Typical Winter Day Research Articles

Spatio-temporal analysis of local thermal environment in waterfront blocks along the both sides of pearl river in Guangzhou, China

Urban water bodies play an important role in regulating the thermal environment in densely populated cities. Typical central urban areas along both sides of the Pearl River in Guangzhou are selected as study sites and have been divided into 25 local zones with different spatial morphology. Mobile surveys are performed on typical summer and winter days. After temporal correction processing, the spatial distribution patterns of air temperature (Ta) and relative humidity (RH) at different times along both sides of the Pearl River are obtained. The daily Ta in the waterfront blocks ranged from 31.5 °C to 39.4 °C during summer, and from 17.50 °C to 27.50 °C during winter. Daily RH ranged from 41.3% to 67.3% during summer and 48.2%–76.4% during winter. This study explored the effects of urban spatial morphology and river wind on the local thermal environment of the waterfront blocks. The results showed that the river wind can have cooling and humidifying effects, especially on the windward side of these waterfront zones. The spatial heterogeneity and spatial autocorrelation characteristics of the block-scale waterfront areas are discovered to be clustered in both seasons. This study contributes to the design and optimization of thermally friendly waterfront blocks.

Influence of cross-ventilation cooling potential on thermal comfort in high-rise buildings in a hot and humid climate

The rising cooling energy demand, caused by the increase in global average temperature and the frequency of heat waves, is currently leading to a significant increase in global electricity consumption. Passive cooling strategies, such as ventilative cooling, can provide acceptable indoor thermal comfort with no or minimal energy consumption, offering an alternative to air conditioning systems in buildings. This paper investigates the effectiveness of natural ventilation in an iconic post-modernist high-rise building in India: Charles Correa's Kanchanjunga Apartments. The research, employing CFD simulation paired with building energy simulation, demonstrates how cross-ventilation can improve the ventilative cooling efficiency in buildings, ensuring affordable indoor thermal conditions even in adverse climatic conditions like the Indian one. Thanks to night-time structural cooling, a maximum reduction in the operative temperature of up to 5.3 °C was achieved compared to the scenario without natural ventilation and up to 6.4 °C compared to the outdoor temperature peak on the hottest day. Consistently with the Indian Model for Adaptive Comfort, cross-ventilation ensures a reduction in discomfort hours of up to 58 % on the hottest day and a total reduction in discomfort hours on a typical monsoon and winter day. The paper aims to assist architects and policymakers in quantifying the cooling potential of natural ventilation in high-rise buildings, suggesting passive solutions for cooling energy saving.

Time spent in outdoor light is associated with the risk of dementia: a prospective cohort study of 362094 participants

AbstractBackgroundFew epidemiological studies in the adult population related these outcomes to daytime sunlight exposure.MethodData were from a prospective cohort of 362094 UK Biobank participants. Questionnaire survey was conducted to investigate how many hours the participants spent outdoors on typical summer and winter days. Restricted cubic spline (RCS) was performed to explore the potential nonlinear relationship between sunlight exposure and the risk of dementia.ResultMore specifically, we prefer to describe this nonlinear relationship with J shape, the lowest risk at three change points (1.5 hours/day on average, 2 hours/day in summer, and 1 hour/day in winter). Since for sunlight exposure, a marked increase in risk was observed at low exposure, but a relatively slow elevation in risk at higher exposure.ConclusionThere is a J‐shaped correlation between outdoor sunlight exposure time and dementia risk.

Building energy-saving potential of a dual-functional solar heating and radiative cooling system

