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This work illustrates the results achieved by ongoing collaboration between the Uffizi Gallery and the University of Florence. This collaboration has focused on the New Uffizi Project and sought to evaluate the energy consumption of the HVAC systems of the Vasari Corridor by applying the typical tools and methods for the Building Energy Model (BEM) of existing buildings. In order to perform a dynamic simulation of the energy behavior and thermal comfort of the Corridor, the Building Energy Model was validated by comparing the hourly measured and simulated indoor temperature values and through the varying of natural ventilation and solar shading. Due to its building characteristics the control of the indoor thermo-hygrometric parameters is a critical issue. These aspects expose the Corridor to climatic variations which necessitate major energy consumption. In estimating energy consumption, three different scenarios of the use of the Corridor itself were referenced: one of which was its return to the original Medici use as a connection between Palazzo Pitti and Palazzo Vecchio through the Uffizi Galleries;the other two were the possible uses for temporary exhibitions of artwork which met the acceptable parameters of indoor air quality (thermal comfort and control of risk of SARS-CoV 2).

A hybrid ventilation system combining both natural and mechanical ventilation has proven very promising in moderating indoor climate, based on its ability to ensure indoor air quality with low energy consumption. The system maintains indoor thermal comfort conditions by switching to mechanical mode whenever natural ventilation is not possible. However, the application of such a system in severe arid climates is still very limited and challenging, and almost half the urban peak load for energy demand is used to supply cooling and air-conditioning in summer. This paper assessed the application of the hybrid ventilation mode for an educational building in a hot, arid climate, with the aim of reducing the building’s energy consumption without compromising the occupants’ thermal comfort. A dynamic simulation was conducted using Integrated Environmental Simulation in a Virtual Environment building energy software, and the outcomes were validated against actual consumption data over one year. The results were then evaluated for indoor thermal comfort and energy reduction and showed the potential of the hybrid system to provide energy savings of 23% across the year. Better energy performance was achieved during the cooler seasons (33.5%) compared to hot (17.1%). When photovoltaic systems were incorporated, by examining different inclination angles and locations for energy savings and carbon emissions (CO2) reductions, the outcomes proved that photovoltaic south and a 25° tilt angle recorded the maximum energy and minimum CO2 emissions annually. This integration of hybrid ventilation and photovoltaics reduced the building’s energy consumption from 106.1 MWh to 36.6 MWh, saving almost 85% in total annual energy and cut down the carbon emissions from 55,227 kgCO2 to 6390 kgCO2.

Natural ventilation is recognized for improving the thermal comfort of the built environment and indoor air quality. It provides comfortable conditions for building occupants and reduces energy consumption for air-conditioning. Therefore, it is important to study and explore effective means of ventilation to improve the building designs. This study investigates the thermal comfort of a naturally ventilated hostel operational building in the composite climate of Jaipur, India using Computational Fluid Dynamics (CFD) simulation tool ‘Cradle scSTREAM’. A 3D building model has been developed to analyze the thermal comfort for different natural ventilation strategies with advanced mesh algorithms which generate fewer mesh elements and maintain good mesh quality. A field study was carried out to collect the actual data and to validate the model which was further used to evaluate the thermal comfort range based on the ASHRAE-55 standard. Several design strategies have been applied to enhance thermal comfort. It was found that an increase in air velocity up to 0.5 m/s was achieved by Cross Ventilation while a drop of 2.0–2.5°C in the air temperature was found using Night Ventilation. It can be stated that cross ventilation increases the air movement while night ventilation gives comparatively higher comfort regarding air temperature and relative humidity.

Natural ventilation is the most energy-efficient method by which to passively cool a building, reducing the energy consumption, and improving the thermal comfort and indoor air quality. How...

A mechanical ventilation system in a residential building provides a more reliable, controllable, and comfortable means of ventilation than natural ventilation through an open window. However, the operation of a mechanical ventilation system consumes energy and may generate noise and secondary air pollutants. Thus, it is worthwhile to study residents' actual ventilation patterns. This study investigated the usage of natural and mechanical ventilation in 46 apartments across five different climate zones in China by on-site monitoring and a questionnaire survey. On average, the daily natural and mechanical ventilation durations were 11 h and 7.2 h, respectively. Large differences existed among climate regions and seasons. From north to south, as the climate became warmer, the usage of natural ventilation increased. From a seasonal perspective, the natural ventilation duration was the longest in summer and the shortest in winter. The trend of mechanical ventilation usage was opposite to that of natural ventilation. Generally, as the outdoor air temperature increased, the duration of natural ventilation increased and the duration of mechanical ventilation decreased. This study found that occupants prioritized their thermal comfort needs over healthy indoor air quality (IAQ). However, occupants were willing to spend money on energy when the health requirement could be met by mechanical ventilation. This study provides further understanding of occupants' ventilation behavior, and the results can serve as more accurate boundary conditions for analyses of IAQ, energy consumption, and thermal comfort in Chinese residential buildings.

Window-opening behavior significantly influences indoor air quality (IAQ), energy consumption, and thermal comfort in residential buildings with natural ventilation. To understand window-opening behavior in Chinese residential buildings, this study conducted a one-year measurement in 58 apartments in 14 cities across five different climate zones in China. The influences of climate region, season, household type, and weekday/weekend pattern on the interaction between occupants and windows were analyzed and presented. The average daily “open-window” duration in Chinese bedrooms was 9.4 h. Generally, the length of time that the windows were open in cold regions was shorter than that in warm regions, even when the outdoor air temperatures among regions were similar. The open-window duration increased from winter to summer, as the outdoor air temperature increased. However, the duration decreased when the mean daily outdoor air temperature reached around 27 °C. Approximately 40% of the window-opening actions occurred in the morning from 6:00 to 9:00. During working hours (9:00–17:00) on weekdays, windows were opened more frequently if non-working persons were in the house. On weekends, residents opened windows at a later time than on weekdays. On the basis of the acquired information, a typical window-operation schedule as occupant behavior was proposed for Chinese bedrooms. It provides a more accurate boundary condition for analyses of IAQ, energy consumption, and thermal comfort in Chinese residential buildings.

