Winter Heating Research Articles

Research on the air pollution reduction effect of winter clean heating policy

The international community is confronted with an urgent need to resolve the global climate crisis, which has emerged as a critical issue. China, in its capacity as a responsible major country, has proposed the “3060” goal and actively advocated for air pollution control. In northern China, a substantial quantity of coal is burned for heating in winter, leading to frequent air pollution, and seriously affecting people's health and quality of life. Clean heating is an important national livelihood strategy related to residents' heating and an essential manifestation of advancing ecological civilization construction. Based on panel data from 126 heating cities in the northern region from 2013 to 2020, this paper adopts the Difference-In-Difference (DID) model to investigate the effect and mechanism of the Winter Clean Heating Plan for Northern China on air pollution reduction. According to the research results, the policy has an abatement effect on northern region's air pollution emissions. The amount of air pollutant emissions has decreased by 17.3% since the policy's implementation. This policy has long-term effectiveness, which can become an effective measure for promoting air pollution reduction in the northern region. Secondly, economic factors, such as fiscal expenditure, and urban development factors, such as car ownership will have a driving effect on reducing air pollution, indicating that air pollution control is a systematic project that requires coordinated measures from all aspects. Thirdly, heterogeneity analysis indicates that the policy exerts a more substantial positive influence on air pollution control in Northwest China's cities and non-provincial capital cities. This indicates that cities should focus on implementing precise heating policies and not be “one size fits”. Finally, based on the theory of whole-process governance, this paper explores the indirect influence mechanism of the impact of the policy on air pollution reduction. By promoting energy structure transformation and promoting technological innovation, policy can indirectly improve the effectiveness of air pollution reduction. As an effective environmental regulation method, the policy can significantly reduce air pollution emissions in northern China, which is of great significance for the Chinese-style green modernization construction in this region.

Experimental and theoretical study on effect of dust deposition on frosting characteristics of fin surface

Since dust accumulates on the fin surface of the outdoor heat exchanger all year round, frost formation inevitably occurs on the fin surface with dust deposition when an air source heat pump is used for heating in winter. However, the effect of dust deposition on frosting characteristics of fin surface has not been clarified. Therefore, visualization experiments were carried out in this paper to study the frosting characteristics on bare and superhydrophobic fin surfaces under different dust deposition levels. Meanwhile, the influence mechanism of dust deposition on frost formation was analyzed theoretically based on phase transition dynamics. The experimental results showed that when the dust deposition on the superhydrophobic fin surface was less than 0.2 g, the dust deposition promoted crystal growth at the initial stage of frost formation, while the frost formation was inhibited when the dust deposition was more than 0.4 g. In the case of bare fin surface, dust deposition always inhibited the frost formation. As the dust deposition mass on the fin surface increased, the thickness and density of the frost layer decreased on both bare and superhydrophobic fin surfaces. In addition, it was worth noting that with the increase of dust deposition, the super hydrophobicity of the superhydrophobic surface was gradually lost. This is not conducive to the practical application of superhydrophobic anti-frosting technology.

Improvement of earth-to-air heat exchanger performance by adding cost-efficient soil

Geothermal research advances earth-to-air heat exchanger (EAHE) technology, offering promising air conditioning solutions for all buildings. Our study targets improved energy efficiency for the EAHE system, focusing on cost-effective approaches to enhance its technical, economic, and environmental performance. The thermal performance and economic viability of the EAHE system hinge on the thermal characteristics of the surrounding soil. The EAHE model features a single pipe with dimensions of 0.5 meters in diameter, 1 centimeter in thickness, and 10 meters in length. These pipes are strategically placed at depths of 1 meter, 2 meters, 3 meters, and 4 meters below the ground's surface. To optimize heat exchange efficiency while minimizing pipe length, we propose using a secondary soil material with high thermal conductivity as a lining for the EAHE pipes. Our innovative approach carefully considers the economic and environmental aspects of various lining materials, resulting in optimal performance at a minimal cost. Extensive simulations and data analysis lead us to identify an ideal lining material, naturally available, environmentally friendly, and cost-effective, ensuring peak efficiency. Our investigation assesses the EAHE system's thermal performance for both summer cooling and winter heating, demonstrating its effectiveness across seasons. This research underscores the case for utilizing EAHE systems during winter and autumn for heating and during spring and summer for cooling. Our findings are supported by robust performance indicators, confirming the effectiveness of our approach.

