Numerical Study on the Suitability of Passive Solar Heating Technology Based on Differentiated Thermal Comfort Demand

Indoor thermal comfort and passive solar heating technologies have been extensively studied.However,few studies have explored the suitability of passive solar heating technologies based on differentiated thermal comfort demands.This work took the rural dwellings in Northwest China as the research object.First,the current indoor and outdoor thermal environment in winter and the mechanism of residents’differentiated demand for indoor thermal comfort were obtained through tests,questionnaires,and statistical analysis.Second,a comprehensive passive optimized design of existing buildings was conducted,and the validity of the optimized combination scheme was explored using DesignBuilder software.Finally,the suitability of passive solar heating technology for each region in Northwest China was analyzed based on residents’differentiated demand for indoor thermal comfort.The regions were then classified according to the suitability of the technology for these.The results showed that the indoor heating energy consumption was high and the indoor thermal environment was not ideal,yet the solar energy resources were abundant.Indoor comfort temperature indexes that match the functional rooms and usage periods were proposed.For the buildings with the optimized combination scheme,the average indoor temperature was increased significantly and the temperature fluctuation was decreased dramatically.Most regions in Northwest China were suitable for the development of passive solar heating technology.Based on the obtained suitability of the technology for the regions of Northwest China,these were classified into most suitable,more suitable,less suitable,and unsuitable regions.

Energy-saving Technology of Vent in Passive Solar Wall of Rural House of Severe Cold Region

This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All these defects prevent the passive solar houses' further development. This paper chooses trombe wall,which has higher thermal efficiency of the passive solar house,as research object. The traditional vent is improved into a new type of ventilation device. This improvement overcomes the shortcoming,which traditional vent loses huge heat,and simplifies the construction of vent. Comparing with traditional trombe wall,the energy saving rate is 15. 69%.

A Study of Passive Solar House Design

This paper deals with the investigation of the principles of passive solar house design, passive solar systems, and techniques for solar house design. It is expected that the research is to be of momentous significance to the design and construction of passive solar house, and may make contribution to the massive energy efficient housing construction in our country.

Optimization of passive solar design and integration of building integrated photovoltaic/thermal(BIPV/T)system in northern housing

In the Canadian north,the cost of space heating is very high due to the harsh weather,its remoteness,lack of transportation,and dependency on the high cost of fossil fuel imported from the South.Since the North has an abundance of solar energy,significant energy savings with some added construction cost in houses could be achieved by applying high-performance building envelopes and solar design strategies.The objective of this paper is to investigate the potential of both passive and active solar design strategies in improving the energy efficiency of northern housing.Firstly,a reference house representing a typical single-family home in the North is modeled using EnergyPlus,and the key passive design parameters are optimized to minimize life-cycle cost.Then,the air-based building integrated photovoltaic/thermal(BIPV/T)system is applied to the optimized house and integrated with HVAC systems.It is found that optimal passive solar design can reduce the heating energy demand by 42%with an incremental cost of 8%for Yellowknife and by 27%without incurring an incremental cost for Kuujjuaq.Integrating BIPV/T with HVAC systems can reduce the defrost time of heat recovery ventilator(HRV),extend the working hours and improve the COP of air source heat pump(ASHP).The reduction in the total energy consumption is in the range of 1,4%-3.0%by integrating HRV and 0.3%-0.6%by integrating ASHP due to the mis-match of solar availability and heating energy demand.To maximize the utilization of solar energy available,the optimal use of thermal energy recovered from BIPV/T system in northern housing requires further investigation.

Thermal comfort in winter incorporating solar radiation effects at high altitudes and performance of improved passive solar design-Case of Lhasa

The solar incidence on an indoor environment and its occupants has significant impacts on indoor thermal comfort.It can bring favorable passive solar heating and can result in undesired overheating(even in winter).This problem becomes more critical for high altitudes with high intensity of solar irradiance,while received limited attention.In this study,we explored the specific overheating and rising thermal discomfort in winter in Lhasa as a typical location of a cold climate at high altitudes.First,we evaluated the thermal comfort incorporating solar radiation effect in winter by field measurements.Subsequently,we investigated local occupant adaptive responses(considering the impact of direct solar irradiance).This was followed by a simulation study of assessment of annual based thermal comfort and the effect on energy-saving potential by current solar adjustment.Finally,we discussed winter shading design for high altitudes for both solar shading and passive solar use at high altitudes,and evaluated thermal mass shading with solar louvers in terms of indoor environment control.The results reveal that considerable indoor overheating occurs during the whole winter season instead of summer in Lhasa,with over two-thirds of daytime beyond the comfort range.Further,various adaptive behaviors are adopted by occupants in response to overheating due to the solar radiation.Moreover,it is found that the energy-saving potential might be overestimated by 1.9 times with current window to wall ratio requirements in local design standards and building codes due to the thermal adaption by drawing curtains.The developed thermal mass shading is efficient in achieving an improved indoor thermal environment by reducing overheating time to an average of 62.2% during the winter and a corresponding increase of comfort time.

