Heat loss analysis review: Parabolic trough and linear Fresnel collectors

Linear concentrating solar power systems represent the most commonly installed types of concentrating solar power systems. These systems can be categorized into two types: parabolic trough collectors and linear Fresnel collectors. Due to their widespread use, they have garnered significant attention in different studies aiming to enhance their efficiency. This study conducts a review of studies conducted over the past decade, focusing on the various types of heat losses, a crucial parameter influencing the efficiency of linear concentrating solar power systems. It encompasses analytical, experimental, numerical, and hybrid studies related to heat losses in three subsystem classifications: simple tubular absorbers, compound parabolic collectors, and cavity receivers. Heat loss literature can be categorized into four parts: three focused on reducing losses through enhancements in geometrical and structural configurations, the use of different heat transfer fluids, and various coating materials. The fourth category involves calculating or measuring heat loss alongside other important parameters in a proposed system. The assessment reveals that most studies (62.23% for parabolic trough collectors and 71.4% for linear Fresnel collectors) have focused on general studies to calculate heat loss. Approximately 14.89% of studies on heat loss mitigation for parabolic trough collectors concern geometry and coating materials, and 7.98% involve using different heat transfer fluids to reduce heat losses. In the case of linear Fresnel collectors, 27.14% of studies focus on geometry, while only 1.46% deal with heat transfer fluids, and no studies have been found regarding the use of materials to decrease heat losses in linear Fresnel collectors.