Motivated by the potential of wind power based electricity generation modules in urban environments, flow properties of wind turbines operating behind a building-like wall-attached cube are investigated through large-eddy simulation. Significant power losses with increased power fluctuations are observed for the first turbine downstream of the cube. Also, the power losses and fluctuations increase

The profitability of investments in photovoltaics (PVs) and batteries in private households depends on the market price of electricity, which in turn is affected by the investments made in and the usage of PVs and batteries. This creates a feedback mechanism between the centralised electricity generation system, and household investments in PVs and batteries. To investigate this feedback effect, we

Solar radiation incident on photovoltaic modules only partly directly convert into electricity; the rest is converted into heat that increases the module layers’ temperature. In order to quantify both the output power and the electrical efficiency, the knowledge of the temperature profile is essential. This study proposes a transient one-dimensional thermal model of photovoltaic modules which provides

Power-to-gas (PtG) is one option to integrate more renewable electricity production to the energy system, by offering flexible load, seasonal energy storage and low-GWP (Global Warming Potential) methane. The first step of the PtG process, hydrogen production by water electrolysis, requires electricity with low specific CO2 emissions. Therefore, the operation of electrolyser is most likely variating

Biogas has emerged as a promising renewable technology that can provide affordable, safe and clean energy to rural area. In Rwanda, the domestic biogas was introduced as a partial solution to the energy security problem in rural areas with a target of 15,000 installed biogas plants by 2012. However, this target has never been achieved. Moreover, there is a high rate of non-functioning biogas plants

Microalgae were grown in 12-L airlift photobioreactors (PBR) containing biodigested swine manure (BSM), cattle manure (BCM) and domestic sewage (BDS), with 5% v/v, 25% v/v and 30% v/v respectively and compared with synthetic medium CHU. BSM with biogas/air mixture (10% CO2) injection on the 8th day led to of 13,257 ± 430 × 104 cell mL−1, and 2.0 ± 0.16 g L−1 dry biomass with a 26% lipid content, which

Environmental concerns have increased over environmental hazards associated with fossil energy source, transition to renewable energy sources have been emphasized, this however requires relevant data for informed decision making. Critical analytical methods in situating bioenergy plants for bioenergy production are advantageous from environmental, economic and sustainable perspectives. A study therefore

In this paper, the cavitating flow and pressure fluctuation in the tip region were simulated based on Delayed Detached Eddy Simulation (DDES). The high-speed photography and transient pressure measurements were employed to capture the cavitation structures and pressure fluctuation. The numerical results show a reasonable agreement with the available experiments. The maximum errors of head and efficiency

In current attempt, swirl generator and four-lobed pipe were installed in a solar collector to achieve higher performance not only in view of cooling rate but also available energy. In outputs, components of irreversibility were illustrated for different values of revolution (N), pumping power (Re (Reynolds number)) and width of tapes (D∗(diameter ratio)). Four functions were scrutinized namely; Xd

This paper proposes an integrated photovoltaic vacuum glazing unit with an intermediate air cavity and a calibrated modelling approach to quantify its thermal properties and evaluate the heat transfer performance. Theoretical analyses of the heat transfer process are conducted with reasonable hypotheses and traceable boundary conditions. Three-dimensional heat transfer models are then established and

A cogeneration solar system for a building located in Sabzevar (Iran) is investigated in this study. In this system, a combination of a solar evacuated tube collector field and an auxiliary natural gas burner drive a single effect absorption chiller. Solar energy is also used to produce consuming hot water. Hourly cooling demands of the building were calculated during April to September. In order to

The demand for renewable energy sources is limited by their inherent intermittent nature. The thermal energy storage technique overcomes this shortcoming by allowing storage of naturally occurring energy (e.g. solar) during “non-peak hours”. The article presents an experimental investigation of the sparsely studied ‘single medium thermocline’ (SMT) based single tank sensible thermal energy storage