Space heating and cooling devices that rely on renewable resources are in demand amid energy crises in parts of the world. However, common renewable space heating and cooling devices are mono-functional. For regions with heating and cooling seasons, using two mono-functional devices might double the installation and maintenance costs, and prolong the payback period. This study proposed a dual-functional renewable heating and cooling device by utilising solar power and nocturnal radiative cooling. The device is a modified solar heating (SH) collector that optimises the nocturnal radiative cooling (RC) to become an SHRC collector. Investigation of the SHRC collector’s performance and energy-saving potential of a building-integrated SHRC collector was conducted using CFD and EnergyPlus. Analysis of the SHRC collector’s performance in various environmental conditions shows that the SHRC collector can reach 42 % thermal efficiency at zero-reduced temperature and > 50 W/m2 of net cooling power. Also, studies on the optimal air duct and air gap height reveal that a 1 cm air duct and 4 cm air gap as the best options for the SHRC collector design. Simulations of the building-integrated SHRC with a collector area of 9.43 m2 for a typical 100 m2 house building demonstrate the multi-seasonal advantage of the SHRC collector, with at least 1.5 kWh more daily savings than the SH and RC collectors in typical winter and summer days. Furthermore, the simulations estimate the annual combined heating and cooling energy savings by the SHRC collector around 32.7 % in Madrid, 25.5 % in Tokyo, and 14.0 % in Isfahan.

Numerical investigation on operational performance of seawater-source heat pump system coupled with capillary-box heat exchangers

In view of the energy-saving potential of the seawater-source heat pump system (SWHPs) coupled with capillary-box heat exchangers (CBHEs), the operational performances of this system were investigated on various temporal scales, including annually, monthly, and daily. An overall system numerical model was developed by integrating the CBHEs, heat pump and dynamic building loads model. The results indicated that the annual COPh was 3.4. In the coldest month, the monthly COPh was 3.3, and the daily COPh was mainly determined by the daily heating demand. The corresponding annual COPc was 4.8. In the hottest month, the monthly COPc was up to 5.0, and the daily COPc was more sensitive to seawater temperature fluctuations. On a typical summer day, the operating time of the heat pump with an hourly capacity ratio above 50 % was about 2.7 times that of a typical winter day. Due to the effective removal of the heat discharged from the CBHEs in the seabed, the impact of heat accumulation on the performance of this system can be neglected in the long-term operation. This study provided practical implications for the design and application of the CBHEs-coupled SWHPs.

Applying the solar solid particles as heat carrier to enhance the solar-driven biomass gasification with dynamic operation power generation performance analysis

Solar-driven biomass gasification is a promising technology to improve the utilization efficiency of solar energy and biomass, which also enhances the thermochemical storage and the subsequent stable utilization. Whereas, the intermittence of solar energy deteriorates the stability and continuity of the thermochemical reaction process, which limits the efficient conversion of the reaction. In this regard, this work proposes a new solar-driven biomass gasification technology based on solid particle heat carrier. Different from the direct solar-driven gasification, solid particles are performed as medium to receive the concentrated solar radiation energy and transfer energy to biomass feedstocks. In addition, the combined power generation scenario is adopted to evaluate the thermodynamics and economics of the technology. The integration of solid particle heat storage, the system dispatch and stable operation will be further enhanced. Results show that under the optimal condition, the system maximum thermal and exergy efficiencies are increased by 12.94% and 12.51%, respectively. Considering the system off-design operation, with the evaluated typical periods of four seasons, the averaged power generation efficiency is increased by 5.16%, with the highest efficiency improvement of 9.41% occurring in the typical winter days. With the change of receiver price and biomass price, the maximum decline of levelized cost of electricity reaches to 17.6%, which presents the favorable economic benefits. As a new solar thermochemical technology, this technology exhibits competitive characteristics, significantly improving the utilization efficiency of solar and biomass energy.

Building integrated vegetation effect on micro-climate conditions for urban heat island adaptation. Lesson learned from Turin and Rome case studies

The proposed study investigates the effect of urban heat island mitigation scenarios by applying extensive green roofs, green façades, and living walls to two built areas within Turin and Rome, Italy. Three mitigation scenarios and a baseline one have been developed in ENVI-met software for each built area and run for a typical winter day, summer day, and summer day with a heat wave. The simulation results show that building integrated vegetation technology-application on a single building has an irrelevant effect on local temperatures; contrariwise, building integrated vegetation technology-wide application can effectively mitigate urban warming. Furthermore, the effect of green roofs and green walls on urban temperature is negligible in winter, likely because of the limited plant activity and the reduced amount of incoming solar radiation. Results also show that green façades are more effective than green roofs in mitigating pedestrian-level air temperature when installed on high-rise buildings, and green walls are more beneficial in mitigating summer urban heat island when installed in canyons parallel to wind direction than in perpendicular ones. Depending on the mitigation scenario, average decreases in urban temperatures up to 1 °C can be reached in the whole selected built area, alleviating urban warming.

