Air Conditioning Energy Research Articles

Techno-Economic and Environmental Feasibility Study of a Hybrid Photovoltaic Electrification System in Back-up Mode : A Case Report

In developing countries, institutions that have to operate continuously during daylight hours consume relatively large amounts of electrical energy for lighting and air conditioning, leading to high bills. Untimely power cuts lead to a fluctuation in the voltage delivered by the conventional network, which induces the malfunctioning of electrical equipment and the discontinuity of judicial work. The use of photovoltaic solar energy makes it possible, on the one hand, to ensure continuity of service in the event of damage, and on the other hand to stem greenhouse gas emissions through the sustainable nature of this energy. Solar installations also make it possible to maintain the permanent power supply in the event of instability of the electrical network and to correct the voltage variations undergone by the energy equipment. Thus, this (case) study is based on the energy balances evaluated on the buildings of the jurisdiction of the city of Kandi (Benin) to propose effective solutions of electrification according to six (6) technical scenarii. Each component of the back up system has been sized considering technical requirements and an economic and environmental study has been carried out. The results indicate that the integrated scenario 6 of a "back-up" system with a solar fraction of up to 37% (49.5 kWc) seems to be the most suitable conf iguration for the current needs of the Kandi jurisdiction due to the shortest time to return on investment (5.1 years) and the maximum annual savings generated (33,674 USD). The environmental impact study has made it possible to determine the CO2 emissions avoided as well as the contribution of Carbon credits that this jurisdiction would reap has been evaluated at 115.8 tCO2 equivalent, or 10.6 hectares of forest carbon preserved over the life of the project. This configuration is therefore strongly recommended for a sustainable energy mix in the jurisdictions of Benin as well as for administrative or similar sites where electricity consumption is maximum during the day.

Energy consumption calculation of campus buildings based on the law of personnel flow

AbstractFor a certain functional building group, the coupling relationship between the load of a single unit and entire building groups lies in the spatial and temporal patterns personnel distribution. Using the DeST (Designer's Simulation Toolkit) method, the personnel flow trajectory in a university campus in Shanghai was analyzed and the established energy consumption calculation model based on personnel flow trajectory of university buildings. It is proposed that personnel mobility should be included in the application of DeST to predict the total load of building groups. The results show that after the people flow trajectory was included, the total annual accumulated load decreased from 27.01 to 19.39 GWh, reducing by 28.20%; the hourly load fluctuation became more stable, the daily peak load decreased by 22.57%, and the daily peak valley difference decreased by 43.74%. The results suggest that the prediction for the air conditioning load of building complexes would be better when the trajectory of human flow is considered, minimizing unnecessary system scale and investments. Under the “double carbon” policy, the personnel flow trajectory model can effectively reduce waste in air conditioning energy consumption in campus buildings.

Predicting Diverse Behaviors of Occupants When Turning Air Conditioners on/off in Residential Buildings: An Extreme Gradient Boosting Approach

Occupant behavior (OB) has a significant impact on household air-conditioner (AC) energy use. In recent years, bottom-up simulation coupled with stochastic OB modeling has been intensively developed for estimating residential AC consumption. However, a comprehensive analysis of the diverse behavioral preference patterns of occupants regarding AC use is hampered by the limited availability of large-scale residential energy demand data. Therefore, this study aimed to develop a prediction model for the residential household’s AC usage considering various OB-related diversity patterns based on monitoring data of appliance-level electricity use in a residential community of 586 households in Osaka, Japan. First, individual operation schedules and thermal preferences were identified and quantitatively extracted as the two main factors for the diverse behaviors across the whole community. Then, a clustering analysis classified the target households, finding four typical patterns for schedule preferences and three typical patterns for thermal preferences. These results were used, with time and meteorological data in the summer seasons of 2013 and 2014, as inputs for the proposed prediction model using Extreme Gradient Boosting (XGBoost). The optimized XGBoost model showed a satisfactory prediction performance for the on/off state in the testing dataset, with an F1 score of 0.80 and an Area under the Receiver Operating Characteristic (ROC) Curve (AUC) of 0.845.