Heating load reduction characteristics of passive solar buildings in Tibet,China

China’s Tibet autonomous region has abundant solar energy resources,cold winters,and cool summers.These are ideal conditions for the application of passive solar heating methods.However,differences in climatic conditions and building types can significantly affect passive solar technology’s feasibility,which makes it challenging to promote passive solar buildings in Tibet.In this study,the suitability zone for passive solar technology is categorized based on the sub-zoning indicators for Tibet.By modeling between direct gain windows,Trombe walls,and attached sunspaces,the effect of indoor thermal environments and the capacity for heating load reduction is compared for different passive solar technologies.The climate-difference impact analysis shows that the I-B-1 zone is better suited for passive solar technology than other climate zones.More specifically,this zone has an average energy-saving rate difference of up to 28.61%compared to the II-A-1 zone.The analysis of the impact of building type differences indicates that residential buildings have higher Trombe wall-to-wall ratio limits and more significant potential for energy savings than office buildings.The study also clarifies the implications of Tibet’s climate conditions and building type differences on the effectiveness of passive solar technology.Moreover,it recommends appropriate passive solar technology adoption methods for every climate zone.This study can be used as a reference and engineering guide to improving the indoor thermal environment of Tibetan buildings,tailored to the highly variable local conditions.

Drying rates of some fruits and vegetables with passive solar dryers

Two passive solar dryers were designed and constructed with available local materials.The passive solar dryers which were direct and indirect types were tested with pepper(Capsicum annum L.),okro(Abelmoschus esculentus L.)and vegetables(Amaranthus hybridus L.)in order to evaluate the drying rate of these produces.The moisture content of 78.9%(w.b.)for 180 g freshly harvested peppers was reduced to 24.0%(w.b.).The drying rate in the direct passive solar dryer was found to be higher than the indirect passive solar dryer.The initial moisture content of 92%(w.b.)for 1000 g okro was reduced to 20%(w.b.).The drying rate in the direct passive solar dryer was also found to be higher than in the indirect passive solar dryer.The initial moisture content of 90%(w.b.)for 400 g vegetable was reduced to 20%(w.b.).The drying rate with the direct passive solar dryer was found to be higher than that with indirect passive solar dryer.During the course of drying,after each crop was kept inside the drying system,the temperature of the drying was monitored at an-hour interval;the moisture content was also monitored at a three-hour interval until there was no more change in the weight of the crop.The crops dried faster with the direct passive solar dryer than with the indirect passive solar dryer.As a result of the highest temperature attained in the direct passive solar dryer,the rate of moisture removal was the highest in this dryer.

Current situation and development of solar heating technology in China

It is introduced the current situation and development for solar heating technology including passive solar heating and solar heating combisystems in China in this paper. Combined with the engineering application projects, the author gave the technical and economic analysis of the passive solar and solar heating combisystems in China and summarized the developing obstacle and the spreading tactics for raising marketing of the solar heating in China.

The Study of Thermal Mass as a Passive Design Technique for Building Comfort and Energy Efficiency

The day/night （diurnal） changes in temperature and solar radiation pose challenges for maintaining human thermal comfort in buildings. Passive and energy-conserving buildings seek to manage the available thermal energy by lowering peaks and dampening the fluctuations in order to maintain conditions for human comfort. Appropriate use of thermal mass moderates the internal temperatures by averaging diurnal extremes. Thermal mass is one of the powerful tools which architects and designers can use to control temperature. It can be used to optimize the performance of energy-conserving buildings that rely primarily on mechanical heating and cooling strategies. Massive building envelopes-such as masonry, concrete, earth, and insulating concrete forms （ICFs） can be utilized as one of the simplest ways of reducing building heating and cooling loads. This article analyses the role and effectiveness of thermal mass as a strategy for providing indoor thermal comfort for passive solar and energy conserving buildings.

