Double Glazing Research Articles

Highly Tunable Cellulosic Hydrogels with Dynamic Solar Modulation for Energy-Efficient Windows.

Smart windows that can passively regulate incident solar radiation by dynamically modulating optical transmittance have attracted increasing scientific interest due to their potential economic and environmental savings. However, challenges remain in the global adoption of such systems, given the extreme variability in climatic and economic conditions across different geographical locations. Aiming these issues, a methylcellulose (MC) salt system is synthesized with high tunability for intrinsic optical transmittance (89.3%), which can be applied globally to various locations. Specifically, the MC window exhibits superior heat shielding potential below transition temperatures, becoming opaque at temperatures above the Lower Critical Solution Temperature and reducing the solar heat gain by 55%. This optical tunability is attributable to the particle size change triggered by the temperature-induced reversible coil-to-globular transition. This leads to effective refractive index and scattering modulation, making them prospective solutions for light management systems, an application ahead of intelligent fenestration systems. During the field tests, MC-based windows demonstrated a 9°C temperature decrease compared to double-pane windows on sunny days and a 5°C increase during winters, with simulations predicting an 11% energy savings. The ubiquitous availability of materials, low cost, and ease-of-manufacturing will provide technological equity and foster the ambition toward net-zero buildings.

Analyzing the effectiveness of building integrated Photovoltaics (BIPV) to reduce the energy consumption in Dubai

In Dubai, 38.9 % of the total energy consumption is related to buildings, and the high-rise building sector is key to energy efficiency. BIPV (Building Integrated Photovoltaic) can be a very efficient alternative in Dubai because of building load reduction and power generation. This paper aims to investigate energy efficiency according to the number of floors with BIPV application. As a methodology, an analysis model for office use was used with the curtain wall with a floor height of 3.6 m, floor area of 400 m2, and a window area ratio to wall area ratio of 80 %. Energy Plus Version 9.0 and TRNSYS were used as evaluation tools. The physical properties of windows and doors in the analysis model were assumed to be low-E double-glazed glass with a Solar Radiation Gain Coefficient (SHGC) of 0.564, a visible light transmittance of 47.2 %, and a thermal transmittance of 1.760 W/m2K. The result showed that when the alternatives of the window replacement type, exterior wall finishing type, and hybrid type BIPV system are applied, heating and cooling energy consumption is reduced by 13.2 % to 32.8 %. It was proven that applying BIPV was effective in high-rise office buildings. It is practical to replace windows and apply light-transmitting amorphous thin film Photovoltaic (PV) double-layered, double-layered Low-E, or triple Low-E windows, replace exterior wall finishing materials with crystalline PV, or use a mixture of both. The simulation results show that applying a roof-top BAPV (Building-Applied Photovoltaic) system is only practical for low-rise buildings.

The potential of the effect of insulation and photovoltaic panel use in buildings on energy performance for Turkey and LCC analysis

This study was carried out in a building located in Antalya in order to determine the optimum combinations of different levels of improvement and PV panel use in existing buildings in terms of energy saving and LCC. Within the framework of TS 825 Thermal Insulation Rules in Buildings, which is the national standard in Turkey, three different levels of insulation in walls, roofs, floors and windows and three different numbers of PV panels for energy production were determined. 18 different alternatives obtained using the orthogonal array for five factors with three levels analyzed have been made. In terms of energy savings, the scenario with the highest levels of insulation for walls, roofs, floors and windows and the use of 12 PV panels is the optimum combination that produces all of its energy needs and switches to surplus energy with +KW after consumption. In terms of LCC, the alternative with 12 PV panels, where wall, floor and windows are the highest and the roof is insulated at level 2, is the best combination. PV panel integration was found to be the most effective parameter in terms of energy savings and LCC.

Optimization of energy-saving renovation technology for existing buildings in a hot summer and cold winter area

Retrofitting existing buildings significantly improves indoor thermal comfort and reduces building energy consumption and greenhouse gas emissions. The optimal combination of energy-saving technologies can improve the energy performance of a specific building. The effective energy-saving renovation of existing buildings is vital for improving the poor indoor comfort and high building energy consumption caused by the inadequate thermal performance of the external enclosure structure. This study proposed a new multi-objective optimization model based on Latin hypercube sampling (LHS). It combines a genetic algorithm (GA) with an artificial neural network (ANN) to evaluate and optimize the technology used for retrofitting projects, aiming to provide solutions for the energy-saving renovation of existing buildings. This study selected an old building in a hot-summer and cold-winter area for the retrofitting project, aiming to optimize indoor comfort, building energy consumption, and retrofitting cost. The proposed model was used to determine the optimum energy-saving technology combinations suitable for the building. The results showed that the optimized model could be used to explore conflicting objectives and determine the Pareto front when retrofitting existing buildings. Subsequently, the optimal technology combinations included using energy-efficient PVC Low-E double-glazed windows (5+6A+5) and XPS insulation with a thickness of 0.315m for the roof and external walls.

