive, less complicated and less time-consuming to install in smaller applications, CHP component manufacturers need to offer building owners pre-engineered, modular CHP systems. Simplified, skid-mounted packaged CHP systems would make it easier for building owners to connect power, piping or ducting systems. M2��, :-!..lilding owners make their decisions on the basis offırst cost, and CHP often costs more than conventional alternatives. The use of modular CHP systems could be a breakthrough in energy efficiency and cost-effectiveness for buildings. According to the Department of Energy (DOE), integrated CHP systems can offer up to a 30-40% improvement in building efficiency over today's besi practice, leading to reduced energy and demand charges for building owners. For higher degrees of inter-operability, CHP component manufacturers need to create equipment that physically fıts together, matches power and thermal loads, and communicates effectively. Universal connection standards would greatly simplify installation and maintenance -and encourage acceptanceofthe technology bythe architectural and engineering community. Controls may be connected to a loca! network, permitting on-site personnel to operate the equipment directly from a desktop PC. Notes Ronald Fiskum: 'in the near future, CHP for building systems will be engineered in the factory instead of in the fıeld. Packaged integrated energy systems -where you deliver a system, make electrical, hol water, and chilled water connections, and push the start buttan - will be on the market. INTEGRATING CHP INTO EXISTING BUILDING SYSTEMS A second obstacle to widespread CHP adoption in commercial buildings is the lack of understanding of how a building's existing energy system and on-site power systems should be integrated. The 'integrated energy systems' (!ES) is a new approach to incorporating CHP systems into a commercial building or industrial plant's energy system - including HVAC, doors, windows, distribution systems, controls, insulation, building materials, lighting and other equipment.
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