Hot Water Tank Research Articles

Optimal Economic Modelling of Hybrid Combined Cooling, Heating, and Energy Storage System Based on Gravitational Search Algorithm-Random Forest Regression

The hybridization of two or more energy sources into a single power station is one of the widely discussed solutions to address the demand and supply havoc generated by renewable production (wind-solar/photovoltaic (PV), heating power, and cooling power) and its energy storage issues. Hybrid energy sources work based on the complementary existence of renewable sources. The combined cooling, heating, and power (CCHP) is one of the significant systems and shows a profit from its low environmental impact, high energy efficiency, low economic investment, and sustainability in the industry. This paper presents an economic model of a microgrid (MG) system containing the CCHP system and energy storage considering the energy coupling and conversion characteristics, the effective characteristics of each microsource, and energy storage unit is proposed. The random forest regression (RFR) model was optimized by the gravitational search algorithm (GSA). The test results show that the GSA-RFR model improves prediction accuracy and reduces the generalization error. The detail of the MG network and the energy storage architecture connected to the other renewable energy sources is discussed. The mathematical formulation of energy coupling and energy flow of the MG network including wind turbines, photovoltaic (PV), CCHP system, fuel cell, and energy storage devices (batteries, cold storage, hot water tanks, and so on) are presented. The testing system has been analysed under load peak cutting and valley filling of energy utilization index, energy utilization rate, the heat pump, the natural gas consumption of the microgas turbine, and the energy storage unit. The energy efficiency costs were observed as 88.2% and 86.9% with heat pump and energy storage operation comparing with GSA-RFR-based operation costs as 93.2% and 93% in summer and winter season, respectively. The simulation results extended the rationality and economy of the proposed model.

Energy management for an electro-thermal renewable–based residential microgrid with energy balance forecasting and demand side management

This paper proposes an energy management strategy for a residential microgrid comprising photovoltaic (PV) panels, a small wind turbine and solar thermal collectors. The microgrid can control the power exchanged with the grid thanks to a battery and a controllable electric water heater, which provide two degrees of freedom to the control strategy. As input data, the proposed control strategy uses the battery state of charge (SOC), the temperature of the hot water tank, the power of each microgrid element as well as the demand and renewable generation forecasts. By using forecasted data and by controlling the electric water heater, the strategy is able to achieve a better grid power profile while using a smaller battery than previous works, hence reducing the overall cost of the system. The strategy is tested by means of simulation with real data for one year and it is also experimentally validated in the microgrid built at the Renewable Energy Laboratory at the UPNA.

Conversion of steam power plant into cogeneration unit - Case study

One of possible solutions leading to the increase of steam power plant thermal efficiency is its conversion into a cogeneration unit. However, it requires the heat recipient to be on-site and, if so, it may be done by implementation of absorption heat pump (AHP) technology with low temperature waste heat recovery and utilization. The paper presents results of an analysis of benefits resulting from implementation of absorption heat pump into the steam power plant for recovery of low temperature waste heat, due to additional demand for heat delivery to dedicated recipient (DHR). The demand for heat along the whole year was assumed and the calculations were performed for two cases. In the first case, which was called the reference case, the heat was produced by dedicated heat exchanger (DHX) fed with steam taken from the pipeline between the medium and low-pressure turbine sections (MPLPP). In the second case, absorption heat pump (AHP) as the main unit for heat production and recovery was assumed. However, due to insufficient heat production in some conditions, peak heat exchanger (PHX) placed directly behind the heat pump was considered. Both heat pump and pick heat exchanger were fed with steam taken from MPLPP, however, due to the AHP requirements the stem was mixed with hot water taken from hot water tank to achieve the steam saturation state. Results of calculations performed show that implementation of a heat recuperation by absorption heat pump implemented to conventional steam power plant increases the overall efficiency of cogeneration system, but at the same time it causes the electricity production to decrease. Moreover, the production of heat by absorption heat pump has lower impact on the electricity generation compared to generation of heat by conventional heat exchanger. If reference power plant without heat production is considered, due to the heat pump implementation the electricity production decreases of about 1.32% for heat production with dedicated heat exchanger, and of about 0.89% for absorption heat pump with peek heat exchanger respectively. It means that, owing to implementation of AHP instead of DHX with the same heat production, the power plant may generate more than 0.4% of total electricity produced.

