Trombe Wall Research Articles

Investigation on heat transfer characteristics of multi-duct Trombe wall based on multi-mode heat exchange in winter

For the areas where solar energy resources are available and the demand is high, the low heat transfer efficiency of the traditional Trombe wall needs to be solved, so this study combines the traditional Trombe wall with tubular solar collectors and proposes a form of Trombe wall with multi-pipe and multi-heat transfer modes. Numerical simulation analysis is conducted based on the measured data near the wall surface of residential buildings in Zhengzhou City, China, in December. The thermal performance of different heat transfer modes is evaluated based on the simulation results, and the structural form of the multi-duct Trombe walls is optimized. The results show that the coupled heat transfer mode achieves the highest thermal efficiency. Compared with the traditional interlayer heat transfer mode, the coupled heat transfer mode has a faster start-up speed and more stable performance, with a 27.8 % increase in average daily thermal efficiency and a 36 % increase in heating capacity. Research has found that the 9-duct multi-duct Trombe wall performs better in terms of overall performance. Increasing the number of branch pipes further has limited effect on improving thermal performance. When the diameter of the heat collection branch pipe is 60 mm, the multi-duct Trombe wall achieves the highest average daily thermal efficiency of 70.3 %; adopting a non-uniform pipe distribution mode with the center distance of the middle 5 branch pipes being twice that of the other branch pipes, the Trombe wall achieves the highest average daily thermal efficiency and heating capacity.

The Performance Analysis of a Novel Sterilizable Trombe Wall Based on the Combined Effect of Heat and UV Light

A Trombe wall is a widely applied heating system that has a single function. An interesting thing is that both the solar heat and UV light received by a Trombe wall have an air sterilization effect. Here, the air sterilization and thermal performances of a Trombe wall in different cities were investigated based on an established heat and mass transfer model. The main results were as follows: (1) UV dose accumulation and high temperature were the most important factors that affect the UV and thermal sterilization performance, respectively. The Trombe wall had the thermal characteristics of high accumulation of UV doses in the morning and afternoon and a high temperature level at noon, which was a good match with the UV and thermal sterilization process. (2) A typical sterilization process in a Trombe wall was divided into three areas: the UV inactivation area, UV and thermal inactivation area and UV inactivation area. (3) The weather conditions played an important role in the sterilization performance. UV sterilization was dominant in cloudy weather, and thermal sterilization was dominant in sunny weather. (4) In Nanjing, Shanghai, Xining and Guangzhou, the average daily clean air volumes in heating months were 39.4, 33.5, 32.2 and 39.8 m3/m2, respectively. (5) When the wall height increased from 1.5 m to 3.5 m, the average daily clean air volume in heating months increased from 31.7 to 43.6 m3/m2.

The experimental and numerical study on a novel all-day PCM thermal-catalytic purified Trombe wall in winter

People pay most of time of evening at home after work. Thus, both the indoor thermal comfort and indoor air quality at nighttime have been obtained more attention. The combination application of PCMs with thermal catalytic purification technology in a Trombe wall that realizes all-day formaldehyde removal and space heating can well solve both issues. Here, an all-day purified Trombe Wall was proposed and designed. The thermal and formaldehyde removal performances were experimentally tested in two continuous days. Then the system heat and mass transfer model were established and experimentally verified. Finally, the optimization works on the type and thickness on PCMs were conducted based on the model. The main results were: (1) The experimental results showed that the thermal efficiency and average formaldehyde removal ratio were 50.8 % and 41.6 %, respectively. The total volume of clean air generated in daytime and nighttime were 249.8 m3 and 241.4 m3, respectively. (2) The RSMD values for the model verification were 5.9–9.6 %, which showed the model had a good prediction on the experimental results. (3) The selection of Butyl palmitate at 44 °C as the PCM and the thickness set to 1 cm could make the system have better energy saving and purification performance.

Enhancing indoor thermal comfort and energy efficiency: A comparative study of RC-PCM Trombe wall performance

In response to the issue of excessive heating during summer in traditional Trombe walls, this study proposes a novel system called RC-PCM Trombe walls, which utilizes radiation cooling and phase change materials (PCMs) to traditional Trombe walls. The thermal performances of RC-PCM Trombe wall, conventional Trombe wall, and PCM Trombe wall were compared and studied under summer conditions. The experimental results demonstrate that the addition of heat pipes and radiant cooling devices to the RC-PCM Trombe wall led to a reduction of peak temperatures on the inner surface of the south wall by 3 °C and 1.2 °C, respectively. Furthermore, the time taken to reach the peak temperature was delayed by 43 min and 38 min, respectively. The standard deviations of indoor air temperature were reduced by 0.04 °C and 0.29 °C, while the indoor heat gain was reduced by 26.5 % and 55.2 %, respectively. These findings indicate that the RC-PCM Trombe wall effectively mitigates indoor overheating and enhances the indoor thermal environment during the summer.

