Numerical study of thermal characteristics of double skin facade system with middle shade

Abstract

Architectural shade is an effective method for improving building energy efficiency. A new shade combined with the double skin façade (DSF) system, called middle shade (MS), was introduced and developed for buildings. In this paper, a 3D dynamic simulation was conducted to analyze the influence of MS combined with DSF on the indoor thermal characteristics. The research on MS for DSF involves the temperature, the ventilation rate, the velocity distribution of the air flow duct, and the indoor temperature. The results show that the angle and position of the shade in the three seasons are different, and different conditions effectively enhance the indoor thermal characteristics. In summer, the appearance of MS in DSF makes the indoor temperature significantly lower. The indoor temperature is obviously lower than that of the air flow duct, and the temperature of the air flow duct is less affected by MS. The influence of the position of blinds on indoor temperature and ventilation rate is greater than the influence of the angle of blinds. According to the climate characteristics of winter and transition season, in winter, early spring, and late autumn, the indoor temperature decreases with the increase of the position of blinds at daytime, but the opposite is true at night. The results found in this paper can provide reference for the design and use of MS combined with DSF in hot summer and cold winter zone.

Keywords

middle shade / position / thermal characteristics / double skin facade

Introduction

Glass, as a transparent material, is applied in buildings as the envelope in modern architectural design. The permeability of glass makes indoor and outdoor visual communication possible, but the energy consumption of heating and refrigeration is increased [¹,²]. Architectural shade is one of the most important research directions of the traditional methods for building energy saving [³–⁵]. The architectural shade is installed to adjust the sun rays entering indoors to reduce solar radiation. The use of shade will be conducive to reducing the indoor temperature and building energy consumption, thus improving the indoor thermal comfort environment [⁶–⁸]. With the development of architectural shade and the use of new materials, many novel shade methods emerge endlessly [⁹–¹¹]. The common ways include external shade, interior shade, and the green shade, etc. Ye et al. [¹²] have proposed that an interior shade is less effective than an external shade when using the same material and the same size. But the performance of the interior shade can be improved by adjusting the solar transmittance, the solar reflection, and the distance between devices and windows. It is of great significance to indoor micro climate to use appropriate shade type for different buildings [¹³].

Architectural shade not only resists the entry of solar radiation, but also improves the indoor lighting environment [¹⁴,¹⁵]. Freewan [¹⁶] has analyzed the influence of sunshade on indoor temperature and illumination intensity in an experiment in combination with simulation, and the indoor temperature and indoor visual environment are improved by setting the shade device. Karlsen et al. [¹⁷]. have adopted a series of sunshade control strategies to analyze the annual indoor performance and energy utilization of the office buildings in the cold region.

Accompanied with the emergence of double skin façade (DSF), and the fact that the poor energy saving effect of interior shade and external shade is difficult to clean, middle shade (MS) arises at the historic moment. MS is recognized by many designers at present because of its good shade effect, dust proof properties, small volume and good regulation. Manz [¹⁸] has found out the relationship between different blind angles and indoor heat quantity by the establishment of a calculation model of DSF. A comparison of the data indicates that the half open shade blinds has a better performance than the closed shade blinds. Gratia and Herde [¹⁹] have studied the influence of different positions and colors of MS on the indoor thermal characteristics. The results show that light color shade is better than dark color shade, and the best position forms is in the middle of DSF, followed by the position at the outside and inside of DSF. Park [²⁰,²¹] has conducted a forecast analysis of the characteristics of heat transfer ventilation when DSF is at different blind angles, ventilation types to realize the automatic control and regulation of DSF. Xu and Yang [²²] have adopted the method of computational fluid dynamics (CFD) for ventilation and heat transfer simulation through calculation of shade blind devices of DSF, other surface heat flux, and the distribution of radiation. Saelens et al. [²³] have used a ray tracing method for shade device to study the solar transmittance and conducted a dynamic numerical simulation of the simplified model.

