Simulating thermochromic and heat mirror glazing systems in hot and cold climates

This paper investigates the potential energy requirements for heating and cooling when using a thermochromic glazing system on a highly glazed tall office building and comparisons are made with the respective performance of two heat mirror units and a clear triple glazed window. The assessment is done with the ESP-r whole building integrated simulation program in order to account for the dynamic optical properties of thermochromic glass in integrated simulations. The glazing systems are assessed for hot, cold and significantly varying between hot and cold climates. Annual heating and cooling energy requirements were quantified and short-period simulations were also run to assess the effect of the glazing systems on indoor temperatures. It was found that thermochromic glazing could significantly reduce cooling loads in hot climates and where cooling could be a significant building energy load (by approximately 30% in comparison with the other glazing systems). On the other hand, thermochromic glass could have a negative impact in cold climates where the use of heat mirror glazing systems could offer the highest energy savings even when compared with the triple glazed window. In seasonally varying climates and for highly glazed office buildings in which simultaneous high internal and solar heat gains are likely to occur, the use of thermochromic glass is an appropriate technique for saving energy and improving thermal comfort

The effect of smart coatings on the radiation passing through glazing / Masoud Kamalisarvestani

Windows provide us with natural light and fine-looking connections to the outdoors. However, a huge amount of energy is lost through these building envelopes. This study reviews the most common and contemporary coatings of the glass surface with thin films. Through this review the various types of intelligent coatings are compared in terms of their performance in saving air-conditioning and electrical lighting energy. Having completed the review, it is determined that electrochromic and thermochromic windows consume less than around 40 kWh/m2 for electric lighting energy and around 10 kWh/m2 for cooling energy.Therefore,these two types feature better performance compared to other smart windows.The thermochromic effect of vanadium dioxide (VO2) thin films has inspired many research teams to apply this type of smart thin films as a promising coating for windows leading to drastic reductions in lighting and ventilation energy. In this study vanadium dioxide thin films have been deposited on clear glass by RF magnetron sputtering. Different film thicknesses (20 nm, 50 nm, 80 nm and 120 nm) were deposited by altering the sputtering duration. The films were characterized for their crystal structure and surface morphology by means of X-Ray Diffractometer (XRD) and Field Emission Scanning Electron Microscope (FESEM). The reflectance and transmittance of samples were measured before and after transition temperature using a UV-Vis-NIR spectrophotometer. Finally, the thermochromic behavior of the samples is compared.The 50 nm sample exhibited better reflective behavior at room temperature, greater reflectance difference (-5.6 %) in the visible range and highest thermochromic efficiency (ɳ (2200 nm) = 54.3%). By the same token, the 80 nm sample performed the best in increasing the reflectance (6.7 %) in near-IR range. However, the thickness should be selected according to the glazing requirements and the priority of visible or near-IR optical properties

تأثیر فعالیت هوازي در آب و خشکی برروی بتا اندورفين پلاسما و آستانه ادراك درد ورزشكاران

چکیده   مقدمه: فعالیت ورزشی با تغییر در میزان مصرف انرژی باعث کنش دستگاه های مختلف بدن از جمله سیستم عصبی- هورمونی و غدد درون ریز می شود. هدف از مطالعه حاضر بررسی تاثیر فعالیت هوازی در آب و خشکی بروی میزان بتااندورفین و آستانه درد ورزشکاران می باشد. مواد و روش ها: ۱۷دختر والیبالیست (با حداقل سه سال سابقه فعالیت مداوم و میانگین سنی 1۲/4±52/۲۷ سال، وزن 29/5±44/۶۱ کیلوگرم و قد 86/4±59/۱70 سانتی متر)، بصورت داوطلبانه در این تحقیق شرکت کردند. آستانه درد و نمونه­گیری خونی از سیاهرگ بازویی قبل، بلافاصله و ۳۰ دقیقه پس از فعالیت هوازی طی دو جلسه در محیط آب و خشکی، اندازه گیری شد. تجزیه و تحلیل آماری داده ها با استفاده از روش آماری اندازه گیری های مکرر(Repeated measurement)، و برای تعیین جفت مقایسه ها از آزمون تعقیبی LSD استفاده شد. همچنین جهت مقایسه سطح بتا اندورفین و آستانه درد در دو محیط آب و خشکی برای مراحل بلافاصله پس از آزمون و پیگیری، پس از محاسبه نمرات افزوده، از آزمون تی همبسته (paired t test)  استفاده شد. یافته ها: طبق نتایج بدست آمده بین میزان بتا اندورفین و آستانه ادراک درد، قبل و بعد از فعالیت ورزشی تفاوت معنی دار وجود داشت، بطوری که فعالیت هوازی منجر به افزایش معنادار بتا اندورفین و نیز آستانه ادراک درد در هر دو محیط شد (۰۰۰۱/۰>P)،(۰۰۱/۰>P). میزان بتا اندورفین خون دختران ورزشکار پس از فعالیت هوازی در آب، در مقایسه با خشکی به‌ طور معناداری کمتر بود. این تفاوت به طورمعناداری 30 دقیقه پس از فعالیت نیز مشاهده شد (۰۱/۰>P). علاوه براین، بین آستانه ادراک درد در شرایط پس از فعالیت هوازی درآب، با شرایط مشابه در خشکی تفاوت معناداری وجود نداشت(۳٤/۰P=). در مرحله 30 دقیقه پس از فعالیت نیز در مقایسه تمرین هوازی در موقعیت‌های مختلف نیز تفاوت معناداری در آستانه ادراک درد مشاهده نشد (56/0P=). نتیجه گیری: فعالیت هوازی در هر دو محیط آب و خشکی منجر به افزایش بتااندورفین و آستانه درد می شود. بنظر می رسد، تغییرات در آستانه درد ناشی از فعالیت هوازی، مستقل از محیط فعالیت است، اما در مورد تغییرات بتا اندورفین ناشی از تمرین، اثرات محیط معنادار است. کلید واژه ها: بتا اندورفین، آستانه ادراک درد، فعالیت هوازی، خشکی و آب، ورزشکارا

Thin film coated windows towards low/zero carbon buildings: Adaptive control of solar, thermal, and optical parameters

Thin film coated windows are considered as the future of fenestration market owing to their characteristic features such as solar radiation and visible light control, UV and IR rejection and promising U-value range. Within the scope of this experimental research, various thin film technologies developed for glazed areas in buildings are comprehensively analysed as a potential retrofit solution to conventional windows. 12 commercial thin film coating products are laminated between clear glass sheets with very high visible light transmittance, and they are subjected to outdoor tests covering different sky conditions. UVA/UVC blockage, visible light and solar radiation control is evaluated for a wide range of thin film coating technologies from ceramic to metallic films as well as EVA and PVB-IR. The results indicate that ceramic and metallic thin film coatings are in general successful at visible light control. 93% of incoming visible light is found to be blocked by I118. EVA welcomes about 49% of incoming solar radiation whereas it is 31% for I178. Thin film coatings are capable of rejecting almost 100% of incoming UV light. It is also achieved from the research that UVC light figures are noticeable and this justifies the ozone layer depletion which needs to be noted