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Understanding the characteristics of residential hot-water consumption can be useful for developing effective water-conservation strategies in response to increasing pressure on natural resources. This study systematically investigates residential hot-water consumption through direct monitoring of over 40 domestic fixtures (belonging to six different end-use categories) in five Italian households, recorded over a period ranging from approximately two weeks to nearly four months, and using smart meters with 5 min resolution. A multi-step analysis is applied—at both household and end-use levels, explicitly differentiating tap uses by purpose and location—to (i) quantify daily per capita hot-water consumption, (ii) calculate hot-water ratios, and (iii) assess daily profiles. The results show an average total water consumption of 106.7 L/person/day, with at least 26.1% attributed to hot water. In addition, daily profiles reveal distinct patterns across end uses: hot- and cold-water consumption at kitchen sinks are not aligned over time (with cold water peaking before meals and hot water used predominantly afterward), while bathroom taps show more synchronized use and a marked evening peak in hot-water consumption. Study findings—along with the related open-access dataset—provide a valuable benchmark based on field measurements to support in the process of water demand modeling and the development of targeted demand-management strategies.

Determining the demand for heat power for domestic hot water preparation is necessary to perform a building energy assessment. For this, we need to predict domestic hot water consumption. Considering the number of factors influencing domestic hot water consumption, it is difficult to develop a highly accurate methodology. The aim of the study was to compare the real domestic hot water consumption and heat power for its preparation with the values calculated based on the available prediction methods in multi-family buildings. The analysis was carried out based on annual monitoring (2021 year) of domestic hot water consumption and the actual demand for heat power in eight multi-family buildings located in Grudziądz, in Central Poland. The results of these measurements were compared with the values determined based on the available methodologies for forecasting the demand for heat power and domestic hot water consumption: Sander’s, Recknagel’s, the standard method and the method according to Polish regulations from 2008 and 2015. The real average demand for heat power for domestic hot water was 89.8 ± 8.5 W/person, 211.2 ± 13.7 W/apartment and 4.8 ± 0.3 W/m2, and the daily domestic hot water consumption was 26.7 ± 3.6 dm3/person·day, 62.6 ± 5.8 dm3/apartment·day and 1.4 ± 0.1 dm3/m2·day. The real demand for heat power for domestic hot water was lower than that determined by the analyzed methods. The values obtained from the modified standard method based on Standard PN-92/B-01706/A1: 1999, with mean relative error of 10.5 ± 4.1%, were the closest to the real values. The current ordinance method (Regulation 2015) is characterized by an error of 45.4 ± 10.2%. The predicted domestic hot water consumption using the current ordinance was the closest to the real consumption. On average, it was higher by 7.7 ± 5.0%.

There is very little knowledge on the occupant actual hot water comfort (temperature and flow), usage practice, and routines (temporal and spatial distribution of hot water usage in a household). This paper describes the results from the total and hot water measurements in two Danish detached houses. The results show that, at the draw-off points, the temperature of 55 °C is never asked by the occupants, not even in the kitchen sink. The domestic water temperature differentiates depending on the function of the draw-off point, with the shower and kitchen taps being most energy- and water-intense. They constitute around 90% of the hot water use in the house. Shower units on average demand for highest temperature (i.e., 35.5 °C to 40.4 °C). Hand washing operates, on average, at temperature between 20.5 °C to 26.5 °C. Average water temperature at the taps located in utility room varies between 23 °C to 26 °C. These in-depth insight in the total and hot water use in two new-built low energy houses, can a) help building professionals designing more efficient hot water installations; b) enhance the research work on energy flexibility buildings by providing knowledge on most energy-intensive draw-off points; and c) facilitate district heating professionals in improving the network performance.

A building’s energy consumption is assessed considering the energy required for heating, cooling, lighting, and domestic hot water (DHW). Methodologies used to calculate energy certificates in European Union countries consider hot water consumption rates per person or per heated (floor) area, giving wide-ranging values (35–88 dm3/person/day). Using extreme parameters, it is possible to obtain a primary energy index that meets the legal requirements, although unrealistically large proportions of domestic hot water use relative to the total energy balance of the building may marginalize the influence of other components, such as fluctuations in heating, ventilation, or lighting. In the current work, the DHW consumption of three residential buildings was measured to verify the energy consumption for hot water preparation. Investigations were conducted based on the consumption of natural gas for DHW preparation. Experimentally obtained water consumption rates were determined per m2 of a dwelling and per person living in the building. The calculated indicators (0.85 ± 0.005 dm3/m2/day and 27.4 ± 1.4 dm3/person/day) were lower than those used for energy certifications of buildings. The experimentally obtained indicators were used in further theoretical energy assessments of six residential buildings. By adopting the designated indicators, the analyzed buildings met the legally required primary energy value (<70 kWh/m2/year) when using natural gas as a heat source. Applying more realistic DHW consumption values resulted in more accurate energy certifications.