The shade performance has been evaluated by complex calculation. MS not only resists the external heat flux, but also changes the air distribution and the speed in DSF, thereby changing the indoor environment. Gavan et al. [²⁴] have analyzed the change of the airflow and the setting angle of the shade device in a DSF experiment. The angle of shade device primarily affects the temperature of the surface and the air, thereby, influencing the airflow in DSF. Lee et al. [²⁵] have considered the influence of different shade angles on air velocity and air flow pattern, and made comparison and analysis of the two aspects. The comparison of the annual energy consumption shows that the shade whose angle is respectively 30, 60, 90 degrees are more effective than the shade whose angle is 0 degree. MS plays a crucial role in the indoor environment of DSF buildings. Therefore, it is of great importance to make a good use of the MS technology to create a better indoor environment and reduce building energy consumption in a greater degree [²⁶].

In recent years, a lot of research has been conducted on architectural shade. However, studies, especially computer software simulation, on DSF with MS are relatively few and far between. To provide reference for future construction designers in the design and evaluate of architectural shade, this paper analyzes the influence of angle and position of MS for DSF on the indoor thermal characteristics by adopting dynamic numerical simulation. It also analyzed the effect of different MS parameters such as temperature, ventilation rate, and velocity field. It provides important theoretical basis for the application of DSF.

Model description

Physical model

The physical model of an office in the Energy Saving Experiment Center in Tianjin in the People’s Republic of China is studied. The model room with DSF is sealed and without air-condition, and the blinds is set in airflow duct to form a system of MS, as shown in Fig. 1. The external curtain wall (ECW) and the internal curtain wall (ICW) of the DSF respectively have the air entrance (AEN), the air exit(AEX), and the inward opening window (IOW). The basic geometry size of the physical model is represented in Table 1.

Simulation method

For the DSF, a numerical simulation is conducted to analyze the impact of MS on indoor thermal characteristics by a practical model of control equations in different seasons. The airflow and heat transfer of the DSF can be strictly observed by the physical essence of mass conservation, momentum conservation and energy conservation, as shown in Eqs.(1-3), respectively.

(1){\displaystyle \frac{\mathrm{\partial }\rho }{\mathrm{\partial }t}}+{\displaystyle \frac{\mathrm{\partial }(\rho u)}{\mathrm{\partial }x}}+{\displaystyle \frac{\mathrm{\partial }(\rho v)}{\mathrm{\partial }y}}+{\displaystyle \frac{\mathrm{\partial }(\rho w)}{\mathrm{\partial }z}}=\mathrm{0},

(2a){\displaystyle \frac{\mathrm{\partial }(\rho u)}{\mathrm{\partial }t}}+\mathrm{d}\mathrm{i}\mathrm{v}(\rho uU)=-{\displaystyle \frac{\mathrm{\partial }p}{\mathrm{\partial }x}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{xx}}{\mathrm{\partial }x}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{yx}}{\mathrm{\partial }y}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{zx}}{\mathrm{\partial }z}}+{{\displaystyle F}}_x,

(2b){\displaystyle \frac{\mathrm{\partial }(\rho v)}{\mathrm{\partial }t}}+\mathrm{d}\mathrm{i}\mathrm{v}(\rho vU)=-{\displaystyle \frac{\mathrm{\partial }p}{\mathrm{\partial }y}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{xy}}{\mathrm{\partial }x}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{yy}}{\mathrm{\partial }y}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{zy}}{\mathrm{\partial }z}}+{{\displaystyle F}}_y,

(2c){\displaystyle \frac{\mathrm{\partial }(\rho w)}{\mathrm{\partial }t}}+\mathrm{d}\mathrm{i}\mathrm{v}(\rho wU)=-{\displaystyle \frac{\mathrm{\partial }p}{\partial z}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{zx}}{\mathrm{\partial }x}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{zy}}{\mathrm{\partial }y}}+{\displaystyle \frac{\mathrm{\partial }{{\displaystyle \tau }}_{zz}}{\mathrm{\partial }z}}+{{\displaystyle F}}_{zx},

(3){\displaystyle \frac{\mathrm{\partial }(\rho h)}{\mathrm{\partial }t}}+{\displaystyle \frac{\mathrm{\partial }(\rho uh)}{\mathrm{\partial }x}}+{\displaystyle \frac{\mathrm{\partial }(\rho vh)}{\mathrm{\partial }y}}+{\displaystyle \frac{\mathrm{\partial }(\rho wh)}{\mathrm{\partial }z}}=-p\mathrm{d}\mathrm{i}\mathrm{v}U+\mathrm{d}\mathrm{i}\mathrm{v}(\lambda \mathrm{g}ra\mathrm{d}T)+\Phi +{{\displaystyle S}}_{\mathrm{h}},

where \rho is density (kg/m³); u, v, and w is respectively the velocity component in the x, y, z direction; \tau is viscous stress; U is velocity vector; F is momentum source (kg/(m²·s²)); p is pressure;\lambda is thermal conductivity (W/(m·K)); T is temperature (K);\Phi is Rayleigh dissipation function (kg/(s³·m)); and S_h is volumetric heat source.