Research on air conditioning energy use and indoor thermal environment with Private Finance Initiative data monitoring of junior high schools before and during the COVID-19 pandemic in Japan

The COVID-19 pandemic began to spread at the beginning of 2020 in the world and in Japan, which is expected to impact the air conditioning (AC) energy use (EU) in educational buildings when AC and natural ventilation are used together as a new regulation to decrease infectious disease transmission. Furthermore, this regulation of natural ventilation is expected to impact the AC EU when the outside temperature affects indoor comfort causing changes in the regular AC setting temperature and AC operating times. This study aims to evaluate the AC EU, and the indoor thermal environment changes with Private Finance Initiative (PFI) data monitoring in junior high schools in Oita City before and during the COVID-19 pandemic during summer and winter through a sensitivity analysis method. The result found that AC EU significantly increased during the pandemic, 2 times escalation in summer and 1.9 times in winter. Besides, during the pandemic, indoor air temperature comfort was achieved with longer AC operation time, lower AC setting temperature in summer, and higher AC setting temperature in winter. The result of this research can be expected to be beneficial for future studies regarding AC energy saving and indoor thermal comfort-related investigation and valuable for new regulations related to air conditioner settings and operations for the new normal during the pandemic.

Renewable Energy in Indonesia: Current Status, Potential, and Future Development

The current use of fossil fuels has a significant impact on increasing greenhouse gas (GHG) emissions. Subsequently, renewable energy is significantly needed to reduce GHG, thereby limiting the impact of extreme weather and climate while ensuring reliable, timely, and cost-effective supply. As a big country with a huge amount natural resource, the demand for renewable energy in Indonesia has increased along with the rise in consumption. Following this, energy consumption increased by 0.99%, which was approximately 939.100 million BOE in 2021 for biogas, oil, electricity, natural gas, coal, LPG, biodiesel, and biomass. Energy consumption in several sectors including transportation has the largest energy consumption with approximately 45.76% of oil. In industries and households sector, the consumption rates are 31.11% for boiler steam generation purposes and 16.89% for electricity as well as LPG. Furthermore, the commercial sector consumes 4.97% of energy for lighting and air conditioning, while the remaining 1.27% is used for other sectors. Meanwhile, Indonesia has high potential for renewable energy at 419 GW including 75 GW of hydro energy, 23.7 GW of geothermal, 32.6 GW of bioenergy, 207.8 GW of solar, 60.6 GW of wind, and 19.3 GW of micro-hydro. Therefore, the main focus of this paper is to provide a detailed analysis of the current status, prospects, and information on Indonesia’s renewable and sustainable energy sources. Furthermore, the novelty of this research entails updating the latest data related to renewable energy and its availability in Indonesia. The essence is to portray a picture of its potential development in the future.

Optimization of top-floor rooms coupling cool roofs, natural ventilation and solar shading for residential buildings in hot-summer and warm-winter zones

The high building energy-saving potential of integrated passive technologies has drawn significant public attention. This paper combined field measurements and multi-objective optimization to reduce lighting and air conditioning (AC) energy by coupling cool roofs, natural ventilation (NV), and solar shading. Experimental measurements verified the cooling effects of cool roofs and NV based on thermal performance. The influences of cool roofs on heating and cooling energy were obtained. A building simulation model was validated by measurement data of thermal performance and AC energy use collected from a Guangzhou residential building. Energy-saving potentials under NV and daylight implemented strategies were then quantified. Compared to the black room without energy-saving strategies, daylight could reduce lighting energy by 3.3 kW h/(m2·yr), and AC energy use could be reduced by 4.7, 22.7 and 26.9 kW h/(m2·yr) in the black, blue and white rooms adopting NV, respectively. The roof albedo, roof insulation thickness and window-to-wall ratio notably impacted AC and lighting energy based on global sensitivity analysis. Optimal design schemes based on multi-objective optimization could reduce the top-floor room energy consumption by up to 52.3 kW h/(m2·yr).

Investigating energy efficiency and solar energy in Saudi mosques to achieve zero energy or zero bill

Energy is essential to achieve thermal comfort; however, energy consumption leads to environmental degradation. This study analyzed the energy consumption of two masjids in the Kingdom of Saudi Arabia (KSA) and identified opportunities for rationalizing energy consumption. A photovoltaic (PV) system was used to ensure that the conditions of nearly zero bill building (nZBB) or nearly zero energy building (nZEB) were fulfilled. The energy use intensities of the Al-Jamil and Al-Omar masjids were 111 kWh/m2 and 121 kWh/m2, respectively. The average electricity consumption per worshiper for the Al-Omar masjid was 1.35 kWh/prayer and that for the Al-Jamil masjid was 1.03 kWh/prayer. The end-use energy was the highest for cooling, accounting for 72–74 % of the total consumption; lighting accounted for 11–12 % of the total consumption at the two masjids. Approximately 60 % of the air-conditioning (AC) energy load was saved by improving the envelope; the electricity requirement for ACs increased by up to 30 % as the ambient temperature increased from 32 °C to 46 °C. Changing the set-point temperature from 20 °C to 27 °C afforded electrical energy savings of approximately 27 % for a summer day. The environmental benefits of using solar energy were also identified.

