Traditional Roof Research Articles

An analysis of the urban heat island of Venice mainland

In Italy, as in the rest of Europe, serious land degradation processes are occurring, mostly due to rural abandonment, urbanization and infrastructure development. In particular Veneto, the region around Venice, has undergone considerable land use and land cover change in the last decades. This work integrates field observations and numerical simulations to study the urban heat island (UHI) effect in the mainland part of Venice. The numerical study was performed using ENVI-met, an environment and micro-climatic simulation tool. Different mitigation scenarios are evaluated in a case study area. The study aims to explore the factors that contribute to urban heat island development proposing practical, feasible and specific solutions for mitigating their effects. The focus of the analysis is, in particular, on the use of permeable surfaces vegetative soil or grassed parking instead of conventional asphalt or cement pavement as soil compensation mechanisms for soil loss. The replacement of traditional roofs with cool or green ones is also considered.

A multi-criteria methodology for comparing the energy and environmental behavior of cool, green and traditional roofs

The reduction of energy demand for space cooling, as well as the mitigation of the Urban Heat Island effect (UHI), require adequate solutions at building and urban scale. In particular, the roofs of buildings have been identified as a possible field of intervention that could contribute to provide significant energy savings and environmental benefits. In this context, cool and green roofs are two very interesting solutions, which may allow obtaining both the reduction of the energy consumption and the improvement of the comfort sensation in the outdoor and indoor environment.This paper presents a numerical comparative analysis of the energy and environmental performance of three typologies of roof, namely a standard roof (SR), a cool roof (CR) and a green roof (GR). This analysis, developed through dynamic energy simulations under temperate climate, highlights the different thermal behavior for the investigated roof scenarios, also as a function of the level of thermal insulation. Moreover, with the aim to obtain a classification between SR, CR and GR in Mediterranean climate, a scoring system is presented, which considers the whole performance of the investigated roof scenarios under a broad perspective.As a result, it is found that green and cool roofs provide higher energy savings and environmental benefits than highly insulated standard roofs. In particular, scarcely insulated green roofs showed the best performance in relation to the UHI mitigation under the climatic conditions typical of the Mediterranean area.

Studies Of Possible Use Of Oleic Imidazoline As Modifying Agent For Hard Bitumen

AbstractHard bitumens are used in the construction industry primarily in it’s unmodified form, for instance for the production of the so-called traditional roofing felt. Due to the low price of these types of membranes, the use of a popular but expensive modifying agent, SBS copolymer, is not justified economically. Research carried out by the authors has shown that chemical organic compounds belonging to a group of imidazolines may potentially be used as much cheaper bitumen modifier. It was demonstrated that a new type of modifier based on oleic imidazoline, developed by the authors, has a significant impact on improving the physical properties of bitumen. The use of this modifier results in a significant increase in the bitumen plasticity range, both before and after laboratory ageing. In addition, there was a considerable increase of bitumen’s resistance to aging. Its use can help improve the quality and durability of popular waterproofing products manufactured with the use of hard bitumen.

檜皮採取によりヒノキ材の木部性質は変わるか

Bark isreproducible by the tree when its cambium is carefully left without damaging it by decorticate technicians.Throughout the world, reproduced bark has been traditionally used for daily commodities such as cork from cork oak (Quercussuber)in Portugal, or house buildings,such as roof tilesof 굴피rom sawtooth oak (Quercusacutissima) in Korea and Hiwadaroof plate from japanese cypress (Chamaecyparisobtusa) in Japan, etc.For traditional roof constructionin Japan, especially for national heritages, Hiwada bark is indispensable, and a number of cultural properties are awaiting for its supply for repairesthat arenecessary approximatedlyevery 40 years. However, Hiwada production is suffering from a shortageof old trees, which must bejapanese cypresstrees of more than 80 years old. Also,there is alack of traditional master technicians, motokawashi, who can decorticate the bark without damaging the cambium, and due tothe misunderstanding oftimber sellersthat decorticationimpaires the mechanical properties of the tree. We have been engaged in a series of research projects to solve this shortage of Hiwada. This study aimed to clarify whether bark decortication for Hiwada production changes the mechanical properties of the xylem,focusing on xylem production in the cambium after decortication, by measuring Young’s modulus and the cellulose-microfibrilangle. It is difficult to discuss the impact of decortication accuratelywithout considering other effectssuch asindividual variabilityand climate change. Bark was carefully removedincontrol experiments and by quantative treatments.A pair of trees, grown under very similar conditions, one of which was decorticated and the other was not treated, were compared. In order to remove the individual variability at each cell level, a series of daughter cells with the same mother cell in the cambium were sampled in annual rings and compared. Then, five to ten annual rings each before and after decortication and the changes in ratios were compared to the control, andthe impact of decortication itself was discussedandinvestigated.