INTEGRATED DESIGN CONSIDERATIONS FOR SOLAR COMMUNITIES

This paper presents design considerations for an integrated design of solar commu-nities highlighting the interactive nature of various design parameters to improve the energy performance of these neighborhoods.These considerations are illus-trated through practical design examples of different neighborhood scenarios and individual buildings,based on extensive studies and analysis of energy performance of a wide spectrum of buildings and neighborhoods.The examples fall under two general categories-design at the neighborhood level,and design at the individ-ual building level.Neighborhood design is illustrated by examples of homogeneous residential neighborhoods consisting of 2-storied housing units and of a mixed-rise neighborhood.Design of individual buildings focuses primarily on design of the envelope-consisting of roof and façades-for maximizing energy generation poten-tial,as a function of height and relative position to adjacent buildings.In addition to examples of application of the design considerations,the paper outlines the process of design of solar communities and the role of simulations in the design process.

Recent progress of colloidal quantum dot based solar cells

Colloidal quantum dot （CQD） solar cells have attracted great interest due to their low cost and superior photo-electric properties. Remarkable improvements in cell performances of both quantum dot sensitized solar cells （QDSCs） and FbX （X = S, Se） based CQD solar cells have been achieved in recent years, and the power conversion efficiencies （PCEs） ex- ceeding 12% were reported so far. In this review, we will focus on the recent progress in CQD solar cells. We firstly summarize the advance of CQD sensitizer materials and the strategies for enhancing carrier collection efficiency in QD- SCs, including developing multi-component alloyed CQDs and core-shell structured CQDs, as well as various methods to suppress interfacial carrier recombination. Then, we discuss the device architecture development of PbX CQD based solar cells and surface/interface passivation methods to increase light absorption and carrier extraction efficiencies. Finally, a short summary, challenge, and perspective are given.

APPLICATION OF LIFE CYCLE ASSESSMENT TO VARIOUS BUILDING LIFETIME SHEARING LAYERS:SITE,STRUCTURE,SKIN,SERVICES,SPACE,AND STUFF

Currently,green rating systems are not directly related to environmental conse-quences.Moreover,rating systems score both building-related tasks with long life-time expectancies and system-related tasks with short lifetime expectancies without separating them.Therefore,passive solar and bio-climatic architectures,which have long lifetime expectancies and thus have a strong,negative impact on the environ-ment,are neglected.The main goal of this study is to explore differences in total environmental impact for a single“typical”building module(with the heavy wall building technology accepted in Israel)in terms of six different lifetime shearing layers,Site,Structure,Skin,Services,Space Plan,and Stuff,each of which reflects a different form of environmental damage.The objective of this study was to evalu-ate the six shearing layers using life cycle assessment(LCA)by applying Eco-indi-cator 99(EI99).It was found that the environmental damage associated with the Building layers(Site,Structure,and Skin)was higher than that associated with the Service layers(Services,Space Plan,and Stuff).The paper may contribute to the development of a more scientific(quantitative)background for green rating systems.As a result,a greater decrease in building-related ecological impacts can be achieved,thus encouraging sustainable building activities.

THE LIMITATIONS OF LEED: A CASE STUDY

The Xanterra houses are situated against the backdrop of one of America’s most spectacular natural landscapes,just a few hundred yards from the north entrance to Yellowstone National Park.The project consists of two single-family homes for seasonal workers,approximately 2000 square feet each.They are mirrored east-to-west but otherwise identical(see Figure 1).The project was completed in 2003,and certified under LEED-NC v2.0,project#1353 on December 10,2004-the first building project in the National Park system to receive LEED(Leadership in Energy and Environmental Design)certification from the USGBC(United States Green Building Council).1 The houses were built with the explicit intent that they would become a model for future green building projects at Yellowstone and other national parks,2 and the project team felt it was fitting that these houses be situated in the nation’s first national park.Indeed,they were fundamentally well-designed and constructed,and they incorporated some of the latest technologies for saving energy and water,authentically earning the label“high-performance.”Yet the project only earned the lowest possible rating(“certified”)from LEED,meaning it is barely considered green.This paper documents the green design strategies through the design and construction process,with special attention paid to the influence of the LEED scorecard on collaborative decision-making and to the difficulties this project encountered during the LEED assessment process.Few academic studies have examined the process of LEED self-reporting and scoring within a professional setting,3 even though contingencies such as common business practices and human limitations clearly affect a project’s LEED score.This paper will show that the LEED scorecard turned out to be a poor assessment tool in this case study,because the reporting procedure inaccurately reflected the architectural design and construction.Furthermore,there have been a few important papers that conclude that a major problem of the LEED rating method is its failure to account for the building’s performance over its projected life.4 This paper will verify those conclusions by showing that the lifespan of concrete construction was not considered by the LEED rating process.The larger questions that stimulated this research are consistent with the problems that have motivated the current widespread interest in green design strategies:How can we design buildings that consume less energy?How can we use materials and construction practices more responsibly in terms of reducing pollution and waste?How should we evaluate our own practices to understand their true efficacy?These questions are particularly urgent for the American homebuilding industry,which has become increasingly extravagant and has lost sight of green design strategies in the design of its dwellings5(and increasingly wasteful in energy consumption).Since the Xanterra houses were consciously developed as a positive alternative to typical homebuilding practices,an analysis of their performance-from design through assessment-may have implications for future projects of a similar type.