Improving the efficiency of the trombe wall by integrating multi-fold glazing and sustainable materials: Ifrane, Morocco as a case study

The Trombe wall is renowned for its effectiveness in passive heating during winter, but it can lead to overheating in summer. To address this issue, this study investigates a Trombe wall with fully opening glazing during the summer season, employing multi-fold glazing. The research, conducted in Ifrane, Morocco, focuses on a residential building using the Conduction Finite Difference Method within the DesignBuilder software, and examines three configurations: a reference configuration, classic Trombe wall, and Trombe wall with multi-fold glazing. The results demonstrate that the last configuration achieves a 63 % (24,94 kWh/m2) reduction in total energy consumption compared to the reference configuration and a 34 % (7,62 kWh/m2) reduction compared to the classic Trombe wall. Additionally, the implementation of sustainable ecological biomaterials, such as timber instead of concrete, is explored to reduce CO2 emissions. Further analysis of the Trombe wall with multi-fold glazing is conducted by considering five parameters: glazing type, emissivity, vent size, insulation, and PCM thicknesses. These parameters are examined across five different variables. Reducing emissivity leads to reductions of 51 % and 30 % in heating energy consumption and discomfort hours, respectively. Modifying the type of glazing results in an 11 % reduction in heating energy consumption. Increasing insulation thickness leads to notable reductions of 15 % in heating energy consumption and 6 % in discomfort hours. Conversely, increasing PCM thickness and vent size yields had minimal impact on total energy consumption, each resulting in a 1 % reduction. This research provides insights into optimizing Trombe walls by integrating multi-fold glazing to address summer overheating issues and by exploring additional parameters to enhance system performance.

Influence of a Built-in Finned Trombe Wall on the Indoor Thermal Environment in Cold Regions

This study focuses on energy conservation, reducing the amount of energy consumed to heat a room, and decreasing the intensity of carbon emissions. The research object is a room heated by a floor with a built-in finned Trombe wall (TW) located in Lanzhou, Gansu Province. ANSYS software was employed to conduct a simulation study on parameters such as fin height, transverse spacing, longitudinal spacing, arrangement mode, and fin apex angle. The simulation results were used to determine the fin parameters’ thermal impact on the TW’s thermal performance, including with respect to a room’s thermal environment (TE). The results show that the heat transfer performance of a TW with respect to the thermal environment of a room is the greatest when the height of the heat-absorbing surface is 20 mm, the transverse spacing is 0.20 m, the longitudinal spacing is 0.533 m, and in-line 90° top-angle fins, that is, isosceles right triangle fins, are used. The average Nu number of the fin-type TW is 154.75. Compared with the average Nu number of the finless TW, which is 141.43, the average Nu number increases by 13.32 due to the addition of fins. The optimized fin-type TW has 7.77% higher convective heat supply efficiency than the finless TW. Although the PMV-PPD results of the two TW-type rooms are not very different, the comfort period of the fin-type TW room is longer. At the same time, the LPD3 of the non-finned TW and the finned TW rooms is less than 10%, the wind speed at the head and ankle is less than 0.12 m/s, the air gust sensation is not strong, and the thermal comfort is good, indicating that the addition of fins is beneficial to the improvement of indoor thermal comfort. Compared to standard rooms, finless TW rooms and fin-type TW rooms have energy-saving rates of 36.38% and 44.63%, respectively. Thus, fin-type TW rooms’ energy saving rate is 8.25% higher, resulting in effective savings in heating energy consumption. Therefore, the indoor TE and auxiliary heating conditions are improved, and the integration of solar building technology can be facilitated, which offers significant reference value for energy transformation.

