Effect of kinetic façades on energy efficiency in office buildings - hot dry climates

In hot dry climates excess solar gain may result in high cooling energy consumption and indoor discomfort; sun control and shading devices is an important aspect of many energy-efficient building design strategies. Advanced CAD systems that integrate computational tools, such as parametric design systems, make possible and explore ways to formulate a responsive building envelope that could interact with sun position. The parametric design provides innovative building envelopes, which are more adaptive and interactive by actively responding to prevailing weather conditions, for enhancing energy performance and indoor thermal comfort levels. This study attempts to examine and evaluate the effect and performance of smart façades in the context of the indoor thermal comfort and energy efficiency. These parameters are achieved by controlling the levels of solar radiation and by calculating shading element sizes for sun control in response to environmental changes. In order to ensure the systems autonomy the semi-transparent PV modules has been used as panel's material. The method is applied to the case study of a reference office building with a fixed glazed façade windows-to-wall ratio in hot arid climate zone of Algeria, in particular the city of Biskra (latitude 34.6N). The results obtained from modeling simulation, using GECO- grasshopper (parametric plugin for Rhinoceros), shown That kinetic facades equipped with PV modules have greatly influenced in a positive way the indoor air temperature, thermal and visual comfort levels and also, work towards a better environment for the inhabitants instead of simply being the part that separates the interior from the exterior

Effet des façades cinétiques sur l'efficacité énergétique dans les immeubles de bureaux - Climat chaud et aride

International audienceIn hot dry climates excess solar gain may result in high cooling energy consumption and indoor discomfort; sun control and shading devices is an important aspect of many energy-efficient building design strategies. Advanced CAD systems that integrate computational tools, such as parametric design systems, make possible and explore ways to formulate a responsive building envelope that could interact with sun position. The parametric design provides innovative building envelopes, which are more adaptive and interactive by actively responding to prevailing weather conditions, for enhancing energy performance and indoor thermal comfort levels. This study attempts to examine and evaluate the effect and performance of smart façades in the context of the indoor thermal comfort and energy efficiency. These parameters are achieved by controlling the levels of solar radiation and by calculating shading element sizes for sun control in response to environmental changes. In order to ensure the systems autonomy the semi-transparent PV modules has been used as panel's material. The method is applied to the case study of a reference office building with a fixed glazed façade windows-to-wall ratio in hot arid climate zone of Algeria, in particular the city of Biskra (latitude 34.6N). The results obtained from modeling simulation, using GECO-grasshopper (parametric plug-in for Rhinoceros), shown That kinetic facades equipped with PV modules have greatly influenced in a positive way the indoor air temperature, thermal and visual comfort levels and also, work towards a better environment for the inhabitants instead of simply being the part that separates the interior from the exterior

Effect of kinetic facades on energy efficiency in office buildings - hot dry climates

In hot dry climates excess solar gain may result in high cooling energy consumption and indoor discomfort; sun control and shading devices is an important aspect of many energy-efficient building design strategies. Advanced CAD systems that integrate computational tools, such as parametric design systems, make possible and explore ways to formulate a responsive building envelope that could interact with sun position. The parametric design provides innovative building envelopes, which are more adaptive and interactive by actively responding to prevailing weather conditions, for enhancing energy performance and indoor thermal comfort levels. This study attempts to examine and evaluate the effect and performance of smart façades in the context of the indoor thermal comfort and energy efficiency. These parameters are achieved by controlling the levels of solar radiation and by calculating shading element sizes for sun control in response to environmental changes. In order to ensure the systems autonomy the semi-transparent PV modules has been used as panel's material. The method is applied to the case study of a reference office building with a fixed glazed façade windows-to-wall ratio in hot arid climate zone of Algeria, in particular the city of Biskra (latitude 34.6N). The results obtained from modeling simulation, using GECO- grasshopper (parametric plugin for Rhinoceros), shown That kinetic facades equipped with PV modules have greatly influenced in a positive way the indoor air temperature, thermal and visual comfort levels and also, work towards a better environment for the inhabitants instead of simply being the part that separates the interior from the exterior

Risk factors and consequences of delayed graft function

The impact of delayed graft function (DGF) on the outcome of renal transplantation remains controversial. We analyzed the risk factors for DGF and its impact on graft and patient survival. A total of 354 renal transplants performed between June 1986 and April 2000 were analyzed. Variables analyzed included donor and recipient age, method and duration of renal replacement therapy, HLA mismatch, cold and warm ischemia times, biopsy-confirmed acute rejection, length of stay in the hospital, serum creatinine at the end of first hospitalization as well as graft and patient survival at one, three, five and ten years. The study patients were divided into two groups: patients with DGF (G1) and those without DGF (G2). DGF occurred in 50 patients (14.1%), and it was seen more frequently in patients transplanted from deceased donors (60% vs. 40%, P <0.0001). The cause of DGF was acute tubular necrosis, seen in 98% of the cases. Univariate analysis showed a statistically significant difference between the two groups G1 and G2 in the following parameters: average duration on dialysis (52.3 vs. 36.4 months, P = 0.006), HLA mismatch (44.9% vs. 32.11% P = 0.015), donor age (35.9 vs. 40.2 years, P = 0.026), cold ischemia time (23 vs. 18.2 h, P = 0.0016), warm ischemia time (41.9 vs. 38.6 mn, P = 0.046), length of stay in the hospital during first hospitalization (54.7 vs. 33.2 days, P <0.0001), serum creatinine at the end of first hospitalization (140 vs. 112 μmol/L, P <0.0001) and at three months following transplantation (159 vs. 119 μmol/L, P = 0.0002). Multivariate analysis revealed the following independent risk factors for DGF: deceased donor (RR = 13.2, P <0.0001) and cold ischemia time (RR = 1.17, P = 0.008). The graft survival at one, three, five and ten years was 100%, 93%, 88.3% and 78.3% in G1 versus 100%, 95.9% 92.8% and 82.3% in G2; there was no statistically significant difference. The patient survival at one, three, five and ten years was 100%, 91.3%, 83.6% and 74.4% in G1 versus 100%, 95.9%, 94% and 82.6% in G2 with a statistically significant difference (P = 0.04). Prolonged cold ischemia time and transplantation of kidneys from deceased donors were the main risk factors for DGF in our study. Also, DGF significantly affected patient survival but had no influence on graft survival