The purpose of this article is the assessment of energy efficiency and indoor air quality for a single-family house located in Cluj-Napoca County, Romania. The studied house is meant to be an energy-efficient building with thermal insulation, low U-value windows, and a high efficiency boiler. Increasing the energy efficiency of the house leads to lower indoor air quality, due to lack of natural ventilation. As the experimental campaign regarding indoor air quality revealed, there is a need to find a balance between energy consumption and the quality of the indoor air. To achieve superior indoor air quality, the proposed mitigation systems (decentralized mechanical ventilation with heat recovery combined with a minimally invasive active sub-slab depressurization) have been installed to reduce the high radon level in the dwelling, achieving an energy reduction loss of up to 86%, compared to the traditional natural ventilation of the house. The sub-slab depressurization system was installed in the room with the highest radon level, while the local ventilation system with heat recovery has been installed in the exterior walls of the house. The results have shown significant improvement in the level of radon decreasing the average concentration from 425 to 70 Bq/m3, respectively the carbon dioxide average of the measurements being around 760 ppm. The thermal comfort improves significantly also, by stabilizing the indoor temperature at 21 °C, without any important fluctuations. The installation of this system has led to higher indoor air quality, with low energy costs and significant energy savings compared to conventional ventilation (by opening windows).

In order to reduce the energy consumption of HVAC systems in buildings, the use of energy-saving solutions is necessary. One of these solutions is ventilation, which is usually used for maintaining acceptable indoor air quality and thermal comfort. As the change in outdoor environment is unpredictable and the occupant control is spontaneous, it is critical to control the windows and HVAC systems to achieve a maximum use of outdoor air for indoor ventilation. A new rule-based control strategy that could change the opening factor of windows is proposed in this study and its effectiveness was tested in five representative climates, ranging from a subtropical region to a severely cold region. A building model was set up and the indoor air temperature and energy consumption were predicted using EnergyPlus. The results show that the proposed control strategy can utilize ventilation to maintain a comfortable indoor environment with an annual uncomfortable percentage in an occupied period lower than 5%, thus leading to an energy-saving rate of 13.5–55.6%. The simulation results indicate that there are periods of ventilation available during the summer in climate zones with hot summers and warm winters, whereas the control strategy has a better energy-saving performance in temperate areas. This study conducted a preliminary exploration for practical applications of the combined operation of controllable natural ventilation and HVAC systems in buildings.

Natural ventilation is one of the most efficient solutions to improve thermal comfort in buildings, particularly for passive and hybrid cooling. This paper analyses the potential of building automation systems for ventilative cooling in residential buildings. In relation to internal and external temperature, an optimized control strategy of window opening is developed to ensure adequate levels of indoor thermal comfort, reducing energy consumption for cooling. In particular, the control of ventilation is calibrated by an optimized variable set-point and a Particle Swarm Optimization (PSO) method is adopted with objective function that minimizes the thermal discomfort hours. The PSO algorithm is implemented in MATLAB and integrated with TRNSYS energy simulation software. A case study focusing on an existing Italian typical building of the’60s, situated in the Mediterranean climatic context is presented. Thermal comfort analysis, according to the adaptive thermal comfort theory (EN 15251-2007), shows that the optimized control logics for natural ventilation determines a significant reduction of overheating discomfort in reference to the case with ventilation only for indoor air quality at fixed hours. Combining the passive cooling system with an active cooling, there are also reductions in energy consumptions for cooling. The results show how the proposed optimized control logics increase the potentialities of natural ventilation strategies to the improvement of energy and thermal performance of buildings, integrating or replacing the conventional efficiency strategies.

In Canada both residential and commercial buildings often require intensive ventilation and air-conditioning to maintain occupant’s thermal comfort and indoor air quality during the operational hours in cooling season. One way to reduce the cooling load consumption is utilizing mixed-mode cooling approach for space conditioning through natural ventilation. This paper presents the potential of control strategies for motorized window opening schedules to reduce the cooling load for a library building that was designed to be net-zero in terms of annual energy consumption (Canada’s first institutional net-zero energy building in Varennes (near Montreal), Québec, Canada). Even though the building is located in cold climate zone, the performance study shows that the building is cooling dominated i.e., it has more cooling load than heating load. To achieve net-zero energy building status, the potential of mixed-mode cooling approach (natural ventilation combined with mechanical ventilation) during the cooling season needs to be investigated. Preliminary simulation results show that the mixed-mode cooling could achieve 10 to 20% energy savings based on hybrid ventilation (HV) with fixed schedules, whereas 65% savings based on HV with variable schedules. This paper also shows 47% reduction of cooling load could be achieved by applying shading control strategies over without shading control strategies.

Buildings around the world are consuming a significant amount of energy. Up to 64% of the power is consumed by Heating, Ventilation and Air-Conditioning (HVAC) appliances. Ventilation is the job of an HVAC system and it takes a substantial amount of energy. Ventilation is one of the strategies of green building that improves indoor air quality, provides better thermal comfort, and strategical ventilations improve energy efficiency of buildings. In this paper, we proposed a Fuzzy Inference System (FIS) that coordinates natural ventilation with the HVAC system and users' occupancy mode, in accordance with temperature, humidity level, and optimal set points. We have added an additional feature of occupancy mode which is an important criterion to start or stop natural ventilation. The proposed model is evaluated using Mamdani FIS. The simulation results show that the efficiency of energy consumption can be improved by better utilization of natural ventilation with the HVAC system by 26%, which led to reduction of electricity bill by 23%.