A Flow Rate Dependent 1D Model for Thermally Stratified Hot-Water Energy Storage

Stratified tank models are used to simulate thermal storage in applications such as residential or commercial hot-water storage tanks, chilled-water storage tanks, and solar thermal systems. The energy efficiency of these applications relates to the system components and the level of stratification maintained during various flow events in the tank. One-dimensional (1D) models are used in building energy simulations because of the short computation time but often do not include flow-rate dependent mixing. The accuracy of 1D models for plug flow, plug flow with axial conduction, and two convection eddy-diffusivity models were compared with experimental data sets for discharging a 50-gal residential tank and recharging the tank with hot water from an external hot-water source. A minimum and maximum relationship for the eddy diffusivity factor were found at Re <2100 and >10,000 for recirculation of hot water to the top of the tank and vertical tubes inletting cold water at the bottom. The root mean square error decreased from >4 °C to near 2 °C when considering flow-based mixing models during heating, while the exponential decay of the eddy diffusion results in a root mean square error reduction of 1 °C for cone-shaped diffusers that begin to relaminarize flow at the inlet.

Первичное регулирование частоты тока в энергосистеме атомными электростанциями на основе водородно-теплового аккумулирования

According to the Technical Requirements for Generating Equipment of Participants in the Wholesale Market of the Unified Energy System (UES) of Russia, 2016 to participate in the general primary frequency regulation (PRCF), the maneuverable characteristics of generating equipment of nuclear power plants with VVER reactors put into operation before 2009 should ensure frequency deviations guaranteed realization of the required primary power for loading up to 2% of the nominal electric power. For this, the current capacity of the reactor installation should be maintained at a level of not more than 98% of the nominal thermal power. The fulfillment of this requirement signifi- cantly reduces the installed capacity utilization factor (CUF) of reactor plant. In addition, at present in the UES of the Russian Federation there is a tendency towards an increase in the deficit of peak and half-peak capacities. The majority of fossil fuel-fired thermal stations are switched to the half-peak mode, which negatively affects their efficiency and reliability. In addition, the rise in price of natural gas makes it more profitable to sell it abroad instead of burning at power plants. On the other hand, an increase in the share of nuclear power plants is observed in the UES, which exacerbates the problems associated with the passage of minima and maxima of the daily load in the power system, due to the economically and technically justified need to load NPPs with maximum CUF. The authors developed an approach to solving this problem by combining NPPs with an environmentally friendly energy source - an autonomous hydrogen complex (AHC), which includes thermal batteries and an additional multi- functional steam turbine unit. The developed energy complex will allow energy to be accumulated during hours of minima load in the power system due to the electrolysis of water to produce hydrogen and oxygen, as well as the accumulation of hot water in the storage tanks. The accumulated energy can be used to generate super-nominal electrici- ty to cover the half-peak load zone in the power system. In addition, the presence of a low-power steam turbine installation will ensure uninterrupted power supply to consumers of their own needs at the NPP by using the energy of the residual heat from the reactor when the station is completely de-energized. Based on the proposed energy complex, a method has been developed to ensure the participation of NPPs in the PRCF in an energy system with a constant CUF. To assess the effectiveness of the proposed solution, a methodology for thermodynamic analysis of the energy complex based on the combination of NPPs with AHC was developed. The dependence of the required hydrogen fuel consumption and the efficiency of using off-peak electricity on the temper- ature of the feed water supplied to the hydrogen-oxygen steam generator from the hot water tanks is constructed. Based on the results obtained, the technical and economic efficiency of the developed energy complex is considered. The accumulated net present value was determined depending on off-peak electricity tariffs with three variants of the forecast dynamics of the half-peak electricity tariff, taking into account natural gas savings, reduced investment in NPP safety systems and the economic effect of ensuring the participation of NPPs in the PRCF with the plant load at 100%.

Understanding the interaction between groundwater and large-scale underground hot-water tanks and pits

In view of the urgent need for energy efficiency measures, renewables-based district heating (R-DH) can prove an efficient approach to meet the heating demand in cities whereby locally-available renewable resources are exploited. Yet, the renewables experience intermittency, which might lead to seasonal mismatch between heat supply and demand. Therefore, large-scale seasonal thermal energy storage (STES) systems are often envisioned as key elements in R-DH. Given their large volumes, these systems are often installed underground whereby groundwater tables are expected to lead to twofold impacts due to the TES-groundwater interaction. This work reports the development of models for the planning and optimization of STES and, then, conducts a calibration study to attain credibility in the models. Next, it examines the planning of STES under such unfavorable hydrogeological conditions whereby a groundwater flow is anticipated. The results indicate that Darcy flow plays a significant role in increasing the thermal losses that result in increasing groundwater temperature. Therefore, it becomes crucial to provide protective measures to maintain acceptable groundwater quality prescribed by national standards. Hence, the work investigates the role of cut-off wall distance and TES insulation quality to mitigate the TES thermal losses, increase the TES efficiency and reduce the groundwater temperature.