Multi-Stage Sensitivity Analysis of the Energy Demand for the Cooling of Grain Warehouses in Cold Regions of China

The early design parameters exert a considerable influence on the cooling energy demand of a granary building in operation. In order to investigate the impact of various parameters on energy use, a grain warehouse energy model was constructed using the Ladybug + Honeybee tools on the Grasshopper platform. Three global energy sensitivity methods were used to analyze the model, and the sizes of the influential parameters were determined and ranked. The study uncovered that the cooling energy demand of the grain warehouse was primarily influenced by factors such as the cooling set-point temperature, roof solar absorptance, roof and exterior wall insulation thickness, window type, and orientation. On this basis, a local sensitivity analysis was conducted for the highly sensitive parameters to identify their influence trend and optimal design range. The results showed that the cooling energy demand of the grain warehouse increases faster as the cooling set-point temperature decreases, with the highest growth rate occurring at a temperature below 18 °C. Lower solar absorptance of the roof is conducive to reducing the cooling energy demand of the grain warehouse. When the thickness of the roof thermal insulation is less than 120 mm and the thickness of the external wall thermal insulation is less than 60 mm, energy use decreases more quickly with greater insulation thickness. It is advisable to use traditional or new windows with thermal insulation and shuttered windows. Furthermore, the optimal position of the long side of the granary was between 10° west and 10° east of north. This research could provide guidance for the energy-saving design and renovation of granary buildings in cold regions of China.

Development of a comprehensive method to estimate the optical, thermal and electrical performance of a complex PV window for building integration

Increasing concerns over energy consumption and greenhouse gas emissions in buildings have contributed to the emerging of innovative PV glazing technologies to improve the building energy performance. However, some of these glazing systems have complex structures, making it challenging to investigate their optical, thermal and electrical performance for estimating their energy saving potential in buildings. In this research, a validated Computational Fluid Dynamics (CFD) combined with a ray-tracing model has been developed to accurately predict the optical, thermal and electrical performance of complex PV glazing systems under varying incident angles. A ray-tracing model is developed to calculate the light transmittance of the window and the solar energy absorbed by each solid element and PV cells. To estimate temperature profiles (e.g., PV temperature and window temperature) and secondary heat within the window, the results from the ray-tracing analysis, which detail the solar flux absorbed by each layer, are inputted into a validated CFD model as boundary conditions. Using the CFD combined ray-tracing calculation illustrated above, the Solar Heat Gain Coefficient (SHGC) of these complex PV window systems can be obtained. Furthermore, a PV modelling algorithm is developed to predict the power output based on the simulated PV temperature. This procedure is implemented to investigate a Crossed Compound Parabolic Concentrator Photovoltaic (CCPC-PV) window, which serves as an example of a complex PV glazing system in this study. The developed optical, thermal and electrical models have been validated through experimental tests. Additionally, new configurations have been designed to explore the impact of the pitch between adjacent optics on the SHGC and power output of the window. The results show that the original window (1.77 mm-pitch) possesses the maximum PV temperature of 64.73 °C and the maximum window inside surface temperature of 61.58 °C under National Fenestration Rating Council (NFRC) standard. Meanwhile the PV efficiency is 15.21 % and the SHGC is 0.463. The SHGC value of this innovative PV window is notably lower than that of a conventional double-glazed window, which has a SHGC value of 0.813. This reduction in SHGC decreases the likelihood of overheating issues, especially during the summer months.

