Heat Consumption Research Articles

An efficient carbon-neutral power and methanol polygeneration system based on biomass decarbonization and CO2 hydrogenation: Thermodynamic and economic analysis

This study presents a novel approach to enhance methanol synthesis (MS) efficiency through integration with an MEA-based decarbonized biomass direct-fired power plant (BFPP-CCS). The integration optimizes the utilization of chemical energy from feedstocks by combining exothermic MS reactions with diverse thermal energies, which effectively captures chemical energy through synergistic utilization from MS and various thermal inputs. Gradual methanol conversion maximizes both its chemical and fuel properties. Through such integration, the enhancement of waste heat and purge gas utilization in MS and BFPP carbon capture processes results in a 3.42 MW improvement in power generation and a 26.0 % reduction in associated energy penalties from CCS. Analysis of a 150 kton/yr MS facility and a 35 MW BFPP-CCS demonstrates 2.87 % increase in overall efficiency and reduction in CCS heat consumption by 1.03 GJ/tCO2. Moreover, this integrated approach yields a 33.1 M$ NPV increase and 3.4 years DPP decrease, achieving carbon-neutral power and liquid fuels production. Sensitivity analysis indicates the polygeneration system performs optimally around 250 °C and 60 bar, with a preference for 0.90 MS recycle ratio. Additionally, factors such as carbon recovery rate, electrolysis efficiency, and fixed carbon content in biomass are quantitatively revealed as crucial for maximizing carbon mitigation potential.

Thermal Analysis of Infrared Heater as an Alternative Heat Source for Flexitank Application Using CFD

The heating pad was a mechanism for heating elements using steam as a heat source and heating the liquid inside a flexitank to liquidise for easy discharge completely. Alternative heat sources such as infrared, electric, and exothermic reactions may improve thermal performance for the heating process. Infrared heating is chosen for this study due to its efficient radiation heat transfer compared to conduction and convection. This study aims to determine the optimal infrared heater configuration to improve the time to liquidify fluid on the flexitank for easier discharge. Nine flexitank and infrared heater geometries were made using SolidWorks with different heater positions and heating element thicknesses. Each geometry was simulated using Ansys Mechanical to study the thermal performance of radiation heat transfer with three different heating element materials. The heat output and energy input obtained from the simulation were used to calculate heating time and energy efficiency, respectively. The effects of each parameter were studied to determine the best configuration of the infrared heater in terms of heating time, energy consumption and both. The results showed that the position of the heater plays the most crucial role in determining the heating time and energy consumption, as a heater position that produces a larger heated surface area on the flexitank can reduce heating time. The thickness of the heating element and its material contributes a minor impact on heating time and energy consumption. Increasing thickness would lower the heating time and increase energy efficiency if the thickness improves heat retention capabilities. Increasing material emissivity will increase the heating time. Higher conductive materials would use more energy compared to lower conductive materials. The heating time was improved by about 30% compared to a steam heating pad. Energy consumption was reduced by about 85% compared to a small steam generator. In conclusion, the infrared heater was a promising alternative as a heat source for flexitank applications.

Effect of Magnesium Hydroxide on the Thermal Stability, Latent Heat and Flammability Properties of composite material based on Phase Change Materials

Abstract Polyurethane-Phase Change Materials (PU-PCM) composites are used for thermal regulation aiming to conserve and efficiently manage thermal energy. These materials combine the properties of PU, such as low thermal conductivity, low density and excellent mechanical properties as a thermal insulator, with the benefits of PCM allowing thermal energy storage, which greatly reduce energy consumption in heating and cooling. Adding a flame retardant to the PU-PCM composition improves fire resistance. The objective of this study is the preparation and characterization of a composite material based on PU rigid foam containing 30% by mass of commercial paraffin waxes as PCM, together with magnesium hydroxide as flame retardant. A series of samples were prepared by incorporating different percentages of Mg(OH)2, ranging from 1 % to 5 %, with and without the PCM. Various thermal and chemical characterization tests were carried out. The results indicate that the structure of the PU cells is not affected by the increase of the Mg(OH)2 incorporation rate. In terms of thermal properties, the addition of 1% flame retardant increases the latent heat from 25.9 J/g to 39.68 J/g. As the amount of Mg(OH)2 incorporated increases, the flame retardancy increases.