Longjing tea is one of China’s most renowned green teas and is enjoyed by tea enthusiasts all over the world. Although its unique aroma is the most important quality attribute, the key aroma compounds were not yet systematically analysed. A sensory-guided screening of the aroma distillate isolated from a high-grade Longjing green tea infusion by application of an aroma extract dilution analysis revealed 60 aroma-active domains in the gas chromatogram with flavour dilution (FD) factors in the range from 32 to the highest FD factor of 4098, as found for 3-methylnonane-2,4-dione (hay-like, aniseed-like) and vanillin (vanilla-like). A quantitation of the 42 aroma compounds eliciting the highest FD factors by means of stable isotope dilution assays (SIDA) followed by a calculation of odour activity values (OAV; ratio of concentration to odour threshold) showed that 30 aroma compounds exceeded their odour threshold in the tea beverage. By mixing 30 purified reference compounds of these odorants in water in exactly the same concentrations as determined in the tea beverage, the genuine aroma of the Longjing tea could successfully be simulated. In ensuing studies, quantitative changes during the traditional manufacturing process of the tea leaves as well as differences induced by the hot water treatment were systematically evaluated based on SIDAs. The results indicated the great importance of the initial pan-frying for the formation of key aroma compounds in the tea leaves. A comparison of the concentrations of selected key aroma compounds in the finished tea leaves and the tea infusion prepared thereof indicated further that large quantities of, for example, 2-methylbutanal, dimethyl sulphide, and 3-methylnonane-2,4-dione were obviously formed from yet unknown precursors by the hot water treatment.

This study proposes a cost-effective and scalable method of fabricating superhydrophobic surfaces on metallic materials by combining sandblasting (SB) and hot water treatment (HWT) to create hierarchical surface roughness. The method successfully produced superhydrophobic surfaces on aluminum alloy, copper, and zinc substrates, achieving contact angles (CAs) exceeding 150°. Micro-scale roughness was introduced via SB, while nano-scale roughness was induced by HWT, resulting in a dual-scale morphology crucial for enhanced hydrophobicity. The effects of varying SB abrasive sizes (60, 120, and 180 mesh) on surface morphology and wettability were thoroughly examined. Among these, 60-mesh abrasives generated the highest surface area and roughness. Post-fluorination, the hierarchically rough surfaces exhibited exceptional superhydrophobic properties, with CAs surpassing 160° and sliding angles (SAs) near 0°, demonstrating the lotus effect. Surfaces with only micro-roughness or nano-roughness resulted in intermediate CAs of 150–160° and SAs between 3 and 17°, underscoring the importance of hierarchical structuring.

Background:Hydrothermal pretreatment using liquid hot water (LHW ) is capable of substantially reducing the cell wall recalcitrance of lignocellulosic biomass. It enhances the saccharification of polysaccharides, particularly cellulose, into glucose with relatively low capital required. Due to the close association with biomass recalcitrance, the structural change of the components of lignocellulosic materials during the pretreatment is crucial to understand pretreatment chemistry and advance the bio-economy. Although the LHW pretreatment has been extensively applied and studied, the molecular structural alteration during pretreatment and its significance to reduced recalcitrance have not been well understood.Results:We investigated the effects of LHW pretreatment with different severity factors (log R0) on the structural changes of fast-grown poplar (Populus trichocarpa). With the severity factor ranging from 3.6 to 4.2, LHW pretreatment resulted in a substantial xylan solubilization by 50–77% (w/w, dry matter). The molecular weights of the remained hemicellulose in pretreated solids also have been significantly reduced by 63–75% corresponding to LHW severity factor from 3.6 to 4.2. In addition, LHW had a considerable impact on the cellulose structure. The cellulose crystallinity increased 6–9%, whereas its degree of polymerization decreased 35–65% after pretreatment. We found that the pretreatment severity had an empirical linear correlation with the xylan solubilization (R2 =0.98, r = +0.99), hemicellulose molecular weight reduction (R2 = 0.97, r = −0.96 and R2 = 0.93, r = −0.98 for number-average and weight-average degree of polymerization, respectively), and cellulose crystallinity index increase (R2 = 0.98, r = +0.99). The LHW pretreatment also resulted in small changes in lignin structure such as decrease of β-O-4′ ether linkages and removal of cinnamyl alcohol end group and acetyl group, while the S/G ratio of lignin in LHW pretreated poplar resi- due remained no significant change compared with the untreated poplar.Conclusions:This study revealed that the solubilization of xylan, the reduction of hemicellulose molecular weights and cellulose degree of polymerization, and the cleavage of alkyl–aryl ether bonds in lignin resulted from LHW pre-treatment are critical factors associated with reduced cell wall recalcitrance. The chemical–structural changes of the three major components, cellulose, lignin, and hemicellulose, during LHW pretreatment provide useful and fundamental information of factors governing feedstock recalcitrance during hydrothermal pretreatment.

In order to improve the accuracy of the stratified hot water storage tank model and simplify the modeling process of the stratified water tank, a modelling method of the stratified water tank based on MATLAB/SIMULINK is proposed. By comparing with TRNSYS platform simulation, the correctness and accuracy of this method are verified. At the same time, this method is used to establish a six-node stratified hot water storage tank. Through the simulation of 8 different working conditions, the influence of different inlet and outlet water flow rates and temperature of the inlet and outlet water on the stratification effect of the hot water storage tank is analyzed.

