Design of Ericsson Heat Engine with Micro Channel Recuperator

Stirling cycle and Rankine cycle heat engines are used to transform the heat energy of solar concentrators to mechanical and electrical energy. The Rankine cycle is used for large-scale solar power plants. The Stirling cycle can be used for small-scale solar power plants. The Stirling cycle heat engine has many advantages such as high efficiencyand long service life. However, the Stirling cycle is good for high-temperature difference. It demands the use of expensive materials. Its efficiency depends on the efficiency of the heat regenerator. The design and manufacture of a heat regenerator are not a trivial problem because the regenerator has to be placed in the internal space of the engine. It is possible to avoid this problem if we place the regenerator out of the internal engine space. To realize this idea it is necessary to develop the Ericsson cycle heat engine. We propose theoretical model and design of this engine. 1. Introduction There are many different sources of sustainable energy. Indirectly many of them are produced as a result of solar activity, but usually the term “solar energy” means direct transformation of sun light to other types of energy. There are different types of solar energy plants. In this paper we will consider a Solar Thermal Energy System (STES). STES consists of a solar concentrator, a heat engine, and a generator of electric current. Sometimes it also includes an energy storage system. The solar concentrator permits us to obtain the high temperature needed for heat engines. In our previous work we described a low-cost solar concentrator based on multiple triangular flat facets [1–3]. Two prototypes of the solar concentrators are presented in Figures 1(a) and 1(b). Figure 1: Two prototypes of the solar concentrators. Two types of heat engines are usually used now in STES: steam turbines and Stirling engines [4–7]. Steam turbines are good for large power plants, and Stirling engines are proposed for distributed installations. The Stirling engine in general has high efficiency, long service life, and many other useful properties, but in existing versions it demands high-temperature difference [8] and for this reason demands expensive materials. This leads to elevated cost of this engine. The Ericsson Cycle Heat Engine at present is investigated not so good as the Stirling Engine, but it has many promising properties and can be considered as a good candidate for STES [9–11]. 2. Stirling Engine The scheme of Stirling engine is shown in Figure 2, it contains a hot cylinder, a heater, a regenerator, a cooler, a cold cylinder,