Boundary conditions

During a daily cycle, the outdoor design temperature of a typical local day is selected as the outdoor calculated temperature, and the hourly outdoor temperature is recorded by using meteorological data instruments. The basic parameters of the main instruments are listed in Table 2. The recorded hourly outdoor temperature data is expressed by a form of sine (or cosine) function term series in Eq. (4). Figure 2 illustrates the difference in temperatures measured by using instruments and calculated by using formula. As is shown in Fig. 2, the outdoor temperature fluctuation measured and calculated are basically consistent. Therefore, the data obtained from Eq.(4) can be used as the outdoor temperature in CFD simulation.

(4){{\displaystyle t}}_{\mathrm{w},t}={{\displaystyle t}}_{\mathrm{w},p}+({{\displaystyle t}}_{\mathrm{w},\mathrm{m}\mathrm{a}\mathrm{x}}-{{\displaystyle t}}_{\mathrm{w},\mathrm{p}})\cos (\mathrm{15}\tau -\mathrm{225}),

where {{\displaystyle t}}_{\mathrm{w},t} is hourly outdoor temperature (K); {{\displaystyle t}}_{\mathrm{w},\mathrm{p}} is average outdoor calculation temperature (K); \tau is time (s); and t_{\mathrm{w},\max } is maximum outdoor temperature (K).

In addition, the boundary conditions of the DSF are set to convective heat, and other walls and roof are considered to be insulation. Meanwhile, the DSF is affected by solar radiation, including diffuse radiation and direct radiation, as illustrated in Fig. 3. The parameters of structural components of the DSF building are tabulated in Table 3, and the overlapping of blinds is 0.2.

Results and discussion

In this paper, with or without blinds, the sun shade angle of blinds and the relative position are investigated separately by using dynamics simulation. The angle of the blinds is set to 0°(also equivalent to 180°), 30°, 45°, 60°, and 90°, which is depicted in Fig. 4 (a) while the relative position is respectively L=0.1 m, 0.2 m, 0.4 m (distance from ECW), as is shown in Fig. 4 (b).

Model validation

The simulation model is validated with the experimental measurements of indoor temperature for the model case shown in Fig. 5. The comparison of the measured and simulated results at L=0.1 m and an angle of 90° is show in Fig. 6. It is observed that both the measured and the simulated indoor temperature are similar in the ascent stage, while the measured result decreases slightly slower than that of the numerical simulation in the decline stage, but with a difference of only about 0.2°C. As can be seen, physically, the numerical simulation model is reliable and can be used to study the parameters of the model.

Temperature distribution

Temperature distribution in summer

In summer, the influence of relative position and angle of blinds on the indoor thermal characteristics in the DSF is mainly studied. After the convergence of iterative calculation, the average temperature of the airflow duct and the room are recorded.

The outdoor temperature and solar radiation of the day of summer solstice which is a typical meteorological day is selected as the outdoor condition to analyze the influence of the angle of blinds on the indoor temperature in the dynamic simulation. MS is set at a fixed position. The temperature of five operating conditions at a blind angle of 0 degree, 30 degrees, 45 degrees, 60 degrees, and 90 degrees are studied. At the same time, the AEN and the AEX always remain open. Figures 7 and 8 are the comparisons of temperature of the airflow duct and the room at different blind angles. It can be seen that in the case of three kinds of relative position of the MS, the temperature of the airflow duct basically remains the same with the change of blind angles, in addition to night (at 23:00–5:00 next day). In contrast, the indoor temperatures are different at different blind angles, and the indoor temperature with blinds is obviously higher than that without blinds. Meanwhile, the maximum temperature difference is more than 2.67°C. Moreover, at a blind angle of 90^o, the indoor temperatures are lower than those at other angles.

