3 research outputs found
Numerical approach and experimental investigation of a stratified hot water storage tank for domestic hot water production
No full textThermal stratification within storage tanks plays a critical role in the efficiency of thermal energy storage systems. In this paper, one-dimensional numerical model of a stratified storage tank is developed to simulate the thermal stratification process within a storage tank during the charging and the discharging processes, capturing the temperature distribution inside the storage tank over time. This work investigates the evolution and transient behavior of stratified flows during the heating and cooling process within sensible-heat energy storage systems under ReD=167 and ReD=616 for heating process. For that purpose, an experimental campaign was performed in an instrumented water storage tank to measure the stratification process when a hot water round jet was injected into a slender cylindrical tank filled with an initially uniform hydrostatic water field stabilized at a lower temperature. This information was used to develop a simple 1D model able to be applied during long-term charging/discharging transients of these kind of systems. The 1D model developed was validated against the experiments performed following prototypical charging/discharging tests according to the standard EN16147 and can be used to describe the energy performance of this kind of systems during long-term charging/discharging sequences. The present model provides a reduction of about 5 % of the error of the time of the water cooling process with respect to other models in the literature
Numerical approach and experimental investigation of a stratified hot water storage tank for domestic hot water production
No full textThermal stratification within storage tanks plays a critical role in the efficiency of thermal energy storage systems. In this paper, one-dimensional numerical model of a stratified storage tank is developed to simulate the thermal stratification process within a storage tank during the charging and the discharging processes, capturing the temperature distribution inside the storage tank over time. This work investigates the evolution and transient behavior of stratified flows during the heating and cooling process within sensible-heat energy storage systems under ReD=167 and ReD=616 for heating process. For that purpose, an experimental campaign was performed in an instrumented water storage tank to measure the stratification process when a hot water round jet was injected into a slender cylindrical tank filled with an initially uniform hydrostatic water field stabilized at a lower temperature. This information was used to develop a simple 1D model able to be applied during long-term charging/discharging transients of these kind of systems. The 1D model developed was validated against the experiments performed following prototypical charging/discharging tests according to the standard EN16147 and can be used to describe the energy performance of this kind of systems during long-term charging/discharging sequences. The present model provides a reduction of about 5 % of the error of the time of the water cooling process with respect to other models in the literature.This work has been performed in the context of the project ‘‘Development of a new DMS-CO2 heat pump system with latent heat thermal storage for DHW and room-heating to boost the implementation of zeroemission buildings (HPCO2Pro)” under the grant PID2022–139566OAI00 funded by MICIU / AEI /10.13039/501100011033/ and European Regional Development Fund “ERDF A way of making Europe
INVESTIGACIÓN NUMÉRICA DE UNA TEST BOX PARA MATERIALES DE REFRIGERACIÓN RADIATIVA
No full textRadiative cooling (RC) has emerged as a promising technology for passive cooling applications, offering a sustainable and energy-efficient solution to alleviate the increasing demand for air conditioning. This study focuses on a numerical investigation aimed at understanding and optimizing the test box used to evaluate the thermal performance of samples of radiative cooling materials. The numerical simulations employ advanced computational models to analyze key factors influencing the thermal behavior of the test box under varying several boundary conditions. The study also explores the thermal interaction between the test box and its surroundings, considering the effects of ambient temperature and air heat transfer coefficient. The numerical simulations provide valuable insights into the dynamic thermal behavior of the test box, aiding in the development of optimized designs that minimize parasitic heat gains, which may hide the actual cooling performance of the RC sample under real conditions. The outcomes of this numerical investigation contribute to the ongoing efforts in the field of radiative cooling, and the development of a test box for radiative cooling materialsEl enfriamiento radiativo (RC) se ha convertido en una tecnología prometedora para aplicaciones de enfriamiento pasivo, ofreciendo una solución sostenible y energéticamente eficiente para aliviar la creciente demanda de aire acondicionado. Este estudio se centra en una investigación numérica destinada a comprender y optimizar la test box utilizada para evaluar el rendimiento térmico de muestras de materiales de enfriamiento radiativo. Las simulaciones numéricas emplean modelos computacionales avanzados para analizar factores clave que influyen en el comportamiento térmico de la test box bajo varias condiciones límite variables. El estudio también explora la interacción térmica entre la test box y su entorno, considerando los efectos de la temperatura ambiente y el coeficiente de transferencia de calor del aire. Las simulaciones numéricas brindan información valiosa sobre el comportamiento térmico dinámico de la test box, lo que ayuda en el desarrollo de diseños optimizados que minimizan las ganancias de calor parásitas, que pueden ocultar el rendimiento de enfriamiento real de la muestra RC en condiciones reales. Los resultados de esta investigación numérica contribuyen a los esfuerzos en curso en el campo del enfriamiento radiativo y al desarrollo de una test box para materiales de enfriamiento radiativo
