Direct Steam Generation in Parabolic Troughs: First Results of the DISS Project

Abstract

This article presents the latest experimental results of the European DISS (DIrect Solar Steam) project. The experiments are subdivided into steady state and transient tests. The goal of the steady state tests is the investigation of the thermohydraulic phenomena of the occurring two phase flow, whereas the transient tests are needed for the controller design. The experimental results are compared to simulation studies. Implications for the plant operation will be discussed. INTRODUCTIONThe direct steam generation (DSG) in parabolic trough collectors is a promising option for the improvement of the reliable parabolic trough technology for solar thermal electricity generation. Several open questions concerning the DSG process have to be answered before a commercial plant can be designed. These are among others the:• operation of single and parallel rows under steady-

Influence of optical errors on the thermal and thermodynamic performance of a solar parabolic trough receiver

“…At the slope error of 3 mrad, a specularity error of 0 mrad and an inlet temperature of 600 K, the absorber tube temperature gradient is about 32 K, the glass cover temperature gradient is about 6 K and the average glass cover temperature is about 332 K or 50 o C when the flow rate is 30.8 m 3 /h. For flow rates greater than 30.8 m 3 /s, the maximum average glass cover temperature is about 78 o C at the highest inlet temperature considered in this study of 650 K. 40 considered, flow rates greater than 30.8 m 3 /h ensured temperature gradients less than 50 K, a value needed for safe operation of the receiver (Wang et al, 2013, Eck andSteinmann, 2002).…”

Heat Transfer Fluids

“…Detailed information on the two-phase multiplier M is provided in Table 3. Compared with the experimental data obtained under real operating conditions, Friedel's correlation overestimated the pressure drop by approximately 25% [21].…”

“…In order to overcome the lack of knowledge and to investigate the technical and commercial feasibility of the DSG, a complete R&D program (DISS project) was initiated in 1995 [17,21,22]. The DISS test facility was Unlike the conventional heat transfer fluids discussed in Section 3, water used in DSG solar fields experiences a transient phase-change process inside the collector tube.…”

“…Methods for predicting the pressure drop in two- Friedel's correlation was determined to be best for DSG applications from the data obtained during the DISS project [21,28,44].…”

Dynamic modeling and simulation of a solar direct steam-generating system

“…In reference [7], the one-dimensional and two-dimensional thermal oil solar parabolic collectors' models were developed using EES software, and validated with experimental data. Zarza et al [8,9] and Eck and Steinmann et al [10] presented the simulation results of the solar direct steam generation in parabolic trough test facility in Almeria Solar Platform in Spain. Besides, the simulated results have been compared with the test data in reference [10].…”