Modelling of green roof hydrological performance for urban drainage applications

Green roofs are being widely implemented for stormwater management and their impact on the urban hydrological cycle can be evaluated by incorporating them into urban drainage models. This paper presents a model of green roof long term and single event hydrological performance. The model includes surface and subsurface storage components representing the overall retention capacity of the green roof which is continuously re-established by evapotranspiration. The runoff from the model is described through a non-linear reservoir approach. The model was calibrated and validated using measurement data from 3 different extensive sedum roofs in Denmark. These data consist of high-resolution measurements of runoff, precipitation and atmospheric variables in the period 2010–2012. The hydrological response of green roofs was quantified based on statistical analysis of the results of a 22-year (1989–2010) continuous simulation with Danish climate data. The results show that during single events, the 10 min runoff intensities were reduced by 10–36% for 5–10 years return period and 40–78% for 0.1–1 year return period; the runoff volumes were reduced by 2–5% for 5–10 years return period and 18–28% for 0.1–1 year return period. Annual runoff volumes were estimated to be 43–68% of the total precipitation. The peak time delay was found to greatly vary from 0 to more than 40 min depending on the type of event, and a general decrease in the time delay was observed for increasing rainfall intensities. Furthermore, the model was used to evaluate the variation of the average annual runoff from green roofs as a function of the total available storage and vegetation type. The results show that even a few millimeters of storage can reduce the mean annual runoff by up to 20% when compared to a traditional roof and that the mean annual runoff is not linearly related to the storage. Green roofs have therefore the potential to be important parts of future urban stormwater management plans.

Analysis on the Application of PV Technology in Terms of Tranditional Roof House. Case Study: Julang Ngapak Sundanese Traditional Roof Form

This study departs from the thought that the implementation of new technology should consider the local context or the concept of “genius loci”. Based on this conception, this study is aimed to investigate whether the implementation of the current technology (here is PV technology) can be in accordance with the initial local traditional architectural form. To accommodate that objective, the roof form of the Sundanese traditional house called “Julang Ngapak”, located in West Java, was studied to analyse its particular orientation, North and South in regards to the solar incident level. The campus building of Bina Nusantara University, located in Jakarta, was selected for the study of PV roof implementation. The method of the study is simulation by applying the EnergyPlus software. There are three types of PV roof which were simulated to investigate the electricity production of the solar cell. The final deliveries of this study are to compare and to analyse the solar irradiance arrive on each type of roof and to define the most appropriate roof form in terms of orientation for implementing the BIPV concept on building particularly in Jakarta region.

Comfort and energy savings with active green roofs

Green roofs have been proposed for energy saving purposes in many countries with different climatic conditions. However, their cooling and heating potential strongly depends on the climate and building characteristics. In particular, the increase of the thermal capacity of green roofs compared to traditional roofs, if not controlled with insulation, may lead to higher cooling and heating loads. This paper discusses the energy saving potential of green roofs adopting a variable insulation strategy. A system consisting of a plenum located between a green roof and the room underneath and a sensor-operated fan that couples (or decouples) the green roof mass with the indoor environment was developed. The fan is activated and stopped using temperature based rules; the plenum is ventilated only when the fan works, creating a variable insulation system. Four cells with an insulated traditional roof, a non-insulated green roof, an insulated green roof, and a green roof with the variable insulation system have been tested in a hot and dry climate with mild winters over several years. This paper compares and discusses different plenum control algorithms. Results are particularly promising because the variable insulating system proved to adjust the thermal capacity of the roof effectively. In summer, the non-insulated green roof and the green roof with variable insulation system achieved the lowest indoor temperature; in winter, the insulated traditional roof and the variable insulation green roof system achieved the highest indoor temperatures. Measurements are hence compared with simulations. Finally, the energy saving potential of the new green roof system is evaluated.