Design, numerical optimisation and experimental validation of an innovative solar-powered tube heater with multiple air impingement jets

This research investigates a novel tube heater designed for the seamless integration of an innovative solar thermal system into the powder-based coating process to heat steel tube at a temperature of 240 °C. It incorporates a comprehensive numerical model developed and assessed using ANSYS FLUENT, concentrating on seven critical parameters that significantly influence the tube heater’s performance and size. These parameters include tube heater length, jets’ length, funnel height, Z/Djet, Y/Djet and X/Djet ratios, as well as jet diameter. The findings underline the critical role of tube heater length in enhancing heat transfer and maximising thermal efficiency, while reducing jet length and funnel height demonstrated negligible effects on thermal performance, promoting material economy. A lower Z/Djet ratio enhanced heat transfer uniformity, improving thermal performance, while optimal X/Djet and Y/Djet ratios were identified as 4 maintaining a balance between heat transfer rate and energy consumption. A smaller jet diameter proved beneficial since the potential core was not achieved, increasing heat transfer to the steel tubes. The experimental model, conducted to validate the novel tube heater’s performance, remarkably aligns with the numerical model, showing an R-squared value of 0.992. These results affirm the numerical setup’s accuracy and reliability in capturing the tube heater’s thermal behaviour. It is concluded that the novel tube heater stands as a highly efficient solution for the seamless integration of solar thermal systems into the powder-based coating process of steel tubes, promising significant emissions reduction.

Co-pyrolysis of biomass/polyurethane foam waste: Thermodynamic study using Aspen Plus

Due to the varieties and identical feature of solid waste, this research aims to consider the use of various feedstocks in pyrolysis process for liquid fuel production. The feedstock considered covers woody and non-woody biomass and plastic waste which are represented by sawdust (SD), palm leaf (PL) and polyurethane foam (PU) waste. In this research, both pure solid waste and the co-pyrolysis of biomass and plastic wastes were determined based on thermodynamics study. The model of pyrolysis process developed through Aspen Plus simulator was implemented to study the product yield, higher heating value (HHV) and energy consumption with a wider range of pyrolysis temperature and blending weight ratio. The simulation results clearly showed the use of pure PU waste can provide the highest oil yield (∼44%wt.) which is corresponded to highest HHV (∼28 MJ/kg). The pyrolysis, operating at 400oC, can provide the most significant quantity of oil. For the co-pyrolysis, the results revealed that more PU waste blended in both biomasses can improve both oil yield and HHV while the energy consumption is lower. From the simulation results, the optimal blending weight ratio of biomass and PU waste at 25:75 can provide suitable oil yield (∼43%wt.), HHV (∼26 MJ/kg) and energy consumption (243kW).

Smart Photovoltaic Windows for Next-Generation Energy-Saving Buildings.

The global energy system transforming from fossil fuels to renewable green energy through the adaption of innovative and dynamic green technologies. Energy-saving buildings (ESBs) are attracting extensive attention as intelligent architectures capable of significantly reducing the energy consumption for heating, air-conditioning, and lighting. They provide comfortable working and living environment by regulating and harnessing solar energy. Smart photovoltaic windows (SPWs) offer a promising platform for designing ESBs due to their unique feature. They can modulate solar energy based on dynamic color switching behavior under external stimuli and generate electrical power by harvesting solar energy. In this review, the-state-of-art of strategies and technologies are summarized putting SPWs toward high-efficiency ESBs. The SPWs are systematically categorized according to the working principle and functional component. For each type of SPWs, material and architecture engineering are focused on to optimize operation mode, optical modulation capability, photovoltaic performance and durability for giving ESBs flexible manipulation, extraordinary energy-saving effect, and high electricity power. In addition, the challenges and opportunities in this cutting-edge research area are discussed, with the aim of promoting the development of advanced multifunctional SPWs and their application in high efficiency ESBs.

