Air Conditioning Energy Research Articles

Improved robust model predictive control for residential building air conditioning and photovoltaic power generation with battery energy storage system under weather forecast uncertainty

The rising demands for comfort alongside energy conservation underscore the importance of intelligent air conditioning control systems. Model Predictive Control (MPC) stands out as an advanced control strategy capable of addressing these demands. However, accurate prediction of all relevant variables remains a challenge in practical scenarios, complicating MPC’s ability to devise effective control actions amid prediction inaccuracies. To counteract this issue, this paper introduces an enhanced Double-Layer Model Predictive Control (DLMPC) algorithm. This innovative approach adjusts for discrepancies between forecasted and actual values without the need for additional variables and models, thereby reducing the adverse effects of prediction errors. Additionally, we develop precise models for room temperature simulation and for calculating air conditioning (AC) load and energy consumption, grounded in empirical data from residential settings and AC performance tests. Validation of these models demonstrates their efficacy in enabling MPC to formulate efficacious control strategies. When juxtaposed with a baseline model, the DLMPC algorithm significantly improves temperature regulation accuracy by up to 15.12% and achieves a 10.50% reduction in energy consumption over the heating season.

The operation strategy of river water source heat pump cold source system in a chemical industrial park in a region with hot summers and cold winters

At present, the energy consumption of the whole process of buildings in China accounts for 45 % of the total energy consumption of the country, and the carbon emissions account for 50.6 % of the total emissions of the country. Among the energy consumption of buildings, air conditioning energy consumption occupies a major proportion, about 2/3. Traditional air conditioning cooling mainly uses refrigerants such as Freon to circulate and cool under high temperature and high pressure, which not only has high energy consumption but also can cause the external environment temperature to be too high. River water source heat pump is a renewable energy technology that can use water bodies including groundwater, surface water such as rivers, lakes, reservoirs and oceans. This project mainly studies the operation strategy of related units using river water as the cold source in a chemical industrial park in Chongqing, from unit selection, establishment of energy consumption model to unit operation strategy analysis and research, to achieve the best state of energy utilization.

Comparative analysis of energy efficiency for three heating and cooling supply schemes in a region with hot summers and cold winters in a chemical industrial park

Building energy consumption in China accounts for 45% of the total national energy consumption, with air conditioning energy consumption representing approximately two-thirds of that. Therefore, energy efficiency in buildings is of utmost importance. This study focuses on a chemical industrial park located along the Fujiang River and compares three heating and cooling supply schemes: the river water source heat pump system, which utilizes river water as the heat source and heat sink; the water cooling unit and boiler system, which uses water-cooled electric compression chillers for cooling and an oil-fired boiler system for heating; and the split air conditioning and gas water heater scheme, which relies on refrigerants such as fluorine-containing compounds for cooling and a gas water heater for heating. By calculating the energy consumption of the above three schemes and conducting a comparative analysis, it is found that the river water source heat pump system exhibits significantly higher energy efficiency throughout the year compared to the water cooling unit and boiler system and the split air conditioning and gas water heater scheme. This highlights the notable energy efficiency advantage of the river water source heat pump system.

Transfer learning integrating similarity analysis for short-term and long-term building energy consumption prediction

Currently, building energy consumption prediction models are usually based on a large amount of historical operational data in high demands of building operating hours and monitoring systems. However, many buildings may lack operational data due to relatively limited monitoring systems, causing the failure to use data-driven methods to characterize the energy profile. In this context, transfer learning is a promising method to establish the knowledge transfer between many high-quality building operation datasets and a small amount of target building data, and to help predict energy consumption in the target building. This paper studies the possibility of employing transfer learning to achieve both short and long-term building energy consumption prediction. Firstly, a similarity analysis method, based on variable modal decomposition and dynamic time warping, is proposed for identifying the source buildings with the most similar energy features to the target building. Then, transfer learning for long-term prediction air-conditioning energy consumption is developed with weather parameters generated by the Morphing method as inputs. For the short-term single-step prediction, the proposed model CV-RMSE improves 81.3% (AEC) and 77.4% (EEC), respectively, compared to the prediction model that does not implement the transfer learning strategy and directly uses the target BEC data. As for the short-term multi-step prediction, the proposed model CV-RMSE improves 62.0% (AEC) and 65.5% (EEC), respectively. For the long-term prediction, the average CV-RMSE for the whole year is 6.62% and 11.15% for the proposed and directly target domain-based model, respectively. The proposed method explores the practicality of transfer learning in building energy forecasting, contributing to the use of existing building operation data for energy management at different timespan.

