Marija Macenić, Tomislav Kurevija^*, Tin Herbst

Energy Engineering, Vol.123, No.1, 2026, DOI:10.32604/ee.2025.067067 - 27 December 2025

Abstract The increased interest in geothermal energy is evident, along with the exploitation of traditional hydrothermal systems, in the growing research and projects developing around the reuse of already-drilled oil, gas, and exploration wells. The Republic of Croatia has around 4000 wells, however, due to a long period since most of these wells were drilled and completed, there is uncertainty about how many are available for retrofitting as deep-borehole heat exchangers. Nevertheless, as hydrocarbon production decreases, it is expected that the number of wells available for the revitalization and exploitation of geothermal energy will increase. The… More >

Lei Wang¹, Hongyang Zhou², Xiaofan Liu³, Junkun Mu², Jinpeng Bi², Youkang Jin², Juan Ge², Yuexia Lv^2,4,*

Frontiers in Heat and Mass Transfer, Vol.23, No.6, pp. 1811-1832, 2025, DOI:10.32604/fhmt.2025.071222 - 31 December 2025

Abstract Membrane gas absorption and solar-assisted absorbent regeneration offer a sustainable approach to reduce the energy penalty of post-combustion CO₂ capture. This study introduces a novel system integrating solar thermal energy with membrane gas absorption to capture CO₂ from a 580 MWe pulverized coal power plant. The environmental impacts across six scenarios at varying solar fractions are evaluated via life cycle assessment. Results show a 7.61%–13.04% reduction in global warming potential compared to a steam-driven CO₂ capture system. Electricity and steam consumption dominate the operational phase, contributing 15%–64% and 18%–61% to environmental impacts in non-TES scenarios, respectively. While More >

Rafah H. Zaidan^*, Najim A. Jasim

Frontiers in Heat and Mass Transfer, Vol.23, No.5, pp. 1595-1620, 2025, DOI:10.32604/fhmt.2025.068205 - 31 October 2025

Abstract This paper presents a comprehensive experimental and numerical investigation of radiant floor heating (RFH) systems integrated with phase change material (PCM)-based thermal energy storage (TES). The study compares two underfloor pipe configurations: double serpentine and spiral. It also looks at how well a paraffin wax PCM system works with compact heat exchanger-type TES units during winter in Iraq. Key performance indicators including discharge temperature, heat transfer rate, liquid fraction evolution, and temperature uniformity were assessed through in situ experimental measurements and ANSYS fluent simulations. Results demonstrate that the spiral design provides slightly more uniform temperature distribution… More >

Rachid Djeffal^1,2, Sidi Mohammed El Amine Bekkouche^1,2, Zakaria Triki², Abir Abboud², Sabrina Lekmine³, Hichem Tahraoui^2,4, Jie Zhang⁵, Abdeltif Amrane^4,*

Frontiers in Heat and Mass Transfer, Vol.23, No.4, pp. 1129-1149, 2025, DOI:10.32604/fhmt.2025.067734 - 29 August 2025

Abstract Refrigeration systems are essential across various sectors, including food preservation, medical storage, and climate control. However, their high energy consumption and environmental impact necessitate innovative solutions to enhance efficiency while minimizing energy usage. This paper investigates the integration of Phase Change Materials (PCMs) into a vapor compression refrigeration system to enhance energy efficiency and temperature regulation for food preservation. A multifunctional prototype was tested under two configurations: (1) a standard thermally insulated room, and (2) the same room augmented with eutectic plates filled with either Glaceol (−10°C melting point) or distilled water (0°C melting point).… More > Graphic Abstract

Orkhan Jafarli^*

Energy Engineering, Vol.122, No.9, pp. 3595-3608, 2025, DOI:10.32604/ee.2025.067982 - 26 August 2025

Abstract This study investigates the feasibility and efficiency of geothermal energy for heating applications in Azerbaijan, with a specific focus on the Khachmaz region. Despite the country’s growing interest in sustainable energy, limited research has addressed the potential of ground-source heat pump (GSHP) systems under local climatic and soil conditions. To address this gap, the study employs GeoT*SOL simulation to evaluate system performance, incorporating site-specific parameters such as soil thermal conductivity, heating demand profiles, and regional weather data. The results show that the GSHP system achieves a maximum seasonal performance factor (SPF) of 5.62 and an… More >

