255Utility Interfacing

As previously noted, Stirling generators can be used for both on- and off-grid applications. It is left to the utility companies and their customers to decide what is most appropriate. Stirling generators are reliable enough that a utility company may consider leasing a unit to a remote off-grid customer, thus avoiding the costs of building power lines or larger generators on site. An off-grid Stirling micro-cogeneration system is a very reliable and cost-effective solution for providing heat...

1026 Stirling Engines

The Stirling engine so named because it is based on the Stirling thermo-dynamic cycle was conceived more than a century ago. Stirling engines produce power not by explosive internal combustion, but by an external heat source usually a continuous-combustion burner. Until recently, reliability problems have limited their use to hobbyists. It is only in the past generation that a viable free-piston Stirling was developed. All Stirling engines can be operated with a wide variety of fuels, including...

254 Controls and Communications Dispatchability

The characteristics of Stirling generators allow them to be located inside homes, businesses, and similar environments where IC generators would be intolerable because of their high noise and maintenance levels. The most popular application of Stirling generators is in micro-cogeneration systems. In these systems, the generator is coupled to a household boiler (a water heater for hydronic space heating), so electricity and hot water are produced simultaneously from the same fuel. Stirling...

25 Stirling External Combustion Engines

A Stirling engine is an external combustion heat engine and, therefore, does not require a specific fuel a Stirling engine-generator can convert any sufficient heat source into useful electrical power. These generator sets are also physically small and very efficient even below 100 W (e). With the added advantages of high reliability, long life, very low noise, and maintenance-free operation, Stirling engines are ideal for distributed generation applications where the generator must be located...

252 Fuels

One of the singular advantages Stirling engines have over internal combustion engines is that they are truly multi-fuel capable. The Stirling cycle requires only a sufficient heat source to operate and does not rely on carefully timed fuel injection and combustion processes as do internal combustion engines. Practical Stirling cycle engines may be operated using propane, natural gas, gasoline, diesel, radioisotopes, solar energy, and even wood or other biomass. The only limitation on fuel...

51 Single Shaft Gas Microturbines

The classic open Brayton cycle described in Chapter 3 is also the basis of gas-fired microturbine (MT) engines. The reader is referred to that chapter for cycle basics. Several single-shaft MTs have been developed recently by Capstone, Elliott, and Honeywell with ratings between about 20-150 kW. Some published specifications for these four MTs are listed in Table 5.1. A number of MT flow-path configurations are depicted in Figure 5.1, the most compact of which is the wrap-around recuperator...

251 Design

Stirling engines operate on a closed thermodynamic cycle where a temperature differential is converted into mechanical and or electrical power. External heat is supplied at a high temperature to the engine heater head, and thermodynamic waste heat is rejected to ambient temperature. An internal displacer piston physically shuttles the helium working fluid between the hot and cold regions, creating a varying pressure value. That pressure wave causes the power piston to reciprocate. The...

1041 CHP Technology Cost and Performance Characteristics

Table 10.4 shows characteristics for application sizes from as small as 50 kW to as large as 25 MW. The heat rates and recoverable thermal energy factors are based on commercial product specifications, with the exception of the microturbine, for which performance factors are estimated. Microturbine cost factors were estimated based on assessment of early market entry economics and not manufacturers' projections for high volume production. Package costs, heat recovery equipment costs, and...

253 Technical Developments and Outstanding Barriers

Stirling cycle engines have developed considerably in recent years. The free-piston configuration has served as an enabling technology for a great deal of energy conversion development. Stirling Technology Company (STC) and Sun Power Inc. are the leading developers of free-piston Stirling cycle engine generators with capacities ranging from 10 W to 5 kW. These generators have demonstrated maintenance-free operating lives far beyond that of gasoline or diesel engine generators. Ongoing endurance...

14 The Distributed Generation Technologies

Distributed generation is any small-scale electrical power generation technology that provides electric power at or near the load site it is either interconnected to the distribution system, directly to the customer's facilities, or both. According to the Distributed Power Coalition of America (DPCA), research indicates that distributed power has the potential to capture up to 20 of all new generating capacity, or 35 Gigawatts (GW), over the next two decades. The Electric Power Research...

What Is The Future Of Fuel Cells

Distributed Generation An Introduction Anne-Marie Borbely and Jan F. Kreider Distributed Centralized Distributed Again 1.1.2 De-Integration of Vertical Stages 1.1.3 Convergence of Utility Companies 1.2.1 The U.S. Transmission System 1.2.2 Utility Choices and Deregulation 1.2.3 Transmission Loading Relief TLR 1.2.4 U.S. Power Generation Assets 1.2.4.1 Non Utility-Owned Power Generation 1.2.5 Double Counting How Much Is Really Out There 1.3.1 Restructuring and Competition 1.3.2 The Future of...