Anthropogenic heat from buildings in Los Angeles County: A simulation framework and assessment

Anthropogenic heat (AH), i.e., waste heat from buildings to the ambient environment, increases urban air temperature and contributes to the urban heat island effect, which leads to more air-conditioning energy use and higher associated waste heat during summer, forming a positive feedback loop. This study used a bottom-up simulation approach to develop a dataset of the annual hourly AH profiles for 1.7 million buildings in Los Angeles (LA) County for the year 2018 aggregated at three spatial resolutions: 450 m, 12 km, and the census tract. Building AH exhibits strong seasonal and diurnal patterns, as well as large spatial variations across the urban areas. Building AH peaks in May and reaches a maximum of 878 W/m2 within one of several AH hotspots in the region. Among the three major AH components (surface convection, heat rejection from HVAC systems, and zonal air exchange), the surface convection component is the largest, accounting for 78% of the total building AH across LA County. Higher AH is attributed to large building density, a high percentage of industrial buildings, and older building stock. While AH peaks during the day, the resulting ambient temperature increases are much larger during the night. During the July 2018 heatwave in LA County, building AH (excluding the surface component) leads to a daily maximum ambient temperature increase of up to 0.6 °C and a daily minimum ambient temperature increase of up to 2.9 °C. It is recommended that reducing summer building AH should be considered by policy makers in developing mitigation measures for cities to transition to clean energy while improving heat resilience.

Influence of the shading nets on indoor thermal environment and air-conditioning energy consumption in lightweight buildings

Lightweight envelopes are increasingly utilized in temporary relief and shelter buildings, due to their cost-effectiveness and efficient construction process. However, these envelopes often result in inadequate indoor thermal conditions during the summer months, which can negatively impact the physical and psychological well-being of occupants, particularly victims and patients in disaster or epidemic situations. Addressing this challenge necessitates the use of simple yet effective materials and technologies to improve indoor thermal environments even with limited resources. This study explores the potential of shading nets to enhance indoor thermal conditions in lightweight buildings by mitigating solar radiation gain during the summer period. A comparative experiment was conducted on two lightweight buildings, one of which was equipped with standard six-needle black shading nets, to assess the impact of shading nets on the indoor thermal environment and air-conditioning energy consumption. The findings reveal that shading nets can reduce solar radiation intensity by approximately 57.86%, resulting in a significant decrease in peak indoor air temperatures by 2.3°C to 3.4°C under natural ventilation and a reduction in air-conditioning energy consumption by up to 23% under air-conditioned conditions. These findings demonstrate that shading nets are effective in improving indoor comfort and reducing energy usage, providing a practical solution for enhancing living conditions in lightweight structures during hot weather.

Thermochromic Hydrogels with Adjustable Transition Behavior for Smart Windows.

With the fast economic development and accelerating urbanization, more and more skyscrapers made entirely of concrete and glass are being constructed. To keep a comfortable indoor environment, massive energy for air conditioning or heating appliances is consumed. A huge amount of heat (>30%) is gained or released through glass windows. Using smart windows with the capability to modulate light is an effective way to reduce building energy consumption. Thermochromic hydrogel is one of the potential smart window materials due to its excellent thermal response, high radiation-blocking efficiency, cost-effectiveness, biocompatibility, and good uniformity. In this work, polyhydroxypropyl acrylate (PHPA) hydrogels with controllable lower critical solution temperature (LCST) were prepared by photopolymerization. The transition temperature and transition rate under "static transition" conditions were investigated. Unlike "static" conditions in which the transition temperature was not affected by the initial and final temperature and heating/cooling ramp, the transition temperature varied with the rate of temperature change under dynamic conditions. The "dynamic" transition temperature of the PHPA hydrogel gradually increased with the increase of the heating rate. It was the result of the movement of the molecular chains lagging behind the temperature change when the temperature change was too fast. The results of the solar irradiation experiment by filling PHPA hydrogels into double glazing windows showed that the indoor temperature was about 15 °C lower than that of ordinary glass windows, indicating that it can significantly reduce the energy consumption of air conditioning. In addition, a wide range of adjustable transition temperatures and fast optical response make PHPA hydrogels potentially applicable to smart windows.