Holy temples represent a unique type of buildings due to their large inner space, purpose, and intermittent use. This review summarizes the essential knowledge embodied in the numerous research studies performed on the topics of thermal comfort, indoor air quality, and energy consumption in temples. The focus is on churches and mosques as two frequent types of temples, but the findings apply also to other temples with similar architectural and occupancy characteristics. The review has revealed that even though the topics of thermal comfort, indoor air quality and energy consumption are interrelated, only one of the studies investigated all of them simultaneously. Though the energy consumption in temples is often high, this may not guarantee that a comfortable indoor environment is attained. Problems with thermal comfort frequently occur under severe climatic conditions. Passive measures such as thermal insulation, shading, using fans, cross-ventilating as well as innovative technical systems and operation strategies have been devised to improve the thermal conditions. It was found that the air quality deteriorates rapidly during prayers and natural ventilation by openings is usually not enough to ventilate the space. Despite that, the amount of research on indoor air pollutants and ventilating solutions in temples is scarce relative to the associated health and comfort costs. Studies on the use of renewable energy in temples are also lacking although the limited research on this topic indicates the feasibility of this energy-saving solution.

The energy required to maintain comfortable indoor environmental conditions is a significant percentage (35%) of the overall energy consumption in office buildings. In the modern-day realization of climate change and global warming potential, the reduction of energy consumption in office buildings (particularly energy consumed using cooling and mechanical ventilation systems) and maintaining indoor environmental conditions, is an essential design requirement particularly for buildings located in hot, arid climates. The mixed-mode ventilation (MMV) strategies have been effectively used in the past for saving energy as well as maintaining indoor air quality for the occupants by sustaining adequate indoor environmental conditions. It has been found that mixed-mode buildings have the potential to save 40% HVAC energy by optimizing window operation schedules, and up to 75% by alternating natural and mechanical ventilation. However, to successfully optimize these strategies, it is imperative to understand what factors affect the performance of mixed-mode buildings in terms of energy savings and comfort of the occupants. A comprehensive literature review was conducted covering the past two decades (1996–2016) to analyze the use of MMV systems in office buildings. The study provides the reader with an impression of which practical objectives have been pursued, what progress has been made in the past two decades, and what the future challenges are for using MMV systems in office buildings.

Building airtightness assumes an important role in the energy saving and the indoor thermal comfort. Ventilation rates bring significant impacts on energy usage in the constructions and indoor contaminant concentrations and also setting them as the key parameters in building performance. Ventilation rate have been measured in building for a long time, and there are some developed measurement methodologies related to it in the research domains. However, most of the investigations in recent years have been done usually in the cold climate conditions, while Mediterranean construction are not deeply investigated in the literature. In this paper, the authors present the obtained results of an experimental research which is carried out on the Portuguese residential buildings. The investigation is done by fan pressurization methods, also known as “Blower Door Test (BDT)” as the measurement method as well as Design Builder (DB) as the simulation software. The airtightness measurement of the existing buildings and the influence of air leakage on energy consumption and indoor comfort in different Portuguese construction typologies are focused on the aim of the research. The important parameters of the building such as whole-building air change rates, building infiltration rates, and ventilation effectiveness rate in the residential building are also considered in this research. info:eu-repo/semantics/publishedVersion

Energy consumption in the building sector is a major concern, especially in tropical climates where high temperatures and humidity force occupants to use electro-mechanical ventilation. Passive design strategies, in particular the application of natural ventilation, are one of the main techniques to moderate temperatures in buildings. Furthermore, many studies have shown reduced operating costs, better thermal comfort and indoor air quality, to be some of the advantages of the application of natural ventilation in buildings. Although existing studies support the efficiency of natural ventilation, the efficiency and practicability of architectural elements to maximise ventilation in buildings remains problematic. This study reviews studies on natural ventilation with other passive design strategies in tropical climates in order to support the argument for the application of natural ventilation in tropical climates. Through a review of studies on the operation of natural ventilation in buildings, it also identifies the most effective architectural elements and techniques in building facades and ventilation openings. The results indicate that ventilation shafts, window-to-wall ratio and building orientation should be applied in future construction. This study also identifies some further specific elements that are worth further investigation, including the shape of louvered windows, different forms of apertures and vernacular elements.

Proper ventilation system is required to provide good indoor air quality. However, unnecessary ventilation can consume a huge amount of energy. Potential saving can be achieved by ensuring that efficient heating, ventilation and air-conditioning systems are used. Moreover, reducing the energy consumption by adopting energy-efficient buildings can improve the thermal comfort of the occupants. In the hot and humid climates, natural ventilation by opening the windows and doors may enhance the humidity inside the building and affect comfort, consequently. Since humidity contributes to poor indoor quality and may be a major cause of discomfort, application of mechanical ventilation systems is increased compared with natural ventilation in tropical climates. Further, the power consumption of the air conditioners is increased. Accordingly, it is necessary to scrutinize the factors that influence the thermal comfort and indoor air quality that can be endured by the residents. In the current study, a review of the available literature on the thermal comfort and ventilation of the offices, classrooms and residential buildings in Malaysia and the surrounding regions was conducted. Additionally, prospective researches on different new cooling technologies were marked. Based on the findings, it concluded that thermal comfort range is higher than expected by international standards for hot-humid climate. It was also found that proper ventilation and healthy indoor air quality has great influence of sensation of thermal comfort via occupants of buildings. In point of fact, this work revealed that further research in these fields can provide a chance to improve thermal comfort and indoor air quality for occupants in hot and humid climate and minimize the energy consumption due to the application of air conditioner.

