Comparative performance evaluation of candidate receivers for an etendue-conserving compact linear Fresnel mirror field

Abstract

While several studies of multitube and monotube linear Fresnel receivers exist in the literature, comparative studies on different types of receivers are limited. This paper therefore aims to address this gap within literature by comparing the optical and thermal performance of four different receivers: an adapted compound parabolic concentrator (CPC)-type monotube receiver, an adapted tailored edge ray concentrator (TERC)-type monotube receiver, a trapezoidal multitube receiver and an adapted TERC-type multitube receiver. Existing literature was used to determine the design elements limiting heat loss, which were then incorporated into the receiver design and optical optimisation of the four receivers. Once the geometry was determined through a series of Monte Carlo ray tracing (MCRT) simulations, a validated two-dimensional computational fluid dynamic (CFD) model was used to determine the heat loss of each receiver for the same thermal conditions. Given that these heat loss studies were decoupled from the optical study, they are valid for any type of mirror field. While both adapted TERC-type receivers performed well optically (with daily optical efficiencies of 56.93% and 56.6% for the monotube and multitube receivers, respectively), the adapted TERC-type multitube receiver had the highest thermal loss of all the receivers, increasing the heat loss of the TERC-type monotube receiver by a factor of 2.5. In contrast, the adapted CPC-type monotube receiver had a lower daily optical efficiency of 51.29% when paired with an etendue-conserving compact linear Fresnel mirror field, but had low thermal loss, second only to the lower heat loss of the adapted TERC-type monotube receiver by a factor of 1.26. The standard trapezoidal receiver had a relatively low daily optical efficiency of 53.69% and relatively high heat losses, higher than the adapted CPC- and TERC-type monotube receivers by a factor of 1.5 and 1.9, respectively. The adapted TERC-type monotube receiver was therefore determined to be the best candidate receiver for an etendue-conserving compact linear Fresnel field.