Trade-offs between cold protection and air pollution-induced mortality of China's heating policy.

The winter heating policy in northern China was designed to safeguard households from the harsh subfreezing temperatures. However, it has inadvertently resulted in seasonal spikes in air pollution levels because of the reliance on coal as an energy source. While the loss of life years attributable to mortality from air pollution caused by winter heating has been estimated, the beneficial effect of protection from cold temperatures has not been assessed, primarily due to a lack of individual-level data linking these variables. Our study aims to address this research gap. We provide individual-level empirical evidence that quantifies the impact of protection from cold temperatures and air pollution on mortality, studying 5,334 older adults living around the Huai River during the period between 2000 and 2018. Our adjusted Cox-proportional hazard models show that winter heating was associated with a 22% lower mortality rate (95% CI: 16-28%). Individuals residing in areas without access to winter heating are subjected to heightened mortality risks during periods of cold temperatures. The protective effect is offset by a 27.8% rise attributed to elevated PM2.5 levels. Our results imply that the equilibrium between the effects of these two factors is achieved when PM2.5 concentration exceeds 24.3 µg/m3 (95% CI: 18.4-30.2). Our research suggests that while the existing winter heating policy significantly mitigates winter mortality by lessening the detrimental effects of cold temperatures, future air pollution reduction could provide further health benefits.

Performance analysis of paraffin microcapsules and phase change concrete based on microporous cenospheres

Combining concrete and phase change materials has created a novel method for building energy conservation. However, introducing phase change materials into the concrete will cause various impacts on its performance. This study explores a novel approach to enhance thermal energy storage in building materials by incorporating phase change materials (PCMs) into concrete. Microporous cenospheres were extracted from fly ash through a three-step process and used to produce composite PCM microcapsules containing paraffin as the core material. The produced PCM microcapsules were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and phase change cycle analysis. Phase change concrete was then formulated by substituting 0–25 % sand with these microcapsules. Effects of the addition of the PCM microcapsule on both the mechanical and thermal properties of concrete were experimentally examined. While the incorporation of microcapsules significantly improved concrete's thermal properties, it also led to a reduction in compressive strength (up to 19.65 % at 28 days), though still meeting specifications. The introduction of microcapsules notably enhanced the temperature control capabilities of concrete. In spring, the model room made with the phase change concrete exhibited a 2.2 °C lower indoor peak temperature 2 h 40 min later than the one room with the ordinary concrete. During active heating in winter, the phase change concrete demonstrated significantly lower indoor temperature fluctuations, with a maximum reduction of 45.39 %. Furthermore, the study found that the particle size of microcapsules had varying effects on concrete performance, with larger particles improving thermal properties and smaller particles enhancing mechanical properties. Overall, this research highlights the potential of composite phase change microcapsules and phase change concrete based on microporous cenospheres for effective temperature control and energy conservation in building applications.

Identification and Number Prediction of Natural Gas Heating Users in a Company in Chengdu

Nowadays, more and more residents in Sichuan and Chongqing area choose to use gas for heating in winter, and the demand for gas is increasing. Therefore, it is necessary to improve the refined management of residential gas consumption. Firstly, this paper uses K-means clustering according to the gas consumption data from 2017 to 2021 provided by a company in Chengdu, so as to obtain the regulation of residents’ gas consumption. According to the different users’ gas consumption habits, the gas heating users in 2017 are identified. Then, a better SVM model is selected in SVM, KNN and logistic regression to classify the gas consumption data in 2018-2021. Finally, according to the classification results, the grey model is used to predict the number of gas heating users in the next two years, and compared with the real data in 2022, the results shows that the model effect is good. This study provides strong theoretical and technical support for gas companies to rationally plan gas consumption and optimize the operation of urban gas pipeline network.