Efficiency investigation of the combined heat storage system using at NPPs with VVER

Using of consumer-regulators at NPPs will make it possible to increase the share of nuclear power plants in the power system due to the expansion of their use range with a constant installed capacity utilization factor of reactors. As a result, the renewal of the maneuverable capacities of the power system can be carried out with the reduction of power plants, operating on fossil fuel, which will lead to a decrease in emissions causing irreparable harm to the environment. In the article, the heat storage system developed by the authors is presented and researched. It includes a phase change accumulator, cold and hot water tanks and additional steam turbines, which will avoid expensive main turbine modernization and its deterioration magnification, also it will provide an additional reserve for the NPP’s own needs. The results of investigation conducted for a wide range of operating conditions have shown that systems pay off completely under certain conditions. The authors also showed that the installation of a hot water tank can reduce capital investment in a heat storage system based on a phase change accumulator.

Performance improvement of an air-to-water heat pump through linear time-varying MPC with adaptive COP predictor

Air-to-water heat pumps are one of the most common and energy efficient heating systems for buildings, particularly floor-heating plants. One way to further improve their effectiveness is to control the heat pump exploiting the dependence of its coefficient of performance (COP) on the external temperature and temperature of the return water from the load. In particular, it is possible to exploit the heat pump when its efficiency is higher, so optimizing its performance in a predictive manner, anticipating the impact of external conditions. For the case of an air-to-water heat pump, the optimization problem is nonlinear due to the load dependence of the heat pump COP and variable supply water flow rate. This may pose implementation problems. If we address a standard control hardware, simplified optimal control formulations are more effective. In this paper, we specifically address this issue, and a reduced-order, linear, but adaptive time-varying predictive model of the heat pump COP is designed. Our solution takes into account the variation of the heat pump efficiency based on the external temperature and the load profile, which are changing within the control horizon. The proposed COP model is then used within a linear time-varying model predictive controller formulation which provides a prediction of the heat pump dynamical behavior based on the load dependence of the heat pump COP, while tackling the nonlinearities of the system imposed by the variable water flow rate in the hot water tank and also by the load dependence of the heat pump COP. The proposed approach has been implemented and in detail tested on a reference model based on a real case study from the Denmark Technical University, Risø Campus, SYSLAB. An intensive simulation analysis and complements the testing, showing the accuracy and the potential of the method, also in the perspective of practical implementation.

The impact of pipeline changes and temperature increase in a hospital historically colonised with Legionella

Healthcare-related Legionnaires’ disease has a devastating impact on high risk patients, with a case fatality rate of 30–50%. Legionella prevention and control in hospitals is therefore crucial. To control Legionella water colonisation in a hospital setting we evaluated the effect of pipeline improvements and temperature increase, analysing 237 samples over a 2-year period (first year: 129, second year: 108). In the first year, 25.58% of samples were positive for Legionella and 16.67% for amoeba. Assessing the distance of the points analysed from the hot water tank, the most distal points presented higher proportion of Legionella colonisation and lower temperatures (nearest points: 6.4% colonised, and temperature 61.4 °C; most distal points: 50% and temperature 59.1 °C). After the first year, the hot water system was repaired and the temperature stabilised. This led to a dramatic reduction in Legionella colonisation, which was negative in all the samples analysed; however, amoeba colonisation remained stable. This study shows the importance of keeping the temperature stable throughout the circuit, at around 60 °C. Special attention should be paid to the most distal points of the circuit; a fall in temperature at these weak points would favour the colonisation and spread of Legionella, because amoeba (the main Legionella reservoir) are not affected by temperature.