The same method is used to analyze the influence of relative position on the indoor thermal characteristics as illustrated in Figs. 9 and 10. As can be seen from Figs. 9 and 10, the temperature in the air flow duct is not affected in at different blind positions during the day, and the room temperature rises with increasing distance from the DSF. Moreover, the maximum temperature difference is 1°C at night. The temperature of the room without blinds is significantly higher than that of the room with blinds, with a maximum temperature difference of more than 2°C.

The maximum temperatures (K) in different design conditions are listed in Tables 4 and 5. As can be seen from Table 4, there is little difference between the temperatures of the air flow duct, with a maximum difference of 0.28°C. In contrast, there is a great difference in indoor temperature in different conditions, and the indoor temperature is the lowest at L=0.4m and a blind position of 90°.

Temperature distribution in winter

In winter, the blinds set in the air flow duct block the sun radiation exposure to the indoor, which is not conducive to the improvement of indoor temperature. Therefore, the shade blinds should be retracted. In this section, the above theory is verified by CFD simulation, and the negative effect of MS on the indoor thermal characteristics is studied. Unlike the summer condition, the AEN and AEX should always be closed, because a greenhouse formed by a closed air flow duct can make the heat transfer to the indoor, thereby reducing building energy consumption.

Three conditions, that is, the blind positions at L=0.1 m, L=0.4 m (distance from ECW), and no blinds are compared, as shown in Fig. 11. It is found that at daytime, the temperatures of the air flow duct and the room without blinds are higher than those of other conditions, with a great difference. At night (21 am to 9 am the next day), the temperatures of the air flow duct and the room without blinds are below those of other conditions. Therefore, the temperature of the air flow duct and that of the room with or without blinds is the same. Table 6 is a comparison of the indoor temperature in different operating conditions. There is a maximum temperature difference of 6.56°C and a minimum temperature difference of 2.67°C between the room with and without blinds. Therefore, blinds have hardly any influence on the winter indoor thermal characteristics, and the impact of blind position is even less. In winter, it appears not suitable to set blinds in the air flow duct during the day, but during the night, setting up the MS is helpful to improve the indoor temperature.

Temperature distribution in early spring and late autumn

The transition season is a special season without air-conditioning. In the case of the cold early spring and late autumn, and the hot late spring and early autumn, people have the minimum fresh air requirement, so it has a strict requirement on the indoor thermal characteristics in transition season. Therefore, it is of great use to study the influence of MS on the indoor thermal characteristics.

Due to the similar climate conditions in winter, early spring and late autumn, in order to reduce the building energy consumption, the indoor temperature needs to be improved by improving the working conditions of DSF. Since the working condition is the same in winter, AEX and AEN should stay closed to prevent the intrusion of cold air into the room.

Figure 12 is a comparison of the indoor temperature and the temperature of the air flow duct for different blind positions at the end of the heating season and the beginning of spring. At daytime, the temperature of the air flow duct in no blind condition is higher than that with the MS, but the temperature difference is not as obvious as that in winter. From 10 pm to 6 am of the next day, the temperature of the air flow duct without MS is slightly lower than that with MS. In addition, the change of the MS position does not exert a great influence on the temperature of the air flow duct. At daytime, the indoor temperature without MS is significantly higher than that with MS. Besides, the maximum indoor temperature without blinds is 296.92 K, and the indoor temperature at L=0.1 m and L=0.4 m is respectively up to 288.41 K and 287.61 K. From 10 pm to 9 am of the next day, the indoor temperature remains steady with or without blinds at night, with a temperature difference of about 0.8 K. At the beginning of the transition season, people need more solar radiation indoor, therefore, shade devices should not be added.

Compared with the climate of the early spring and late autumn, the outdoor temperature and solar radiation of late spring or early autumn is relatively high, which is similar to the condition in summer. In order to ensure the quality of indoor air and prevent the local overheating in DSF, the AEX and AEN should be open, and the MS should also be set.