Low-cost gel-polymer electrolytes for smart windows: Effects on yearly energy consumption and visual comfort

The experimental analysis of the main figures of merit of an innovative electrochromic (EC) prototype, based on low cost gel-polymer electrolytes, is at the basis of the numerical simulation exposed hereafter, aiming at the assessment of energy and visual comfort benefits deriving from building integration of smart windows in a multi-storey office building. The effectiveness of the dynamic modulation of glazing properties to improve energy efficiency and users’ comfort was tested comparing the EC windows with a typical law-compliant static commercial glazing system and with a clear windows. To better understand the performances of the proposed EC film, six different locations – ranging from Seville to Helsinki – were selected throughout the European continent to conduct energy and daylighting analyses on three different exposures (east, south, west). The results obtained show reductions of summer cooling and winter heating as well in all the locations considered. Eventually, the effect of electrochromic switching of transmittance on the indoor visual comfort, is considered using a well-established metric: Useful Daylight Illuminance; with regards to daylight analyses, a significant reduction of hours in which excessive illuminance occurs was observed in all the locations considered, confirming that properly controlled EC devices improve both energy efficiency and visual comfort.

Skilful sub‐seasonal forecasts of aggregated temperature over Europe

AbstractSubseasonal‐to‐seasonal (S2S) forecasts span the prediction range of weeks to 2–3 months ahead, bridging the gap between medium‐range and seasonal weather forecasts. There has been growing interest in S2S forecasts in recent years, largely because of the many potential uses of forecasts spanning these timescales. However, the skill of S2S forecasts beyond the first 2 weeks or so is poor, potentially limiting the usability of these forecasts. We show in this study that when considering accumulated temperatures, there is in fact good forecasting skill over Europe for accumulation periods up to 30 days ahead. Using a set of S2S hindcasts, we show using both a deterministic and a probabilistic measure of skill that the accumulated 2‐metre temperature forecasts out to 30 days are skilful over most of Europe. In summer, South West Europe has highest skill, while in winter North East Europe has highest skill. As an example application of such forecasts, we also evaluate the skill for summer cooling degree‐days (CDD) and winter heating degree‐days (HDD). For 30‐day winter HDD, there is good skill in all four European regions; for 30‐day summer CDD, the skill is limited in North West Europe, but still good in other regions.

Numerical simulations on the thermal performance of ventilated walls with passive solar heating and latent heat storage in winter

Numerical simulations on the thermal performance of ventilated walls with passive solar heating and latent heat storage in winter

Electrochemical cell power generation systems for socially important facilities

There is an estimation of application of power installations in a mode of trigeneration: with gas at the input, and with electric power, heat and cold at the output, functioning in an automatic mode, positive and negative sides of their use are considered. Cogeneration systems based on gas turbine with compression or absorption chillers, satisfying consumers in electric, heat and cooling energy in a building or a group of buildings, are considered. The use of trigeneration systems allows efficient utilization of heat for heating in winter and for air conditioning and process needs in summer, for example, use of cold for freezers in hospitals. At the same time, there is no reduction in efficiency throughout the year. The trigeneration technology is an excellent alternative to conventional power plants with a large amount of electrical energy and allows the use of absorption chillers in case of high cost or shortage of electricity. Such units consume less electricity compared to compressor units and require lower costs. At the same time, the use of absorption refrigeration machines (ARM) is totally justified when operating in the mode of a mini-CHP, which produces heat in winter (as cold is not needed or is needed only in small amounts), and in summer there is no need for it, but there is a need for cold. The payback period of such a system is relatively low, the net present value is high, and the profitability index is usually greater than one. Cold storage contributes to the economic viability of a trigeneration system. Since the payback period does not take into account the time factor of investment, the net present value or, better yet, the profitability index should be used. A trigeneration system consists of several units with different service lives and different investment results.

