Validation of the Coupled Heat and Moisture in the Soil for Underground Thermal Energy Storage Systems

The Renewable Energy System for Residential Building Heating and Electricity Production (RESHeat ) system is a typical application of the utilisation of sun-tracked Photovoltaic Thermal (PVT) panels and underground heat storage units. This work introduces a MATLAB simulation model coupled with moisture and heat transfer processes. Validation of the proposed model from experimental measurements was conducted. The simulations were performed for a single year of RESHeat system operation for demo sites located in Cracow City. Results showed that the relative error between calculation and measurement varies from 0.258 % to 5.829 %, along with the same temperature trend. A Control Volume method is used to simulate coupled heat transfer in the ground

Review of Developments in Plate Heat Exchanger Heat Transfer Enhancement for Single-Phase Applications in Process Industries

A plate heat exchanger (PHE) is a modern, effective type of heat transfer equipment capable of increasing heat recuperation and energy efficiency. For PHEs, enhanced methods of heat transfer intensification can be further applied using the analysis and knowledge already available in the literature. A review of the main developments in the construction and exploration of PHEs and in the methods of heat transfer intensification is presented in this paper with an analysis of the main construction modifications, such as plate-and-frame, brazed and welded PHEs. The differences between these construction modifications and their influences on the thermal and hydraulic performance of PHEs are discussed. Most modern PHEs have plates with inclined corrugations on their surface that create a strong, rigid construction with multiple contact points between the plates. The methods of PHE exploration are mostly experimental studies and/or CFD modelling. The main corrugation parameters influencing PHE performance are the corrugation inclination angle in relation to the main flow direction and the corrugation aspect ratio. Optimisation of these parameters is one way to enhance PHE performance. Other methods of heat transfer enhancement, including improving the form of the plate corrugations, use of nanofluids and active methods, are considered. Future research directions are proposed, such as improving fundamental understanding, developing new corrugation shapes and optimisation methods and area and cost estimations

Using a Neural Network Approach to Predict Deposits on the Surfaces of Heat Exchange Equipment

This work proposes a neural network (NN) approach for predicting the following values: the heat transfer coefficient at the point of interest in the operational period of plate heat exchangers (PHEs), and the time-point to reach the lower allowable limit of the heat transfer coefficient. In this approach, neural network models replace complex mathematical modelling that used systems of differential equations and matrices of heuristic coefficients to calculate the flow rate of deposits on PHE plates, which required the involvement of serious computing resources. Training a feed-forward neural network (FFNN) on a small dataset simulated in the vicinity of reference points obtained by industrial measurements showed the proper coefficient of determination R2 = 0.99 (accuracy) of the short-term prediction forecasts and for operational evaluation of the heat transfer coefficient due to the static type of NN

Optimal HEN with PHEs for Carbon Dioxide Capture by Amine Absorption Unit at Coal Fired Power Station

The CO2 capture processes are of growing interest to scholars in the struggle against global warming, and for the use of CO2 in the production of clean fuels, chemicals, plastics, and other materials. The post-combustion capture of carbon dioxide from flue gases with monoethanolamine (MEA) Absorption Desorption Unit (ADU) is studied with Process Integration methodology. The optimal structure of the Heat Exchanger Network (HEN) is determined. The study aims to find economically viable options for desorption column parameters by computer modelling and to evaluate the use of novel compact plate heat exchangers (PHEs) with intensified heat transfer. Based on a presented case study, the variation of temperature approach on rich/lean heat exchanger and its influence on heat consumption is discussed. The effect of minimal temperature difference in HEN on the investment cost and its energy efficiency is analyzed. It is shown that the optimal value of minimal temperature difference for HEN with PHEs is 7 °C, which is two times smaller than for HEN based on shell and tube heat exchangers. The use of PHEs in HEN ADU at the same or even smaller purchased cost of heat exchangers saves up to 24 % energy compared to the base case. It is 13 % higher than for the option based on the use of conventional tubular heat exchangers