Intensity of solar irradiance directly affects solar power generation and this makes solar irradiance forecasting a vital process in energy management systems. Existing forecasting systems show positive solar irradiance forecasting performance, but most of them are not accurate in real-life especially when there are fast-moving clouds, causing highly fluctuating solar irradiance profile, which is difficult

The present work includes a review of solar ejector cooling cycle (SECC) systems. In the first section of the paper, an overview of the fundamentals of SECCs is presented. The most important aspects of the design, operation and performance of ejector devices and solar ejector cooling cycles are discussed. The second part of the paper includes a literature review encompassing studies focusing on SECCs

A novel solar driven hybrid system composed of a concentrated solar collector, thermionic generator and thermoelectric device is proposed. Thermoelectric device uses the waste heat of the thermionic generator to generate further power and cooling. Analytical explanations for the power output and efficiency of the thermionic generator, thermoelectric device and hybrid system are investigated. In order

The thermal stress plays an important role to assess the security of the solar receiver and is mainly affected by the temperature gradient. To study the thermal stress of the receiver, a MATLAB program was developed to study the distribution of temperature and thermal stress numerically, and the program was verified on the lab-scale receiver and it was found that the error between the calculated result

The catalytic co-pyrolysis of torrefied poplar wood sawdust (TPW) and high-density polyethylene (HDPE) was investigated over hierarchical HZSM-5. Compared with raw PW/HDPE, the bio-oil yield from co-pyrolysis of TPW/HDPE decreased gradually while the quality of bio-oil was upgraded. With increasing torrefaction temperature from 220 to 280 °C, the amounts of acids, furans, and anhydrosugars in bio-oil

Since the 2000s, renewable energy production has been increased throughout Europe. Biogas plants should also contribute to the reduction in CO2 emissions. However, developments in numbers of biogas plants and management varied in individual countries and regions. In order to illustrate these different developments, the legal framework conditions for three countries (Switzerland, Germany and Austria)

Biodiesel production using supercritical methanolysis has received immense interest over the last few years. It has the ability to convert high acid value feedstock into biodiesel using a single-pot reaction. However, the energy intensive process is the main disadvantage of supercritical biodiesel process. Herein, a conceptual design for the integration of supercritical biodiesel process with organic

A novel variable-volume tank is lately designed to cater for the varying needs of tank volume. Based on the validated models of collector and the novel tank, a mathematical model for the solar heating system with the novel tank is proposed in this paper. The system is designed for space heating and consists of solar collector, variable-volume water tank and auxiliary heat source. A case of office building

As an emerging subway waste heat utilization system, capillary network subway source heat pump system has high practical value. At present, there are many researches on capillary network heat exchanger, but little research has been done on the influencing factors and design optimization of the entire system. The orthogonal test method is used to determine the key design parameters affecting the subway

To study the effect of different inorganic iron compounds on the biological methanation of CO2 sequestered in coal seams, a biogas production experiment was carried out through use of bituminous coal D (China) and indigenous microorganisms, by adding bicarbonate and inorganic iron compounds. It is found that the addition of FeCl2 or FeS2 promoted methane production. FeS2 resulted in the highest methane

Accurate prediction for short-term wind speed can reduce the adverse impact of wind farm on power system effectively. To this end, a novel hybrid forecasting approach combining two-layer decomposition, improved hybrid differential evolution-Harris hawks optimization (IHDEHHO), phase space reconstruction (PSR) and kernel extreme learning machine (KELM) is proposed. Primarily, a set of sub-components

Low concentrating photovoltaic (LCPV) system has been studied extensively, which showed excellent potential for the building integration application. However, such a system suffers from higher operating temperatures due to the concentrated light exposed into the solar cell. In this work, two different methods have been used to regulate the operating temperature of the solar cell without the interference

Neat biodiesels are not preferred for use in the compression ignition (CI) engines due to their high viscosities and related operational difficulties. This study investigated the fuel properties and combustion characteristics when 2-butoxyethanol additive was mixed separately with waste cooking oil biodiesel (W100) and rapeseed oil biodiesel (R100). Compared to neat biodiesels, the viscosities (at