In recent years, the issues of indoor air quality and thermal comfort in underground garages have attained considerable importance. The purpose of this study is to present a green natural ventilation system with a ventilation shaft connected to the outdoors through a horizontal branch pipe. The system combines with a diaphragm wall and steel cage frame for an underground garage or similar underground enclosed spaces. The design system reduces use of tradition fans and motors used in mechanical ventilation. It improves exhaust from indoor spaces and reduces energy consumption. The green design of the ventilation system in this study is cost effective, saves energy and improves the air quality in an underground garage.

Designing climatically responsive dwellings not only can achieve thermal comfort for occupants, but also can make a significant improvement in energy conservation. Consequently, interest in the microclimate around buildings in urban areas has increased because its affects other things; outdoor and indoor thermal comfort, energy consumption in heating and cooling, and the spreading of air pollution. This paper aims to investigate the influence of open spaces (outer courtyards) between building “Shallow canyons” with a H/W ratio of 0.24∼0.6 in one of the urban patterns of youth housing sectors in New Assiut city and deep canyons with a H/W ratio of 4 in one of the new residential houses (El-Abrahimia and El-Moalemen complexes) in the center of Assiut city on indoor thermal comfort. A comparison was made between the two cases based on indoor thermal comfort, energy consumption and IAQ in hot arid climate. The st**udy shows a decrease of indoor temperature inside living rooms that overlook the deep canyons in El-Abrahimia complex with a difference of 11 °C from the outdoor in the hottest day of July. The design of deep canyons causes a temperature decrease of 6∼9.4 °C compared to outdoor temperature in different points of the courtyard. Indoor temperature in these cases reach the upper limit of 90% acceptable range of ASHRAE during July with a maximum indoor temperature 32.5 °C based on the strategy of using natural ventilation. The findings show decreases of cooling demand and energy consumption in deep canyons. This is considered a basic monitoring method that could be used in the future strategy of sustainable housing design of new cities in hot arid climate.

Abstract Window operation is not only an important method for improving the indoor thermal environment and air quality, but also a significant way to reduce energy consumption of air-conditioned rooms during off-running periods in transition seasons. The occupants' window-operation behavior is influenced by both objective factors, such as thermal comfort and indoor air quality; and objective sensation, such as psychology and physiology, introducing considerable randomness and uncertainty. A two-month field observation of occupant window-opening behaviors for natural ventilation in an office building during the transition seasons was carried out in Chongqing, China. Multi-factor analysis of variance was conducted in data analysis using SPSS statistical software. The results showed that outdoor air temperature significantly affected window opening among other factors such as outdoor relative humidity, indoor air temperature, indoor relative humidity, and indoor CO2 concentration, which have much less effect. The main trigger point for opening windows in the transition seasons is from occupants' desire to improve the indoor thermal and air quality environment. A probability model of occupants' window operation was proposed based on logistic regression analysis. Meanwhile, the Monte Carlo simulation results indicate that during transition seasons (when outdoor temperature varied from 15 to 30 °C), the probability of window opening in office buildings follows a normal distribution and increases linearly along with the outdoor temperature growth.

