This chapter explores the impact of incorporating various types of inserts—both steady and spinning—within the receiver tubes of Parabolic Solar Trough Collectors (PTCs) to improve thermal performance. Through a detailed literature review, it examines how these internal modifications enhance turbulence, heat transfer rates, and overall thermal efficiency without altering the external geometry of the collector. Steady inserts like twisted tapes and wire coils boost the heat transfer coefficient by disrupting laminar flow, while spinning inserts generate swirling motion that further intensifies fluid mixing. The chapter also addresses the trade-offs, including mechanical complexities and pressure drops introduced by these designs. By highlighting both the benefits and challenges, this chapter underscores the significance of insert diversity in advancing PTC technology and contributing to the development of more efficient and cost-effective solar thermal systems.