Implementation of renewable energy support policies in many countries for the sake of energy security and climate change mitigation worldwide raises the importance of renewable energy power plants (REPPs) in analyzing power market features. In this article, an analytical method is introduced to examine the effect of REPPs on locational marginal price (LMP). To this end, taking into account REPPs, according

For applications involving very low specific speeds resulting from very low flow rates with medium to high heads, a special class of hydraulic turbine known as Positive displacement turbine (PDT) is most suited. These turbines are not very common, but they can effectively harness the micro and Pico hydropower. For the present work, the effect of inlet and outlet pipe’s cross-sectional shape on the

The building sector plays a crucial role in the advocated transition towards a carbon-free economy, and thus the zero-carbon building concept is taking hold. The paper focuses on the issue of existing hotels, with the aim of investigating the possibility of meeting the ambitious zero-carbon targets for this category of buildings, in which guests’ comfort and satisfaction is the core business. A reference

This paper presents a frequency domain transfer function methodology for thermal characterization and design for energy flexibility of zones with hydronic radiant heating/cooling systems and significant thermal mass. The modeling methodology is validated with experiments in an environmental chamber. Using the developed frequency domain model of the zone, key transfer functions are calculated for a

This study investigates the use of a direct ground cooling system (DGCS) using active chilled beams for the cooling of office buildings in Sweden. The methodology of the study entails laboratory experiments to develop and validate a simulation model of the cooling system. The sensitivity of the input parameters, such as borehole heat exchanger (BHE) length, internal heat gains and room temperature

The half-cycle time effect on the performance of a solar single-stage dual-bed adsorption chiller, in Athens, Greece, in July, is investigated. The adsorption chiller coupled with the solar system is simulated, in real time, during the day for a) constant and b) adjusted half-cycle times and the system performance is monitored. In the former case, the half-cycle time is fixed, while in the latter one

With the rapid development of microelectronic devices, efficient thermal management in narrow spaces faces significant challenges. Two-phase heat transfer technology is proposed as a breakthrough in this field; however, big challenges, especially in designing a high-performance wick within limited space, are urgent to be addressed before ultrathin two-phase heat transfer devices (TPHTDs) can be further

Au-based bimetallic electrocatalysts supported on multiwalled carbon nanotubes (MWCNTs) were investigated to improve the selectivity and activity of the catalysts for direct borohydride–hydrogen peroxide fuel cells (DBPFCs). Au–Pd and Au–Ni catalysts were used as the anode and cathode catalysts, respectively. The Au-based bimetallic catalysts with various atomic percentage ratios were investigated

The variation of blade axial force of pump-turbine, which may cause instability on impeller shaft system, can be influenced by cavitation. However, the mechanism of this phenomenon is still not clarified. In this study, numerical simulation and experimental research are combined to investigate the influence of leading-edge cavitation on impeller blade axial force in the pump mode of reversible pump-turbine

We propose a novel multilateral-well coaxial closed-loop geothermal system (CCGS) to help realize the commercial exploitation of hot dry rock. Compared with the enhanced geothermal system, it avoids the high-cost fracturing and environmental problems by closed-loop circulation. Also, the multilateral-well CCGS can significantly increase heat production than traditional vertical-well or horizontal-well

To study the difference in pressure pulsation characteristics between full tubular and axial-flow pumps, CFD (Computational Fluid Dynamics) was used to perform unsteady simulation calculation on full tubular and axial-flow pumps based on the RNG k-ε turbulence model. The accuracy and reliability of the CFD results were verified by the model test. Results show that the regulars of the inlet pressure

The use of cascade multi-functional heat pumps to provide simultaneous cooling or heating, and hot water has become essential in recent times. This study analyzed the performance of a water-to-water cascade multi-functional heat pump according to the variation of heat source and heat sink temperatures in cooling mode, hot water mode and cooling hot water mode. The cooling-hot water cycle was optimized