The Impact of Vegetation Canopy on the Outdoor Thermal Environment in Cold Winter and Spring

The current study investigated the impact of vegetation canopy on the outdoor thermal environment in cold winter and spring, a less-explored aspect of its climate effects. Firstly, we conducted on-site observations of meteorology parameters on a campus in a hot summer and cold winter region. Then the ENVI-met microclimate simulation model was utilized to simulate the air temperature, relative humidity, wind speed and direction, and solar radiation of typical winter and spring days. Furthermore, the PET index was calculated to evaluate the thermal conditions. Our findings revealed that during the daytime, the vegetation canopy raised air temperature and relative humidity, reduced wind speed, and mitigated solar radiation. Solar radiation emerged as the primary factor affecting thermal comfort in the cold winter and spring. The presence of deciduous broad-leaved vegetation notably reduced cold discomfort and improved thermal comfort in the cold winter and spring. Finally, we propose replacing evergreen broad-leaved vegetation with deciduous broad-leaved vegetation in hot summer and cold winter regions to ensure year-round thermal comfort, especially in the cold winter and spring.

Performance prediction on a novel dual-mode heat pump with a hybrid photovoltaic/micro-channel heat pipe/fin heat exchanger

In traditional photovoltaic heat pumps, the photovoltaic (PV) cells and condenser would hinder each other’s heat dissipation in the reverse cooling mode, resulting in a drop in both cooling and electrical performance. Besides, it also has an excessive dependence on irradiance in the heating mode. To address these problems, a novel dual-mode heat pump with a hybrid photovoltaic/micro-channel heat pipe/fin heat exchanger is proposed in this paper. The novel system utilizes micro-channel heat pipe and double-circuit to adjust the heat transfer direction of refrigerant and PV, so that the refrigerant could absorb heat from PV when heating and not release heat to it when cooling. The mathematical model is established and validated. The system performance in cooling and heating modes is investigated in dynamic condition. Additionally, a study on the impact of solar irradiance, ambient temperature, wind speed, and water temperature is conducted. On a typical summer day, the novel system can provide 1993 W cooling capacity and generate electricity at 127.9 W with 22.73 °C PV temperature averagely. On a typical winter day, its mean heating capacity, electricity generation, and comprehensive coefficient of performance are 1756 W, 148.6 W, and 5.28 respectively. In the cooling mode, with the irradiance increasing from 200 W/m2 to 1000 W/m2, the PV output is lifted by 182.5 W, and the cooling capacity drops by only 0.11%. In the heating mode, the ambient temperature has a more obvious influence on heating capacity than other factors. Results show that the novel system demonstrates an excellent comprehensive performance, especially improving the cooling and electrical capacity in the clear summer day.

Thermodynamic and economic analysis of a multi-energy complementary distributed CCHP system coupled with solar thermochemistry and active energy storage regulation process

The combination of distributed energy systems (DES) and solar energy is considered a vital measure to save the usage of fossil energy. A new distributed combined cooling, heating and power (CCHP) system integrated with solar thermochemistry (STC) and energy storage (ES) units is proposed. The methane steam reforming (MSR) reaction is driven by solar energy to produce hydrogen-rich syngas, which is fed with high-efficiency solid oxide fuel cell (SOFC) – micro gas turbine (MGT) to produce electricity. The residual heat of the flue gas drives a double effect lithium bromide unit for cooling and a heat exchanger for heating, while a parabolic trough collector (PTC) is used to supplement cooling and heating supply. Under different weather conditions and user load demands, simulation analysis of the matching between system outputs and user loads is conducted, and the thermodynamic and economic performance are analyzed. The results show that through active energy storage regulation, the new system outputs can meet the hourly user loads with a matching degree of 1. The total exergy efficiencies of the system on typical summer, transition and winter days are 69.93%, 62.03%, and 52.28%, respectively, and the specific CO2 emission rates are 152.57 g/kWh, 191.75 g/kWh, and 234.16 g/kWh, respectively, indicating that the system has higher exergy efficiency and is more environmentally friendly under strong solar radiation. Economic analysis indicates that the capital investment cost is 779.34 k$, and the revenue begins in the 9-th year.