From Double Skin Facade to Closed Cavity Façade with Triple Glazed Unite as Inner Skin Without Coatings in the Tropical Climate of Malaysia

The Close Cavity Façade (CCF) has undergone significant advancements from its predecessor, the Double Skin Façade (DSF), resulting in improved thermal insulation and reduced solar penetration. The core principle behind a CCF is a hermetically sealed and non-ventilated construction that incorporates an automatic shading system, triple glazing (TGU) on the inner surface, and single glass on the outer surface. The technique described above effectively regulates the ingress of solar energy and natural light into the building. The experimentation involved the utilisation of various combinations of CCF-TGU designs, employing software tools such as Window 7.8, EnergyPlus, and DesignBuilder. Then, a comparison analysis was undertaken to compare the aforementioned designs with the presently employed single-glazed units (SGU) featuring a grey coating. The inquiry was initiated through the implementation of a case study carried out on a condominium located on Penang Island, Malaysia. The CCF-TGU has superior thermal performance and provides enhanced occupant comfort when compared to SGUs. The effectiveness of CCF-TGU designs in reducing operating temperature ratios has been observed to be higher in Malaysia's humid tropical climate than that of SGUs. The annual rate of decrease varies between 29.8% and 77.8%, thereby successfully attaining the required level of thermal comfort. The research highlights the potential advantages of implementing an innovative CCF technology that has been modified to accommodate the distinct meteorological conditions of Malaysia. The findings suggest that the implementation of advanced glazing technology holds the potential to enhance both operational temperatures and overall occupant comfort within buildings.

Impact of the Saudi Building Code on Residential Construction Costs

The government of Saudi has implemented the Saudi Building Code (SBC) for residential buildings to set standards for their design, construction, and maintenance. However, this may result in unexpected costs that are passed on to the citizens and thus have a certain economic impact. Therefore, this study examined the additional costs imposed on citizens and the economic impact of implementing the SBC on residential buildings. This study surveyed building developers, architects, and citizens to gather data on the costs associated with adhering to the code such as material and labor costs. This study found that the additional costs imposed on citizens and the economic impact of implementing the SBC in residential buildings were relatively small. The potential long-term benefits of the SBC such as energy efficiency savings and reduced environmental impact outweigh the short-term costs. The case that applied the SBC had operating costs that were almost 44% lower. Energy efficiency was increased by the SBC’s contribution to reducing heat transfer through building components and external elements. In order to minimize heat absorption and electricity usage, thermal insulation, double and heat-reflecting glass, and light exterior colors are all recommended. The findings of this research provide valuable insights for policymakers and stakeholders in the construction industry because they consider the implementation and enforcement of building codes in the Kingdom of Saudi Arabia.

Holistic design of energy-efficient temporary houses: Meeting ventilation, heating, cooling, and lighting demands

Recent disasters around the world have brought attention to the challenges faced by the homeless. Energy-efficient container houses (EECHs) offer a comfortable, sustainable, and temporary solution. A holistic design of EECH was conducted for mixed and hot climates using DesignBuilder software. The design, performed initially according to design criteria derived from ASHRAE Standards and previous studies, was subsequently examined for five passive strategies: envelope layering, WWR, windows opening ratio, glazing type, and shading. Optimal conditions were determined by the trade-off between heating and cooling demands, ventilation rate, and minimum daylight factor (DF) and uniformity (UDF). Results reveal that in mixed climates, using insulation materials and thermal mass is recommended, while in hot climates, it is advisable to avoid using them and instead rely solely on internal finishing layers. Complete reliance on natural ventilation is achieved by combining an opening ratio of 35 % with a WWR of 9%–25 % for south and north facades, and 6%–12 % for west façade. In mixed climates, argon gap double clear glazing is suitable, while a low-e layer is added for hot climates. Installing overhangs on south windows enhances UDF, unlike vertical fins on north and west windows. The designed EECHs consume 176 kWh/m2 of electricity annually.

A data-driven approach to thermal transmittance (U-factor) calculation of double-glazed windows with or without inert gases between the panes

Understanding the thermal performance of window units is of utmost importance for the advancement of energy-efficient building design. Thermal transmittance (U-factor) is one of the most important indicators of a window system's efficiency, especially in colder climates. Presently, the Window U-factor is typically calculated using one of two standard approaches: experimental methods and computational modeling both having significant limitations. This makes it crucial to develop methods that can calculate the thermal performance of windows in the field and more on already installed windows. This research introduces a data-driven approach to calculating the U-factor of double-glazed windows filled with and without inert gases. The study is confined to double-glazed windows containing either air or a defined percentage of inert gases (75 % Argon, 85 % Argon, and 95 % Argon). The study reveals that the center of glazing, due to its prominence in window construction, plays a significant role in determining the window's thermal attributes. It also establishes a correlation between glass emissivity and center of glass U-factor (thermal transmittance). Furthermore, our developed data-driven approach exhibits considerable reliability in calculating the thermal transmittance of double-glazed windows, as validated by comparison with industry-standard NFRC 100-certified U-factor values. The insights garnered from this research contribute significantly to the understanding of double-glazed window design and the development of more energy-efficient fenestration products. It provides a robust foundation for industry professionals aiming to reduce energy consumption and work towards a sustainable future.