Cooling of photovoltaic panels is an important factor in enhancing electrical efficiency, reducing solar cell destruction, and maximizing the lifetime of these useful solar systems. Generally, the traditional cooling techniques consume considerable amount of water, which can be a major problem for large scale photovoltaic power stations. In this experimental study, a pulsed-spray water cooling system

Industrial process heating applications in the temperature range of 50°–250 °C consumes about 35% of the global fossil fuels, wherein solar thermal is envisaged as an alternative option. Outlet temperatures of both flat-plate collector (FPC) and photovoltaic thermal collector (PVT) are not high enough to serve industrial processes. In this article, a solar assisted process heating (SAPH) system, wherein

The impact of this research is to present results obtained from synthesis of nanoencapsulated Paraffin wax core/Thermoplastic elastomer Polyurethane shell with various particle size distribution via mini-emulsion polymerization that could be utilized in thermal energy storage. To achieve this objective, five different types of Polyurethane shell/Paraffin wax core nanocapsules have been synthesized

A first estimate of the energy potential in the tidal streams on the Faroe Shelf is derived from a barotropic numerical model with 100 m resolution. A total of 13 sites are identified as potential candidates for the harvest of the tidal stream energy with a total available mean energy flux in transects through these locations exceeding 2 GW. Of this 214–886 MW is in areas with depths larger than 40

The present work is carried out to study the performance of a Savonius rotor for small-scale hydropower generation. It has been observed that some of the irrigation channels available in the rural areas are having enough bed slope to generate kinetic energy, which can be harnessed through a Savonius rotor. An in-house fabricated scale-down model of the Savonius rotor is tested at an inclination of

Renewable energy is a promising solution for addressing social and environmental issues related to the rapidly rising electric power consumption of manufacturers. Recently, a number of policies have been proposed by governments to stimulate the use of renewable energy by manufacturers. Financial incentives are considered as an efficient lever to increase the penetration of renewable energy. This study

The wind condition around floating offshore wind turbines (FOWTs) can be largely different from that developed around bottom-mounted wind turbines due to the platform motions. The existing literature identifies four working state of FOWTs, one of them being the vortex ring state (VRS) which may occur as the rotor moves in its own wake. It is potentially a problem that influences the aerodynamic performance

The lack of high efficient, predictable, and reliable power take-off (PTO) systems limits developments of ocean wave energy technology. In this paper, a two-body self-reacting wave energy converter (WEC) with a novel PTO is designed, modelled and implemented for efficiency enhancement. A novel mechanical motion rectifier (MMR) using a ball screw mechanism and an enclosed gear set is integrated to improve

The goal of the work is to determine unknown parameters of reactor heating in the process of biomass solar pyrolysis. The lab-scale reactor is heated by a xenon lamp, but the fraction of heat absorbed by the reactor is unknown, as well as the heat transfer coefficient from the reactor walls to the nitrogen flowing through internal reactor channels, and the overall heat transfer coefficient through

Reduction of carbon dioxide (CO2) emissions will have a positive impact on the environment by preventing adverse effects of global warming. To achieve an eco-environment, the primary source of energy needs to shift from fossil fuels to clean renewable energy. Thus, increased utilization of renewable energy overtime reduces air pollution and contributes to securing sustainable energy supply to satisfy

This study analyzed the impacts from multi-crystalline silicon (m-Si), organic thin-film (OPV), and perovskite thin-film (PSC) panels over each products’ lifetime using a cradle-to-grave system model. The rate of panel installation each year was modeled to account for efficiency, functional lifetime, and degradation. Landfill and recycling scenarios were used to compare end-of-life impacts and the

Co-pyrolysis of rice straw (RS) and ulva prolifera macroalgae (UPM) was studied over a series of nickel-iron-layered double oxides (NiFe-LDO) supported on activated bio-char catalysts. Results showed that, co-pyrolysis produced higher bio-oil yield compared to the individual pyrolysis. Maximum bio-oil yield (46.68 wt%). was found with RS/A-UPM mixture biomass at 500 °C. While RS and UPM and it mixture