Multiphase numerical analysis of heat pipe with different working fluids for solar applications
01 Nov 2017-Vol. 263, Iss: 6, pp 062049
TL;DR: In this paper, the authors carried out a computational analysis on a comparative simulation between two working fluids within heat pipe of same geometry and further endeavored to study the multiphase transitions within the heat pipe.
Abstract: Energy crisis is a prognosis predicted in many cases with the indiscriminate encroachment of conventional energy sources for applications on a massive scale. This prediction, further emboldened by the marked surge in global average temperatures, attributed to climate change and global warming, the necessity to conserve the environment and explore alternate sources of energy is at an all-time high. Despite being among the lead candidates for such sources, solar energy is utilized far from its vast potential possibilities due to predominant economic constraints. Even while there is a growing need for solar panels at more affordable rates, the other options to harness better out of sun's energy is to optimize and improvise existing technology. One such technology is the heat pipe used in Evacuated Tube Collectors (ETC). The applications of heat pipe have been gaining momentum in various fields since its inception and substantial volumes of research have explored optimizing and improving the technology which is proving effective in heat recovery and heat transfer better than conventional systems. This paper carries out a computational analysis on a comparative simulation between two working fluids within heat pipe of same geometry. It further endeavors to study the multiphase transitions within the heat pipe. The work is carried out using ANSYS Fluent with inputs taken from solar data for the location of Vellore, Tamil Nadu. A wickless, gravity-assisted heat pipe (GAHP) is taken for the simulation. Water and ammonia are used as the working fluids for comparative multiphase analysis to arrive at the difference in heat transfer at the condenser section. It is demonstrated that a heat pipe ETC with ammonia as working fluid showed higher heat exchange (temperature difference) as against that of water as working fluid. The multiphase model taken aided in study of phase transitions within both cases and supported the result of ammonia as fluid being a better candidate.
Citations
More filters
TL;DR: In this paper, the authors introduced the solar thermal collectors and the fundamental heat transfer processes that govern their thermal performance, and the existing literature on applications of LBM in STC and heat transfer modeling is reviewed, culminating into the introduction of several workflows for applying LBM to STC heat transfer modelling.
7 citations
TL;DR: In this article, the authors presented a novel hybrid computational method in order to simulate the collectors' thermal behavior during day/night time operation, which is comprised of a previously developed resistance network based proper orthogonal decomposition method for simulation during operation hours where solar irradiation values are greater than zero.
4 citations
TL;DR: In this article, the authors investigated the effect of inserting a new internal tube packing (TP) on the thermal performance of a thermosyphon heat pipe (THP), which was made from copper with an inner diameter of 17.4 mm and length of 600 mm.
Abstract: The aim of this study was to investigate the effect of inserting a new internal tube packing (TP) on the thermal performance of a thermosyphon heat pipe (THP). The THP pipe was made from copper with an inner diameter of 17.4 mm and length of 600 mm. The new internal tube packing (TP) had a central copper disc with two copper tubes soldered onto both sides to transport vapor and condensate. The upper tube or riser had an inner diameter of 8.3 mm and was 300 mm long; it was connected to a hole in the disc from the upper side to transport the steam to the condenser section. The lower tube or downcomer had an inner diameter of 5 mm, was 225 mm long and was connected to the lower side of the disc to collect the condensate and transport it to the evaporator. The TP was inserted inside the THP to complete the design of the improved heat pipe (TPTHP). Experimental results showed that the TPTHP reduces the transit time from 16 to 11 min and the thermal resistance by 17–62% based on the input power and depending on the conditions of the THP. The results also showed that the inclination angle and filling ratio have no effect on the thermal resistance of the TPTHP.
1 citations
References
More filters
TL;DR: In this paper, the authors present a review of tubular heat pipe systems for heat recovery and renewable applications utility and show that standard tubular pipe systems present the largest operating temperature range in comparison to other systems and therefore offer viable potential for optimization and integration into renewable energy systems.
Abstract: Advancements into the computational studies have increased the development of heat pipe arrangements, displaying multiphase flow regimes and highlighting the broad scope of the respective technology for utilization in passive and active applications. The purpose of this review is to evaluate current heat pipe systems for heat recovery and renewable applications utility. Basic features and limitations are outlined and theoretical comparisons are drawn with respect to the operating temperature profiles for the reviewed industrial systems. Working fluids are compared on the basis of the figure of merit for the range of temperatures. The review established that standard tubular heat pipe systems present the largest operating temperature range in comparison to other systems and therefore offer viable potential for optimization and integration into renewable energy systems.
228 citations
TL;DR: In this paper, the thermal characteristics of a finned heat pipe-assisted latent heat thermal energy storage system are investigated numerically using a transient two-dimensional finite volume based model employing enthalpy-porosity technique.
226 citations
TL;DR: In this paper, the authors present a year round energy performance monitoring results of two solar water heaters with 4m 2 flat plate and 3m 2 heat pipe evacuated tube collectors (ETCs) operating under the same weather conditions in Dublin, Ireland.
171 citations
TL;DR: In this article, a CFD model was built to simulate the details of the two-phase flow and heat transfer phenomena during the start-up and steady-state operation of a thermosyphon.
135 citations
TL;DR: In this article, a novel gravity-assisted heat pipe type thermal storage unit (GAHP-TSU) has been presented for the potential application in solar air conditioning and refrigeration systems, in which composite granular solid liquid PCMs compounded by RT100 and high-density polyethylene with phase change temperature of 100°C are piled up as a porous PCMs medium layer.
32 citations