Energy efficiency of a house in Mediterranean region: insulation and glazing impact

The insulation of a building's envelope is critical for reducing energy consumption, enhancing indoor thermal comfort, and achieving sustainable development goals. This theoretical work focused on the energy and thermal aspect of insulators and glazing to determine the optimal thermal insulation and the best glazing for the building envelope in the Mediterranean region where the province of Ain Temouchent, Algeria, was taken in this study. This study evaluated the effectiveness of insulation materials, which are expanded polystyrene, glass wool, rock wool, and wood fiber of varying thicknesses, and glazing in the Algerian market. The TRNSYS 17 software is used to simulate the building's behavior. The study finds that wood fiber insulation with a 9 cm thickness provides the best thermal performance, resulting in a 26% reduction in energy costs compared to 3cm of expanded polystyrene. Furthermore, upgrading from single to double glazing can reduce heating and cooling costs by 23% and 10%, respectively, demonstrating the importance of proper insulation and glazing in achieving energy efficiency, and enhancing indoor thermal comfort for occupants. In conclusion, this study provides valuable findings for designing energy-efficient buildings with optimal thermal insulation and glazing. Future research should explore broader factors affecting building performance, such as the long-term performance and durability of materials in varying climates and building designs, as well as the impact of occupancy and building orientation. Although the study acknowledges its limited examination of factors and options, it still provides valuable insights into building performance with insulation and glazing.

The effect of insulation on boil-off gas in liquid air storage tank

Increasing renewable energy is posing a challenge to the stability of electricity grid, and the importance of an energy storage system (ESS) is becoming clearer. A Liquid Air Energy Storage System (LAES) is proposed as one of the promising ESS technologies. LAES converts electricity to liquid air efficiently and economically. However, since the storage temperature of liquid air is −196 °C, loss of liquid air is inevitable due to evaporation, i.e., boil-off gas (BOG). A loss of liquid air has negative effect on the round-trip efficiency of LAES; therefore, the BOG rate must be minimized. In this research, the insulation performance of liquid air tank is evaluated. To calculate the heat ingress and BOG rate, a partial equilibrium model is developed. The insulation performance is evaluated with varying insulation thickness, emissivity, aspect ratio and materials. The results show that the BOG rate of vacuum insulation can reach 1.8 %/day. For foam glass insulation, the BOG rate can become 2.25 %/day. With optimal geometry, 0.7 %/day for vacuum insulation and 1 %/day for foam glass insulation can be achieved. The vacuum insulation generally shows better insulation performance, however, there is area where the foam glass insulation shows better performance depending on the insulation thickness and emissivity.

Thermo-environmental performance of polycarbonate materials as a glazing substitute in hot climates

ABSTRACT Buildings consume substantial energy, primarily for cooling and heating, resulting in equivalent CO2 emissions. Proper building envelope design in hot climates is crucial for reducing heat transmission, especially in transparent glazed-dominated envelopes with low thermal insulation compared to opaque walls. Compared to conventional glass, this study investigates the impact resistance, thermal performance, and environmental impact of polycarbonate (PC) sheets used as exterior glazing for windows and skylights. The study conducted literature reviews, Solar Heat Gain Coefficient (SHGC) measurements, and energy simulations of PC alternatives using a hotel in Madinah. Findings indicate that all PC alternatives' thermal and environmental performance performed better than ordinary glass, reducing total energy consumption and greenhouse gas (GHG) emissions. Single glazing decreased energy from 1% to 15%, double glazing from 1% to 19%, and triple glazing from 1% to 20% as window glazing. Skylight glazing also lowered overall energy use and gas emissions, with single glazing reducing 2% to 28%, double glazing 3% to 42%, and triple glazing 4% to 49%. Furthermore, the 25mm 9 wall X-Structure PC sheet performed best for windows and skylights in all glazing systems (single, double, and triple). The PC sheets' thickness and section composition affect thermal and environmental performance.