Chemical Composition and Source of PM2.5 during Winter Heating Period in Guanzhong Basin

An intensive field campaign was carried out from December 2022 to March 2023 at six different sites across five major cities (Xi’an, Baoji, Xianyang, Weinan, and Hancheng) in the Guanzhong Basin, China, covering most of the heating period there, which is characterized by high PM2.5 pollution levels. During the campaign, the mean PM2.5 concentrations at these sites exceeded the 24 h PM2.5 standard (75 μg m−3), except the site at Hancheng, with mean PM2.5 concentrations of 57.8 ± 32.3 μg m−3. The source apportionment of PM2.5 varied significantly across sites, with vehicle exhaust being the dominant source at urban sites located in Xi’an and Baoji, coal combustion at suburban sites in Hancheng, and comparable contribution from coal combustion and industrial emissions at suburban sites in Xianyang and Weinan. Compared with clean condition, the contribution of vehicle exhaust and secondary inorganic sources (SIs) were largely enhanced during heavy PM2.5 pollution periods, while the contribution from biomass burning (BB) and dust decreased significantly at all sites. Combined with an analysis of meteorological parameters, the study further found that higher contributions of SIs and heavy PM2.5 pollution were generally associated with higher relative humidity (RH). In addition, higher PM2.5 concentrations at suburban sites were related to lower wind speeds, which could be explained by the stagnant condition favoring the accumulation of local emissions as well as the formation of secondary pollutants. In contrast, at urban sites (e.g., Xianyang), higher PM2.5 concentrations were more associated with the strong influence of vehicle exhaust at slightly higher wind speeds.

Comparative analysis of heating characteristics of convective-radiant systems using various terminal air source heat pumps

The escalating demand for efficient heating solutions in hot summer and cold winter area has directed substantial attention towards convective-radiant combined systems. These systems offer enhanced comfort while conserving energy. In the context of office buildings, it becomes imperative to consider structural attributes. Under identical operational strategies, disparities in energy consumption and thermal comfort arise from variations in water supply temperature and terminal configurations. Here, we have established a dedicated laboratory to examine convective-radiant heating systems utilizing air source heat pumps. The primary objective is to analyze the impact of distinct heating terminal types and water supply temperatures on indoor thermal comfort, energy consumption, and energy efficiency. By analyzing the dynamics of indoor parameter, and interrelations among air temperature, average radiant temperature, operative temperature, and comfort levels, optimal strategies are determined. Empirical findings demonstrate that independently opening the Fan coil convection system (FC) leads to significant fluctuations in air temperature and creates an unstable heat environment. However, the Radiant floor system (RF) and Convective-radiant combined heating systems (FC + RF) exhibit superior stability in maintaining indoor air temperature. Compared among the three systems, while FC displays the lowest energy consumption upon activation, it compromises comfort levels. Remarkably, there is a strong relationship between operative temperature and Predicted Mean Vote (PMV) for the three systems, with high correlation coefficients of 0.998, 0.999, and 0.997, respectively. Conversely, the association between air temperature and PMV proves weak, with correlation coefficients of only 0.415, 0.469, and 0.841. Consequently, it is advised to prioritize operative temperature as the benchmark for winter air temperature control. For sustained adherence to Level II comfort zone criteria during indoor occupancy, it is recommended to employ (FC + RF) or RF for winter heating. Notably, energy savings of 26.87 %, 30.07 %, and 32.86 % are respectively achieved for (FC + RF), FC, and RF configurations when utilizing a water supply temperature of 35℃ as opposed to 45℃. Hence, the adoption of low-temperature water heating during winter is strongly advocated.