Optimized thermal envelope of low-income dwellings in Santiago de Chile incorporating Pinus radiata wood impregnated with phase change materials

The demand for air conditioning and heating in the construction sector has increased in about two decades, mainly because of demographic and economic growth. The result of this increase in energy consumption has been more greenhouse gas emissions (GHGs). This paper proposes a multi-objective optimization design that helps reduce heating, ventilation, and air-conditioning (HVAC) energy consumption and increases the thermal comfort levels in low-income housing. Achieving these objectives required choosing a dwelling unit that is representative of the Chilean housing stock, which was identified with the help of the National Housing Monitoring Network (ReNaM). The selected optimization variables correspond to the type of windows, type and thickness of ceiling insulation, and type of PCM-impregnated Pinus radiata wood panel, with PCM melting points between 8 and 27 °C. Subsequently, we minimized the hours of thermal discomfort and the dwelling typology's electrical consumption of heating and cooling by using the algorithm the Non-dominated Sorting Genetic Algorithm-II (NSGA-II). The main results include a reduction of up to 21.5 % in the thermal discomfort hours and a decrease of up to 80.5 % in energy consumption associated with the optimal housing typology compared to the base case. Additionally, the economic analysis indicated the payback period is 12.9 years for the Pareto solution, which presents a lower distance to the utopic point (UP).

Architectural Design Strategies for Enhancement of Thermal and Energy Performance of PCMs-Embedded Envelope System for an Office Building in a Typical Arid Saharan Climate

The literature showed many studies that evaluated single or multiple Phase change materials (PCMs) layers in passive, active, or in hybrid configurations for building applications. However, little attention has been given to evaluating the energy performance of buildings when PCMs are used together with other passive design strategies. In this work, the energy performance of an office building in a typical arid Saharan climate is simulated using EnergyPlus when a PCMs-embedded envelope is implemented. The office building was analyzed without/with PCMs using various thicknesses. Results indicated that the annual electrical energy for heating, ventilation and air conditioning (HVAC) could be reduced between 3.54% and 6.18%, depending on the PCM thickness. The performance of the office building, including PCMs, was then simulated using two practical architectural design strategies, namely windows-to-wall ratio (WWR) and rezoning of the interior spaces. Outcomes revealed that the annual energy consumption for HVAC can be reduced from 10% to 15.5% and from 6.1% and 8.54% when WWR is reduced by half to three-quarters, and the perimeter zones are enlarged by one-third to two-thirds of the original space area, respectively. By combining both architectural design strategies and PCM, the annual electrical HVAC energy can be reduced between 12.08% and 15.69%, depending on the design configuration and PCM thickness. This design option provides additional benefits also since it reduces the vulnerability of increasing the lighting and fuel gas heating energy because more perimeter zones are exposed to daylighting and solar radiation, respectively.

IoT-Based Air Conditioning Control System for Energy Saving

A high portion of electric consumption is air conditioning in householders or offices, reaching 42%. Therefore, it is necessary to automatically regulate air conditioning operations for energy saving using a control system, usually involving its hardware. As another option, the control system also involves electronic devices and software. This research developed an automatic control system using an ESP32 microcontroller integrated into the Blynk-based internet of things (IoT) for energy-saving air conditioning. The ESP32 was programmed using Arduino IDE and combined with a motion sensor to maximize energy saving. The motion sensor was a trigger to turn on the system. The recorded data were current, voltage, power, temperature, and motion detection. Based on the recorded power, the consumed energy was computed using trapezoidal and Simpson's composite rules of numerical integrations and ordinary methods. The testing was conducted in conventional, manual, and automatic operations. The yielded automatic control system operated adequately. The testing results revealed that the automatic operation saved 1.15 kWh (15.00%),0.99 kWh (13.66%), and 1.14 kWh (14.87%) average daily energy compared to the conventional operation, respectively, by using the ordinary, Simpson's composite rule, and trapezoidal composite rule computations. While the automatic compared to the manualmethodssaved1.68 kWh (20.44%), 1.78 kWh (22.14%), and 1.66 kWh (20.24%), respectively, for the same computations. Thus, the automatic system considerably saved energy compared to conventional and manual operations. Moreover, these energy savings were also higher than some previous research on air conditioning energy savings.