On the energy impact of cool roofs in Dubai

Urban warming can significantly increase the energy demand for building cooling. As temperatures rise, buildings require additional energy for air conditioning, which can lead to higher electricity demand and increased greenhouse gas emissions. This can create a positive feedback loop, as increased energy demand leads to increased waste heat and further exacerbates the urban warming effect. To solve this issue, this study integrates high-resolution meteorological data from the Weather Research and Forecasting coupled with Single Layer Urban Canopy Model (WRF/SLUCM) into CitySim for the first time to evaluate the building energy demands at various building types in Dubai metropolis. Examining how cool materials reduced cooling loads was achievable utilizing modified albedo in Dubai's downtown buildings. An increase of urban albedo from 0.2 to 0.8 significantly lowers the urban heating effect, as well as the building cooling needs. The study shows that for albedo scenario 0.8, Low-rise residential buildings experienced cooling load reductions of about 13.1 kWh/m2 and 6 kWh/m2 for buildings without insulation and those with insulation, respectively, compared to the base case. Additionally, high-rise residential buildings saw cooling load reductions ranging from 7.7 kWh/m2 to 11.7 kWh/m2 for buildings without insulation and a cooling load reduction of 3.6 kWh/m2 to 5.4 kWh/m2 for insulated buildings. This study provides a tool for regulating the energy impact of cool roofs in different urban settings using energy simulation, which could help policymakers control the energy needs in subtropical desert urban environments.

Energy-saving regulation methods and energy consumption characteristics of office air-conditioning loads in hot summer and cold winter areas

The air-conditioning system of an office building may have much higher operational energy consumption than its designed value due to the actual use behavior which significantly deviates from the predicted one. To precisely analyze the actual air-conditioning energy consumption, in this paper, based on the impact of occupant air-conditioning behavior on the energy consumption of air-conditioning systems, a Supply-Side Cooling Load Regulation Method (SSRM) is proposed, and its air-conditioning energy consumption analysis model is established. The energy consumption characteristics of the air-conditioning system under SSRM were analyzed, with the assumption that the example office building is located in a hot summer and cold winter areas. The results indicate that the indoor air conditioning set temperature and the actual fresh air volume are important factors affecting the variation of the air conditioning system cooling load under the Demand-Side Cooling Load Regulation Method (DSRM) method, whereas under SSRM, the air conditioning system cooling load is not affected by the variation of the indoor set temperature and the fresh air volume; meanwhile, regulating human air-conditioning use behaviors is the key point of reducing air-conditioning cooling load. The increasing fresh air volume from 30 m3/(p∙h) to 90 m3/(p∙h) can result in about a 5°C increase in the average daily indoor air temperature in the rooms used by SSRM, and it also causes an increase in the total air-conditioning load in the rooms under DSRM by more than 45 kWh/day. Further, compared to the DSRM, the SSRM can well regulate occupant air-conditioning use behaviors, which reduces energy consumption by more than 35% in the summer.

Optimization of the Air-Conditioning Energy Performance and Daylight Performance of AResidential Building According to the Bioclimatic Design Principles: An Application to the Moroccan Mediterranean

The bioclimatic architecture concept refers to an approach that takes into account the various characteristics of a building environment to make it more comfortable for its occupants. This work aims to improve the passive design parameters of an air-conditioned residential building located in the north of Morocco, in accordance with bioclimatic principles. The bioclimatic chart diagram is used to select the passive design measures that are the most appropriate for the north Morocco climate characteristics. Then, a set of design parameters are selected for more delimitation in the optimization study. The optimization problem is multi-objective and aims to find the design solution that simultaneously includes the best air-conditioning energy performance and daylight performance. The obtained results showed that the multi-objective optimum design solution is characterized by massive walls and roof, exterior insulation, double window glazing type, and a high summer ventilation rate. Also, a small glazing area with a large sun-shading covering is needed for the east facade. Ultimately, the building performance analysis revealed that the optimum bioclimatic design solution fully meets the requirements establishedby the Moroccan Building Thermal Regulation (MBTR), leading to an energy performance improvement of about 52%.

