Karam H. Mohammed¹, Ashraf E. Al-Mirani¹, Bashar Mahmood Ali², Omar Rafae Alomar^1,*

Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 839-854, 2024, DOI:10.32604/fhmt.2024.052671 - 11 July 2024

Abstract This work involves an experimental study on the performance of automobile air-conditioning systems by adding Al₂O₃ nanoparticles to oil compressors to investigate their impacts on the enhancement of the speed cooling of refrigeration systems and to compare it with the system operated using only oil. The Al₂O₃ nanoparticles have been added to the oil compressor for different ranges of mass concentration (Ø = 0.1%, Ø = 0.15% and Ø = 0.2%). The stability of Al₂O₃ nanoparticles has been tested by direct observation for different time periods. The results indicated that the air conditioning system that operated by More >

Ali Jaber Abdulhamed^1,*, Aws Al-Akam¹, Ahmed A. Abduljabbar², Mohammed H. Alkhafaji³

Energy Engineering, Vol.120, No.8, pp. 1729-1746, 2023, DOI:10.32604/ee.2023.029069 - 05 June 2023

Abstract Thermoelectric generators (TEGs) are considered promising devices for waste heat recovery from various systems. The Seebeck effect can be utilized to generate power using the residual heat emitted by the filter dryer receiver (FDR) of an air conditioning (A/C) system, which would otherwise go to waste. The study aims to build a set of thermoelectric generators (TEG) to collect the waste heat of the FDR and generate low-power electricity. A novel electrical circuit with two transformers is designed and fabricated to produce a more stable voltage for operation and charging. The thermoelectric generator (TEGs) was… More >

Ghaith Yahya Abusaibaa^a , Kamaruzzaman Sopian^a,*, Hasila Jarimi^a , Adnan Ibrahim^a, Saffa Riffat^b

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-6, 2023, DOI:10.5098/hmt.20.21

Abstract This study will demonstrate the performance of a photovoltaic (PV) powered vapour compression cooling system connected to a Phase Change Material (PCM) storage tank. Three options were studied, namely (a) PV vapour compression with a PCM storage tank and an air-conditioned room with chilled water circulation with transparent membrane/desiccant; (b) PV vapour compression with a PCM storage tank and an air-conditioned room with chilled air dehumidification; and (c) PV vapour compression with a PCM storage tank and an air-conditioned room chilled by combined water circulation, a transparent membrane/desiccant, and air duct dehumidification. Simulation using TRNSYS,… More >

Peter van den Engel^1,*, Michael Malin², Nikhilesh Kodur Venkatesh¹, Luigi Antonio de Araujo Passos¹

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.3, pp. 783-805, 2023, DOI:10.32604/fdmp.2022.021962 - 29 September 2022

Abstract This research evaluates the performance of a Phase Change Material (PCM) battery integrated into the climate system of a new transparent meeting center. The main research questions are: a. “Can the performance of the battery be calculated?” and b. “Can the battery reduce the heating and cooling energy demand in a significant way?” The first question is answered in this document. In order to be able to answer the second question, especially the way the heat loading in winter should be improved, then more research is necessary. In addition to the thermal battery, which consists… More > Graphic Abstract

Wenwei Li¹, Xinjie Zhan^2,*, Baotian Wang¹, Jinyu Zuo¹

Journal of Renewable Materials, Vol.11, No.1, pp. 363-378, 2023, DOI:10.32604/jrm.2022.022254 - 10 August 2022

Abstract Municipal sludge is a sedimentation waste produced during the wastewater process in sewage treatment plants. Among recent studies, pilot and field tests showed that chemical conditioning combined with vacuum preloading can effectively treat municipal sludge. To further understand the drainage and consolidation characteristics of the conditioning sludge during vacuum preloading, a large deformation nonlinear numerical simulation model based on the equal strain condition was developed to simulate and analyze the pilot and field tests, whereas the simulation results were not satisfactory. The results of the numerical analysis of the pilot test showed that the predicted… More >

Ayad S. Abdallah^a,b,*, Nabil Jamil Yasin^a, Hani Aziz Ameen^a

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-7, 2022, DOI:10.5098/hmt.18.10

Abstract To reduce the energy consumption in air-conditioning systems without changing the required temperature level in the air-conditioned space, Heat Pipe Heat Exchanger (HPHE) has been experimentally used and tested. The heat pipe has been filled with working fluid by about 50% of the volume of the evaporator which represents the filling ratio. In this research, three mass concentration of nanoparticle from copper oxide (CuO), 1wt%, 3wt% and 5wt% have been used and studied. Additionally, its effect on the HPHE effectiveness and the heat recovery ratio at different inlet air temperatures, 30, 35, 40, 45, 50,… More >

Hawraa T. Gatea^a , Atheer S. Hasson^a, Adil A. Alwan^b, Mohammed Y. Jabbar^b, Azher M. Abed^a

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-6, 2022, DOI:10.5098/hmt.18.5

Abstract The present work is an experimental study into the thermal performance of air conditioning system (split unit), bases on using renewable energy as an assisted facter. The serpentine tube flat plate solar collector (STFPSC) is combined with 1-ton capacity split air conditioning system, which is installed after the compressor to superheat the refrigerant that leaves the compressor. The conventional air conditioning (A/C) system is compared with the suggested system. The results show that the coefficient of performance (COP) of the solar assisted air conditioning system (SAAC), is affected by the enhancement of the solar collector, More >

Albio D. Gutierrez^a,*, Hayri Sezer^b, Jose L. Ramirez^c

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-12, 2022, DOI:10.5098/hmt.18.4

Abstract This paper presents a computational model along with a thermal comfort criterion aimed at assisting the design of operating rooms (ORs) from the perspective of meeting suitable flow patterns and thermal comfort conditions for the occupants. The computational model is based on the finite volume method (FVM) to describe the air inside ORs along with the human thermoregulation model implemented in virtual mannequins for thermal comfort. The air model considers turbulent fluid motion, species transport and the conservation of energy, including thermal radiation. The human thermoregulation model incorporates two interacting systems of thermoregulation. Namely, the… More >

FATIMA CVRČKOVÁ^*, HANA KONRÁDOVÁ

BIOCELL, Vol.46, No.3, pp. 645-649, 2022, DOI:10.32604/biocell.2022.018114 - 18 November 2021

Abstract The possibility of associative learning in plants is a topic of ongoing controversy. In one published study, growing pea plants were reported to associate two stimuli (airflow and light) and thereafter use one (airflow) as an indicator for the other (light), similar to dogs in Pavlov’s famous experiments. However, this observation could not be independently repeated. Here we examine a possible reason for the failure of a published reproduction attempt, which used substantially different light quality during plant cultivation prior to experimental treatments than in the original study. This could have resulted in dramatically different More >

Rongwei Xiong^1,#, Xiufang Gao^1,2,#,*, Xinyue Tu³, Yilin Mao¹, Li Jiang¹, Lu Zheng³, Yitong Du³

Journal of Renewable Materials, Vol.10, No.2, pp. 469-486, 2022, DOI:10.32604/jrm.2022.017226 - 30 August 2021

Abstract The safe and efficient disposal and utilization of sludge are major issues to be solved in solid waste treatment and environmental protection due to the complex characteristics of sludge and the low rate of innocuous treatments. Composting is a process of decomposing organic matter and transformed low-molecular organic acids into high-molecular humus substances under the action of microorganisms. Although land-use after composting has become an important direction for sludge treatment, heavy metal pollution is still the bottleneck problem restricting land use of sludge compost. Adding zeolite, hydroxyapatite, and other conditioning agents to the composting process More >