Predictive building energy management with user feedback in the loop

Retrofitting buildings with predictive control strategies can reduce their energy demand and improve thermal comfort by considering their thermal inertia and future weather conditions. A key challenge is minimizing additional infrastructure, such as sensors and actuators, while ensuring user comfort at all times. This study focuses on retrofitting with intelligent software, incorporating the users’ feedback directly into the control loop. We propose a predictive control strategy using an optimisation-based energy management system (EMS) to control thermal zones in an office building. It uses a physically motivated grey-box model to predict and adjust thermal demand, with individual zones modelled using an RC-approach and parameter estimation handled by an unscented Kalman filter (UKF). This reduces deployment effort as the parameters are learned from historical data. The objective function ensures user comfort, penalises undesirable behaviour and minimises heating and cooling costs. An internal comfort model, automatically calibrated with user feedback by another UKF, further improves system performance. The practical case study is an office building at the ”Innovation District Inffeld”. Operation of the system for one year yielded significant results compared to conventional control. Thermal comfort was improved by 12% and thermal energy consumption for heating and cooling was reduced by about 35%.

Improved understanding of thermal comfort could yield energy savings in heritage buildings

Abstract It is necessary to improve the understanding of thermal comfort to reduce energy consumption for heating and cooling in heritage buildings, which are often energy inefficient and where interventions are limited. Personal thermal comfort models based on measurements of environmental conditions and the individual’s physiological and subjective responses represent a potential solution to ensure the optimization of existing systems. Past research shows that lighting could impact thermophysiology and subjective perception of thermal conditions, but it is not clear whether the impact is sufficient to make light adaptation an appropriate solution to reduce energy consumption in heritage buildings, where people live and work. The research conducted under realistic semi-controlled conditions in an office environment of an existing building addresses this research gap. The paper presents the first partial simplified analyses and preliminary results of a wider ongoing study, mainly showing a correlation between skin temperature and air temperature and a partially promising effect of light on subjective thermal perception. Our research on the effect of light on thermal comfort does not provide definitive conclusions but rather highlights the need for further investigation in actual heritage buildings.

Comparative Study of Energy Consumption Intensity: A Case Study of the Faculty of Electrical Engineering and Informatics (FEI) Versus the Faculty of Chemical Technology (FChT) in the City of Pardubice

Abstract The study’s comparative aspect between the Faculty of Electrical Engineering and Informatics (FEI) and the Faculty of Chemical Technology (FChT) buildings is pivotal for elucidating nuanced differences in energy consumption practices within academic institutions, facilitating targeted energy efficiency measures. The research methodology adopts a comparative case study approach to examine two focal research buildings. Analysis entails computing energy consumption intensity per unit area for both buildings and comparing energy consumption data to identify disparities. The need for understanding energy consumption patterns and improving energy efficiency in academic infrastructure is directly addressed through variables studied in the comparative analysis, including energy consumption comparison, annual and monthly variations, ratio, and intensity. The data indicates that the average heating intensity in the FChT building surpasses that of the FEI building by a factor of 2.3, signifying significant disparities in heating energy consumption trends between the two structures and suggesting potential areas for targeted energy efficiency interventions. Moreover, the average electrical intensity in the FChT building is over 1.7 times higher than in the FEI building. Interestingly, despite the FChT building being 2.6 times larger than the FEI, its intensity does not always correspond with the increase in building area, indicating additional factors influencing energy consumption.