Performance and CO2 emissions assessment of a novel combined solar photovoltaic and thermal, with a Stirling engine micro-CHP system for domestic environments

This paper presents a novel installation where a set of photovoltaic modules and solar thermal collectors work in conjunction with a micro-CHP Stirling Engine to provide a reliable and self-sufficient energy system. A literature review showed that, while there are implementations of micro-CHP systems in household environments, there are no installations where the micro-CHP unit worked in conjunction with solar systems, photovoltaic and thermal. With the usage of Li-ion battery storage and a hot water tank for heat storage, as well as the micro-CHP unit, the system increases its reliability and independence from climatic conditions. The results obtained show that this system can supply 75.6% of the total energetic demand of a typical household, while achieving a reduction of 36.2% in the CO2 emitted to produce all the consumed energy in the system. The complete thermal demand has been met, while the usage from the electric grid has been required to meet 33.5% of the electric demand. However, with an increase in battery capacity to 20 kWh (doubling the actual capacity), the system is expected to become fully autonomous, as 31.8% of the electricity generated in the modules was exported to the grid due to saturation in storage capacity. In the thermal energy balance, sufficient heat was generated to provide enough energy for space heating or cooling, as well as domestic hot water.

Generalized Additive Modeling of Building Inertia Thermal Energy Storage for Integration Into Smart Grid Control

The structural mass of a building provides inherent thermal storage capability. Through sector coupling, the building mass can provide additional flexibility to the electric power system, using, for instance, combined heat and power plants or power-to-heat. In this work, a mathematical model of building inertia thermal energy storage (BITES) for integration into optimized smart grid control is introduced. It is shown how necessary model parameters can be obtained using generalized additive modeling (GAM) based on measurable building data. For this purpose, it is demonstrated that the ceiling surface temperature can serve as a proxy for the current state of energy. This allows for real-world implementation using only temperature sensors as additionally required hardware. Compared with linear modeling, GAM enable improved modeling of the nonlinear characteristics and interactions of external factors influencing the storage operation. Two case studies demonstrate the potential of using building storage as part of a virtual power plant (VPP) for optimized smart grid control. In the first case study, BITES is compared with conventionally used hot water tanks, revealing economic benefits for both the VPP and building operator. The second case study investigates the potential for savings in CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> emission and grid connection capacity. It shows similar benefits when using BITES compared to using battery storage, without the need for hardware investment. Given the ubiquity of buildings and the recent advances in building control systems, BITES offers great potential as an additional source of flexibility to the low-carbon energy systems of the future.

Design and Optimization of a Hybrid Energy System for Decentralized Heating

The performances of a hybrid energy system for decentralized heating are investigated. The proposed energy system consists of a solar collector, an air-source heat pump, a gas-fired boiler and a hot water tank. A mathematical... | Find, read and cite all the research you need on Tech Science Press

Parametric Cost Optimization of Solar Systems with Seasonal Thermal Energy Storage for Buildings

In combination with seasonal thermal energy storage (STES), solar energy offers a vast potential for decarbonizing the residential heat supply. In this work, a parametric optimization is conducted to assess the potential of reducing the costs of water-based STES through the use of alternative thermal insulation materials and the integration of an underground storage outside the building. The investigated configurations include: a hot-water tank, a solar collector installation, and a multifamily building with a solar fraction of 100%. The storage is either integrated inside the building or buried underground in its direct vicinity. A simulation-based analysis shows that if the tank is integrated inside an existing building (as part of a retrofitting action) – where costs are primarily driven by the loss of living space – vacuum-insulation panels can lead to significant savings in living space and a cost advantage compared to the use of conventional glass wool. Nevertheless, storage integration inside an existing building is a more expensive option compared to an external integration due to the high costs associated to the internal building modification and loss of living space. Despite the high excavation costs and increased heat losses, the concept of burying the storage underground is a promising option to allow the integration of large-volume seasonal storage systems in new and existing buildings.

Sizing and performance analyses of a combined heating and cooling system with the integration of short- and long-term storages

Technological advancements in the utilization of renewable energy sources have unveiled potentials for increasing building energy efficiency. Integrating heat pump-based energy systems with thermal storages is a suitable option to meet the thermal requirements of modern buildings and exploiting the available renewable energy sources. However, how to size the main components of a heat pump-based energy system with the integration of short- and long-term storages is not yet well explored. Therefore, this study focused on the design and performance analyses of an integrated heating and cooling system consist of a heat pump, borehole long-term thermal storage, and hot water tank short-term thermal. Heat pump models were introduced as parametric models based on the producer data. The dynamic thermal model of the energy system was developed and analysed in MATLAB. Different combinations of heating and cooling loads were tested. Integration of cooling and heating systems was discussed through different operation strategies and challenges were addressed. The results of the parametric analysis identified the key parameters affecting the design of components and efficiency of the system. Moreover, the results showed that lower cooling to heating load ratio leads to an excessive reduction of the ground temperature and overall efficiency over the long-term operation.