Assessment of climate change's impact on energy demand in Mexican buildings: Projection in single-family houses based on Representative Concentration Pathways

In Mexico, buildings' deficient thermal performance is one of the leading causes of the intensive use of energy. This research analyzes the perspective of energy demand required to meet the cooling needs in the country through the Weather-based technical indexes: Cooling Degree Hour (CDH) and Operation Hours (OH). The study considered the 2440 municipalities that make up the 32 states of the Mexican Republic and three chronological progressions throughout the 21st century (2020, 2050, and 2100). Meteorological data was collected through the Meteonorm software considering climate change projections, precisely two Representative Concentration Pathway scenarios (RCP 4.5 - Intermediate) and (RCP 8.5 - High). Based on the calculations, spatial and temporal panoramas of the behavior of air conditioning hours under various target temperatures (20 °C, 23 °C, and 26 °C) were established. Taking the most important type of housing in Mexico (Social Interest Housing) as a case study, a database of air conditioning energy demand was performed and subsequently grouped the states according to cluster similarities. The results show that >50 % of the Mexican Republic requires high air conditioning levels. The maximum CDH for 2100-RCP 8.5 will be 70 % higher than currently needed. Even for the year 2050-RCP8.5, an increase of >40 % of CDH was obtained. Regarding the OH, the results show an increase of >50 % concerning the current behavior of the country. Regardless of the scenario, the range of operating hours with the highest operating requirements is between 11 am and 4 pm, peaking in the summer season. The simulations showed that some Mexican regions exceed 12,000 kWh in air conditioning. An increase of 20 % and 35 % is expected for the years 2050 and 2100. The simulations showed that a considerable percentage of Mexico exceeds 12,000 kWh in air conditioning, while by 2050 and 2100, this consumption will increase by 20 % and 35 %, respectively. Based on these results, the first classification of groups in energy demand was generated, allowing a focus on energy efficiency strategies to obtain net zero Buildings. The data obtained shows that relative humidity is a variable that affects the increase in energy consumption in refrigeration and simplifies the process of classifying regions with similar patterns in air conditioning.

Compensating Solar Prosumers Using Buy-All, Sell-All as an Alternative to Net Metering and Net Purchasing: Total Use, Rebound, and Cross Subsidization

Electric utilities are challenging net metering, which compensates owners of residential solar photovoltaic systems by crediting solar generation at the retail rate instead of reflecting the value of solar to the utility. In 2012, Austin Energy was the first US utility to replace net metering with Buy-All, Sell-All, where prosumers purchase all electricity at the retail rate and sell all electricity at the utility’s value of solar rate. Using Austin Energy customer data for hot weather months, a load curve comparison of comparably sized houses shows that prosumers have higher consumption than non-solar customers during system peak hours. Regression analysis finds that prosumers use more energy for air conditioning, with a rebound effect of 20%. A simulation shows that under net metering and net purchasing almost 7% of prosumer bills would be paid by non-solar customers while total subsidy would be 18% due to the inclusion of increasing block rates.

Air conditioning energy consumption measurement and saving strategy analysis for an office building in hot summer and cold winter area

ABSTRACT The energy consumption of different air conditioning systems varies greatly. In order to analyse the energy consumption status and energy-saving potential of air conditioning in existing office buildings, this paper takes an existing office building in hot summer and cold winter area as an example. The office and air conditioning energy consumption were continuously measured. The air conditioning energy consumption analysis model was established. With the measured data as input, the simulation calculation of the annual air conditioning energy consumption was carried out. The results showed that the measured value was quite different from the recommended value of the building energy efficiency standard. Changes in indoor air temperature or fresh air volume had a significant impact on air conditioning energy consumption. When the indoor set air conditioning temperature was 22°C in summer and 22°C in winter, the fresh air volume increased from 0 to 180 m3/(p·h), the increase of air conditioning power consumption reached 109.9% and 115.2%, respectively. The energy-saving envelope of the office building can obtain about 15% of the energy-saving benefits. However, users’ adjustment of operating parameters such as fresh air volume and indoor design temperature can easily lead to energy loss greater than that of energy-saving envelope.