1917-1921년 창덕궁 대조전 재건공사에 적용된 조선식 목조 지붕틀과 방화계획

This research aims to find the architectural significances in the Daejojeon of Changdeokgung which was rebuilt during the period from 1917 to 1921 when compared to other new buildings built from 1907, Emperor Soonjong crowned. Through the literature research and field research, this study finds two architectural issues. First, traditional roof frame had been adopted again to the new palace buildings since the reconstruction of Daejojeon complex. Second, Daejojeon was the sole royal building with the fire prevention design introduced to the traditional wood structure in the palace. So, Daejojeon complex reconstruction became the turning point in maintaining traditional landscape of Changdeokgung as well as an opportunity for traditional architectural experts of Joseon to participate in. As a result, the usage of traditional roof frame and fire prevention design in the reconstruction of the Daejojeon complex shows that architectural norm of using traditional roof frame for the buildings of the inner palace was valid even during Japanese colonial period.

Summer and Winter Effect of Innovative Cool Roof Tiles on the Dynamic Thermal Behavior of Buildings

Cool roofs represent an acknowledged passive cooling technique to reduce building energy consumption for cooling and to mitigate urban heat island effects. This paper concerns the evaluation of the dynamic effect of new cool roof clay tiles on building thermal performance in summer and winter conditions. To this end, these properties have been analyzed on traditional roof brick tiles through an indoor and outdoor two-year long continuous monitoring campaign set up in a residential building located in central Italy. The analysis and the cooperation with industrial companies producing brick tiles and reflective coatings allowed the production of a new tile with notable “cool roof” properties through the traditional industrial manufacturing path of such tiles. Notable results show that during summer the high reflection tiles are able to decrease the average external roof surface temperature by more than 10 °C and the indoor operative temperature by more than 3 °C. During winter the average external surface temperature is lower with high reflection tiles by about 1 °C. Singular optic-thermal phenomena are registered while evaluating the dynamics of the cool roof effect. Interesting findings show how the sloped cool roof application could suggest further considerations about the dynamic effect of cool roofs.

Evaluation of acoustic diversity of religious buildings; case study from churches and mosques in Turkey

In this study, by analyzing the reverberation time and noise insulation features of religious structures, effects of differences on the forms, materials, and functions on interior acoustics are discussed. For this purpose, calculations were made working on the projects of the selected sample mosques and churches built by different materials and their interior reverberation times were measured and compared. Two different types of areas were compared using RT60 reverberation time calculations and T30 and T20 frequency band analysis measurement systems. In the comparison, interior functions are evaluated. In this evaluation, it was observed that in mosques since there is excessive speaking, medium frequency resulting from people was more dense whereas in churches high frequency was also involved with rite taking place alongside the medium frequency resulting from talking. Therefore, interior frequency band width was observed to increase. Selected churches have cross and basilic type plan and mosques have square type plan. It is observed that selected traditional mosque roofs have circular forms and churches have sharp forms. Hereby variations of the acoustic features of the sites with different forms and functions used for similar purposes were compared.

PLANTS INFLUENCED BY GROWING MEDIA AND COMPOST ADDITION ON MOCK GREEN ROOFS WITHIN THE OZARK HIGHLANDS

ABSTRACT Green roof technology and other low impact development practices help mitigate hydrologic impacts from urbanization. Green roofs are widely recognized for stormwater retention, and these systems provide many other ecological functions, such as habitat, air quality improvements, insulation, reduced noise pollution and aesthetic quality. Green roofs are composed of a plant palette (species selected for a specific condition), growing media and drainage system on top of a traditional roof membrane. This study investigated species survival under local environmental conditions, in the southwestern Ozark Highlands from September 2008 through 2009. There were four treatments consisting of two different growing media particle sizes and two different fertilization regimens (with and without compost). Sixteen plant species and/or varieties were monitored to determine the effect of treatments on survival and spread. Plant response varied by species, but the fine media with compost provided the greatest survi...

고도(古都) 경주의 역사문화환경지구 내 상업가로경관 디자인가이드라인에 관한 연구

The objective of this study is to provide a townscape design guideline that harmonized with a historic landscape via condition investigation and landscape analysis of the cultural /commercial environment district where an improvement is a necessity. The followings are the conclusions: 1.To enhance the identity of Gyeongju, should pursue diversity in unity by making the image of architectural landscape a similar peculiarity. 2.The central commercial district where the tradition is valued and contemporary figures meet the tradition needs a landscape formation by CONTEXT. 3.Since a characteristic of the target area is a regional commercial center, to reduce its congestion, reforming the area to simple environment is required. 4.Induce buildings located on the streets with cultural properties to have Korean traditional tiled roof in order to fit in with their surroundings. 5.Make it a rule to partition a wall into tripartition, the wall surface exposed should be the same finishing materials. 6.Consider the visual aspect of pedestrians and a building's width, the recommendable height of the facade should be 3~3.6m. 7.For the design archetype of cornice, four traditional types based on Korean traditional eaves are suggested. 8.The design of signboards should break existing square-shapes, and seek a design to take advantage of icons that historicity and traditionalist of the city are expressed.