Velocity field

The settings of MS have a certain influence on the air flow in the DSF. Based on the DSF, the air flow in the air flow duct is simulated to observe the effects of MS. Figure 13 shows the velocity vector diagram of the air flow duct at 12 o’clock at different blind positions. It can be seen from Fig.13 that at L= 0.1 m, obvious vortexes can be produced when the blind angle is respectively 0°, 30°, 45°, 60° and 90^o. But in the working condition of 90°, because the closed blinds blocks the air from flowing back, the vortex is not obvious. At L=0.2 m, the vortex almost disappears. But there exists a small reflux all over the entrance, especially near the outside wall at 90°. At L=0.4 m, the reflow is more obvious above the entrance, and the returned air gradually increases with the increase of blind angles, which produces a small vortex when the blind angle is 90°. Taking into consideration each working condition of air distribution, it can be concluded that the change of blind angle basically has no effect on the vortex. But the position of the sunshade has a great influence on the vortex. Therefore, to avoid vortex, the design of the position of blinds should be considered.

To better demonstrate the air condition in air flow duct in a day, a blind angle of 60° at L = 0.1 m (distance from ECW) with a relatively obvious vortex is selected. The hourly velocity vector diagram is intercepted at 5 am and 6 pm respectively, as shown in Fig. 14. It can be seen from Fig. 14 that in the absence of solar radiation, the air in the air flow duct flows from top to bottom. With the increase of solar radiation, the air in the air flow duct flows faster from bottom to top. The velocity reaches the maximum value at 2 or 3 pm basically. Before 8 am in the morning, the vortex near the AEX is not obvious. After 8 am, with the enhancement of solar radiation, the air flow increases and the vortex intensifies.

Ventilation rate

In summer, the ventilation rate of the air flow duct shows much volatility with the cycles of the outdoor air temperature and solar radiation. Figure 15 shows the ventilation rate of the air flow duct at different blind angles. Regardless of the location of the blinds, the ventilation rate increases with the increase of the blind angle, and the ventilation rate is lower than that with no blinds. It can be seen from Fig. 16 that the ventilation rate decreases with the blinds position L (distance from ECW) increasing, but when the blind angle is 90°, the blind position has no effect on the ventilation rate. Table 7 displays the maximum air volume in different working conditions. It can be seen from Table 7 that the ventilation rate (kg/s) at an angle of 90° and L=0.1 m is the largest, and that at an angle of 0° and L=0.4 m is the smallest.

Conclusions

MS is a kind of sunshade installed in the air flow duct in DSF. It combines the advantages of both external and internal shade, and protects the glass of the window from being influenced by outside factors. Based on the indoor thermal characteristics evaluation system, the design of the MS is optimized and an experimental test is conducted to validate the design. The ventilation and heat transfer problems of the MS in the DSF in summer, winter and transition seasons are studied.

The influence of MS on the temperature field of the air flow duct and indoor room, velocity field and ventilation rate is compared and analyzed. In summer, the temperature of the air flow duct, the indoor temperature, and the ventilation rate vary with the cyclical changes of the outdoor temperature and solar radiation. The temperature of the air flow duct is basically not affected by MS factors, and the influence of blinds position on the indoor temperature and the ventilation rate is greater than that of blinds angle.

According to the climate conditions of winter and transition seasons, no matter it is in winter or in the transition season, the position of blinds becomes closer to ICW and the temperature increases. The temperature of the air flow duct without blinds is higher than that with blinds, and the opposite is true at night. The indoor temperature without blinds is also higher than that with blinds at daytime. Moreover, there are certain delays in the rise and fall of the indoor temperature and the temperature of the air flow duct. In late spring, it is suitable to open MS which is conducive to improving the comfort of the indoor working environment. This paper can provide reference in the analysis of design and use of DSF with MS for hot summer and cold winter areas.

References

[1] Poirazis H. ÅkeBlomsterberg, Wall M. Energy simulations for glazed office buildings in Sweden. Energy & Buildings,  2008,  40(7):1161–1170

[2] Zhang S M, Da-Lei M A, Ran C Y, BaiL. The influence analysis of the building outside window on the building energy-saving. Journal of Jilin Institute of Architectural & Civil Engineering, 2008, 25(4):49–52

[3] Wang Z Y. Research on energy saving for the case analysis of building energy conservation in Xichang city. Advanced Materials Research, 2014, 886: 478–483

[4] Wan L Q, Peng X Y. Comparison of evaluation methods for energy saving effect of building sunshade outside the window. Building Energy & Environment, 2013, 32(2):46–48