Using a Neural Network Approach to Predict Deposits on the Surfaces of Heat Exchange Equipment

This work proposes a neural network (NN) approach for predicting the following values: the heat transfer coefficient at the point of interest in the operational period of plate heat exchangers (PHEs), and the time-point to reach the lower allowable limit of the heat transfer coefficient. In this approach, neural network models replace complex mathematical modelling that used systems of differential equations and matrices of heuristic coefficients to calculate the flow rate of deposits on PHE plates, which required the involvement of serious computing resources. Training a feed-forward neural network (FFNN) on a small dataset simulated in the vicinity of reference points obtained by industrial measurements showed the proper coefficient of determination R2 = 0.99 (accuracy) of the short-term prediction forecasts and for operational evaluation of the heat transfer coefficient due to the static type of NN

The effect of plate corrugations geometry on performance of plate heat exchangers subjected to fouling

The novel approach of estimating the influence of plate corrugations geometry on plate heat exchanger (PHE) operation in conditions of fouling is proposed. It is based on the presented mathematical model of the PHE with commercially produced plates. To account for fouling on the heat transfer surface, the fouling model of reaction and transport type presented in dimensionless form is employed. The influence of plate corrugations geometry on PHE performance is discussed on results of modelling PHE installed for thin juice heating at evaporation station of the sugar factory. The corrugations inclination angle to the main flow direction is considered as the main influencing parameter. The effect of this parameter on fouling intensity is shown for the cases when the plates with different corrugations angle are used in one PHE. The measures to mitigate fouling in PHE by optimal selection of plate corrugations geometry are discussed

The optimal design of welded plate heat exchanger with intensified heat transfer for ammonia synthesis column

The modification of heat exchanger networks of industrial enterprises targeting energy saving solutions requires proper heat transfer equipment. The estimation of the optimal design parameters for heat exchangers requires reliable mathematical models for the description of the thermo-hydraulic processes inside the channels, and adequate optimisation methods. This work proposes the novel mathematical model and optimisation algorithm for the selection of welded plate heat exchanger (WPHE) operating in ammonia synthesis column. It enables finding the optimal design with the specified shape of the corrugated plates, distribution of flows and number of plates and passes. The developed algorithm is implemented in Mathcad software. The application of the proposed approach is illustrated by example in which the resulted WPHE with the cross flow in one pass and overall symmetric counterflow of streams has shown a reduction of heat transfer area 25 % compared to previously tested in industry WPHE with unsymmetric passes arrangement

Mathematical modelling of the thermal and hydraulic behaviour of plate heat exchanger in the fouling conditions

The mathematical model of Plate Heat Exchanger (PHE) subjected to fouling is proposed. It is represented by the system of ordinary differential equations. The model is accounting for the distribution of process parameters along the PHE channel that allows predicting fouling development in time at different locations along the channel length. The development of the fouling deposit is accounted with the fouling model presented by the equation in dimensionless form. The relative influence of different terms is characterized by empirical coefficients which can be identified with the data of monitoring the PHE thermal and hydraulic performance. The model allows also the prediction of pressure drop variation in PHE with the development of fouling deposition layer and respective reduction in channels cross-section area. The application of the model and its accuracy is demonstrated with two case studies considering the monitoring of PHEs thermal and hydraulic performance in the industry at sugar factory and in District Heating system

Mathematical model of plate heat exchanger for utilisation of waste heat from condensable gaseous streams

The mathematical model of vapour condensation from the mixture with noncondensing gas in Plate Heat Exchanger (PHE) channels is presented. The model accounts for the change of process parameters along the heat transfer surface and local features of heat and mass transfer processes in PHEs channels with plates of different corrugations geometry. It consists of the system of ordinary differential equations with considerably nonlinear right parts. The software for its solution by finite difference method is developed. The validity of the model is confirmed by comparison with the experiment for steam-air mixture condensation in a PHE channel sample