by Mikhail Granovskiy

Received: 17 October 2023;  Published: 14 November 2023;  doi: 10.21926/jept.2304034

According to the United States Department of Energy, waste heat recovery would allow up to a 20% reduction in greenhouse gases (GHG) emission. Most of the waste energy is discharged as a low-grade heat at temperatures less than 250°C. Therefore, the development of new technologies and the enhancement of existing ones to convert low-grade heat into electrical or mechanical energy are of great importance. The working principle of adsorption-desorption heat pumps with cyclic switching between adsorption and desorp [...]

by Kesiena Owebor  , Smith Orode Otuagoma  , Ogheneakpobo Jonathan Eyenubo  , Arthur Gogo Uranta  , Friday Erhimudia Ukrakpor  , Kesiena Ezewu  and Ebimene Ezekiel Ebisine

Received: 01 August 2023;  Published: 08 November 2023;  doi: 10.21926/jept.2304033

The proper management of sawdust is critical to socioeconomic development. In this research, waste-to-energy has been proposed to utilize sawdust in selected timber markets in Port Harcourt, namely, Illoabuchi Timber Market, Marine Base Timber Market, and Mile 3 Timber Market. A quantitative approach has been taken to estimate the sawdust generation, energy potential, power generation capacities, and pollutant reduction of indiscriminate combustion of sawdust. The findings suggest that, annually, 171 ktons, 42 kton [...]

by Fariba Moradipour  , Andreas Markert  , Thomas Rudszuck  , Niklas Röttgen  , Gerald Dück  , Martin Finsterbusch  , Felix Gerbig  , Hermann Nirschl  and Gisela Guthausen

Received: 04 August 2023;  Published: 02 November 2023;  doi: 10.21926/jept.2304032

Charge transfer and mobility are essential for electrochemical processes in batteries, which need to be understood in detail for optimization, especially in the case of all-solid-state batteries. Wide line NMR is well-known in solid-state NMR and allows the quantification of ion mobility in ordered crystalline and amorphous structures. Temperature-dependent 23Na-NMR is sensitive to ion mobility via longitudinal relaxation, but also via line analysis and transverse relaxation. As 23Na is a spin 3/2 nucleus, 23Na-NMR [...]

by Kamal A.R. Ismail  , Fatima A.M Lino  , Jorge R. Henriquez  , Mohamed Teggar  , Abdelghani Laouer  , Muslum Arici  , Amani Benhorma  and Daniel Rodríguez

Received: 12 June 2023;  Published: 19 October 2023;  doi: 10.21926/jept.2304031

The building sector is rated as a big consumer of electric energy and emissions, responsible for about 40% of final electric energy consumption. As a result, the Paris Agreement 2015 set a goal for buildings and the construction sector to reach a nearly zero-carbon stage by 2050. This urged most countries to create regulations for the construction sector and invest in energy efficiency programs. The present paper aims to present an updated review of building energy-saving solutions and techniques to contribute to c [...]

by Sadmanul Hoque  , Md. Rashidul Islam  , Md Shafiullah  , Saymun Adnan  and Md. Samiul Azam

Received: 18 June 2023;  Published: 28 September 2023;  doi: 10.21926/jept.2303030

In an electric power system operation, the main goal of economic dispatch (ED) is to schedule the power outputs of committed generating units efficiently. This involves consideration of relevant system equality and inequality constraints to meet the required power demand at the lowest possible operational cost. This is a challenging optimization problem for power system operators that can be dealt with efficient meta-heuristic algorithms. This article uses a recent meta-heuristic approach named the generalized norm [...]

by Ann Lee  and Shaokoon Cheng

Received: 26 March 2023;  Published: 18 September 2023;  doi: 10.21926/jept.2303029

In the context of decarbonization efforts, heat pump water heaters (HPWHs) offer an attractive solution over conventional electric resistance type hot water systems due to their 2-3 times higher efficiency. However, the high manufacturing costs and taxes associated with using hydrofluorocarbon (HFC) refrigerant make HPWHs expensive. As a means to tackle this issue, this paper explores the use of propane (R290) as a refrigerant in HPWHs. The study involves an experimental comparison of R290 and R134a, with refrigera [...]

by Mahdi Yousefi  , Scott Donne  , Shabnam Bahremand Abrasi  and Mohammad Yousefi

Received: 10 April 2023;  Published: 13 September 2023;  doi: 10.21926/jept.2303028

The thermal cracking of methane (TMC) is a significant reaction occurring above 850°C, which proceeds in two stages: non-isothermally and isothermally. However, most existing studies have focused on obtaining reaction rates under isothermal conditions [1], limiting their applicability to practical industrial reactor conditions. This novel research aims to determine the overall thermal decomposition rate of methane to hydrogen and carbon in adiabatic conditions, covering the range of unstable industrial reactor temp [...]

by Zachary Brozzesi  , Darson Dezheng Li  and Ann Lee

Received: 16 June 2023;  Published: 08 September 2023;  doi: 10.21926/jept.2303027

Buildings, with their significant energy consumption, pose a pressing concern for the future. Inadequate heating, ventilation, and air-conditioning (HVAC) systems further exacerbate thermal management difficulties and energy requirements. To address these challenges, Phase Change Materials (PCMs) offer valuable potential for sustainable energy reduction within the building sector, leveraging passive cooling and heating techniques. Numerical study has been conducted to explore the impact of embedding PCM within the [...]

by Ken Shimomukai  , Haruka Maeda  , Zahirah binti Muhammad Azman  , Sandro Sitompul  and Goro Fujita

Received: 09 March 2023;  Published: 03 August 2023;  doi: 10.21926/jept.2303026

One way to increase solar photovoltaic penetration in the grid is the management of voltage fluctuations. This is because a photovoltaic plant cannot be interconnected to the grid if it causes voltage violations. Voltage violation is where voltage exceeds the acceptable range. Often, grid operators request photovoltaic plant owners to regulate voltage sufficiently with expensive and space-consuming static Var compensators. Unfortunately, this sometimes makes the project less feasible. This paper argues that there a [...]

by Carlos Armenta-Déu

Received: 18 May 2023;  Published: 27 July 2023;  doi: 10.21926/jept.2303025

The paper analyses the performance of a spherical solar collector compared to the efficiency of a flat-plate solar collector, which is the type of solar collector that does not use a tracking system in collecting solar radiation for energy conversion. Spherical solar collector benefits from a constant value of the angle of incidence, which optimizes the solar radiation that strikes the absorber of the solar device and maximizes the energy collection. Besides, the spherical geometry has a larger area for equal dimen [...]