Analysis of the influence of outer envelope structure on indoor thermal environment of zero energy building

Zero-energy building is the main development trend in the current construction field. Reducing the carbon emission of the building, enhancing the indoor comfort of the building, and improving the comprehensive performance of the building are the current research hotspots in the field of construction, and it is necessary to explore the impact of the envelope on the performance of the building as the main medium for the transfer of indoor and outdoor heat in the building. In this paper, zero energy consumption buildings in Northwest China are taken as the study application. Numerical simulation and experimental research are combined to compare and analyze the changes of indoor thermal environment under the conditions of external wall insulation layer thickness of 150mm, 140mm, 130mm and window-wall ratio of 0.36 and 0.5 in the heating season. The results show that the indoor comfort level of 130mm is lower than that of 140mm and 150mm external wall insulation layer thickness, and in winter, the increase of window wall ratio improves indoor thermal comfort. In general, increasing the thickness of external wall insulation layer and window wall ratio can be effective means to improve indoor comfort. However, blindly increasing the thickness of insulation layer and window wall ratio will only cause resource waste and cost increase, affecting the long-term development of zero-energy buildings.

Evaluation the life cycle carbon emissions of the aerogel glazing under different weather conditions

Carbon emissions are widely recognized as the primary cause of global warming over the past few decades. The Aerogel Glazing System (AGS) stands out as one of the most advanced glazing systems currently available. In order to evaluate the carbon-saving potential of AGS, the life cycle carbon emission model of AGS was established. The carbon emission of production, transportation, construction, operation, maintenance, and waste disposal are considered. The results showed that AGS has higher carbon-saving potential. The life cycle carbon emissions of AGS in commercial, double glazing system (DGS), triple glazing system (TGS) are −144.8 kg CO2/m2, 593.6 kg CO2/m2, 250.8 kg CO2/m2 in Beijing horizontal direction. Under high temperature supercritical drying (in Commercial), low temperature supercritical drying, and freeze-drying, the life carbon emissions of AGS are lower compared to both DGS and TGS. Then the life cycle carbon emissions of AGS in different climates were analyzed. The results show that the life cycle carbon emissions of AGS under different climatic conditions are as follows (in ascending order): subtropical climate < polar climate < temperate climate < arid climate < tropical climate, with a maximum of 4929.9 kg CO2/m2 and a minimum of −634.5 kg CO2/m2. The use of AGS in tropical climate produced 5.9 times increase in life carbon emissions compared to its use in subtropical climate. In the heating-dominated climate, AGS has the greatest potential for carbon savings when orientated southwards. In cooling dominated climates, the carbon emissions are higher in the southward direction, with a weaker potential for carbon savings. Interestingly, in polar and tropical climates, increasing the aerogel thickness layer effectively reduces the life cycle carbon emissions of AGS. This study provides valuable insights for selecting sustainable curtain wall systems and window configurations, offering a pathway to minimize environmental impacts.

Towards A Design Approach to Achieve Environmental Safety in Diagnostic and Therapeutic Units in Hospitals Using Nanotechnology

In The environmental safety was investigated in this study, with an initial focus on defining the general concept of environmental safety. Subsequently, the study delved into the environmental safety within hospitals, particularly in diagnostic and treatment spaces. Air pollutants and their types were examined, along with permissible levels, emphasizing the adverse effects of increased pollutants on human health. Additionally, attention was given to the physical hazards within these spaces, such as temperature, noise, and lighting. In the context of studying diagnostic and treatment spaces in hospitals, a review was conducted on the currently used traditional finishing materials and an evaluation of their harmful effects. The concept of "sick buildings" and its impact on human safety was also explored. The study placed a particular emphasis on nanotechnology and how nano-materials can be employed to mitigate the detrimental effects of non-compliant "sick buildings" with environmental safety standards. Global examples of nano-applications were analyzed, along with an examination of a hospital in Egypt that utilizes nano-technology in its glass structure. Furthermore, a simulation was performed on a local hospital to measure the difference in carbon dioxide emission within the space. This comparison was conducted between the current state of the building using traditional finishing materials and the scenario where nano-alternatives are employed in the glass and thermal insulation of exterior walls.

Regulating the valence state of lead ions in lead aluminosilicate glass to improve the passivation performance for advanced chip packaging

Eliminating surface ion contamination, increasing the reverse breakdown voltage and reducing the leakage current are extremely important for semiconductor devices. Herein, we demonstrated that regulating the valence state of lead ions in lead aluminosilicate glass can efficiently improve the performance of glass passivation technique for chip packaging. It was found that heat treatment technique can be utilized to control valence state of lead ions from +4 into +2 in 20PbO-4.8Al2O3-75.2SiO2 (mol%) (PAS) glass powder, which induces transformation of [PbO3] units into stable glass former units of [PbO4] and generates a free state and charge compensator of Pb2+, therefore contributing to a more stable structure and discoloration of glass. As a result, the optical band gap of glass powder was enhanced from 4.1772 to 4.3184, which could significantly improve glass insulation. As a demonstration of chip packaging, PAS glass powder, after heat treatment processing into a paste for the passivation layer of metal–oxide–semiconductor (MOS) structure devices shows a tight and integrated structure and exhibits a lower fixed charge density from 3.97 × 1010cm−2 to 2.73 × 1010 cm−2. This work provides techniques to adjust the structure of glass to enhance the passivation performance of glass for chip packaging.