Impact of COVID-19 on energy consumption in a residential complex in Hyderabad, India

When the Indian government declared the first lockdown on 25 March 2020 to control the increasing number of COVID-19 cases, people were forced to stay and work from home. The aim of this study is to quantify the impact of stay-at-home orders on residential Air Conditioning (AC) energy and household electricity consumption (excluding AC energy). This was done using monitored data from 380 homes in a group of five buildings in Hyderabad, India. We gathered AC energy and household electricity consumption data at a 30-min interval for each home individually in April 2019 and April 2020. Descriptive and inferential statistical analysis was done on this data. To offset the difference in temperatures for the month of April in 2019 and 2020, only those weekdays were selected where the average temperature in 2019 was same as the average temperature in 2020. The study establishes that the average number of hours the AC was used per day in each home increased in the range 4.90–7.45% depending on the temperature for the year 2020. Correspondingly, the overall AC consumption increased in the range 3.60–4.5%, however the daytime (8:00 AM to 8:00 PM) AC energy consumption increased in the range 22–26% and nighttime (8:00 PM to 8:00 AM) AC energy consumption decreased by 5–7% in the year 2020. The study showed a rise in household electricity consumption of about 15% for the entire day in the year 2020. The household electricity consumption increased during daytime by 22- 27.50% and 1.90- 6.6% during the nighttime. It was observed that the morning household electricity peak demand shifted from 7:00 AM in 2019 to 9:00 AM in 2020. Conversely, the evening peak demand shifted from 9:00 PM in 2019 to 7:00 PM in 2020. An additional peak was observed during afternoon hours in the lockdown.

Energy tunnels as an opportunity for sustainable development of urban areas

The use of renewable energies will be increasingly necessary to reduce carbon dioxide emissions. An important contribution can be provided by energy tunnels, which make it possible to draw on a form of clean, renewable and locally accessible thermal energy for heating and air conditioning of buildings. The paper describes the characteristics of an energy tunnel and the design aspects necessary for its conception. Explicit reference will be made to the studies conducted at the Politecnico di Torino which led to the development of an innovative energy segment then used to create an experimental prototype in the true size of an energy tunnel. The data collected allowed to evaluate the performance of the system and to study the possibility of thermally activating the tunnels of the future Line 2 of the Turin Metro, allocating the heat partly to the air conditioning of the stations and partly to external users. With a view to sustainable urban development, the possibility of integration with district heating systems and the possible creation of local heat distribution networks at different temperatures, directly connected to the underground infrastructure, is particularly attractive and promising.

Prediction and evaluation of air conditioner energy consumption of residential buildings in the Yangtze River Basin

Prediction and evaluation of energy consumption can guide energy usage behavior and promote energy saving. In view of the impact of many factors, like regional meteorological conditions, availability of passive techniques and occupant behavior, evaluation is complex. This paper focuses on the air conditioner energy consumption of residential buildings in the Yangtze River Basin. In terms of nature resources and climate conditions, A new zoning map with eight sub-zones for the adaptability of passive techniques was developed. The adaptability of single passive techniques and passive technique combinations in every sub-zone were summarized by comparing heating/cooling load, non-air-conditioning time and indoor thermal comfortable time. Moreover, the concepts of operational heating/cooling degree hours (OHDH/OCDH) and relative energy consumption index were proposed. A method to quantify and evaluate the impact of occupant behavior on the energy consumption of air conditioners was built. The occupant behavior was divided into three levels: Saving-level (S-level), Comfortable-level (C-level) and Lavish-level (L-level), based on the OCDH/OHDH. Furthermore, the energy consumption targets of diverse sub-zones are obtained, considering the indoor thermal comfort, occupant behavior and adaptive passive techniques. A case study demonstrates that the relative energy consumption index can avoid an unreasonable judgment caused by only focusing on energy consumption while neglecting indoor thermal comfort.

Enhancing the cooling properties of low‐density polyethylene films by combining near‐infrared reflective additives

AbstractIn the last years, the rising temperature caused by global warming brought the research to find new efficient solutions to lower the temperature of buildings and reduce the consumption of electrical energy for air conditioning. In this work, we propose the combined use of organic and inorganic near‐infrared (NIR) reflective additives in low‐density polyethylene (PE) films as an accessible plastic coating with enhanced cooling features. Two ‘cool’ pigments, the inorganic Sicopal® Black (Si Black) and the organic Paliogen® Black (Pa Black), were investigated for black‐tinted coatings, while TiO2 (TI) and glass bubbles (GB) were tested for opaque white coatings. The additive's size and concentration influence the composite processing, and their ultimate optical properties were determined in terms of total solar reflectance (TSR) and cooling effect under solar radiation. TI and GB dispersed in PE showed the highest TSR, whereas the organic Pa Black confirmed its superior reflective features with respect to the traditional carbon black (CB). Moreover, a significant increase in the TSR occurred when TI or GB was added to the black pigments (12.7% and 13.6%, respectively). TSR increasing led to a cooler black‐tinted PE film under solar irradiation. When using reflective pigments, a cooling effect of about 10°C was measured with respect to the traditional CB.