Optimal Design of Tilted Building Envelope Considering Air Conditioning Energy Demand, Daylight Utilization and Glare Protection—Case Study

An important energy-saving method to optimize building envelope design is the integration of local climate characteristics. This study attempts to find sloped facade configurations to balance air conditioning energy demand and daylight utilization for four directions in an area with a hot climate. Tilt angle dependence of the air conditioning energy demand, useful daylight illuminance (UDI) and daylight glare index (DGI) are selected to investigate the acceptance thresholds of the tilt angle. The final facade’s configuration is achieved by employing the graphical optimization method. An acceptable solution that balances better daylight performance and less energy consumption by air conditioning is developed. Due to the considered city being located in a low-latitude area with great daylight availability as well as a fully dimmable light control strategy, unbearable glare reduction can be achieved by benefiting from the sloped facades, without necessarily sacrificing much usable daylight. Meanwhile, there is no obvious increase in the demand for lighting energy consumption, and a good outward view is preserved. The sloped rather than vertical facade provides natural solar shading to the east-, south- and west-oriented windows while allowing low-angle winter solar heat to warm the building space. Tilt angles between 35°and 40° are preferred for the east facade, and smaller tilt angles of between 30°and 35° are recommended for the south facade. Larger tilt angles of between 40°and 45° are preferred for the west facade. However, the north-facing facade’s outward tilt would cause an undesirable increase in air conditioning energy demand. The annual air conditioning energy demand of the east-, south- and west-facing space is found to separately decrease by 7.1%, 7.3% and 9.9%, respectively, benefiting from the sloped facades.

Irrigation and Thermal Buffering Using Mathematical Modeling

Two methods of irrigation, drip, and sprinkler were studied to determine the response of the Javits green roof to irrigation. The control study was dry unirrigated plots. Drip irrigation consisted of irrigation tubes running through the green roof that would water the soil throughout and sprinkler irrigation used a sprinkler system to irrigate the green roof from above. In all cases, the irrigated roofs had increased the soil moisture, reduced temperatures of both the upper and lower surfaces, reduced growing medium temperatures and reduced air temperatures above the green roof relative to the unirrigated roof. The buffered temperature fluctuations were also studied via air conditioner energy consumption. There was a 28% reduction in air conditioner energy consumption and a 33% reduction in overall energy consumption between dry and irrigated plots. Values of thermal resistance or S were determined for accuracy and for this study, there was little change which is ideal. A series of infra-red and thermal probe measurements were used to determine temperatures in the air and sedum. It was determined that the sprinkler irrigation did a better job than the drip irrigation in keeping cooler temperatures within the green roof. A Mann-Whitney U test was performed to verify the variation in moisture temperatures buffering energy consumption. By getting a p-value < 0.05, it indicates that the model is accurate for prediction and medium temperatures were statistically different.

Annual analysis and comparison of the comprehensive performance of a CdTe PV ventilated window integrated with vacuum glazing in different climate regions

In this paper, a CdTe photovoltaic double-skin ventilated window integrated with vacuum glazing (VPV-DSV) is proposed. The mathematical model of VPV-DSV was developed and validated through tests in Hefei, China. Annual energy performance and the economic analysis of the VPV-DSV was evaluated and compared with the other two PV-DSVs and an insulating glazed window (IG) under climate conditions of five selected cities, including Changchun, Hefei, Kunming, Shenzhen, and Shijiazhuang. Moreover, effects of window design factors, including the window-to-wall ratio, PV coverage, and pillar spacing of the VG, were explored. Results indicated that: (1) the VPV-DSV produced the best energy saving results and the least energy consumption. (2) NECs of the VPV-DSV in the five cities above was 955.05 kW•h, 464.31 kW•h, 110.66 kW•h, 53.71 kW•h, and 443.14 kW•h, respectively. (3) Due to high cost of the VG, the VPV-DSV only had the best economic performance in Shenzhen and the NPV was 3931.47 CNY. (4) The WWR and PV coverage had obvious impacts on the overall performance of the VPV-DSV, while the pillar spacing only had a more significant impact on the air conditioning energy consumption.

