Thermodynamic performance of a novel shell-and-tube heat exchanger incorporating paraffin as thermal storage solution for domestic and commercial applications

Abstract

This article is focused to evaluate thermal performance of commercial grade paraffin in a novel shell-and-tube heat exchanger with multi-tube passes and longitudinal fins as latent heat storage (LHS) system. Thermal performance assessments of latent heat storage system are conducted with respects to charging/discharging power, accumulative thermal energy storage/retrieval, thermal efficiencies and effectiveness, heat transfer characterisation and nature of melt front propagation. The average charging and discharging powers are significantly enhanced by 75.53% and 27.04% with an increase in temperature gradient between paraffin and inlet water from 52 o C-62 o C and 15 o C-5 o C, respectively. Likewise, the maximum charging and discharging powers are augmented from 2.15 kW-2.63 kW and 5.18-10.37 kW with an increase in flow rate from 1.5-3 l/min, respectively. Furthermore, the average effectiveness, Nu-Ra and heat transfer coefficient are significantly improved with an increase in temperature gradient and moderately reduced with upgrading volume flow rate. The range of Rayleigh numbers for charging cycles have indicated turbulent nature of melt front movement and supportive behaviour of longitudinal fins orientations towards natural convection. Empirical correlations for average effectiveness and Nu-Ra are developed from experimental results to facilitate design estimation for employment of proposed LHS systems in domestic and commercial applications. These empirical correlations, to evaluate feasibility and employability of LHS systems in practical applications such as domestic hot water supply and space heating to maintain control room temperature, have been successfully implemented in real operating conditions.

The Impact of Heat Exchangers’ Constructions on the Melting and Solidification Time of Phase Change Materials

“…Construction of some heat exchangers is specific, and therefore it is difficult to assign them to the categories described in Sections 3.1-3.7. These other heat exchangers can be made of a cylindrical [34,[148][149][150][151][152][153] or rectangular cuboid enclosure [25,62,[154][155][156][157] filled with PCM. Heat is transferred between PCM and HTF through pipes, however, in contrast to the MTHXs, the HTF flows successively through each subsequent pipe, as shown in Figure 16.…”

Performance Evaluation of Coupled Thermal Enhancement through Novel Wire-Wound Fins Design and Graphene Nano-Platelets in Shell-and-Tube Latent Heat Storage System

“…An optimised novel design comprising 21 copper-based multi-tubes and 76 longitudinal fins in a shell container was proposed. Later on, the proposed optimal design was experimentally analysed for charging and discharging cycles at the range of operating conditions to gauge its robustness and effectiveness for potential practical applications [21][22][23]. It was observed that the proposed optimal design was effective in charging 14.36 MJ of thermal enthalpy in 3.12 h and discharging 12.09 MJ in 1.5 h, respectively.…”

Role of extended fins and graphene nano-platelets in coupled thermal enhancement of latent heat storage system

“…In terms of design effectiveness, the type and orientations of extended surfaces in container are crucially influential for thermal reach and natural convection. Khan and Khan [26] reported that the charging effectiveness for vertical orientation of longitudinal fins was higher than horizontal orientation of longitudinal fins, compact fins and transversal squared fins. It can be construed from literature that extended surfaces have significant potential for thermal enhancement, however it can simultaneously increase the overall weight of LHS system.…”