Optimal energy management strategy for distributed renewable energy power generation system based on “three-flow” theory

Aiming at the off-grid application of distributed renewable energy, this study proposes a combined hydrogen, heating and power system based on solar energy, which mainly includes alkaline water electrolysis, metal-hydride hydrogen storage and proton exchange membrane fuel cells. To achieve the best combination of electricity, heat, and hydrogen, four energy management strategies based on mass, energy, and information flow are proposed. Taking an ecological community in Ningbo as the application scenario, the system performance under four control strategies in typical summer and winter days is studied, and the best control strategies in summer and winter are given, respectively. Electricity-led and high-led strategies are recommended for summer and winter, and both strategies can achieve a real-time supply of electric power, heating power, and hydrogen. After a day of operation, the two strategies have surpluses of 0 and 221.5 kW h of electricity, 5706 and 102.16 MJ of heat, and 57 and 17.82 kg of hydrogen, respectively.

Energy scheduling of a fuel cell based residential cogeneration system using stochastic dynamic programming

Decarbonization of residential systems is one of the effective ways to achieve the low carbon goal. Due to the advantages of cleanness, efficiency and flexibility, hydrogen fuel cells play a key role in driving the transition to low carbon or carbon-neutral systems. This paper studies the optimal energy scheduling of an off-grid residential cogeneration system composed of a fuel cell, photovoltaic (PV) device, battery, thermal energy storage (TES) and heat pump. With the objective function being fuel cost, the economic optimization scheduling model is developed based on security constraints of devices and power balances of supply and demand. To handle the system uncertainties and achieve global optimality, the stochastic dynamic programming (SDP) algorithm is used, where the random variables are modeled as time-varying Markov chains. Simulation results under the typical winter day scenarios show that the SDP algorithm can achieve efficient scheduling while enhancing the device sustainability. Besides, comparison results with dynamic programming (DP) in scenarios with different uncertainty degrees demonstrate the optimality and robustness of SDP. Additionally, the impact of TES capacity on the system operation is also discussed, which has certain instructive significance for system capacity configuration in terms of economy and sustainability.

Association of time spent in outdoor light and genetic susceptibility with the risk of type 2 diabetes

To explore the joint association of time spent in outdoor light and genetic susceptibility with the risk of type 2 diabetes (T2D). A total of 395,809 individuals of European ancestry with diabetes-free at baseline in the UK Biobank were included. Time spent in outdoor light on a typical day in summer or winter was obtained from the questionnaire. T2D genetic risk was quantified via the polygenic risk score (PRS) and divided into three levels based on tertiles (lower, intermediate, and higher). T2D cases were ascertained according to the hospital records of diagnoses. After the median follow-up of 12.55 years, the association of outdoor light time and T2D risk demonstrated a nonlinear (J–shaped) trend. Compared to individuals with an average of 1.5–2.5 h/day of outdoor light, individuals who spent <1.5 h/day or >2.5 h/day in outdoor light both had an elevated risk of T2D, and the risk of T2D related to <1.5 h/day outdoor light time was much higher (hazard ratio [HR] = 1.10, 95 % confidence interval [CI]: 1.06 to 1.15). After combining with PRS, in comparison with the lower PRS – average 1.5–2.5 h/day outdoor light group (reference), the higher PRS – <1.5 h/day outdoor light group had the highest T2D risk (HR = 2.74, 95 % CI: 2.55 to 2.94), the higher PRS – >2.5 h/day outdoor light group also had a higher risk of T2D (HR = 2.58, 95 % CI: 2.43 to 2.74). The interaction between average outdoor light time and genetic susceptibility for T2D was statistically significant (Paverage for interaction <0.001). We found that optimal outdoor light time may modify the genetic risk for T2D. This suggests the T2D risk related to genetic factors could be prevented by spending optimal outdoor light time.