Trade-Off Judgement for Daylighting and Energy Consumption in the High and Large Space of the University Gymnasium in Beijing

Taking the high and large space of the University of Science and Technology Beijing Gymnasium as this research object, this paper analyzes the influence of different window positions, window-to-wall ratio (WWR), solar heat gain coefficient (SHGC), heat transfer coefficient (K), and visible light transmittance (VT) on the total indoor energy consumption in winter and summer and obtains the relationship between the daylight factor and VT formed when the window is opened per unit area. Through energy consumption simulation, the variation law and calculation formula for indoor total energy consumption are obtained. The results show that the SHGC and K of the exterior window have a significant influence on the total energy consumption. By using the energy consumption simulation of different types of exterior windows, it is concluded that the SHGC of the south-facing window is negatively correlated with the variation of air conditioning energy consumption per unit area Δe1,w, while the others are positively correlated. Moreover, the SHGC and K of the skylight have the most significant influence on the Δe1,w. The total energy consumption decreases and then increases with the increase in the window area, and there is a lowest point, so the right side of the lowest point is less than or equal to 105% of the lowest total energy consumption as a reasonable window area zone. Finally, a progressive optimization method for weighing daylighting and energy consumption in university gymnasiums in Beijing is proposed.

Optimization control strategy for mixed-mode buildings based on thermal comfort model: A case study of office buildings

Mixed-mode (MM) buildings reduce air conditioning (AC) energy consumption while maintaining indoor thermal comfort through the appropriate use of natural ventilation (NV). The objective of this investigation was to propose a method to determine the best NV operation range suitable for MM buildings and further to propose a change-over control strategy. First, the usual natural ventilation operating range (NV-range) was obtained based on the upper and lower comfort temperature limits of the adaptive comfort model. The usual NV-range was extended by adding threshold conditions, and then, it was divided into nine natural ventilation operation subranges (NVOSs). Second, the comfort and energy performance of each NVOS were analyzed through a co-simulation for an MM office building in Xi'an, China, as an example to obtain the optimal NV-range for the local climate. The results showed that the proposed optimal NV-range reduced the number of discomfort hours by 248.33 h while increasing the energy savings by 13.29% compared to those of the commonly used NV-ranges. Finally, the control scheme with the adaptive comfort model changed to the PMV model (ACM-PMV-CS) with the addition of a 1.5-h transition period was proposed in order to solve the problem of using the steady-state PMV model directly in the AC mode under the frequent switching conditions between the NV and AC modes. The results showed that ACM-PMV-1.5 h transition period resulted in a reduction in the number of discomfort hours (248.33 h) and a 35.46% increase in the energy savings compared to those of ACM-PMV-CS without a transition period.

New control methodology of electric vehicles energy consumption optimization based on air conditioning thermal comfort

This article discusses the new control methodology of vehicle energy consumption optimization for thermal comfort. To address the issues of exceeding boundaries and redundancy in the application of PMV(Predicted Mean Vote) indicators in vehicles, three different control strategies for electric vehicles are proposed. To address the issue of inaccurate prediction results caused by considering air conditioning energy consumption as a part of vehicle driving energy consumption, a method combining air conditioning average power method is proposed to estimate the remaining range of vehicles. The impact of air conditioning energy consumption on the estimation results of vehicle remaining range under three control strategies is analyzed. Finally, the simulation and experimental results demonstrate the differences in the energy consumption values of the entire vehicle under the three modes, providing a solution for balancing energy saving and comfort control in the use of electric vehicles. In addition, the experimental results show that the error rate between the actual value of estimating the remaining driving distance of vehicles using the average power method of air conditioning and the simulated data is less than 3%. The proposed algorithm provides new ideas and methods for estimating the remaining driving range of electric vehicles.

Research on energy-saving strategies in the architectural design of the Eastern Railway in the era of artificial intelligence

Abstract This paper takes the air conditioning energy consumption in railroad building design as the main object of analysis and uses an orthogonal experimental design method to study the influencing factors and effects of energy consumption in the Middle East railroad construction design. Stochastic working condition simulation is carried out for the typical models of passenger stations in five climate zones to obtain the data set of the passenger station energy consumption model, and the multiple linear regression prediction models of air conditioning energy consumption in different regions are established. Combined with the hour-by-hour average outdoor temperature, hour-by-hour passenger flow and lighting and related equipment data in the waiting hall of a city in July, the air-conditioning cold load of railroad passenger stations is simulated and analyzed. Explore the implementation effect of energy-saving strategies for railroad passenger station air-conditioning system, and for the traditional PID control strategy, put forward the control strategy based on model prediction, analyze the change of centralized air-conditioning system cold load and the change of the actual performance coefficient of the chiller unit under different control strategies. The data show that compared with the traditional PID control, the model prediction control reduces the total energy consumption by 0.2063, which realizes the energy-saving optimization of the air conditioning system for railroad building design.