Unveiling the pollution and risk of atmospheric (gaseous and particulate) polycyclic aromatic hydrocarbons (PAHs) in a heavily polluted Chinese city: A multi-site observation research

Linfen, one of the most polluted cities in China, releases huge amounts of polycyclic aromatic hydrocarbons (PAHs) into the atmosphere. The pollution characteristics of Linfen's PAHs, along with their emission sources and health risks, were scarcely discussed. This study conducted a multi-site observation campaign in Linfen during the non-heating and heating periods (2018–2019) using passive air samplers. Sixteen PAHs were analyzed for the gaseous and particulate samples collected at the 15 sites in the urban, rural, and background areas. The PAH concentrations in Linfen's atmosphere were 225.7 ± 81.9 ng m−3 during the heating period and 139.9 ± 47.5 ng m−3 during the non-heating period, annually averaged to 168.1 ± 58.6 ng m−3, which was predominantly contributed by the rural and urban emissions. Combustion was highly responsible for the PAHs, including the burning of coal for industrial production and winter heating, coupled with the utilization of oils by automobile engines. The spatiotemporal variations of PAHs were associated with the discrepancy of emission intensity rather than that of emission type. The BaP equivalent concentrations for the rural and urban areas were 1-2 orders of magnitude higher than the various international standards, indicating the considerable carcinogenic risk for the majority of local residents. These findings are informative for better understanding the atmospheric PAH pollution in a typical resource-based Chinese city.

High-precision spatio-temporal variations and future perspectives of multiple air pollutant emissions from Chinese biomass-fired industrial boilers

Biomass-fired industrial boilers (BFIBs) are one of the neglected and important anthropogenic sources of air pollutants. A comprehensive boiler-based emission inventory of multiple air pollutants from BFIBs in China in 2020 was first developed based on the activity level database and updated emission factors. Results showed that national emissions of air pollutants from BFIBs in 2020 were estimated to be 11.5 kt of PM, 10.8 kt of PM10, 7.4 kt of PM2.5, 40.5 kt of SO2, 79.8 kt of NOx, 4.2 kt of organic carbon (OC), 1.0 kt of elemental carbon (EC), 31.7 kt of nonmethane volatile organic compounds (NMVOCs), 15.9 kt of NH3, and 116.5 t of five trace metals (Hg, Cr, Cd, Pb, and As), respectively. Air pollutant emissions exhibited significant spatio-temporal heterogeneity. Monthly air pollutant emissions varied by geographical division due to the combined effects of industrial production and winter heating demand. These emissions were mainly concentrated in the eastern coastal region, with Guangdong, Guangxi, Fujian, Jiangsu, and Zhejiang being the five provinces having the highest emissions. In addition, scenario predictions indicate that as the pollution and carbon reduction strategy is implemented, air pollutant emissions from BFIBs in China could become well controlled, with PM, NOx, SO2, and Hg emissions in 2050 projected to be 3.0–8.3 kt, 36.5–75.7 kt, 16.2–32.8 kt, and 0.52–0.87 t, respectively. Our results can provide a highly spatio-temporal resolution inventory of multiple air pollutant emissions from BFIBs for air quality modelling and support the formulation of air pollution control policies for biomass fuel utilization in the context of the pollution and carbon reduction strategy.

Fostering the use of sustainable design to reduce energy use and GHG emissions at Canadian universities: a life cycle cost analysis approach