Structure and properties of CIGS films based on one-stage RF-sputtering process at low substrate temperature

Currently, Nanjing South Railway Station planning to implement slate roof renovation is integrating solar cell modules into traditional roof materials to generate clean energy. Copper–indium–gallium diselenide (CuIn1−xGa x Se2, CIGS) is one of the most promising materials for thin film solar cells. Cu(In1−xGa x )Se2 films were deposited by a one-step radio frequency magnetron sputtering process at low substrate temperature. X-ray diffraction, Raman, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electrical and optical measurements were carried out to investigate the deposited films. The results reveal that a temperature of 320 °C is critical for near-stoichiometric CIGS films with uniform surface morphology. Cu-rich phase particulates are found at less than this temperature. The sample deposited at 380 °C gives well-crystalline single-phase CIGS film. Furthermore, the electrical and optical performances of the absorber layer are improved significantly with the increasing substrate temperature.

Thermal lag and decrement factor of a coconut-ferrocement roofing system

In this paper, coconut fibre filled precast ferrocement roofing channel components were developed, their thermal behaviour was characterized and its performance was compared to precast ferrocement-only roofing channel components in a real-scale prototype house built at CIIDIR facilities in Oaxaca, Mexico. The experimental analysis performed in this study was based on dynamic climatology. A solar orientation chart of the place was constructed to identify the solar radiation intensity acting on the house. Measurements of roof surface temperatures were conducted to determine temperature damping and temperature wave lag. Monthly average temperature and direct solar radiation data of the site was considered. Coconut fibre filled precast ferrocement roofing performance was compared to a ferrocement-only roofing and to a traditional concrete slab roofing. Results indicate that, coconut fibre filled precast ferrocement roofing channel components experience higher solar radiation intensity but its thermal damping is 40% and its thermal lag of about three and a half hours. Precast ferrocement-only roofing channel showed no thermal lag or damping and traditional concrete slab roofing exhibit a thermal damping of only 13% and its thermal lag of zero. Thus it is concluded that coconut fibre filled precast ferrocement roofing channel components are an ecological alternative for energy saving and thermal comfort.

A Construction Model of Ancient Architecture Protection Domain Ontology based on Software Engineering and CLT

In allusion to the lack of formal mathematical methods and engineering characteristics on the construction of AAPDO (ancient architecture protection domain ontology, AAPDO), a construction model on AAPDO based on software engineering and CLT (Concept Lattice Theory, CLT) is proposed, and the application steps and methods of the model are also elaborated on. The model uses a guiding ideology of engineering, a formal way of expression and the standardized work steps to complete the construction of AAPDO. Finally, taking Chinese Traditional Roof as an example, an instance on the construction of the field ontology of Chinese Traditional Roof based on software engineering and CLT is given.

Business Model Innovation on the Photovoltaic Water Pumping Systems for Grassland and Farmland Conservation in China

Penetration of the renewable market of Photovoltaic PV technologies calls for the extension of the additional values generated from the technology including climate and social co-benefits as radical innovations in a new business model. Compared with existing PV business models, this paper extends the value proposition into operation system and customer segmentation, investigated by a pilot demonstration of PV water pumping (PVWP) systems for the conservation of grassland and farmland in China. The paper suggests that the integrated PVWP systems can combine the implementation of technology with environmental co-benefits, agricultural products by developing an interactive interface to link a social network. This can further disseminate benefits to stimulate the active participations of investments from individuals and corporations. Discounted cash flow (DCF) model and net present value (NPV) evaluations have been conducted on the traditional PV roof, PVWP pilot and PVWP scale up scenarios. The results show that the scenario of integrated PVWP system with social network products can significantly improve the payback period (PP) and increase internal rate of return (IRR). Based on the PVWP pilots and relevant industrial environments, the results in this paper provide how the innovative PV business model innovation can improve the present practices and policies on PV technologies implementation.

The Retrofit of Existing Buildings Through the Exploitation of the Green Roofs – A Simulation Study

Green roofs have several environmental benefits, such as improving building energy efficiency. As the existing Italy building stock was built before any roof insulation was required, the existing buildings will benefit most by the green roofs. The exploitation of a green roof for retrofitting of an existing house-holiday placed in the south part of Sicily was studied. The building energy performance and the dynamic thermal behavior of the green roof has been evaluated using a transient simulation program. The results of this study indicate a remarkable reduction both of the cooling and heating load respectively of about 80% and 34%. Dynamic simulations have proven essential that the typology of green roof investigated delays and attenuates the outdoor heat wave better of traditional roof diminishing the average daily temperature fluctuations. Therefore, the green roof shows a strong potential for the retrofit of not well-insulated building in Mediterranean area.