[5] Xiao Y Q, Ren T. The layout and form design research on BIPV external sun-shading skin in hot-humid areas. Advanced Materials Research, 2011, 374–377: 220–229

[6] Kim M, Leigh S B, Kim T, Cho S. A study on external shading devices for reducing cooling loads and improving daylighting in office buildings. Journal of Asian Architecture and Building Engineering, 2015, 14(3): 687–694

[7] Zheng Q R, Ding Y F, Teng-Fei W U. Analysis of the energy saving potential of horizontal external shading in Guangzhou buildings. Journal of Guangzhou University, 2008, 7(6):69–72

[8] Cui Y Q, Sun N, Peng Y L, Wang Y. Simulation analysis on sun-shading design case of buildings in cold regions. Applied Mechanics & Materials, 2014, 638–640: 1656–1659

[9] Zeng X D, Huang F A. A study of the optimization of building external shading methods in Chongqing area. Advanced Materials Research, 2011, 368–373: 3753–3756

[10] Sun L P. The sun-shading technologies of the existing traditional dwellings in China. Advanced Materials Research, 2013, 689: 163–166

[11] He Y D, Li N P, Liu W B, Zheng D X. Building sun-shading in Changsha area. Building Energy Efficiency, 2014, 42(3):60–62

[12] Ye Y, Xu P, Mao J, Ji Y. Experimental study on the effectiveness of internal shading devices. Energy and Building, 2016, 111: 154–163

[13] Kirimtat A, Koyunbaba B K, Chatzikonstantinou I, Sariyildiz S. Review of simulation modeling for shading devices in buildings. Renewable & Sustainable Energy Reviews, 2016, 53: 23–49

[14] Nielsen M V, Svendsen S, Jensen L B. Quantifying the potential of automated dynamic solar shading in office buildings through integrated simulations of energy and daylight. Solar Energy, 2011, 85(5): 757–768

[15] David M, Donn M, Garde F, Lenoir A. Assessment of the thermal and visual efficiency of solar shades. Building and Environment, 2011, 46(7): 1489–1496

[16] Freewan A A Y. Impact of external shading devices on thermal and daylighting performance of offices in hot climate regions. Solar Energy, 2014, 102(4): 14–30

[17] Karlsen L, Heiselberg P, Bryn I, Johra HSolar shading control strategy for office buildings in cold climate. Energy and Buildings, 2016, 118:316–328

[18] Manz H. Total solar energy transmittance of glass double facades with free convection. Energy and Building, 2004, 36(2): 127–136

[19] Gratia E, De Herde A. The most efficient position of shading devices in a double-skin facade. Energy and Building, 2007, 39(3): 364–373

[20] Park C S, Augenbroe G, Messadi T, Thitisawat M, Sadegh N. Calibration of a lumped simulation model for double-skin façade systems. Energy and Buildings, 2004, 36(11):1117–1130

[21] Park C S, Augenbroe G, Sadegh N, Thitisawat M, Messadi T. Real-time optimization of a double-skin façade based on lumped modeling and occupant preference. Building and Environment, 2004, 39(8): 939–948

[22] Xu X L, Yang Z. Natural ventilation in the double skin façade with venetian blind. Energy and Building, 2008, 40(8): 1498–1504

[23] Saelens D, Parys W, Roofthooft J, de la Torre A T. Reprint of “Assessment of approaches for modeling louver shading devices in building energy simulation programs”. Energy & Buildings, 2014, 68(Part C): 799–810

[24] Gavan V, Woloszyn M, Kuznik F, Roux J J. Experimental study of a mechanically ventilated double-skin facade with Venetian sun-shading device: a full-scale investigation in controlled environment. Solar Energy, 2010, 84(2): 183–195

[25] Lee J, Alshayeb M, Chang J D. A study of shading device configuration on the natural ventilation efficiency and energy performance of a double skin façade. Procedia Engineering, 2015, 118: 310–317

[26] Kong X, Liu S, Yang H, Zhong Y, Qi C. An experimental study of all-season operation strategy for a respiration-type double-layer glass curtain wall system in cold zone of China. Building & Environment, 2015, 97:166–176

RIGHTS & PERMISSIONS

Higher Education Press