Performance of a modified built-middle photovoltaic-thermocatalytic Trombe wall system by fins

The photovoltaic-thermocatalytic Trombe wall is attracting attention due to the ability to generate electricity, heat and purify indoor air, while it has the disadvantages of low electrical and degradation performance. Also the overall performance evaluation method of multi-functional Trombe walls still needs to be further improved. To fill these gaps, a modified built-middle photovoltaic-thermocatalytic Trombe wall by vertical fins was proposed in this study. Based on the first and second laws of thermodynamics, the effects of fins spacing and fins height under different solar radiation intensities on the performance were investigated by numerical simulation method. In addition, the performance of this modified system was compared with other relevant systems. The results reveal that the existence of an optimal fins spacing or fins height can maximize the thermal efficiency. The narrower fins spacing and higher fins can enhance electrical efficiency and degradation rate. Without sacrificing or even improving thermal performance, the presence of fins with suitable structural parameters leads to higher electrical and purification performance. Compared with the system with no fins, when the solar radiation intensity is 400 W/m2 and 800 W/m2 respectively, the thermal efficiency, electrical efficiency, degradation rate, and overall exergy efficiency gain relative enhancements of 1.81 % and 2.71 %, 2.47 % and 5.18 %, 2.27 times and 2.19 times, and 3.53 % and 6.67 %; and the overall exergy efficiency reaches 12.26 % and 12.20 % at the fins spacing of 31.25 mm and fins height of 30 mm. The introduction of exergy concept provides an effective way for overall performance evaluation of multi-functional Trombe walls with different grades of energies (products). The obtained thermal exergy and electrical exergy dominate the overall exergy efficiency, and the diffusion exergy accounts for a negligible proportion due to the relatively low concentration of pollutant. In comparison with other relevant systems, the modified system shows the best comprehensive utilization of solar energy, and has great application potential. This study provides a new direction for the performance improvement and assessment of multi-functional Trombe wall systems.

Research Optimizing Building Ventilation Performance through the Application of Trombe Walls in Regions with Hot Summers and Cold Winters: A Case Study in China

The hot-summer and cold-winter climate zone spans a large latitude, where the passive means of retrofitting the Trombe wall (TW) can be utilized to effectively improve the indoor wind environment and thermal comfort. In this study, a public building in Wenzhou, China, was selected as the object, and CFD numerical simulations and the wind environment data in spring, summer, and fall were collected through field experimental measurements. Comparative analyses were carried out to explore the adaptive strategy and effectiveness of the application of the Trombe wall on the local wind environment and climate and to quantify the improvement effect of the application of the Trombe wall on the Indoor environment. The results showed that the application of the Trombe wall in spring and fall in hot-summer and cold-winter regions could obviously increase the average indoor wind speed and the wind speed at the building outlet by 0.2–0.8 m/s and 0.9–3.6 m/s, respectively. This further effectively prolongs the indoor thermal comfort hours in spring and fall, which is a relatively applicable season, while the ventilation performance in summer is poor compared to spring and fall seasons.

Thermal design of insulation on the outside of the cavity for a Trombe wall with phase change materials

A Trombe wall with a phase change material (TW-PCM) is a practical and low-carbon passive solar heating method. However, the heat efficiency is not high due to the large amount of heat loss at night. Insulation on the outside of the cavity is a suitable solution, but the design method has not been obtained, which hinders the realization of zero energy buildings. In the present study, we analyzed the thermal performance of a TW-PCM with insulation on the outside of the cavity at nighttime to develop the design approach. A mathematical model was established and validated based on experiments. This model was used to analyze the heat efficiency in different outdoor climates for a TW-PCM with insulation on the outside of the cavity. As well, the solar heating fraction (SHF) was analyzed. The results indicated that insulation on the outside of the cavity could significantly improve the thermal performance due to the reduced heat loss during the nighttime. The recommended additional thermal resistance due to the insulation on the outside of the cavity was negatively correlated with the average outdoor air temperature in January based on the analysis of various climates in China. The thermal resistance of the closed air cavity, formed by the TW-PCM and the insulation component, at the same wall emissivity was similar under the recommended additional thermal resistance in different outdoor climates. The SHF was improved significantly for the TW-PCM buildings with insulation on the outside of the cavity and it had a linear relationship with the solar heating load ratio (SLR).

