Micro-CHP technologies for distributed generation

In this report different [.]-CHP technologies were reviewed. Typical features of [.]-CHP units based on internal combustion engine are: low costs, high efficiency, wide power range and ability to run on different fuels. Internal combustion engine power plants are modular, i.e. standardised units can easily be combined. Their weak points include noise, high emissions and high maintenance costs. Advantage of gas turbines is small size. Disadvantages include poor efficiency at part load and high investment cost. Advantages of Stirling engine, when compared with internal combustion engines, include stable combustion, low noise and emissions and longer maintenance intervals. Advantages of fuel cells are: high electrical efficiency (also at part load), low noise and emissions. Disadvantages are very high costs and fuel quality requirements. Besides natural gas and heating oil, wood chips or other biomass may be used in ICE, Stirling engines or microturbines. Gasification stage and gas purification is required with ICE and microturbine. The benefit is the wide availability, renewability and often low cost of biomass. Finally, [.]-CHP can use solar radiation as energy source. The disadvantage will be that output cannot be modulated according to user and system needs.