Doğal havalandırma, binalarda, soğutma ve hava üflemeye ilişkin elektrik enerjisi tüketimini azaltma potansiyeline sahiptir. İki ana fonksiyonu: (i) havanın hareket ettirilmesi için elektrik harcanmadan iyi bir iç mekan hava kalitesi sağlanması ve (ii) gün içinde hava hızının artırılması ve gece boyunca yüksek havalandırma oranları aracılığıyla yaz aylarında konfor sıcaklığının iyileştirilmesidir. Esas fayda, dışsal enerji gereksinimine ihtiyaç duymaksızın, yaz aylarında soğutma için gerekli olan yüksek havalandırma oranlarına ulaşılması olasılığıdır. Ancak ana sorun, kış aylarında, ılık oda sıcaklığından ısının geri kazanılmasıdır. Doğal havalandırma, çok katlı ofis binaları için hala yaygın olarak tercih edilen bir havalandırma yöntemi değildir. Konfor sıcaklığı kestirimlerindeki belirsizliklere bağlı olarak, mimar ve mühendisler, pasif teknolojilerin uygulanmasına hala çekinceli yaklaşmaktadırlar. Bunun nedeni, klima tesisatı olmadan iyi bir konfor sıcaklığı ve iç mekan hava kalitesinin elde edilebilmesi için gerekli olan elverişli sistem tasarımı konusunda sınırlı düzeyde bilginin var olmasıdır. Plancıları doğal havalandırma sistemlerinin tasarımı konusunda destekleyebilecek, hazır standartlar bulunmamaktadır. Hava deliklerinin efektif olarak boyutlandırılması için ön değerlendirme araç ve aygıtları bulunsa da, bunlar sadece bazı bina ve havalandırma tasarımları için geçerlidir ve karmaşık akım yolu tasarımlarında kullanılmak için elverişli değildir. Doğal olarak havalandırılan çok katlı ofis binalarının, özellikle enerji korunumu ile ilgili performansları konusunda, yok denecek kadar az sonuca rastlanmaktadır. Akım yolu tasarımının içerdiği ögelerin boyutları ve havalandırma stratejilerinin araştırılması konusunda nihai bir ihtiyaç bulunmaktadır. Pasif soğutma yaklaşımının sadece sağlam bir doğal havalandırmaya değil, aynı zamanda ısı kazanımlarının azaltılmasına ve gece soğuğunun depolanması sistemlerine de dayandığı görülmüştür.Bu tez, bahsi geçen araştırma açığına dayanmaktadır ve dolayısıyla amaçlanan, ılıman Avrupa iklimlerinde enerji korunumu sağlanabilmesi için doğal havalandırmadan faydalanılmasının elverişliliğini incelemektir. Bu amaç doğrultusunda tezin başlangıç noktası, doğal havalandırma için büyük bir uygulama alanı olan ofis binalarına yoğunlaşarak, doğal havalandırma kavramını incelemektir. Buradaki ana önerme, pasif teknolojilerin etkin şekilde uygulanması yoluyla, sürdürülebilir binalar tasarlanması ve inşa edilmesinin mümkün olduğudur. Esasen, doğal havalandırmanın soğutma potansiyeli üzerine vurgu yapılmaktadır. En önemli kapsayıcı hedef, yeni binaların tasarlanması ve mevcut olanların geliştirilmesi ile bağlantılı enerji tasarrufu önlemleri konusundaki bilimsel anlayışı derinleştirmektir. Tasarım süreciyle ilgili bütün girdi parametrelerini tanımlayan, ölçülebilir bir çerçeve yaratılması aracılığıyla, pasif teknolojilerin pratik olarak uygulanabilmesi önündeki mevcut engellerin azaltılması sağlanabilir. Bu hedefe ulaşmak amacıyla, gerekli sistem tasarımı için bir planlama ve simülasyon yaklaşımı geliştirilmiş ve ardından, kontrollü doğal havalandırmanın fonksiyonelliği değerlendirilmiştir. Simülasyon sonuçları, referans alınan örnek alan ile karşılaştırılmıştır.İstanbul / Türkiye'de yer alan çok katlı ofis kulesi Kanyon (28 kat), yüksek konfor beklentileri ve karmaşık mekanik sistemleri ile en son teknoloji ile inşa edilmiş bir bina olarak temsili özellikler taşıması nedeniyle, uygulamayı göstermek amacıyla seçilmiştir. Binanın ölçülen enerji tüketiminden yola çıkarak, solar ve içsel ısı kazanımı ile temiz hava kontrolünün, mekanik soğutma ve havalandırma için önemli düzeyde elektrik tüketimine neden olduğu sonucuna varılmıştır. Bina ve işletme konusundaki detaylı bilgi, bina yönetimi tarafından sağlanmıştır. Esas alan araştırmasına ek olarak, üç farklı ılıman iklim konumunun etkisi üzerine bir karşılaştırmalı değerlendirme yapmak üzere, İstanbul, Torino ve Stuttgart sistematik olarak analiz edilmiştir. Bu değerlendirme, farklı iklim koşullarının, tasarım ve performans üzerindeki etkilerini daha iyi anlamak için gerçekleştirilmiştir. Kapsamın bu şekilde genişletilmesi ile öngörülen, pasif soğutma sistem tasarımları için anlamlı sınır koşullarının sağlanmasıdır.Tezin başlıca hedefleri şu şekilde sıralanabilir: (i) çok katlı ofis binalarının pasif soğutma ve havalandırması için bir tasarım yaklaşımı geliştirmek, (ii) önerilen tasarımın fizibilitesini incelemek adına, özellikle bu amaç için sanal olarak uyarlanmış mevcut bir binaya dayalı alan araştırması gerçekleştirmek.Doğal havalandırma tasarımının farklı analiz araçları ve örnek alan entegrasyonu ile planlanması için bir yaklaşım geliştirilmiştir. Yöntem üç aşamadan oluşmaktadır: (i) ilgili bina tipi üzerindeki mimari sonuçlara odaklanan kavramsal tasarım değerlendirmesi, (ii) havalandırma sistemini boyutlandırmak için elektrik devresi analojilerine dayalı özgün bir ön tasarım aracının geliştirilmesi ve (iii) isteğe bağlı havalandırma kontrolünü de içeren, yıllık bina enerji performansı simülasyonlarına dayalı daha detaylı bir tasarım geliştirilmesi.İlk aşamada, basit çapraz havalandırma ya da tek yönlü havalandırma uygulamalarının imkânsız olduğu geniş yapılı çok katlı binalarda, pasif soğutma için genel bir kavram geliştirilmiştir. Tasarım yaklaşımına ilişkin araştırma sorusu mimarı sonuçlar üzerine yoğunlaşmıştır. Bulgular, dikkate alınan spesifik bina türünün incelenmesine ek olarak, örnek alan olan Kanyon binasının ve iklim değerlendirmesinin incelenmesinden elde edilen bulgulara dayanmaktadır. Kavramsal tasarım sürecinde bir takım zorluklar ortaya çıkmıştır. Akım yolu tasarımına yönelik kavramsal uyarlamalar şunlardır: (i) bina genişliğine bağlı olarak merkezi baca stratejisi, (ii) her biri orta yükseklikte bir bina olarak değerlendirilebilecek izole, modüler parçalar ve (iii) istenilen akım yönünü garantilemek ve rüzgâr basınç farklılıklarını maksimize etmek için karşılıklı, rüzgâra göre ayarlanmış açıklıklar. Pasif soğutma için önerilen diğer kavramsal tasarım çözümleri şunlardır: (iv) binaya giren solar radyasyon miktarını düşürme kapasitesine sahip, iyileştirilmiş dışsal gölgelik aygıtları ve (v) gece havalandırması için binanın yapısal kütlesinin aktive edilmesi.Tasarım yaklaşımının ikinci aşamasında, iklime özgü yaz gündüz tasarımı için gerekli olan hava değişimi oranını ve sistem boyutunu belirlemek amacıyla özgün olarak geliştirilmiş 'HighVent' ('YüksekHavaDeliği') planlama aracı tanıtılmıştır. Basit elektrik devre analojileri, hem havalandırma hem termal modellerde, doğal havalandırma sistemleri odaklı pasif sistem planlamasını desteklemek için uygun görülmüştür. Sonuçların geçerliliği, 'EnergyPlus' bina enerjisi simülasyon programı ile karşılaştırmalı doğrulama yapılması yoluyla kanıtlanmıştır. Mekanik tesis boyutlandırması ile ilgili klasik gündüz koşulları tasarımının, pasif soğutma sistem tasarımı için fazla katı olduğu ve uyarlanmış konfor yaklaşımını yansıtmadığı sonucuna varılması neticesinde anlamlı tasarım sınır koşulları, yaz günü profillerinin özgün olarak geliştirilmesi aracılığıyla sağlanmıştır. Yaklaşım, aşırı sıcak ve normal yaz dönemleri için ortalama hava sıcaklığı, nem oranı, radyasyon ve rüzgâr bilgisini organize etmektedir. Açıklıklar, optimizasyon sürecini de içeren ters çözücü yöntemi ile otomatik olarak boyutlandırılabilmektedirler. Yöntem, arazi ve kat yükseklikleri için düzeltme faktörü önermektedir. Varsayılan basınç dağılımı ve akım dirençleri düzenlenebilmektedir. Kanyon binası için, basınç katsayıları, rüzgâr tüneli ölçülerinden elde edilmiştir. Program öncelikle, değişmeyen sınır koşulları ile verilmiş hava akımı oranına göre akım yolu tasarımını hesaplamaktadır. İlk modülden alınan bu değerler, dinamik konfor ısısını hesaplayan termal modüle aktarılmaktadır. Ardından, işlemler, sistem boyutu pasif soğutma için yeterli olana dek tekrarlanmaktadır. Bina, hava sızdırmazlığı, yönelim, solar kontrol, parlama oranı, ısı kütlesi, konumu ve içsel ısı kazanımları gibi tasarım seçenekleriyle tanımlanabilmektedir. Termal modeli de içeren dinamik gündüz simülasyon tasarımları, tek bölge modeli için yürütülmektedir. Bu tasarımlar, seçilen havalandırma stratejisi ve boyuta göre binanın termal davranışı üzerindeki etki değerlendirmesinin yapılmasına olanak tanımaktadırlar. Araç sonuçları, eğer yaz günü tasarımları için belirli bir uyarlanmış konfor ısısı ölçütü elde edilebilirse, öneriler de içermektedir.