Energy-Saving Potential Comparison of Different Photovoltaic Integrated Shading Devices (PVSDs) for Single-Story and Multi-Story Buildings

Building-integrated photovoltaic (BIPV) façades are a promising technique for improving building energy performance. This study develops energy simulation models of different photovoltaic-integrated shading devices (PVSDs) in single-story and multi-story office buildings. A cross-region study in China is carried out to explore the energy performance of PVSDs in five climate zones. The shading effect of the upper PVSDs is taken into account. The results show that (1) PVSDs can be applicable in hot and cold climates; shading effects lead to a notable difference in the optimal PVSDs style. The average comprehensive energy saving ratios of different PVSDs ranged from 16.12% (fixed PV louvres in the vertical plane) to 51.95% (lower single panel). The most rewarding PVSDs are for single-story buildings in Kunming and the least suitable are for multi-story buildings in Guangzhou. (2) In climate zones with little air-conditioning energy consumption, avoiding considerably increased lighting consumption by PVSDs is vital. (3) To reduce shading effects, solar panels with smaller widths or vertical placements can be adopted. In addition, the distance of the PV modules from the top edge of the windows is also critical. Building performance evaluation in the early design stage enables maximum benefits for the same input (total area of PV panels). The research methodology and data analysis presented can guide parameters design and the geographical applicability of PVSDs, providing a reference for optimal building energy performance.

MTL-Deep-STF: A multitask learning based deep spatiotemporal fusion model for outdoor air temperature prediction in building HVAC systems

Buildings consume large quantities of energy. Reducing building energy consumption is essential to achieving carbon neutrality goals. Building energy consumption is strongly influenced by various meteorological factors for which outdoor air temperature is a proxy. This study proposes a data-driven multitask-learning deep spatiotemporal fusion model (MTL-Deep-STF) that predicts outdoor air temperature to provide baseline data against which improvements to conserve energy in heating, ventilation, and air conditioning (HVAC) systems can be proposed and assessed. MTL-Deep-STF is a generic multiple input–multiple output model that predicts temperatures for successive time points in separate high-level tasks. Each task uses a multilayer perceptron to combine meteorological data from neighboring observation stations. CNN-GRU is used to extract spatially local long-term and short-term temporal features that are shared between different tasks via CNN. Comparative validation experiments using real world datasets for complex terrains showed that the model was highly accurate in both single step and multistep predictions. One-step-ahead predictions for winter (MAE = 0.428 °C, RMSE = 0.705, Acc ≤2 °C = 97.832%) and summer (MAE = 0.467 °C, RMSE = 0.706, Acc ≤2 °C = 97.899%) datasets were particularly accurate. This accuracy was coupled with high robustness ( R 2 = 0.976 for winter and R 2 = 0.981 for summer). Use of the model can conserve building energy. • The spatiotemporal fusion model MTL-Deep-STF uses data from neighboring stations to predict air temperature at multiple future time steps. • MTL-Deep-STF treats temperature prediction for successive prediction horizons as distinct tasks. • MTL-Deep-STF extracts global spatial features of multiple stations through fully connected networks. • MTL-Deep-STF is extremely accurate and robust in predicting outdoor temperatures and is therefore suitable for controlling HVAC systems, particularly in complex terrains.

Investigation of optical and physico-chemical properties of titanium-doped V₂O₅ nanofilms

In this paper, undoped and Ti-doped V2O5 thin films were fabricated and deposited onto glass substrates using a «doctor blading» method. Then, the effects of Ti-doping on the optical properties of the thin films were investigated. Titanium doping concentration of 0.25-0.75 at.% has been investigated. After treatment in air at different temperatures, the obtained films was characterised by various techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL). It was found that the as-obtained doped films possessed thermochromic properties and optical switching characters. According to optical tests, thin linings of vanadium dioxide alloyed with Ti have optical properties that are effective for application. Because of their capacity to automatically control interior solar irradiation, lower air-conditioning energy consumption, and maintain a comfortable internal thermal climate, smart windows have drawn increased interest in recent years. The doping strategy and integrating with functional coatings can regulate the properties of obtained V2O5 films.