Food preparation using solar oven with automated two axes sun following

In this work, a solar oven with automated two axes sun seeking system was designed, constructed, and operated. The results of experiments on globular solar oven with automated two axes sun seeking system, under Jordanian climatic conditions, in a typical winter day from 8:00 AM to 4:00 PM, show that this system can raise the inside temperature of the pot with water volume of 3.1 L from 15 °C to 100 °C during 25 min. This type of solar oven was used for preparation of different meals and heating of water.

Research on Multiple Load Short-Term Forecasting Model of Integrated Energy Distribution System Based on Mogrifier-Quantum Weighted MELSTM

Accurate and efficient short-term forecasting of multiple loads is of great significance to the operation control and scheduling of integrated energy distribution systems. In order to improve the effect of load forecasting, a mogrifier-quantum weighted memory enhancement long short-term memory (Mogrifier-QWMELSTM) neural network forecasting model is proposed. Compared with the conventional LSTM neural network model, the model proposed in this paper has three improvements in model structure and model composition. First, the mogrifier is added to make the data fully interact with each other. This addition can help enhance the correlation between the front and rear data and improve generalization, which is the main disadvantage of LSTM neural network. Second, the memory enhancement mechanism is added on the forget gate to realize the extraction and recovery of forgotten information. The addition can help improve the gradient transmission ability in the learning process of the neural network, make the neural network remain sensitive to distant data information, and enhance the memory ability. Third, the model is composed of quantum weighted neurons. Compared with conventional neurons, quantum weighted neurons have significant advantages in nonlinear data processing and parallel computing, which help to improve the accuracy of load forecasting. The simulation results show that the weighted mean accuracy of the proposed model can reach more than 97.5% in summer and winter. Moreover, the proposed model has good forecasting effect on seven typical days in winter, which shows that the model has good stability.

Optimized Operation of Park-level Integrated Energy System Based on Particle Swarm Optimization with Curve Increasing

In the traditional park, the electric energy is completely provided by the power grid, in addition, the thermal energy is provided by the gas boiler. The single energy structure leads to higher operating cost and lower energy utilization rate of the park. Therefore, firstly, a park-level integrated energy system composed of gas turbine, heat recovery boiler, gas boiler, storage battery, and the load of heat and power has been proposed in this composition. Secondly, considering time-sharing tariff and the randomness of load, the objective function is established with the minimum daily operation cost as the optimization aim. Then, a particle swarm optimization with curve increasing strategy is proposed to solve the objective function. Finally, the load data of a typical day in winter is analyzed as an example. The simulation results show that the proposed method can optimize the energy structure of the park, improve the economy of the system operation, and reduce the daily operation cost of the system by 12.32%.

Performance Evaluation of a Linear CPV/T System in Different Working Conditions

The performance of Concentrating Photovoltaic and Thermal (CPV/T) systems is also linked to climatic conditions. In this paper, the main purpose is to determine the energy and economic performance of a line-focus CPV/T system used for a residential user, considering three cities with different weather conditions: Amsterdam (The Netherlands), Marrakech (Morocco), and Salerno (Italy). A modular configuration of a CPV/T system, with a concentration factor equal to 90 and module of 60 Triple-Junction (TJ) cells, is considered. The electrical power is linked to the values of TJ cell temperature and concentrated radiation by an experimental model. Electric production is highly influenced by the TJ cell temperature values. Hence, Marrakech presents lower power generation in summer than Amsterdam, 126 W, and 134 W respectively; in winter season the trend is reversed. However, the electric production in Marrakech will be higher because presents a higher number of daylight hours than other cities considered. The CPV/T system electrical and thermal producibility is evaluated for each city and for typical winter and summer sunny days, together with the modules number able to obtain the investment profitability.