Purpose The purpose of this study is to examine the application of sustainable building design and operation within a university setting to determine its economic efficacy and potential for further university investment. Design/methodology/approach This study incorporated a life cycle cost analysis (LCCA), simple payback period and discounted payback period calculations to determine the return on investment, including a sensitivity analysis when comparing the energy use and financial benefits of the sustainable design of a multi-use facility at Toronto Metropolitan University with buildings of similar size and use-type. Findings It was found that there is a positive business argument for Canadian Universities to consider the use of sustainable design to reduce energy use and greenhouse gas (GHG) emissions. A reasonable payback period and net present value within an institutional context were determined using a life-cycle cost assessment approach. Research limitations/implications This study was limited to the measure of only a single location. Certain assumptions regarding energy pricing and interest rates and the related sensitivities were anchored on a single year of time, and the results of this study may be subject to change should those prices or rates become significantly different over time. Considerations for future research include a longitudinal approach combined with a more detailed analysis of the effect of use-type on the variables discussed. Practical implications For university administrators, the results of this study may encourage institutions such as universities to approach new building projects through the lens of energy efficiency and environmental sustainability. Social implications GHG emissions are a well-proven contributor to global climate change, and buildings remain a significant source of GHG emissions in Canada due to their winter heating and summer cooling loads. As a result, sustainable building design on university campuses can mitigate this impact by optimizing and reducing energy consumption. Originality/value Research related to the economic evaluation of sustainable building design on university campuses is generally limited, and this study represents the first of its kind in regard to an LCCA of a sustainably designed building on a Canadian University campus.

Background Characteristics and Influence Analysis of Greenhouse Gases at Jinsha Atmospheric Background Station in China

Central China has been acting as a major convergence zone for sources and sinks in China, such that the climate change studies of Central China have taken on critical significance. The Jinsha atmospheric background station refers to the sole background monitoring site in Central China. It is noteworthy that the greenhouse gas attributes of the Jinsha atmospheric background station represent the greenhouse gas conditions of Central China. The seasonal and daily variations in CO2, CH4, and CO in the scope of time between October 2019 to April 2021 at the station were examined in this study. The effect of meteorological conditions on greenhouse gas concentrations at the site was evaluated. Furthermore, the primary transmission origins affecting the station were identified using the backward trajectory through potential source contribution function analysis. As indicated by the results, the background concentrations at the Jinsha station in 2020 for CO2, CH4, and CO reached 424.1 ± 0.1 ppm, 2046.2 ± 0.6 ppb, and 324.1 ± 1.1 ppb, respectively. CO2 varied on a daily basis with higher nighttime levels, which was affected by the boundary layer elevation, photosynthesis, and human activities. In autumn, CH4 levels peaked under the effect of agricultural activities in Central China. However, CO2 and CO concentrations reached the maximum in winter, majorly affected by the transmissions from the Beijing–Tianjin–Hebei region and Hubei. Under China’s comprehensive carbon neutrality, more attention should be paid to the emissions from winter heating and industrial activities in the Beijing–Tianjin–Hebei region, and effects exerted by transport in the monitoring process should be differentiated in depth.

Threats to human health and ecosystem caused by coal-fired winter heating in China since 2010

Coal-fired winter heating (CWH) results in serious air pollution, but limited studies have investigated its threats to health and ecosystem. The environmental impact and social cost of CWH in China at the province level was quantified via a “bottom-up” life cycle assessment approach. The ecosystem damage and social cost of CWH maintained high values over the last decade, although exhibited a downward trend. Approximately 688 Mt CO2 eq of greenhouse gas emitted from CWH activity in 2019, accounting for 4.9% of China's total emission. Shandong and Liaoning Provinces dominated the nationwide environmental and economic burdens of CWH. Heavy metals atmospherically emitted from CWH exerted significant carcinogenic impacts and showed a correlation with regional cancer incidence (e.g., respiratory, reproductive, urinary, neurological, and blood-lymphatic systems), indicating the potential multi-system damage of CWH. Energy-saving buildings, geothermal utilization, efficient heavy metal end-point control technology, and improving emission factors quality are highly recommended.