Investigating the impact of Trombe wall parameters on thermal performance and room temperature in the Iraqi climate

AbstractTrombe wall serves as an effective passive heating element, and its performance is heavily reliant on local climate conditions. This study involved both experimental and numerical analyses of a full‐scale test room equipped with a Trombe wall under Iraqi climate conditions. To facilitate this investigation, an experimental test room was constructed in Kirkuk city with dimensions of 4.0 m × 3.0 m × 2.75 m. In addition, a numerical simulation method based on computational fluid dynamics was developed and a computer code was created to investigate the performance of the system. The accuracy of the developed numerical approach was validated against experimental data collected from the test room. This analysis was conducted specifically for the period of February 17–18, which represents the coldest month of winter in the study area. The performance of the system was assessed with respect to various parameters; air gap width variations (2, 4, 6, and 10 cm), massive wall thickness ranging from 15 to 35 cm with 5 cm increments, channel width options (3, 5, 10, 15, and 20 cm), and vent heights ranging from 5 to 20 cm in 5 cm increments. Furthermore, an investigation of the impact of replacing the air in the air gap with inert gases, specifically argon, krypton, and a mixture of these gases with air was conducted, as well. The outcomes indicate that both the channel width and vent height do not have a significant impact on the system's performance. However, the width of the air gap has a modest effect on system performance, and the best performance was observed with a smaller gap width, specifically 2 cm. The most significant impact on room temperature is observed when the storage wall thickness is varied. In the case of wall thickness of 15 cm, there is a notably higher fluctuation in room temperature between the maximum and minimum values, reaching approximately 16°C. For a wall thickness of 35 cm, however, this fluctuation is significantly reduced to about 3°C. The system efficiency as determined after 24 h of operation period improved significantly when the air was replaced by an inert gases or a mixture of gases in the air gap. Compared to air, the increase in efficiency is about 14.8% for argon, 17.7% for krypton, and 20.6% for the mixture of gases.

Enhancing energy efficiency for buildings in hot-desert climate: CFD investigation of Trombe walls using several thermal fins configuration

This study presents a comprehensive computational fluid dynamics (CFD) analysis of Trombe walls in laminar flow conditions, focusing on the impact of thermal fins. The investigation explores configurations with 3 and 5 fins, considering varying fin heights, numbers, and rotation angles. The Nusselt number, friction factor, heat transfer rate, and thermal efficiency are meticulously examined for Reynolds numbers ranging from 600 to 1600. Results reveal that for configurations with three fins, a rotation angle of 70° yields the highest thermal efficiency, showcasing a notable increase from 32.3 % to 44 % across all Reynolds numbers. In contrast, configurations with five fins exhibit enhanced thermal efficiency when fins are maintained horizontally (90°) at low Reynolds numbers but experience a decline as Reynolds numbers increase. Specifically, the thermal efficiency drops from 62.48 % to 55.5 % for Re = 1400 and from 64.7 % to 58 % for Re = 1600. The study concludes that Trombe walls with three fins should be designed with a 70° rotation angle, while those with five fins should feature horizontally oriented fins for optimal thermal performance. These findings offer valuable insights for the design and optimization of Trombe walls, providing guidance for achieving enhanced energy efficiency in passive heating systems.

Performance analysis on a wood-color thermal catalytic Trombe wall in wood buildings

The wood buildings had huge advantages such as high thermal insulation performance and carbon fixation. While the indoor air pollution caused by the release from volatile organic compounds (VOCs) from the artificial boards in wood buildings creates huge threat on human health. Considering architectural aesthetics and solar building-integration principles, this article proposed a novel thermal catalytic Trombe wall with wood-color thermal catalysts that realized heating and air purification. Firstly, the color difference between thermal catalysts and wood board was analyzed. Secondly, the heat and mass transfer model of the wood building with Trombe wall was developed and verified. Thirdly, the thermal and purification performance under different occupancy ratios of Trombe wall to whole wall (RT) and wood species were discussed. The main results were: (1) The color difference between thermal catalysts and wood was 0.97, which was similar and acceptable to meet architectural aesthetics; (2) Compared to ordinary wood building, the indoor temperature increased by 18 ℃ when combined with Trombe wall. The average thermal efficiency, purification efficiency and generated clean air were 26.91 %, 94.34 % and 385.58 m3, respectively. (3) With the increase of RT, the formaldehyde degradation performance and indoor air temperature increased from 73.52 % to 94.34 %, 25 to 38 ℃, respectively. (4) When considering natural running in daytime and forced running in nighttime, more than 90 % of indoor formaldehyde was degraded for five wood boards with different formaldehyde emission rates. The indoor formaldehyde concentration would be below 80 ppb for the release rate of 0.98 and 1.40 mg/L.

