The usage of fossil fuel in the energy sector is the primary factor for global GHG emissions, so it is crucial to better utilize RE sources. One way to do that is to hybridize RE technologies to make up for their deficiencies while enabling a more synergistic power production. This study utilizes such an approach to hybridize the KZD-2 Geothermal Power Plant (GPP) with CST and biomass in the southwest region of Turkiye. The main motivation is to address the two main issues of GPPs—excess turbine capacities happening over the operating years and decreasing performance during hot summer months—while also increasing the flexibility of KZD-2. A topping cycle of CST–biomass is added utilizing a PTC field as the CST technology and olive residual biomass combustion as the biomass technology. The hybrid plant is simulated on TRNSYS, and the energetic data show that it is possible to generate more than 20 MW_e of additional power during sunny and clear sky conditions while also increasing the Capacity Factor (CF) from 69% to 74–76%. Moreover, the financial results show that the resulting LCOAE is 81.19 USD/MWh, and the payback period is five or nine years for using the YEKDEM incentive or the spot market prices, respectively.

Dynamic phase change materials (dynPCMs) offer high heat transfer rates over extended times due to a force applied to the PCM that pumps away melted liquid and maintains a thin melt layer. The melt layer dynamics governs the system behavior; however, little is known about how the melt layer forms and flows, especially when the heat source has a complex three-dimensional shape. This study investigates heat transfer and fluid flow during dynPCM cooling of heated finned copper heat sinks. Melt flow is visualized using computer vision, and these results are coupled with thermal measurements and simulations to gain a fundamental understanding of the flow physics. By measuring the shape of the liquid–solid interface, we resolve the coupling between the heat transfer and melt flow. Four extended surface designs are investigated consisting of fins with varying tip shapes and spacings. Experiments show a reduction in thermal resistance up to 36% with sharp-tip fins compared with rectangular fins, with the thinnest melt layer forming at the fin tips. Using experimental observations as inputs, a three-dimensional simulation investigates heat transfer and fluid flow in the liquid PCM. Simulations show that liquid drainage is a key limitation to dynPCM performance and that the melt layer is thinnest in the center of the heat sink, growing as the melted PCM flows out. The results demonstrate that dynPCM heat transfer is governed by the interplay of surface area, fin geometry, and liquid drainage. The outcomes presented here may be used to design higher-performing dynPCM systems.

While Geothermal Power Plants (GPPs) can be a reliable renewable energy source, this reliability can decrease over the years due to brine mass flow declining. This reduced mass flow causes extra capacity unused in the GPP turbines. This problem can be overcome by hybridizing GPPs with CST and biomass. These three thermal technologies can, in theory, complement each other if all the resources are present at the exact location. This is the scenario for this study, as the location for the case study is the Kızıldere 2 (KZD2) GPP in Denizli, Turkiye, operated by Zorlu Energy. This region has sufficient potential for all three technologies: CST, geothermal, and biomass. Furthermore, by building a topping cycle using CST and biomass, it is possible to generate additional power. This study utilizes a topping steam Rankine cycle run equally by CST and biomass, and, as a result, the 20% excess capacity in the GPP turbine is used while generating an additional 20 MWe of power.