Daily and annual performance analyses of the BIPV/T system in typical cities of Sudan

• A mathematical model of the BIPV/T system is established. • The energy-saving potential of the system for different regions of Sudan is analyzed. • Wadi Halfa has the highest total annual electrical power output. • The BIPV/T HVAC system satisfies a high percentage of the heating needs of Sudan. In this paper, a numerical study is carried out to investigate the performance of a coupled BIPV/T-AHU system in Sudan. A mathematical model was utilized, Matlab Simulink was used to do simulation. Results showed good agreement with experimental data from the literature. The problem studied in this paper is reducing the energy required for heating in winter (preheating BIPV/T) and avoiding the high photovoltaic cell temperature in summer. We compare the energy consumption with and without BIPV/T-AHU in different cities in Sudan. The results showed that utilizing the exhaust air to cool the photovoltaic cell could reduce the PV/T cell temperature in the range ( 9 − 12 ) ∘ C , which can increase the electrical power output in a range of ( 12 − 21.44 ) W / m 2 . In winter, utilization of the preheating BIPV/T system can decrease the heating load in Wadi Halfa in the range of ( 6 − 107.1 % ) . Damazein does not need a high heating power in the daytime for the air conditioning system depending on the local climate, so the heat energy produced by the system can be used for drying, desiccant cooling, or heating water, with increasing the electric power produced by cooling PV/T cells. The results indicated a great possibility to use the BIPV / T system under the studied conditions, in addition, this study provides important information for the application of the BIPV / T system in these areas.

A harmonic oscillator model of atmospheric dynamics using the Newton-Kepler planetary approach

Projection of future meteorological patterns such as median temperature and precipitation are necessary for governments to facilitate civil aviation, forecast agricultural productions, and advise future public energy policies. Various models were proposed based on historical data such as the short-term 7-day forecast or the long-term Global Forecast System to study climate change over the coming decades. We strike a balance by examining the harmonic oscillator model in mid-term weather projections. This model is the starting point to provide general mathematical guidelines to inform governmental agencies to forecast levels of energy consumptions for residential cooling in summer and heating in winter to provide energy subsidies for low-income populations and for non-profit organizations to support countries needing energy assistance. Additionally, mid-term meteorological models are especially useful during time of global energy disruptions. A model is derived based on orbital mechanics, planetary science, and astronomy using Newton’s Law of Universal Gravitation and Kepler’s Laws of Planetary Motions. We optimize the model with historical data on a specific region. The model’s predictions were then statistically compared with the actual data in the same time period in the region in a reverse goodness of fit test. We also gave certain directions on the generalized harmonic oscillator model in the future. In sum, the current harmonic oscillator method can be beneficially utilized by governments to forecast natural phenomena in order to provide timely assistance to respective populations such as in the control of infectious diseases or predicting extreme temperature fluctuations in the planning of agricultural productions.

Applying recent efficient numerical methods for long-term simulations of heat transfer in walls to optimize thermal insulation

Since transient simulations are quite resource intensive, the winter heat loss through building walls is often estimated by simple steady-state calculation based on e.g. the Degree-days method, which is often rather inaccurate. In this work, transient simulations are performed using the very recent leapfrog-hopscotch and modified Dufort-Frankel techniques, which are the most effective explicit and stable numerical algorithms to cope with heat transport issues, according to prior investigations. The optimum insulation thickness, energy savings, and payback time are determined using an economic model that takes into account the orientation of the outside walls, solar radiation, the cost of insulating material, the present cost of energy consumption, and the cost over the 25-year lifetime of a building in Miskolc City and a case is studied in the cold season. Three materials (Expanded Polystyrene (EPS), glass-wool, and rock-wool) and several thicknesses are examined. As a result, it was found that for the north-oriented wall, the optimum insulation thickness is (17, 22, and 12 cm) and the life cycle energy savings are (142.5, 153, and 132.12 kWh/m2) for the EPS, glass-wool, and rock-wool, respectively, while the payback time is (3.73, 3.14, and 4.33 years). According to the analysis of the life cycle energy savings, the optimal insulation properties can be achieved using 22 cm thick glass wool, which only slightly depends on the orientation of the wall.