Cross‐adaptation occurs when exposure to one environmental stressor (e.g., heat) induces protective responses to another (e.g., hypoxia). Although post‐exercise hot‐water immersion (HWI) induces heat acclimation, its potential to elicit cross‐adaptation remains unclear. This study evaluated the effectiveness of a 6‐week post‐exercise HWI intervention on exercise performance in hypoxia (O2 = 13%). Twenty healthy volunteers (28 ± 5 years; V̇O2peak ${\\dot V_{{{\\mathrm{O}}_2}{\\mathrm{peak}}}$47.4 ± 8.9 mL kg−1 min−1; 12 males, 8 females) completed interval cycling (4×4 min at 90 ± 5% maximal heart rate, 3×/week) followed by water immersion at either 34.5°C (control) or 42°C (HWI) for 40–50 min, five times per week. Following the 6‐week intervention, the post‐exercise HWI group exhibited lower resting heart rate (P < 0.01, q = 0.02; d = −1.32) and core temperature (P < 0.01, q = 0.001; d = −1.88) and elevated haemoglobin concentration (P < 0.01, q = 0.02; d = 1.38). Compared to the control group, the HWI group also showed greater improvements in time‐to‐exhaustion (TTE) trial (P and q < 0.01; d = 1.2) under hypoxia, but not in aerobic peak power (P = 0.03, q = 0.08; d = 0.86) or peak oxygen consumption (V̇O2peak ${\\dot V_{{{\\mathrm{O}}_2}{\\mathrm{peak}}}$ ) (P = 0.04, q = 0.10; d = 0.82). Throughout the TTE, lower core temperature and tidal volume, with increased oxygen saturation and V̇O2 ${\\dot V_{{{\\mathrm{O}}_2}}}$were observed (P and q < 0.05). During hypoxic steady‐state exercise at 60% of V̇O2peak ${\\dot V_{{{\\mathrm{O}}_2}{\\mathrm{peak}}}$ , the HWI group exhibited lower core temperature and higher peripheral oxygen saturation in hypoxia. No between‐group differences were observed in mean V̇O2 ${\\dot V_{{{\\mathrm{O}}_2}}}$ , respiratory exchange ratio, heart rate or rate of perceived exertion, nor in V̇O2peak ${\\dot V_{{{\\mathrm{O}}_2}{\\mathrm{peak}}}$and aerobic peak power under normoxia (P and q > 0.05). In conclusion, post‐exercise HWI enhances maximal exercise performance under acute hypoxia, likely due to increased haemoglobin concentration, lower core temperature and improved respiratory efficiency. What is the central question of this study? Can post‐exercise hot‐water immersion (HWI) induce a cross‐adaptation effect enhancing exercise performance in acute hypoxia? What is the main finding and its importance? Six weeks of daily post‐exercise HWI at 42°C (chest level, 40–50 min) elicits a cross‐adaptation effect in healthy, active cyclists. Post‐exercise HWI intervention improves exercise performance in acute hypoxia (13% O₂, simulating ∼4300 m altitude), as demonstrated by increased time‐to‐exhaustion at 80% of V̇O2peak ${\\dot V_{{{\\mathrm{O}}_2}{\\mathrm{peak}}}$ . This improvement may be attributed to increased haemoglobin concentration, lower core temperature and enhanced respiratory efficiency (i.e., lower tidal volume, reduced V̇E ${\\dot V_{\\mathrm{E}}}$and increased absolute V̇O2 ${\\dot V_{{{\\mathrm{O}}_2}}}$and oxygen saturation).

Hot water mound drench treatment has broad application prospects in the control of the red imported fire ant (RIFA), Solenopsis invicta Buren (Hymenoptera: Formicidae). However, much work still needs to be carried out to provide a theoretical basis and technical support for the use of this method against RIFAs under field conditions. In this study, we monitored the temperature changes at different depths within RIFA nests during laboratory-simulated hot water mound drench experiments and evaluated the lethal effect of hot water treatment on RIFAs. Furthermore, the targeted removal effect of hot water mound drench treatment on RIFA nests under field conditions was evaluated. Results indicated that the temperature at depths of 5, 15, and 25 cm inside the simulated ant nests was higher than 51.1 °C within 30 min after treatment, resulting in a 100% mortality rate for RIFAs at all tested depths. Under field conditions, when nests were disturbed, the percentage of RIFAs crawling out of their nests gradually increased with time after disturbance, reached its maximum value at 25 or 30 s after the disturbance, and then gradually decreased. Single hot water mound drench treatment (each ant nest was treated with 17.8–21.6 liter of hot water at a temperature of 97–100 °C) can significantly reduce the RIFA population in ant nests and lead to a 72.7% reduction in the number of surviving ant nests. However, the safety, operability, and timelines of hot water mound drench treatment for RIFA field control still need further investigation.