In-situ U-value measurements of typical building envelopes in a severe cold region of China: U-value variations and energy Implications

Building energy consumption in the severe cold regions of China is an important consideration in building energy conservation because of the high amount of energy consumed by heating. As an important thermal parameter, the thermal transmittance (U-value) of building envelopes can directly affect the operational energy consumption of buildings. Understanding the U-values of buildings in severe cold regions is important to predict building energy accurately. However, the U-values of envelopes fluctuate constantly due to environmental impacts. Therefore, this study aimed to examine the influence of dynamic U-values on building energy efficiency. To achieve this, this study focused on the in-situ measurement of the U-values of two typical building envelopes in Harbin from winter to summer in 2023 to determine the average and dynamic U-values of the tested envelope, comprising a brick envelope and reinforced concrete (RC) envelope. The building energy simulation results based on theoretical U-values were compared with the measured average and dynamic U-values of the tested envelopes. The findings revealed that the fluctuations in the U-values were significant. In the dynamic U-values of tested brick and RC envelopes, the U-values in winter were 159.8% and 30.8% higher than those in summer, respectively. Furthermore, the dynamic U-values significantly influenced heating energy consumption, with an increase of up to 15.9%.

Beyond the g-Value: A comparative study of solar control coated glass and spectrally selective glass in terms of building energy efficiency

The thermal efficiency of transparent envelopes is a key factor in building energy consumption and indoor thermal comfort, with the g-value being a critical metric for evaluating these effects. Solar control film glass and low-emissivity (Low-E) glass, recognized for their distinct advantages, are extensively used in construction. However, comprehensive research on their photothermal properties, especially regarding spectral and angular dependencies, remains limited. In this study, a meticulous field experiment was conducted under six distinct conditions during both winter and summer to examine the thermal performance between solar control coated glass (SCCG) and spectrally selective glass (SSG). The results show that, despite having similar heat transfer and solar heat gain coefficients, their indoor peak temperatures can differ by 1.2 °C to 5.6 °C under typical sunny conditions, and variations in cooling and heating energy consumption range from 6.9 % to 14.4 %. Further analysis reveals that the standard g-value overestimates the solar heat gain of SSG by approximately 10 %, with significant discrepancies in the direct transmission heat and secondary heat transfer of 17.8 % and 37.4 %, respectively. In contrast, the standard g-value is more suitable for SCCG, with a measured g-value that is only 1.2 % higher than the standard g-value. The spectral and angular dependencies of both glasses were also compared in this study, and SSG was found to have a strong spectral dependence and a higher angular dependence than SCCG. These findings indicate that SCCG is more beneficial for energy conservation in cold climates when the thermal parameters are identical. Moreover, the research underscores the limitations of current standards and calculation methods for evaluating solar heat gain in transparent envelopes, particularly for glasses with spectral selectivity.

OPTIMIZATION OF HEAT CONSUMPTION IN CENTRAL HEATING SYSTEMS AT COMMERCIAL FACILITIES

Rising energy prices and stricter environmental regulations are exacerbating the problem of inefficient heat consumption in the commercial sector. Central heating systems of office buildings, shopping malls, and industrial complexes are often characterized by excessive thermal energy consumption, which leads to significant economic losses and a negative impact on the natural environment. The purpose of the study is to study the directions and trends of optimization in the field under consideration (taking into account modern technological capabilities, and economic factors). There are disagreements in the professional community about the priority of measures to improve energy efficiency: some experts prefer improving the thermal insulation of buildings, others — the introduction of intelligent control systems, and others — the integration of renewable energy sources. The present study demonstrates that the greatest effect is achieved with a systematic approach combining various initiatives. The conclusion is formulated that in the current conditions and the future, a comprehensive application of modern thermal insulation materials, highly efficient heating equipment, intelligent management mechanisms, and alternative energy sources is required. The article is of interest to engineers-designers of heating systems, energy managers of commercial facilities, specialists in energy efficiency of buildings, and heads of companies interested in optimizing operating costs and improving the environmental friendliness of their real estate.