Transient numerical analysis of charging a heat accumulator in a combined heat and power plant

This paper presents a technical description and characteristics of heat accumulation system operation in one of the Polish combined heat and power (CHP) plants. The total thermal capacity of the nonpressure hot water accumulator is 75 MWh. An important issue in the case of hot water tanks is thermal stratification caused by the difference in density between higher-temperature water, located in the top of the hot water storage tank and colder water in its bottom. The article presents the results of numerical analysis based on axial-symmetric model of hot water tank using Ansys Fluent software. Simulations with the Computational Fluid Dynamics (CFD) method were carried out for the process of charging the heat accumulator lasting 10 hours. The results were compared with the measurement data from the CHP plant.

Integration of solid-oxide fuel cells and absorption refrigeration for efficient combined cooling, heat and power production

Abstract Combined cooling, heating and power (CCHP) systems are characterized by a substantially higher energy-utilization efficiency compared to standalone systems. In this study, an integrated system comprising a solid-oxide fuel cell (SOFC), hot-water storage tank (HWST) and absorption refrigeration (AR) cycle is considered. The SOFC model was developed in Aspen Plus®. It was used to determine the thermodynamic properties of the exhaust gas that was then used to provide heat for the HWST and to drive the AR cycle. Thermodynamic models for the AR cycles were developed in Engineering Equation Solver, considering LiBr–H2O and NH3–H2O as working fluids. The sensitivity analysis of a number of SOFC output parameters has been carried out. The most optimal case was characterized with the coefficient of performance (COP) and CCHP efficiency of 0.806 and 85.2% for the LiBr–H2O system, and 0.649 and 83.6% for the NH3–H2O system, respectively. Under such optimal operating conditions, the SOFC was characterized by the net electrical efficiency of 57.5% and the net power output of 123.66 kW. Data from the optimal solution were used to perform the thermodynamic study and sensitivity analysis to assess the influence of different absorption cycle operating conditions and to identify possible applications for the considered integrated systems.

A Parametric Study of a Hybrid Photovoltaic Thermal (PVT) System Coupled with a Domestic Hot Water (DHW) Storage Tank

Photovoltaic-thermal panels are hybrid systems that combine the two types of conventional solar energy technologies (photovoltaic and thermal panels) and simultaneously generate both thermal and electrical energy in a micro-cogeneration system. Like any co-generation system, there is an optimal balance that can be achieved between the thermal and electrical energy produced. For this reason, it is important to establish the relationship and inter-connection between the two. Limited research is available on the cogeneration interaction in a PVT system, so the novelty of this article lies in the consideration of the entire energy system connected to the PVT panel, including the storage tank and the consumer demand curve, and the investigation of the thermal parametric variation. This study analyses the impact of the variation of some thermal parameters of a domestic hot water tank on the electrical efficiency of a photovoltaic-thermal panel. A model of a system of photovoltaic-thermal panels is built in a transient systems simulation program (TRNSYS) and a one-factor-at-a-time analysis is carried out for the cold-water main temperature, tank size, tank outlet flow and consumer demand curve. The results show that the variation of the outlet flow to the consumer has the highest impact on the electrical efficiency, of about 6.8%. The next highest impact factor is the size of the tank with a variation of 4.7%. Matching the profile of the consumer is also an important aspect. It was observed that the peak electrical efficiency occurs during peak consumer demand. Finally, the instantaneous variation of the thermal and electrical power of the system was analysed as a function of the temperature at the inlet of the photovoltaic-thermal panel.

Failure Analyses on Corrosion of Hot Water Tank Storage Made from Stainless Steel

Hot water storage tank that was made from stainless still was investigated in this case. The tank was found failure in service due to corrosion in welded section. Corrosion also was found at the bottom part of the storage tank. The tank was used for no longer than one year but unfortunately severe corrosion was found. The purpose of this research is to find the reason why the tank easily corroded especially at the bottom part and at the welding section. The research was carried out by conducting metallographic examination directly in situ by utilizing portable metallographic microscope. It is found from investigation that the corrosion was happen due to galvanic corrosion. Investigation by using X ray fluorescence also agree that the composition of the bottom part of the tank was different with the wall, and upper section. The welding filler also was found not correctly prepared that make pitting corrosion to occur. It is suggested to conduct advance research to investigate the correct composition for the filler during welding.