New Building Typologies for Zero Energy Mass Custom Housing(ZEMCH)in More Sustainable Patterns of Development

Conferences and publications on Smart Cities and self-styled ecological buildings such as“Vertical Forests”,“Biophilic”building complexes and other similar are multiplying.But then,in reality,we continue to design as we have always done for the last ninety years:with the consolidated rules and formal solutions of international post-modern composition,in its various forms.The only attentions are(and not always)to super-insulate the envelopes,arrange photovoltaic panels on the roofs,make the systems smart and cover the facades and roofs with appropriate green washing.Even in the awareness that human settlements and cities are extremely complex phenomena,mostly determined by economic and social factors,rather than by conscious typological-settlement choices,perhaps the time has come to acknowledge that the traditional paradigms of design must be changed.First of all,the types of settlements must be renewed,because it is through their optimization that the greatest savings in terms of energy and sustainability can be achieved.The research presented here is the application of a ten-year study that involved the development of net Zero Energy Mass Custom Housing(ZEMCH)in specific context in southern Italy.The Innovation and Transparency of Tenders Environmental Compatibility(ITACA)Assessment Protocol,derived from the Green Building Challenge’s GBTool,was used as a design guide,which is normally used for the assessment and judgment of sustainability at the building scale and not of the urban design.The result is a settlement model in which network of pedestrian,cycle and public transport is fully integrated with adjacent urban areas;effective landscaping connects public and private green and kitchen-gardens/orchards everywhere;buildings are made with new semi-underground typologies;net ZEMCHs are made with local,recyclable materials with low impact or positive energy balance;wastewater and rainwater are collected,in-loco phyto-purified and reused;renewable energies(sun,earth,wind)satisfy remaining necessities,with a minimum of plant interventions.

HILLTOP RESIDENCE AND SITE SUSTAINABLE DESIGN

Sustainability on a residential renovation can be difficult to achieve.As this project was a complete gut renovation and two small additions,which included a new third story space,roof,and a rear addition,it was easy to investigate a wide variety of sustainable options.The building envelope was improved,interior aspects modified,and the energy generation systems explored and selected to all work in unison to enhance the end result of the project.In order to measure the degree of sustainability,ODG wanted to use a residential design rating system.At the time this house was designed there were few recognized residential rating systems available and none appeared to be as stringent and broad reaching as the LEED Commercial Rating system.ODG used the LEED 2.2 rating system as a guideline.When this project began,LEED for Homes had not yet been developed.The Hilltop Residence project sought to infuse an existing residence with the following qualities:cost effective technology,a“not to exceed”budget,a 75-year life cycle,the client’s aesthetics,functional living,sustainable design,and allow for productive healthy residents.ODG used the LEED categories of Sustainable Sites,Water Efficiency,Materials&Resources,Energy&Atmosphere,and Indoor Air Quality.The sustainable goals that were met affect both the building and the site.The home was designed to use rapidly renewable materials,use less water,conserve energy,generate its own electricity,automate the mechanical house processes,and reduce stormwater runoff.The renovated home conserved existing material and used new materials that are rapidly renewable.By designing to a 75-year life cycle,materials selected were either rapidly renewable or incredibly durable.Buildings designed for longer lifespans are inherently sustainable because their components will not need to be replaced as often.The reduction of operating and maintenance costs will pass savings directly to the client,providing a return on investment for the costs of the renovation and addition.By increasing the native vegetation,the site reduced runoff from the roof and decreased the amount of water being added to the storm sewer system.These goals,once realized and incorporated into the redesign of the townhome provide a clean,healthy indoor environment and highlight a residence with a climate responsive design and conservation practices.