Off-grid solar photovoltaic-alkaline electrolysis-metal hydrogen storage-fuel cell system: An investigation for application in eco-neighborhood in Ningbo, China

This study proposes a combined hydrogen, heating and power system based on solar energy for the off-grid application of distributed renewable energy. With hydrogen as the energy carrier, the stable consumption of renewable energy can be achieved by integrating alkaline water electrolysis (AWE), metal hydride (MH) hydrogen storage, and proton exchange membrane fuel cells (PEMFCs). An energy management strategy is proposed based on the coordinated control of mass, energy, and information flow. Fluctuations in multi-source heat flow during solar photovoltaic (PV) power generation, hydrogen production, hydrogen-storage, and PEMFC power generation were studied based on electric and heating loads of typical winter and summer days in an eco-neighborhood in Ningbo, China. Owing to differences in solar radiation between summer and winter, the total electric energy generated by PV panels was 6179 kWh and 3667 kWh for summer and winter, respectively. The start-up times for AWE and MHs were 0.92 h and 0.32 h in summer and 1.70 h and 0.55 h in winter, respectively. After one day of operation, the hydrogen and heat surpluses were 57.17 kg and 5735.83 MJ in summer, while in winter the hydrogen surplus and heat deficit were 30.87 kg and 226.41 MJ, respectively.

Fog-Induced Alteration in Airborne Microbial Community: a Study over Central Indo-Gangetic Plain in India.

Fog supports an increase in airborne microbial loading by providing water with nutrients and protecting it from harmful incoming solar radiation. To improve our present understanding of fog-induced alteration in an atmospheric microbial community, a study was conducted during 1 to 14 January 2021 for continuous investigation of airborne bacteria over a rural site, Arthauli (25.95°N, 85.10°E), in central Indo-Gangetic Plain (IGP) in India. An increase of 36% ± 0.4% in airborne bacterial loading was noticed under fog versus prefog conditions, and a decrease of 48% ± 0.4% was noticed under the postfog condition. Airborne bacterial loading had a strong correlation with RH (R2 = 0.56; P < 0.05), temperature (R2 = -0.55, P < 0.05), and wind speed (R2 = -0.52, P < 0.05). Unique types of bacteria, representing about 29% of the whole community, were detected only under foggy conditions, likely by a continuous supply of nutrients and water from a cold, calm, and humid atmosphere. As a result, no significant diurnal variation of bacterial loading was noticed on a foggy day, with a higher daily mean concentration of about (8.4 ± 1.7) × 105 cells · m-3 than that on a typical winter day [(6.3 ± 3.8) × 105 cells · m-3]. A typical winter day experienced about a 60% decrease in bacterial loading in the afternoon in comparison to that in the morning. A 3-day back-trajectory analysis suggests a slow movement of airmass along with the wind blowing from west to central IGP. Fog pauses wind movement, which reduces continuous transportation of urban sources while increasing airborne bacteria from local sources. The abundances of Gp6 (14.8% ± 8.6%), Anaeromyxobacter (7.1% ± 2.8%), and Gp7 (6.8 ± 2.6%) have been observed to increase due to occurrences of fog over central IGP. IMPORTANCE Fog was investigated in the present study as a cause of alteration in the airborne microbial community. Occurrences of fog were responsible for an increase in airborne microbial loading (36%) over central IGP in India due to the easy availability of nutrients and water in the air and dimming of harmful solar radiation. More than 90% of unique bacteria were detected under fog (64%) and postfog (28%) conditions. A few bacteria, like Gp18 (0.5% ± 0.3%), Alicyclobacillus (0.5% ± 0.1%), Sinomonas (0.4% ± 0.2%), and Phenylobacterium (0.4% ± 0.2%), were detected only under foggy conditions. A strong correlation between meteorological parameters and bacterial loading was found in the current research work. The present study provides additional support toward a new direction in interdisciplinary science for the detailed investigations of the effects of meteorological conditions on airborne bacteria and their implications for society.

Energy Saving Simulation of Phase Change Materials in the Enclosure Structure of Archives Warehouse in Different Climatic Regions

Different climates in different regions have an important influence on the latent heat performance of PCMs, especially outdoor temperature and solar irradiance. This paper describes the addition of PCMs outside the archives warehouse in Guangzhou and Lhasa, and the temperature change and energy conservation of the exterior enclosure of the warehouse in summer and winter. In typical summer days in Guangzhou, PCMs with a phase change temperature of 30°C should be added to reduce the indoor cooling load by 23.91%. In typical winter days in Lhasa, PCMs with a phase change temperature of 8°C should be added, which can reduce the indoor heat load by 17.28%.