Üçüncü aşamada, uyarlanmış Kanyon binasının yıllık performansı, hava akımı ağlarını da içeren EnergyPlus bina enerji simülasyonları ile örnek oluşturacak şekilde modellenmiştir. Model, 'HighVent' aracının ilk havalandırma tasarım sonuçlarını, 'işlem sonrası' model girdilerini, iyileştirilmiş gölgelik ve ısı kütle aktivasyonları için yapılmış kavramsal uyarlamaları ve bina yöneticileri tarafından sağlanmış veriler doğrultusunda Kanyon binasının uygulama çizimlerine ilişkin diğer özelliklerini de içermektedir. Belirli parametrelerin etkilerinin incelenebilmesi için kullanıcılara duyarlılık analizi yürütme olanağı tanınmaktadır. Programlanmış isteğe bağlı havalandırma kontrolü ile dinamik olarak elde edilmeye çalışılan: (i) EN 13779'a bağlı yüksek iç mekân hava kalitesi elde edilmesi ve (ii) EN 15251 kategori II'ye bağlı olarak uyarlanabilir konfor sınırları içerisinde kalmasıdır. Hedeflenen hava değişimi oranı, uygulanması amaçlanan hava miktarını temsil ederken, ulaşılan hava değişimi oranı, simülasyonda ortaya çıkan havalandırmanın küçük olan miktarıdır. Yıllık konfor ısısı, pasif soğutma kavramlarının değerlendirilmesi için en önemli göstergedir; dolayısıyla son karar alma aşaması için önerilmiştir. Bina hacminin pahalı bir kaynak olmasından dolayı, tasarımcının, beklenen uyarlanabilir konfor ve doğal havalandırma sistem boyutu arasında bir önem değerlendirmesi yapması gerekmektedir. Tasarım özelliklerinin göreli etkisinin araştırılması için duyarlılık analizi yapılması suretiyle sistem yeniden boyutlandırılabilir. Karma bir yaklaşımın benimsenmesi durumunda, mekanik sistem donanımı ve enerji tüketim parametrelerinin de dikkate alınması gerekmektedir.Yöntem yaklaşımının uygulanabilirliği, mevcut Kanyon ofis kulesinin sanal olarak uyarlanması yoluyla tanıtılmış ve değerlendirilmiştir. Sanal izleme, modelleme ve simülasyon aracılığıyla, yöntem, hava sıcaklığı dağılımı ve hava akımı örüntülerini, doğal olarak havalandırılan bir ofis kulesi binasının prototipinde öngörebilmektedir. İşleyiş düzeyi, bina enerji performansı simülasyon sonuçlarının Avrupa standartları veya diğer referans ölçütlerine göre sınıflandırılabilmesi için performans göstergelerinin kullanılması yoluyla tasdik edilmektedir. Farklı iklimsel koşulların etkisi, üç farklı iklimsel konumdaki örnek binanın karşılaştırmalı performans değerlendirmeleri aracılığıyla ortaya koyulmakta, böylece, Avrupa Birliği'nin, Bina Enerji Performansı Yönergesinde belirlenen iddialı hedefler desteklenmektedir.Açıklıkların kontrol edilmesinin bütün örneklerde önemli olduğu görülmüştür; aksi takdirde, havalandırma oranları fazla yükselerek, yaz aylarında bile ofis odalarının fazla soğumasına neden olmaktadır. Haftalık tasarım simülasyonlarının karşılaştırılması ile geliştirilen 'uyarlanabilir hava sıcaklığı yükselticisi' kontrol algoritmasının, aşırı soğuma olmaksızın ve sıklıkla yüksek ayarı yapılmasına gerek kalmaksızın pasif soğutma için gerekli akım oranlarının uyarlanmasında, basit kontrollerden daha dirençli olduğu gösterilmiştir. Sonuçlar, doğru tasarlanan ve kontrol altındaki doğal havalandırmanın iyi işlediğini ve EN 15251 kategori II'deki uyarlanmış konfor sınırlarının nadiren aşıldığını göstermektedir. Stuttgart ikliminde, ileri tasarım uyarlamalarına ya da karma soğutmaya ihtiyaç olmadığı sonucuna varılmıştır. İstanbul'da, %3 ile %5 arasında ortalama bir aşma sıklığı ile ileri tasarım uyarlaması ya da karma soğutma makul ancak zorunlu değildir. Ancak, Torino'daki konfor beklentilerinin karşılanması için, daha fazla tasarım uyarlaması veya bir karma soğutma kavramına ihtiyaç olduğu saptanmıştır. Duyarlılık analizi, parlama alanı ya da teçhizat ısı kazanımının yarıya indirilmesi veya binanın ağır olması durumunda, Torino'daki ortalama aşma sıklığının %3'ün altında bir değere düşürülebileceğini göstermektedir. Nem değerlerinin konfor beklentilerini karşılaması tartışılmalı ve tüm proje taraflarınca kabul edilmelidir, aksi takdirde karma operasyon yaklaşımı iyi bir alternatif oluşturabilir.Kontrol edilen tüm örneklerde, EN 13779'a uygun olarak, dış mekân havası üzerinde 400 ppm'nin altında CO2 seviyesine rastlanmış, yüksek iç mekân hava kalitesine erişilmiştir. Bunun nedeni, bir saniyede kişi başı en az 14 litre ile tanımlanan gerekli hava akım oranlarının sağlandığı, mekanik ve doğal havalandırma sistem boyutunun yeterli olmasıdır.Konfor ısısının devamlılığı sağlanırken olası enerji korunumunun incelenebilmesi için, simülasyon aracılığıyla, birbiriyle aynı olup varyantları (pasif/karma/aktif) farklı olan binalar karşılaştırılmıştır. Enerji tüketimi için uygulanmış senaryolar referans alınmıştır. Kanyon ofis binasının başlıca enerji girdisi, pasif işlem için yaklaşık olarak %30-40 arasında ve karma işlem için %28-34 arasında düşürülmüştür. Kontrollü doğal havalandırmayı da içeren pasif soğutmada, soğutma ve havalandırma için enerji tüketimi yoktur ve pompa işlemi ısıtma sezonuyla sınırlandırılmıştır. Bu durum, ilk başta yapılan varsayımı doğrulamaktadır; tamamen pasif olarak soğutulan ve havalandırılan ofis mekânları için enerji korunumu kayda değerdir, özellikle de yüksek enerji tüketen son teknoloji ofis kuleleri ile kıyaslandığında. Karma stratejilerin, işlem için maksimum 26 °C hava sıcaklığı sınırı sağlaması nedeniyle, pasif soğutma ve havalandırma kaynaklı enerji korunumunda en yüksek paya sahip olduğu görülmüştür. Yıllık küresel ısınma potansiyelinde azalmanın, yaklaşık olarak, Stuttgart'ta 1 200 ton CO2'ye, Torino'da 1 300 CO2'ye ve İstanbul'da 1 700 ton CO2'ye eşdeğer olduğu görülmektedir. Natural ventilation of buildings has the potential to significantly reduce energy consumption related to cooling and fanning. This can be achieved by (i) providing good indoor air quality without any electricity demand and (ii) improving thermal comfort in the summer through increased daytime airspeed and high night ventilation rates. In high-rise office buildings, however, natural ventilation is still not a widely preferred means of ventilation. The main reason is the lack of information on the required system design. There are neither standards nor tools and instrument that support planners in the design of natural ventilation systems. Evaluation tools and instruments that are usually applied for effective vent sizing during preliminary planning are not suitable for complex flow path design. Only few results, if any, are available on the performance of naturally ventilated high-rise office buildings, especially where energy conservation is considered. In addition, a passive cooling approach can rely not only on intense natural ventilation but also on the reduction of heat gains, and on night cold storage systems. Considering these aspects together, there is a definitive need for research on the flow path design taking vent sizing for the provision of good indoor air quality and thermal comfort into account.. The current thesis is predicated on the above mentioned research gap. Towards this end, the thesis sets out to explore the concept of natural ventilation with focus on office buildings as a major application area. Emphasis is laid on the cooling potential of natural ventilation. The existing barriers for practically implementing passive technologies can be lowered by creating a