Design, manufacture, and test of a prototype for a parabolic trough collector for industrial process heat

• The manufacture of low-cost PTCs for industrial process heat is a key issue.
• We present a small PTC built in fiberglass and extruded polystyrene.
• Main features are the low cost and weight, high resistance and ease of manufacture.
• Tests were performed using demineralized water for temperatures up to 85 °C.
• The intercept of the thermal efficiency equation is 0.658 and the slope is −0.683.

The manufacture of low-cost parabolic trough collectors (PTCs) for industrial process heat applications ranging from 70 to 250 °C is crucial for the widespread availability of this solar technology. Thus, we present a prototype of a PTC with a 90° rim angle and a small concentration ratio of 9.25 built in fiberglass and extruded polystyrene, called UNIVPM.01. Fiberglass is used as the external shell and extruded polystyrene as the inside fill component. The receiver is an aluminum pipe of circular cross-section, contained within a low-iron glass envelope. The tracking system is based on a solar-position computer program. The main features of this prototype are its cost-effectiveness, low weight, high mechanical resistance, and ease of manufacture. First, we show the design and manufacturing process in detail. Then, we describe the test bench used to evaluate the collector thermal efficiency. Tests were performed following the directives of ASHRAE Standard 93-2010 and using demineralized water for temperatures up to 85 °C. Results show that the equation for thermal efficiency is comparable to that of other similar collectors available in the literature: the intercept is 0.658 and the slope is −0.683.