Renovating Post-First-Energy-Regulation Housing: Achieving Nearly Zero-Energy buildings under typical and extreme warm conditions in a temperate European city

Decarbonising the built environment is essential for achieving the 2050 European objectives. Multi-family buildings comprise nearly half of Europe’s building stock, yet there is no regulation mandating all housing renovations to be Nearly Zero-Energy Buildings (NZEBs). This paper highlights the role of NZEB renovation for residential buildings constructed between the first energy regulations, after the first oil crisis, and the EPBD 2002 implementation (post-first-energy-regulation housing), as a pivotal factor towards energy transition. In Spain, this period (1980–2006) encompasses approximately 45% of existing dwellings. A case study was conducted in a city with a Cfb temperate climate, focusing on the most representative residential typology of the target period: the linear block. The study evaluates its current state and defines potential measures to meet NZEB requirements, achieving zero consumption when renovation of thermal envelope is combined with heat recovery systems, heat pumps, and PV panels.This research is based on energy simulations for two climate scenarios: the typical meteorological year (TMY, official series 1970–2000) and the most extreme warm year (EWY, 2022) in Spain. Results indicate active cooling systems are necessary for NZEB renovations in Spanish Cfb climates. Furthermore, low-temperature radiators significantly reduce heating consumption, while splits are the most suitable cooling systems. This study shows Spain is not adequately preparing its housing stock to face climate change, as most typical renovation works are based on official weather files that need updating to reflect harsher summer conditions. Finally, the study aims to encourage new policies and enhance existing regulations to address rising temperatures and heatwaves.

Relative contribution of the ocean-air heat exchange and advective heat transport to the increase of the Barents Sea water temperature in the early 21st century

The annual water temperature in the major water masses of the Barents Sea (BS) has significantly increased since the early 2000s. Advective heat transport from the neighboring water areas and heat exchange through the sea surface are the major factors, which shape the hydrological conditions in the BS. The paper estimates the contributions of heat exchange at the sea-atmosphere boundary and advective heat transport to changes in the average water temperature of the BS for the entire sea area. The average annual heat balance of the BS is calculated using atmospheric and oceanic reanalysis data. The change in the average temperature of the BS water is estimated taking into account the heat consumption for ice melting. The average surface heat balance from 1993 to 2018 was negative throughout the entire sea area: –70…–100 W/m2 in the south and –10…–20 W/m2 in the north. The advective heat supply was calculated for 9 straits with neighboring water areas. The determining source of advective heat is the influx of Atlantic waters from the Norwegian Sea between Cape Nordkapp and Bear Island. An average of 40.8 TW of advective heat is supplied through this margin. The calculations showed the predominance of annual heat influx due to advection over heat loss from the sea surface. This excess heat influx resulted in an estimated increase in the water temperature of the BS from 1993 to 2018 at a rate of 0.28 °C per year (taking into account the heat consumption for ice melting). In conclusion, it can be argued that the analysis has validated the hypothesis proposed in the article about compensation of heat losses from the surface of the BS by advective heat flow. The hypothesis is quantitatively confirmed by calculations on a simple box model (with an accuracy of up to an order of magnitude) based on atmospheric and oceanic reanalysis data. The ERA5 and GLORYS12V1 reanalysis data reliably describe the basic patterns of observed variability of ocean, sea ice and atmospheric parameters in the Barents Sea.