quantifiable framework that accounts for all the relevant input parameters in the design process. In order to reach this goal, a planning and simulation approach is developed for the required system design, and the functionality is subsequently evaluated. The results of simulations are compared to those of a reference case-study.The 28-floor Kanyon high-rise office tower, situated in Istanbul, Turkey, is selected to demonstrate the applicability as it is considered to be a representative, state-of-the art building. From the energy metering, it is concluded that mechanical cooling and ventilation result in significant electricity consumption. Detailed information on the building and its operation has been made available by the building management. In addition to the primary case-study, a comparative assessment of the impact of three different moderate climate locations, viz., Istanbul, Turin and Stuttgart, is systematically analysed.The primary objectives of the thesis can be stated as (i) the development of a design approach, and (ii) the investigation of the feasibility of the proposed design, based on an existing case-study building virtually adapted specifically for this purpose. The approach is developed in three steps, including (i) conceptual design considerations with focus on the architectural consequences on the building type of concern, (ii) the original development of a preliminary design tool based on electrical circuit analogies for sizing the natural ventilation system, and (iii) a more detailed design development based on annual building energy performance simulations including custom ventilation control. In the first step, an architectural concept is developed for passive cooling in wide-shaped high-rise buildings where it is impossible to realise simple cross ventilation or single-sided ventilation. During the conceptual design process several challenges emerged. Conceptual adaptations addressing the flow path design are (i) a central chimney strategy in respect to the building width, (ii) isolated, modular segments, as each can then be treated as a medium-rise building and (iii) opposed, wind adapting openings to guarantee the intended flow direction and to maximise the wind pressure differences. Other solutions proposed for passive cooling are (iv) improved external shading devices (v) activation of the structural mass for night-time ventilation.In the second step of the design approach, the originally developed 'HighVent' planning tool is introduced with the aim to determine the design air change rate and system sizes necessary for climate specific summer design days. Simple electrical circuit analogies, for both ventilation and thermal models, are found to be suitable in supporting the passive system planning. As it is concluded that the classic design day conditions for mechanical plant sizing are too strict for passive cooling system design, meaningful design boundary conditions are provided. Openings can be sized automatically by the inverse solver method including an optimization process. For the Kanyon building, the pressure distribution is deduced from wind tunnel measurements. The program first calculates the flow-path design for a given airflow rate with unchanging boundary conditions. These values are then provided to the thermal module, which calculates the dynamic thermal comfort. The procedure is then repeated till the system size is sufficient for passive cooling. The tool outputs include advice if certain adaptive thermal comfort criteria can be reached for a summer design day. In the third step, the annual performance is exemplarily modelled with EnergyPlus building energy performance simulations including airflow networks. This includes the 'HighVent' tool preliminary ventilation design outputs, further 'post-processed' as model inputs, the conceptual adaptations made for improved shading and thermal mass activation, and the remaining features of the as-built Kanyon building in accordance with the data provided by the building management. It allows the users to perform sensitivity analysis for the investigation of the impact of specific parameters. The custom ventilation control dynamically targets to achieve (i) good indoor air quality according to EN 13779, and (ii) stay within adaptive comfort limits category II according to EN 15251. Annual thermal comfort is the most crucial indicator for evaluating passive cooling concepts, and is therefore proposed for final decision making. As the volume of a building is an expensive resource, the designer needs to do a weighting between the expected comfort and the size of the natural ventilation system.The applicability of the '3-step' design approach is then further evaluated by comparing the fully mechanical operated as-built Kanyon building with an operation based on passive and the hybrid control. The assessment is carried out with the help of performance indicators, and the results are intended to assist decision making in the design phase. Indicators proposed to evaluate the functionality are the energy consumption compared to that of mechanical ventilation and cooling systems, and compliance with the thermal comfort limits; additional aspects are the ventilation rates and the indoor air quality reached.A significant result of this comparative study is that control over the openings is crucial for all the scenarios when it comes to natural ventilation applications; otherwise ventilation rates can get too high and the office rooms tend to cool down way too much even during summer. It is shown that the 'adaptive temperature amplifier' control algorithm developed is more robust than simplistic controls. Furthermore, simulation results indicate that properly designed and controlled natural ventilation shows a good functionality and the comfort limits are rarely exceeded. However, differences in climate among geographical regions have a varying impact on the simulation results. For example, in the climate of Stuttgart, further adaptations to the preliminary design of the 'HighVent' tool or hybrid cooling are not necessary, whereas in Istanbul adaptations might be reasonable. However, to satisfy the comfort expectations in Turin, there is a necessity for further passive design adaptations or a hybrid cooling concept. That humidity values meet comfort expectations must be discussed and accepted by all project stakeholders, else a hybrid operation approach might be a good alternative. Nonetheless, in all controlled scenarios, high indoor air quality is achieved. To systematically study the possible energy conservation while maintaining thermal comfort, the energy consumption of identical buildings with different variants (passive/hybrid/active) is compared and benchmarked against the as-built scenario. Results show that the primary energy input for the Kanyon office-tower building can be reduced by approximately 30% to 40% for passive operation and by 28% to 34% for hybrid operation. For passive cooling including controlled natural ventilation, there is even no energy consumption for cooling and ventilation required, while energy usage for pump operation is limited only to the heating season. The hybrid strategies are found to be capable of exploiting the biggest share of passive cooling and ventilation energy conservation by providing a maximum operative temperature limit of 26 °C. This verifies the initial assumption that energy conservation of purely passively cooled and ventilated office spaces is significant, especially when compared to highly energy consuming state-of-the-art office towers.The results of this research work are intended, on the one hand, to support building planners in better understanding and implementing passive cooling measures and, on the other hand, to contribute to further development of sustainable building practices. 329