On a Cool Coating for Roof Clay Tiles: Development of the Prototype and Thermal-energy Assessment

Clay tiles are the most common roof covering in Italian buildings, in particular in traditional residential buildings. Given the important role of the roof characteristics for building energy efficiency and indoor thermal comfort conditions, innovative solutions for improving the thermal-energy performance of such diffused roof element has become a key research issue. In this view, cool roof applications represent an effective solution to this aim. The present work deals with the analysis of innovative coatings for traditional clay tiles, aimed at increasing their “cooling” potential. Several pigments with the sodium silicate as binder are tested in terms of reflectance and emittance, which mainly determine the cool roof performance. Additionally, the year-round performance of the proposed tile is evaluated when applied to a single family residential building located in central Italy. The developed cool roof solution is characterized by the same visual appearance of traditional “natural brick” color tiles, while the solar reflectance is higher than natural terracotta tile by 13%. Therefore its thermal performance is optimized in order to reduce the roof overheating and the consequent energy requirement for cooling. Results of dynamic simulation of the case study building show how the proposed tile is able to decrease the number of hours when the indoor operative temperature of the attic is higher than 26°C by 18%, while the same effect in lowering the indoor temperature below 20°C in winter is less than 1%. Therefore, the proposed solution could be considered as an interesting strategy for new buildings or for traditional roof retrofitting, without producing any significant architectural impact, even in traditional or historic buildings, where more invasive solutions are too difficult to be implemented.

Effect of Turf Roof Slabs on Indoor Thermal Performance in Tropical Climates: A Life Cycle Cost Approach

Urbanization related to population growth is one of the burning issues that the world is facing today. Parallel to this, there is visible evidence of a possible energy crisis in the near future. Thus, scientists have paid attention to sustainable development methods, and in the field of building construction also, several innovations have been proposed. For example, green roof concept is one of such which is considered a viable method mainly to reduce urban heat island effect, to regain lost land spaces in cities, and to increase aesthetics in cities. The present study was aimed at investigating the impact of green roofs on indoor temperature of buildings, the effect of different types of roofs on the air conditioning loads, and the life cycle cost of buildings with different types of roofing. The study was conducted in several phases: initial small-scale models to determine the heat flow characteristics of roof top soil layers with different thicknesses, a large-scale model applying the findings of the small-scale models to determine temperature fluctuations within a building with other common roofing systems, a computer simulation to investigate air conditioning loads in a typical building with cement fiber sheets and green roof slabs, a comparative analysis of the effect of traditional type roofs and green roofs on the air conditioning loads, and finally an analysis to predict the influence of traditional type roofs and green roofs on life cycle cost of the buildings. The main findings of the study were that green roofs are able to reduce the indoor temperature of buildings and are able to achieve better heat transfer through the roof, and, thus a lower cooling load is necessary for air conditioning and has the possibility of reducing life cycle cost of a building.

The thermal effect of an innovative cool roof on residential buildings in Italy: Results from two years of continuous monitoring

Cool roofs represent an innovative and relatively inexpensive technique to reduce building energy requirements for cooling and to improve indoor thermal comfort conditions. These applications primarily consist of high-reflectance and high-emissivity coatings or membranes commonly applied to the flat roofs of non-residential buildings located in both hot and mild climates. This paper discusses the possibility of applying an innovative “cool roof” solution, consisting of a prototyped cool clay tile, on a traditional residential building in central Italy to improve the thermal conditions of the indoor environment that is adjacent to the roof. In particular, the results of a two-year continuous monitoring campaign are presented. The building was monitored for an entire year in the original configuration and for another entire year in the optimized configuration, with the final objective of quantifying both the summer benefits and the winter penalties of such a solution in residential buildings in temperate climate conditions. The year-round analysis shows that the proposed cool roof solution produces a maximum effect of decreasing summer peak indoor overheating of the attic by up to 4.7°C. The corresponding winter maximum overcooling reduction is 1.2°C. These experimental results show that this innovative cool roof solution can be implemented on traditional sloped roofs with a clay tile covering, producing substantial benefits in summer and relatively small penalties in winter for residential buildings, even in temperate climates.