Thermal performance of multifunctional louver window integrated phase change material and spherical louver

The integration of phase change material (PCM) into glazed envelope is an effective measure to enhance its thermal inertia and reduce energy consumption. However, the inefficient utilization of latent heat stored in double-glazed unit filled with PCM (PCMW) in winter and overheating in summer restricts the adoption of PCM in cold regions. Therefore, this work proposed a multifunctional new phase-change louver window integrating PCM and spherical louvers, and numerically investigated its thermal behaviour in summer and winter seasons. The effects of different melting temperatures and ventilation mechanisms on the thermal performance and energy efficiency of phase change louvers were analyzed. The results show that the new phase-change louver window can significantly improve the thermal comfort and energy efficiency of the window. In winter, insulated PCM louver window has the best performance, reducing heating energy consumption by 2618.56kJ/(m2·d) compared to hollow window, with energy saving of 54.03 %, whereas in summer, reflective PCM louver window performed best, reducing cooling energy consumption by 3584.47 kJ/(m2·d) compared to hollow window, with an energy saving rate of 37.08 %. The analysis of various melting temperatures shows that the melting temperature of RT14 is the most suitable in the annual basis, and the introduction of ventilating mechanism for ventilated reflective PCM louvers window can significantly enhance the performance of the window.

1-Tetradecanol phase change material microcapsules coating on cotton fabric for enhanced thermoregulation

Rising climate change and extreme weather conditions underpin thermoregulation limitations of conventional textiles. This study investigates enhancing the thermal properties of cotton fabric by incorporating synthesized 1-tetradecanol (TD) phase change material (PCM) microcapsules. Characterization of the TD microcapsules was performed using dynamic light scattering (DLS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The microcapsules (average size of 0.49 μm) displayed a melting enthalpy (∆Hm) of 105 J·g−1 and a crystallization enthalpy (∆Hc) of 51 J·g−1. The microcapsules were mixed with the acrylic binder in three different ratios (75:25, 50:50, and 25:75). Hydrothermal, knife-over-roll, and pad-dry-cure methods were employed for coating microcapsules to cotton fabric. Microcapsule coating on cotton fabric using hydrothermal coating with a 75:25 microcapsule binder ratio achieved the highest add-on (55 %) and good durability after 25 home washes. The thermal insulation R-value of the coated fabric was enhanced (0.0029 m2 K·W−1) at 40 °C. The real-time test showed a temperature difference of 2.8 °C and thermal imaging displayed lower emissivity for TD-coated fabric. The TD microcapsule coating offers a promising method for developing climate-responsive textiles, enhancing thermal comfort, and reducing energy consumption in heating and cooling systems.

Determining the efficiency of local heat recycling wastewater based on a heat exchanger

RELEVANCE. The authors research the potential energy, economic and environmental effects of using local heat recovery from wastewater generated in showers. At the moment in Russia, almost all household wastewater is disposed of in sewer networks without the beneficial use of the heat that they possess. It is important to determine the effect of implementing this method of heat recovery, to identify and analyze the problems that prevent this from being done.THE PURPOSE. The purpose of the work is to determine the potential effect of using local heat recovery from wastewater generated in showers.METHODS. Based on a verified mathematical model of the heat exchanger, the energy effect from the individual use of the shower room is determined. A number of assumptions are applied to the heat consumption structure of an individual building and, based on available data on the average annual heat consumption of residential buildings in Moscow, the economic and environmental effect of energy-saving measures is calculated.RESULTS. Relative savings within the annual heat consumption of a building with a decentralized and centralized hot water supply system were 5,3% and 3,1%, respectively (64 and 37 GCal). Fuel economy amounted to: 9145 toe and 5227 toe for a building with a decentralized and centralized hot water supply system, respectively (14,5 and 8,5 thousand tons of CO2-eq). The payback period for energy-saving measures for the case of a decentralized hot water system based on an instantaneous electric water heater was 1,5 years.CONCLUSION. Local waste heat recovery makes it possible to obtain a significant energy and environmental effect within any locality, but at the moment there are no measures to support consumers implementing energy-saving measures. Currently, this method of heat recovery is of interest only to those consumers whose source of thermal energy for the needs of hot water supply is electricity.