A significant turning point was reached in th e early 70s with the oil crisis driving a movement for airtight buildings to minimize energy consumption. Unfortunately this turn resulted in a significant deterioration of the indoor air quality, raising health concerns around the world. This started a more involved study of human comfort with respect to air quality, lighting and temperature among other factors. There has been a drive in recent years to enhance current Building Environmental Management Systems (BEMS) with decision logic that takes into account all of the aforementioned issues namely thermal comfort, visual comfort, air quality and energy consumption. In order to maximize performance on all of the above indexes, the BEMS controller can use among other things the mechanical HVAC system, natural ventilation through windows, artificial lighting and shading devices. There are several aspects of the problem that make it attractive to intelligent control implementations. First of all the knowledge of the state of the indoor environment is imprecise due to several reasons. Localized phenomena can affect parameters like temperature or air velocity making it impossible to measure them accurately. Building environments are also characterized by changing dynamics due to human activity as well as equipment and building aging. Some parameters like clothing and activity type that are normally required to accurately estimate thermal comfort are difficult or even impossible to measure. Finally it should also be noted that despite the existence of mathematical models, thermal comfort remains a subjective measure and thus any such model is characterized by some error. On the other hand the action space is discrete and of small dimensionality. The nature of the problem therefore indicates that controllers that are able to generalize can offer a good performance. This is also suggested by the numerous controllers proposed in the literature ranging from classic PD/PID to fuzzy, neural networks and their combinations.