Scalable and Flexible Multi-Layer Prismatic Photonic Metamaterial Film for Efficient Daytime Radiative Cooling.

To maintain a comfortable indoor living environment in low latitude or tropical regions, humans consume significant amounts of electrical energy in air conditioning, leading to substantial CO2 emissions. Passive daytime radiative cooling (PDRC) allows objects to cool down during the daytime without any energy consumption by dissipating heat through the atmospheric transparency window (8-13µm) to outer space, which has garnered significant attention. However, the practical applications of common PDRC materials are hindered by their poor optical selectivity and high-reflective silver backing. Additionally, the availability of artificial photon emitters with complex structures and excellent performance is also limited by their high cost. Herein, a novel multilayer prismatic photonic metamaterial film without any silver reflector, easily scalable and produced by a roll-to-roll method is demonstrated, which exhibits ≈96.4% sunlight reflectance (0.3-2.5µm) and ≈97.2% emissivity in mid-infrared (IR) (8-13µm). At an average solar intensity of ≈920Wm-2, it is on average 6.8°C below ambient temperature during the day and theoretically yields a radiative cooling power of 88.9Wm-2. Furthermore, the film exhibits excellent hydrophobicity, superior flexibility, and robust mechanical strength, providing an attractive and viable pathway for practical applications addressing the pressing challenges of climate and energy issues.

Life cycle energy and greenhouse gas emissions of a traditional and a smart HVAC control system for Australian office buildings

In recent years, many novel smart technologies have been proposed to reduce the energy consumption and greenhouse gas (GHG) emissions attributed to the building sector. One such application of these technologies is the reduction of the Heating, Ventilation and Air Conditioning (HVAC) energy needs and GHG emissions using smart control systems. The environmental benefits of smart control systems during building operation have been explored in many studies, however, their embodied effects, associated with the extraction of raw materials, manufacturing and replacement are often overlooked. Accordingly, this study quantifies the life cycle energy needs and GHG emissions of a smart HVAC control system and assesses its potential for reducing the HVAC operational energy and GHG emissions in an Australian office building. A comparative assessment is performed, considering a traditional HVAC control system and an equivalent smart HVAC control system. The components of both the traditional and smart control systems are specified based on the characteristics of these systems as well as the layout of the serviced spaces in the reference building. The embodied energy and GHG emissions of both the traditional and smart control systems are quantified through a hybrid life cycle inventory (LCI) approach. To evaluate the effects of these control systems on the building HVAC operational energy, a building energy simulation is performed by applying the control logics of both systems. The results show that energy and GHG emissions savings in the HVAC operational offset the additional energy needs and GHG emissions of deploying the smart HVAC control system.

Investigation on alkali-activated insulation mortar containing high-volume recycled concrete powder for energy-efficient buildings

The influence of recycled concrete powder (RCP) on the thermal insulation of alkali-activated materials remains unclear. Hence, this study develops an innovative alkali-activated insulation mortar, serving RCP and blast furnace slag as the precursor and expanded polystyrene (EPS) beads as fine aggregate, together with air entrainer. Experimental results show that the mortar had satisfactory workability owing to the RCP substitution, supported by appearance and infrared thermal imaging tests. As the ratio increased, the density, compressive strength, and thermal conductivity of the mortar decreased, due to the increasing volume of porous paste and internal air voids. Subsequently, the material design of the mortar was optimized through the adjusted Box-Behnken design. The obtained mortar achieved a high-volume use (61.7 wt%) of RCP, and exhibited an extremely low conductivity (∼0.030 W/(m∙K)) among novel lightweight building materials. Energy simulation further indicates that the optimized mortar can surpass traditional insulation materials, including EPS, polyurethane, and rock wool panels, in reducing air conditioning energy consumption across all seasons and climate zones. This was particularly evident in colder cities such as Harbin and Lhasa. Given that increasing the thermal resistance of the envelope can effectively reduce building energy consumption, the development of such sustainable alkali-activated insulation mortar would undoubtedly contribute to the implementation of energy-efficient buildings.