Development of Residential Fuel Cell "Ene-Farm Mini"

Tokyo Gas Co., Ltd. has launched residential distributed power generation system “ENE-FARM” which is a micro-CHP system in 2009. The number of cumulative sales reached 300,000 in Japan and 130,000 in Tokyo Gas in FY2019. In order to further spread of “ENE-FARM”, the world's smallest residential fuel cell "ENE-FARM mini" manufactured by Kyocera Corporation was released in October 2019.“ENE-FARM mini” has been developed with the concept to minimize the system size, optimize the rated power of the system with ensuring the power generation efficiency, add the function of continuous power generation during blackout, utilize the IoT technologies, and reduce the cost for installation work.To minimize the system size, the SOFC system integrated of the cell stack and the reformer was adopted. The cell stack’s size was reduced by lowering the rated power to 400 W. The lowered power is also suitable to the recent energy demand decreasing by the spread of energy saving house. The system was introduced to minimize the size of the hot water tank to 20 L, much smaller compared to the conventional “ENE-FARM”. As a result, the size of the whole system is minimized to the point of the smallest in the world, as small as the size of the air conditioner outdoor unit. It is expected to meet more demands from the customers who were not able to afford the large space for the installation due to the limited space available in their residences.In order to lower the rated power to 400 W power with securing the power generation efficiency, it is challenge to secure the heat required for power generation. Hot Box covering the cell stack was designed to achieve high thermal insulation by reducing the heat dissipation loss. As a result, the high power generation efficiency of 47% (LHV) was achieved due to maintain high-temperature conditions.Moreover, the function of continuous power generation during blackout was introduced to “ENE-FARM mini”. Although the blackout occurs during power generation, it is capable to supply the power to the emergency outlet and the boiler, as long as the city gas lines are operating. Therefore, it is possible for users to operate some of the household appliances through the emergency outlet. The hot water supply system and the floor heating system can be functional if the water lines are operating.“ENE-FARM mini” was compatible with the IoT system. Many features such as the usage amount of gas, electricity, water and utility costs can be easily checked on the user’s smartphones. The users also can remotely control many systems such as the hot bath and the floor heating system. Additionally, the usability was improved by implementing the smart speaker compatibility.It is the critical challenge to reduce the cost for installation work. The minimized and weight saved system made it possible to carry the whole assembly with a subcompact car. It only requires two persons to carry and install the system even in a narrow space with a depth of 500 mm. Because the center of gravity point was set to be lower, the base components could be compact and lightweight. The typical weight of the base components was about 27 kg which consists of two components of 13.5 kg. Therefore, the base components can be carried by only one person. It leads to simplify the installation work and reduce the cost for installation.We will continue to contribute to the comfortable living of customers, the preservation of the global environment, and the enhancement of resilience through the spread of "ENE-FARM". Figure 1

Empirical characterization of vertical-tube inlets in hot-water storage tanks

Hot-water storage in residential and commercial tanks is of growing interest for peak-shifting the electrical demand associated with hot-water loads. How the water enters the tank can significantly affect the extraction efficiency of the storage. Vertical-tube inlets (VTIs) direct cold water into the tank. The VTI design influences whether large-scale mixing occurs, which can reduce the delivery capacity of the hot-water storage. In this work, the mixing at the VTI discharge was characterized by the eddy diffusivity factor (EDF) in an allometric curve fit to the ratio Re:Ri using inlet superficial velocities. The full experimental campaign tested VTI's with Re’s between 170 and 22,300 and Ri's between 0 and 376. Animated visualization of the experimentally measured data is provided, showing tank temperature evolution during inlet flows. The most predictive correlations for EDF are for VTI Re in the transition zone (i.e. ~2300 < Re < ~10,000) and at a Ri corresponding to a stably stratified tank (i.e. Ri > 5). For vertical-tubes that distribute cold water below the thermocline, increasing the EDF will decrease the stratification in a hot-water tank as EDF quantifies inlet mixing. The new correlations for VTIs can be used to design and model thermally-stratified storage tanks.