A validated multi-physic model for the optimization of an innovative Trombe Wall for winter use

Trombe walls are passive systems integrated into the building envelopes that contribute to limiting heating demands. Usually, to rationally use the absorbed solar radiation, traditional configurations are not equipped with an insulating layer in the massive structure, and this feature could be in contrast with rules that impose the achievement of limited thermal transmittances. Alternative modifications such as the Thermo-Diode Trombe Wall, partially transparent and with appreciable insulation properties, can overcome this issue. This study proposed the validation of a multi-physics model of such an innovative solution through data provided by an experimental set-up properly monitored. A parametric study was then conducted to investigate how important geometrical and physical properties affect the thermal performances of the proposed solution. Results confirm that air temperatures over 35 °C can be achieved in the upper part of the solar space maintaining air velocity below 0.2 m/s and allowing for transferring significant thermal loads to the adjacent room. Simulations identified 24 cm as the optimum solar space thickness, whereas insulation layers over 12 cm do not improve thermal performances significantly but increase the system encumbrance. If the thermal conductivity of the separating wall is doubled, a percentage increase of 24% of the transferred peak heating load was detected reaching a value of 28 W/m2. Results confirm the proposed system as a feasible solution to meet energy-saving purposes and regulation constraints in the building design.

CFD Analysis for a New Trombe Wall Concept

The envelope (façade) of a building is the first barrier between the exterior and the interior of the building and withstands the highest variation in temperature and solar radiation. Trombe walls are used to take advantage of that and contribute to the heating of interior air, helping the heating system. In this study, a new Trombe wall design is presented to contribute significantly to the indoor ventilation of residential buildings. For this, an exterior wall equipped with a proposed Trombe system was studied in a numerical simulation analysis. The proposed systems consist of two important sections, an exterior one and an interior one. The air cavities on the exterior of the wall, covered with silica glass, are the first heat-transfer layer. The secondary layer used for heat transfer, on the interior, is comprised of a MPCLB wall of 115 mm. The air circulation from the exterior to the interior was established as forced convection with a ventilator. The air circulates through the first heating layer on the exterior air cavities and then passes through the second heating layer on the interior MPCLBs. Two cities in Romania were considered to represent the coldest and hottest climates in Romania. Brașov represents the cold climate and Constanța represents the hot climate. In the investigation, both the presence and absence of solar radiation were taken into account. In total, four cases were established. For all four cases, monthly research was made using monthly mean temperatures, and direct and diffuse solar radiation. The results are promising and illustrate that the system works best during the transitional seasons of spring and autumn. The lower the outdoor temperature, the higher the temperature can be increased. Overall, solar radiation accounted for an average 2 °C increase. The temperature increase varied between 3.4 °C and 15.99 °C for Brașov and between 6.42 °C and 12.07 °C in Constanța. This study presents an alternative way to use the Trombe wall for indoor ventilation purposes throughout the year, compared to traditional uses for the Trombe wall for indoor heating.

Towards a net-zero-energy building with smart control of Trombe walls, underground air ducts, and optimal microgrid composed of renewable energy systems

In recent years, permanent outages and lack of access to electricity have been significant problems in most cities of Iran. The increasing growth of fossil fuel consumption made it necessary to change the design of buildings. Designing a net-zero energy building (with natural ventilation and renewable energy systems) is a solution for reducing fossil fuels. In this paper, dynamic energy modeling of the building for the smart operation of the trapezoidal Trombe wall and underground air ducts is performed. In the first step, the Trombe Zones are considered for heating. Then the combination of the Trombe zones with underground air ducts for cooling is simulated. Then the system combination with a solar hot water system to supply hot water energy is evaluated. Finally, the economic analysis of the optimal hybrid system (with a photovoltaic system, wind turbine, battery, and inverter) for supplying the electricity of the building equipped with both passive energy strategies was evaluated by Homer software. The results show that by integrating the Trombe wall, the heating load is reduced by 44 %, and by integrating a coupled geothermal cooling system with the air duct and the Trombe wall, the cooling load is reduced by 39%. Also, the net present cost over the 25-year life of the optimized renewable system is reduced by about 12.5% due to both passive strategies. The average daily electricity energy demand of the base building is equal to 86.37 kWh and for the passive building, it is equal to 67.49 kWh.

