Page 402 - Advances in Renewable Energies and Power Technologies

1. Introduction 375

FIGURE 12.2
Solar collectors: (A) parabolic troughs; (B) parabolic dishes; (C) tower; and (D) linear
Fresnel reflectors.
Courtesy R. Guerrero-Lemus, J.M.M. Martı ´nez-Duart, Concentrated solar power, in: Renewable Energies and
CO 2 , Springer-Verlag, London, 2013, pp. 135e151.
climatic conditions, such as clouds or low solar irradiation. Short-term thermal stor-
age systems, with a 1-h capacity, can be used to ensure the production of energy on a
cloudy day. Despite clear benefits, most of the early operating pilot and commercial
solar power plants lacked significant thermal storage, typically relying on steam or
1
oil accumulators for thermal inertia. For large-scale power plant applications, the
use of battery storage has not been explored due to economic limitations.
Table 12.1 compares the main CSP technologies, considering storage integration
possibilities, advantages, and disadvantages: parabolic trough collector (PTC), LFR,
solar power tower with heliostat field, and PD.
In a heat engine, power conversion efficiency is theoretically limited by Carnot’s
efficiency and is related to the quality of energy, and thus temperature, of the thermal
energy supply. In an electricity generation system based on solar energy, the high-
quality thermal energy required must be supplied by the collectors. Solar collectors
are affected by energy losses (reflection, glazing absorption, convective heat transfer,

1
P. Gauche ´, J. Rudman, M. Mabaso, W.A. Landman, T.W. von Backstro ¨m, A.C. Brent, System value
and progress of CSP, Sol. Energy. 152 (2017) 106e139