Economical and technological performances as well as collector efficiency have to be taken into consideration to evaluate the low temperature solar thermal power system with two – stage collectors. However, this work is concerned about influences of working fluids on heat collection and power conversion efficiency. In addition to key factors such as irradiation and […]

The parameters for simulation are listed in table 2. The collectors and turbine are key issues of the low temperature solar thermal power system and the performance is proposed according to market available product [20, 21, 22]. The second-stage heat storage medium appropriate for the low temperature solar thermal electric system could be erythritol, which […]

Viscosity of the oil is generally larger as compared with that of working fluid or water. For precise simulation, flow frictional resistance of oil should be evaluated. With N lines of the parallel concentric tubes, the required pump power is obtained by the following [17]:

Energy balance of the conduction oil remains to be controlled by Eq.17. However, energy balance (dryness) of organic fluid is controlled by the following: = П (T – Tf) (19) dY mf(hf, v – hf tl) Convection heat transfer coefficient of two-phase flow can be obtained in Rohsenow’s handbook [19].

The controlling equations for the energy balance of working fluid and conduction oil are as follows: dTf UnDi (Th – Tf) (16) dY mfCp, f T = UnDi (Th – Tf) (17) dY mhCp, h Total heat transfer coefficient is calculated by the following: U = 1 (i + ± hi K where The convectional […]

Thermal efficiency of FPCs can be calculated directly by the inlet and outlet temperatures of working fluid, according to Eq.14. On the other hand, thermal efficiency of CPC collectors is determined by the heat transfer process in the evaporator. The temperature relationship between working fluid and conduction oil must be established. This section focuses on […]

The FPC or CPC collector module available in the market has an effective area of approximately 2.0 m2 . Its thermal efficiency can be expressed by the following equation: П = П -|(T – T“) –B(T – Ta)2 (7) Solar thermal electric generation system may demand tens or hundreds of collectors in series, and the […]

1.1 Calculation of thermodynamic cycle Figure 2 presents the scheme of thermodynamic cycle of a typical dry fluid. Point 1 illustrates the state of fluid at the condenser outlet; Point 2 at the Pump 1 outlet; Point 2′ at the regenerator outlet; Point 3 at the FPC collectors outlet; Point 4 at the evaporator outlet […]