Thermal performance and ventilation analysis of a zigzag Trombe wall: Full numerical and experimental investigations

Solar energy building applications are gaining more attention due to their benefits in sustainable development, including energy conservation, cost reduction, and environmental protection. Present work proposed the zigzag Trombe wall, and its performance was investigated by on-site reduced-scale experiments and delicate CFD simulations, on a typical winter day in Wuhan, China. Unlike the traditional Trombe walls, our proposed zigzag Trombe wall has two sections, one of the sections comprises a southeast-facing window that provides both natural light and direct heat gain in the morning when promotion of heating efficiency is most needed; whereas the other consists of a southwest-facing Trombe wall with circulating vents that stores the afternoon sun’s heat for redistribution during the relatively cold night hours. Here, fluid flow, heat distribution, and thermal comfort were introduced as key indices to investigate the performance of the zigzag Trombe wall around the whole typical day, regarding of the effects of the angle α and area ratio γ between two sections. Simulation results of the zigzag Trombe wall were compared with that of the classical Trombe wall, and which showed that this new one could effectively distribute heat throughout the day, especially in the morning period. This paper provides theoretical support and optimization ideas for the design and operation of the novel zigzag Trombe wall through a combination of experimental and numerical simulation methods.

Effects of the position and melting point of the PCM layer on the comprehensive thermal performance of a Trombe wall under mixed dry climate

PCM Trombe walls have been an effective passive technology to achieve energy efficiency. However, the majority of previous research investigated the PCM Trombe walls primarily focused on structural improvement, and very few studies have focused on mixed-dry climate Therefore, in this study, ten scenarios were created and simulated by the validated CFD model under a mixed dry climate. The findings indicate that in summer, an external PCM layer with a melting point of 38 °C could reduce the maximum peak load by 48.9 %, decrease the fluctuation amplitude by 76 %, reduce the cooling load by 14.4 %, compared to the reference case, and yields time lags of 4.5 h and 6.1 h for the maximum and minimum indoor temperatures, respectively. In winter, an external PCM layer with a melting point of 30 °C can reduce the thermal load by 38.2 %, decrease the fluctuation amplitude by 28.5 %, compared to the reference case, and achieve time lags of 4.0 h and 1.7 h for the minimal and maximum indoor temperatures, respectively. Overall, the PCM layer should be placed adjacent to the air channel, and the appropriate PCM melting points in summer and winter are different.

Enhancing thermal efficiency of passive solar heating systems through copper chip integration: experimental investigation and analysis

Abstract This study aims to upgrade the thermal performance of a passive solar system, specifically a Trombe wall (TW), by incorporating a metallic absorbent made of copper chips into its absorbent surfaces. The paper compares the thermal performance of a classic TW with that of a copper chip-enhanced TW. An experimental test was set up for classic and copper chip–TW systems, and a full-day experiment was conducted in January 2018 to investigate the thermal performance under the same operating conditions. The experimental data were used to verify a mathematical model based on energy balance. The theoretical study agreed well with the experimental data, with a maximum error of 11% in the absorbent surface temperature valuation. The results revealed that adding copper chips to the TW system boosts its performance by increasing heat gains and improving thermal efficiency. It improves thermal efficiency and enhances the mean room temperature by 12.44% and 14.1%, respectively.

Passive solar systems enhanced efficiency

This article discusses the efficiency of passive solar systems auxiliary integrated into buildings and focuses on trombe wall. The first paragraph deals with measurement methods applicable for passive systems. Following chapter describes the elimination and correction of result uncertainities. The main part focuses on measurement and evaluation of trombe wall. The real passive solar system is integrated into model family house. The optimisation process and improvements are explained as the main result of this research.

Performance study of an isolated small scale Trombe wall with partially evacuated air gap

The Trombe wall is a passive solar heating system that aims to mitigate heating load. However, its efficiency is impeded by significant heat loss through the glazing. To address this issue, a novel technique has been developed that involves partial evacuation of the space between the storage wall and the glazing. This approach, which has already found successful application in double-paned windows and solar collectors, is examined in this study to evaluate its impact on the performance of an isolated Trombe wall. An effectiveness criterion based on the ability of a system to preserve its stored thermal energy is defined and used for assessing the performance of a vacuumed system relative to a non-vacuumed one. An experimental test cell, composed of a solid concrete wall serving as a thermal storage and a glazing separated from the wall by an air gap, facing south is constructed in Kirkuk, Iraq. The wall is insulated at all its sides except the side facing the glass. The gap has been sealed meticulously to maintain a vacuum. Due to unrepeatability of the testing conditions experimentally, a numerical method and a computer code is also developed for simulation of the system. Measurement results obtained from the test cell under normal atmospheric pressure and a gage pressure of −0.3 bar of the air gap are used to validate the numerical method. The code is then used to simulate the performance of the system under the same ambient conditions but at different vacuum pressures of the air gap. Results obtained from the numerical tests show that partial evacuation of the air gap can be an efficient way to enhance the performance of the Trombe wall and the absolute pressure of 0.1 bar results in the most significant increase in the effectiveness of the studied model.