Thermal Performance Evaluation of TIM Combined with Residential Windows in Different Climatic Regions in Iran

Windows play a significant role in the increase and loss of heat from the building envelope and determine the quantity, quality, and distribution of daylight. A strategy that involves incorporating transparent insulating materials into a double-glazed window offers the potential to provide combined improvements in thermal and daylighting performance. The thermal properties of transparent insulation materials in windows depend on various factors, such as the type of insulation material, thickness, geometry and insulation structure, location, and orientation of the window, among others. The aim of this research is to optimize three criteria: "thickness," "location of transparent insulation relative to window layers," and "direction of the wall with transparent insulation of the building window." The goal is to minimize thermal loads and reduce energy consumption in residential buildings. To achieve this, a real model was selected, and Design Builder software was used to measure the "heating load," "cooling load," and the sum of these two loads as the "total thermal load" for all three criteria in three cities of Iran with different climates: Tehran (moderate climate), Ahvaz (warm climate), and Tabriz (cold climate). The results of the research showed that for the city of Tehran, 3-inch insulation in the middle of the double-glazed window and the south front is optimal. For the city of Tabriz, 5-inch insulation on the inner surface of the window and the western front is optimal. And for the city of Ahvaz, 3-inch insulation on the outer surface of the window and the eastern front is optimal. It is worth noting that the annual heating load and total annual heating load for all three criteria have the highest values in Tabriz city. Therefore, it is recommended to use HSNPS insulation in transparent windows to reduce energy consumption in Tabriz (cold climate).

Towards a quantification of thermal and thermomechanical stress for modules in building‐integrated photovoltaics configurations

AbstractDue to reduced rear‐side ventilation, building‐integrated photovoltaics (BIPV) are prone to higher operating temperatures, which may impact their long‐term performance and reliability. However, often overlooked in the study of thermomechanical stress in PV modules are the intraday temperature variations, resulting from factors such as cloud movements and subsequent changes in irradiance. This work proposes a statistical analysis of cell and module temperature measurements in single‐cell c‐Si modules on a test bench in Neuchâtel, Switzerland. The goal is to study and compare various BIPV‐relevant module topologies with a range of factors such as the insulation type, tilt angle, and glass thickness. The standard indicators such as the 98th percentile temperature and diurnal temperature variations are examined, as well as proposed new thermomechanical stress indicators based on temperature gradients and cell versus module temperature differences. Unexpectedly, results indicate that, considering the intraday temperature variations, close‐roof module configurations (with small ventilation gaps) are potentially at a higher risk of suffering long‐term thermomechanical fatigue than fully insulated modules, which are exposed to higher operating temperatures.

Research on energy-saving renovation of solar greenhouses based on multiple factors and multiple objectives

The applicability of the traditional energy-saving renovation method for greenhouses is limited and influenced by the subjective decisions of researchers. Therefore, in this paper, a multifactor and multiobjective unbiased evaluation method is proposed based on the orthogonal test and entropy methods to study energy-saving transformation of solar greenhouses. The results show that the thickness of the gas layer, type of front roof glass and thermal insulation material of the rear roof greatly influence energy consumption, accounting for 45.5 %, 34.4 % and 15.3 %, respectively, of the total energy consumption, followed by the type of gas, thickness of glass and thermal insulation material of the heat storage wall, accounting for 3.2 %, 1.1 % and 0.5 %, respectively, of the total energy consumption. Based on energy savings, carbon emission reduction, investment cost and payback period, all renovation cases are comprehensively analyzed by the entropy weight method. The results show that Case m is the best renovation case, i.e., the front roof comprises three-layer glass, the glass thickness is 3 mm, the width of the cavity is 6 mm, which is filled with krypton gas, the rear roof insulation material is 100-mm thick extruded polystyrene (XPS), and the heat storage wall insulation material is 100-mm thick expandable polystyrene (EPS). This renovation method provides a systematic and objective theoretical basis for energy-saving renovation of solar greenhouses in cold regions.