Martin Nyanzi Mawejje, Jon Pocock, Santiago Septien^*

Energy Engineering, Vol.122, No.8, pp. 3177-3199, 2025, DOI:10.32604/ee.2025.063898 - 24 July 2025

Abstract Onsite sanitation offers a sustainable alternative to centralized wastewater treatment; however, effective faecal sludge management is crucial for safe disposal and resource recovery. Among emerging treatment solutions, solar thermal drying holds significant promise to reduce sludge moisture content and enhance handling. Despite this potential, its application remains limited, with important knowledge gaps, particularly concerning the drying kinetics under different environmental and operational conditions. This study aims to fill these gaps by investigating the solar thermal drying behaviour of faecal sludge from ventilated improved pit latrines (VIPs) and urine-diverting dry toilets (UDs), with a specific focus… More >

Ahmad Mola¹, Sahira H. Ibrahim¹, Nagham Q. Shari², Hasanain A. Abdul Wahhab^3,*

Energy Engineering, Vol.122, No.6, pp. 2239-2255, 2025, DOI:10.32604/ee.2025.061590 - 29 May 2025

Abstract High-efficiency solar energy systems are characterized by their designs, which primarily rely on effective concentration and conversion methods of solar radiation. Evaluation of the performance enhancement of flat plate solar collectors by integration with thermal energy storage could be achieved through simulation of proposed designs. The work aims to analyze a new solar collector integrated with a porous medium and shell and coiled tube heat exchanger. The heat transfer enhancement was investigated by varying the geometrical parameters in shell and helically coiled tubes operating with CuFe₂O₄/water with different volume fractions of 0.02%, 0.05%, and 0.1 vol.%.… More >

Matiewos Mekonen Abera^1,2,*, Venkata Ramayya Ancha¹, Balewgize Amare¹, L. Syam Sundar³, Kotturu V. V. Chandra Mouli⁴, Sambasivam Sangaraju⁵

Frontiers in Heat and Mass Transfer, Vol.22, No.4, pp. 1043-1070, 2024, DOI:10.32604/fhmt.2024.049525 - 30 August 2024

Abstract This study is focused on the simulation and optimization of packed-bed solar thermal energy storage by using sand as a storage material and hot-water is used as a heat transfer fluid and storage as well. The analysis has been done by using the COMSOL multi-physics software and used to compute an optimization charging time of the storage. Parameters that control this optimization are storage height, storage diameter, heat transfer fluid flow rate, and sand bed particle size. The result of COMSOL multi-physics optimized thermal storage has been validated with Taguchi method. Accordingly, the optimized parameters… More >

Chia-Nan Wang, Thuy-Duong Thi Pham^*, Nhat-Luong Nhieu

Energy Engineering, Vol.121, No.8, pp. 2039-2064, 2024, DOI:10.32604/ee.2024.050224 - 19 July 2024

Abstract Geothermal energy is considered a renewable, environmentally friendly, especially carbon-free, sustainable energy source that can solve the problem of climate change. In general, countries with geothermal energy resources are the ones going through the ring of fire. Therefore, not every country is lucky enough to own this resource. As a country with 117 active volcanoes and within the world’s ring of fire, it is a country whose geothermal resources are estimated to be about 40% of the world’s geothermal energy potential. However, the percentage used compared to the geothermal potential is too small. Therefore, this… More >

Hao Qi¹, Mohamed Sharaf², Andres Annuk³, Adrian Ilinca⁴, Mohamed A. Mohamed^5,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.2, pp. 1387-1404, 2024, DOI:10.32604/cmes.2024.048672 - 20 May 2024

Abstract Hot dry rock (HDR) is rich in reserve, widely distributed, green, low-carbon, and has broad development potential and prospects. In this paper, a distributionally robust optimization (DRO) scheduling model for a regionally integrated energy system (RIES) considering HDR co-generation is proposed. First, the HDR-enhanced geothermal system (HDR-EGS) is introduced into the RIES. HDR-EGS realizes the thermoelectric decoupling of combined heat and power (CHP) through coordinated operation with the regional power grid and the regional heat grid, which enhances the system wind power (WP) feed-in space. Secondly, peak-hour loads are shifted using price demand response guidance More >