Performance Analysis of Channels in Adiabatic and Non-adiabatic Spiral Plate Heat Exchangers: A Thermodynamic Study

This paper presents a systematic analysis of the thermodynamic performance of spiral turns in spiral plate heat exchangers (SPHEs), with and without heat leakage to the environment. An optimal design algorithm for SPHEs is developed to find higher compactness and overall heat transfer coefficient by increasing channels' pressure drops, maintaining geometric aspect ratio and minimizing the total costs. To specify the rate of heat loss to the environment, rate of internal heat transfer and channel temperature distribution, a mathematical model is proposed based on mass and energy balance equations to model the SPHE as a hypothetical heat exchanger network (HENs). Entropy-based and entransy-based performance evaluation methods in Heat Exchangers (HEs) are also examined to investigate the impact of heat leakage on the performance and irreversibility of the SPHEs. A single-phase counter-current SPHE is then designed as a case study, to examine the proposed mathematical and performance assessment models. The case study is defined and analyzed based on heat leakage to the environment. Three scenarios are then introduced namely heat leakage and no heat leakage to the environment and transferring the net heat between the streams. Results highlight the applicability of the proposed mathematical modelling and temperature distributions of channels in thermodynamics analysis of SPHEs with/without heat leakage to the environment. The findings also suggest that smaller adiabatic SPHEs can be a suitable substitute for non-adiabatic SPHEs providing appropriate insulation that covers outermost channels and prevent the leakage of the heat to the environment.