SUSTAINABLE MICRO-VILLAGES AND THE CARWOOLA HOUSE PROJECT IN CANBERRA,AUSTRALIA

INTRODUCTION Our needs as social and familial beings change over the course of our lives;however,it has become common practice to build as though these needs remain static through time.The needs of a child,young adult,family,middle age and the elderly are dynamic between generations,and adding to these evolving life needs is the crisis of housing affordability.ree decades ago a house could cost 3-4 times an individual’s annual income,today that cost is closer to 10-12 times.In response to these chal-lenges,this article explores the concept of Sustainable Micro-Villages,providing insight into a new approach to energy-efficient housing with reference to our case-study project-Carwoola House.Sustainable Micro-Villages can be defined as a cluster of integrated dwellings,referred to here as Living Pods.Essentially a“single house”on a single site,these micro-villages can be comprised of two or more smaller buildings that provide private dwelling space for a single person,couples,couples with children,parents,elderly,friends and any combination of social groups.Living pods cluster around a natural garden setting,enhanced by waterharvesting,and are connected with covered,open or enclosed links depending on the climate of the site.The recent iterations of this type of dwelling also incorporate solar passive design,passive house and green-house technology.In Australia,new house designs are evaluated as part of an approvals process for their energy rating.1e Australian Building Code requires a minimum 6-star rating,ranging up to 10 stars for any new home to be built.A 6-star rating provides a good level of insulation and energy performance if built correctly,while 10 stars represent the highest level of energy performance and refers to a dwelling that needs no heating or cooling.Sustainable Micro-Villages consistently achieve an 8 to 10-star rating by combining Solar Passive Design principles(good orientation,thermal mass and thermal performance)and Passive House Technology(high thermally performing building with low air leakage,no thermal bridging,high performance glazing and heat recovery ventilation)in various combinations to suit the climate,context and budget.

Performance improvement of c-Si solar cell by a combination of SiNx/SiOx passivation and double P-diffusion gettering treatment

SiNx/SiOx passivation and double side P-diffusion gettering treatment have been used for the fabrication of c-Si solar cells. The solar cells fabricated have high open circuit voltage and short circuit current after the double P-diffusion treatment. In addition to better surface passivation effect, SiNx/SiOx layer has lower reflectivity in long wavelength range than conventional SiNx film. As a consequence, such solar cells exhibit higher conversion efficiency and better internal quantum efficiency, compared with conventional c-Si solar cells.

A Novel Combined Trombe Wall System for Village Houses in Cold Regions of China

Trombe walls have significant energy-saving features and are therefore of great interest to researchers.However,additional research about the Trombe wall is needed to reduce indoor temperature fluctuations and to improve thermal behavior under different climatic conditions.A new Trombe wall system was proposed which uses Venetian blinds and a basement.The field tests were conducted to compare the thermal performance of four types of rooms:(ⅰ)no Trombe wall(control),(ⅱ)classical Trombe wall(TW),(ⅲ)Trombe wall with Venetian blinds(TW+VB),and(ⅳ)Trombe wall with Venetian blinds and a basement(TW+VB+B).The field measurements were conducted during the winter near Shihezi City in northwest China.The objective of this study was(ⅰ)to evaluate the thermal performance of a novel Trombe wall system under different operation conditions,and(ⅱ)to confirm the optimal angle of Venetian blinds during the heating period.The results demonstrated that the TW+VB+B system effectively reduced indoor temperature fluctuations after sunset.Furthermore,during the daytime,the average air temperatures in the test rooms were 13.6℃higher in the TW+VB+B system than in the control.The average temperature at the air outlet in the TW+VB+B system was 4.9℃higher than that in the TW+VB system during the daytime,and the average predicted mean vote(PMV)of the test room was 1.02 units greater in the TW+VB+B system than in the control.The thermal efficiency remains in the range of 40%-65%when the Venetian blind angle was set at 45°.In conclusion,the experiment results showed that the TW+VB+B system can not only reduce indoor temperature fluctuations but also improve thermal performance in winter.Both the heating energy consumption in buildings and pollutants emission in the environment were lessened through the application of this passive solar energy-saving technology.Therefore,this can provide valuable insights for improving the thermal performance of the novel Trombe Wall system in such village houses.

A computational approach for achieving optimum daylight inside buildings through automated kinetic shading systems

Parametric architecture can be used to improve design quality by integrating and coordinating design components,and any change in one parameter affects the final design.Daylight is a crucial parameter in designing energy-efficient buildings.In this research,daylight inside a building was improved by designing a kinetic shading system with independent units parametrically responding to sunlight through 3D rotation(around the centers of the units)and 2D movement(on the surface of the shading system).Various patterns were determined to create the unit’s basic form and allow the designer to have a wide range of options.The units were defined with the plugin“Grasshopper.”Their rotation was parametrically controlled on the basis of sun path and weather data by using“Honeybee”and“Ladybug”plugins to provide constant optimized daylighting inside the building.Results showed that the use of such a shading system in optimal situations can greatly increase the efficiency of indoor daylight.