Analytical approach to ground heat losses for high temperature thermal storage systems

Abstract

Summary A new approach to estimate the heat loss from thermal energy storage tank foundations is presented. Results are presented through analytical correlations based on numerical solutions for the steady‐state heat conduction problem for thermal energy slab‐on‐grade tanks with uniform insulation. Model results were verified with other well‐established benchmark problems with similar boundary conditions and validated with experimental data with excellent agreement. In addition to the TES foundation heat loss, new correlations for the maximum temperature and for the radial evolution of the temperature underneath the insulation layer are also provided, giving important information related to the tank foundation design. The correlated variables are of primordial importance in the tank foundation design because, due to the typical high operating storage temperatures, an inappropriate tank foundation insulation would lead not only to a not desired loss of energy but also to an inadmissible increase of the temperatures underneath the insulation layer, affecting the structural stability of the tank. The proposed correlations provide a quick method for the estimation of total tank foundation heat losses and soil maximum temperature reached underneath the insulation layer, saving time, and cost on the engineering tank foundation design process. Finally, a comprehensive parametric analysis of the variables of interest is made and a set of cases covering a wide range of tank sizes, insulation levels, depths to water table, and storage temperatures are solved.

Experimental and numerical analysis of seasonal solar‐energy storage in buildings

“…In the case of SSHS, we made simulations for volumes from 1 to 4 m 3 , and for areas of SSE 30, 35, 40, and 45 m 2 . In the case of TCHS, we made simulations for volumes from 1 to 5 m 3 and for areas of SSE 5,10,15,20, and 30 m 2 . The main purpose of the simulation for different ranges of volumes and SSEs for both storages was to show the essential differences between them; also, we wanted to show the trend of changing the heat demand coverage for each type of storage.…”

“…Suarez et al presented new approach to estimate the heat loss from thermal‐energy–storage tank foundations. The proposed analytical correlations based on numerical solutions for the steady‐state heat‐conduction problem provide a quick method for the estimation of total tank foundation heat losses and soil maximum temperature reached underneath the insulation layer, saving time, and cost on the engineering tank‐foundation design process.…”

“…Composite sorbents were made from porous materials and active salts. [11][12][13] Thermochemical-sorption energy-storage system may be as efficient as and even more stable than other types of thermal-energy-storage system, showed exergy analysis performed by Abedin et al 14 Suarez et al 15 presented new approach to estimate the heat loss from thermal-energy-storage tank foundations. The proposed analytical correlations based on numerical solutions for the steady-state heat-conduction problem provide a quick method for the estimation of total tank foundation heat losses and soil maximum temperature reached underneath the insulation layer, saving time, and cost on the engineering tank-foundation design process.…”