Control of deposits on pipeline systems by the method of free oscillations

RELEVANCE. There are a large number of heat exchangers in operation enterprises that operate under various temperature conditions. Steam, hot water, heated products of oil refining and other industries, which may contain oxides of iron, aluminum, calcium sulfate silicates, etc., are used as a heating agent. The efficiency of the heat exchange equipment depends on the condition of the heating surfaces. Contamination of these surfaces with various deposits dramatically reduces the heat transfer coefficient, which leads to a significant increase in heat consumption. The nature of the deposits depends on the properties of the heating agent and the heated medium.THE PURPOSE. The purpose is to assess the possibility of controlling deposits on the surfaces of heat exchange equipment by the free oscillation method. The presence of deposits changes the mass of structures and, consequently, the natural frequencies of vibrations, the analysis of which can determine not only the presence and thickness of deposits, as well as their appearance.METHODS. The paper shows the results of experimental studies conducted using a hardware and software package and calculations of natural vibrations of the surfaces of heat exchange equipment in the ANSYS software package to identify their dependence on the thickness and density of deposits. A plate, a pipe, and a pressurized pipe were modeled as heat transfer surfaces.RESULTS. The results obtained experimentally and computationally coincided, and it was concluded that the free oscillation method makes it possible to determine not only the presence of deposits on heat exchange surfaces, but their thickness and appearance.CONCLUSION. The free oscillation method can detect deposits in a timely manner and monitor their condition, which in turn will, reduce overall operating costs, increase energy efficiency and extend service life.

Intermittent freshwater extraction and cold-water recharge for mitigating seawater intrusion in coastal aquifers

Decreasing groundwater temperature by freshwater extraction and cold-water recharge can mitigate seawater intrusion in coastal aquifers. However, the impact of frequently employed and easily executed intermittent well operations on this has been overlooked. This study numerically examines temperature and salinity distributions in coastal aquifers subject to intermittent freshwater extraction and cold-water recharge (IER) at an equal rate. Results show that IER maintains an equivalent effect on inhibiting seawater intrusion as the continuous method, while IER during cold seasons reduces operational time and cooling heat consumption. For instance, numerical test on a realistic aquifer shows that 90 d of IER could lead to a 75% decrease in operational time and a 29% reduction in cooling energy usage compared to the continuous method. The mitigation effectiveness depends on the averaged seaward hydraulic gradient, which is affected by heat storage reduction above the saltwater wedge. The cold-water plume from IER is convergently transported and discharged, creating a pronounced fluctuation of heat storage reduction and thereby resulting in a delayed periodic variation of the hydraulic gradient. As salt efflux is an integrated result of periodically changing hydraulic gradients, total salt mass exhibits a delayed and prolonged response to the variation of heat storage reduction. Sensitivity analyses show that a far recharge distance and reduced aquifer permeability increase the delay between heat storage reduction and total salt mass, and low recharge temperature facilitates seawater intrusion mitigation. This study demonstrates the importance of the intermittent method in inhibiting seawater intrusion and has implications for sustainable management of coastal groundwater resources.

An energy consumption rectification method based on Bayesian linear regression and heating degree‐days

AbstractThe time‐varying external environment is one of the main variables influencing heating energy consumptions, so that its influence should be rectified when energy savings of different heating modes are calculated. This paper proposes an energy consumption rectification method based on Bayesian linear regression and heating degree‐days, to obtain heating energy consumptions without the influence of different outdoor temperatures. The proposed method consists of three main steps. First, a physical model of heating houses is used to prove a relationship between energy consumptions and heating degree‐days. Second, Bayesian linear regression is exploited to estimate uncertainty ranges of heating energy consumptions. Finally, heating energy consumptions are rectified, and energy savings with their uncertainty ranges for different heating modes under the same outdoor temperature are obtained. The proposed method does not require the physical parameters of heating houses to facilitate practical implementation. Additionally, it provides uncertainty ranges of heating energy consumptions to measure the estimation accuracy. Numerical and experimental examples show that the proposed method provides more accurate estimates of heating energy consumptions than existing methods.