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Conventional, concrete-based building materials have a high level of embodied energy in their production – as do typical insulation materials, which are crucial for addressing operational energy demands for building climatization. Here, a life-cycle energy (LCEA) and carbon (LCCO 2 A) analysis is performed to evaluate the potential benefits of using an alternative, bio-composite building material made from hemp shives mixed with a lime binder, in the context of an arid environment. The physical properties and thermal performance of the hemp-lime building material are compared with conventional materials through lab tests, temperature measurements in test cells and thermal simulations. This study concludes that hemp-lime not only has a clear advantage over comparable conventional materials in terms of embodied energy, but also in terms of net CO 2 emissions over the entire life cycle of a typical building. This is primarily due to the active carbon sequestration of the hemp plant during its growing phase, and the gradual sequestration of carbon emitted during the production of lime. The thermal properties and behaviour of a hemp-lime wall material were found experimentally to be virtually identical to those of a commonly-used lightweight concrete insulation material with a similar density.

As of 2007 more than half of the world’s population is living in urban areas (a figure expected to rise to 60% by 2030). Thus, the liveability of the high-density city is gradually becoming a central point of focus and concern. A successful skyscraper model of urban planning could provide the possibility to increase city-space vertically as opposed to the current continuous expansion outward, which has obvious environmental consequences. However, skyscraper development, as well as all other new construction and gradually the older building stock, has to comply with current strict regulations on building energy efficiency. Contemporary high-rise examples do not present a sustainable solution to an increasing population or as models of prosperity, as they are linked to high-energy demand, environmental and social imbalances. This paper looks at design strategies towards promoting skyscraper energy efficiency by considering a climatically responsive design, where orientation, the thermal properties of the building envelope and the effect of altitude, become the main design tools. Initial simulations were performed for a residential and an office reference structure 100 m high. Different scenarios were implemented for gradually upgrading the building envelope and studying its relationship with the changing microclimate with altitude (wind speed increase and dry bulb temperature drop) between ground and top level. The advanced envelope was then simulated to up to 400 m high (120 stories high), and heating and cooling loads were compared in relation to different building heights and uses. EnergyPlus is used as the main simulation tool as it accounts for wind speed increase and dry bulb temperature drop with height. The location chosen is Tel Aviv, Israel, a city already growing upwards and expected to have a significant increase in skyscraper construction in the coming years. The results of the simulations performed present the base upon which further design strategies can be implemented towards reducing the environmental impact of this challenging building type.

The fast growing numbers of high-rise buildings around the world, a product of expanding urbanization and population growth, dictate the implementation of design strategies towards the reduction of their high energy loads. This study focuses on an office high-rise building in the Mediterranean climate of Tel Aviv and the reduction of high cooling loads relevant to this climate. In this process, the design of the building envelope becomes the most important constituent between indoor and outdoor environment, by dictating the required use of energy for achieving thermal comfort. A double skin facade (DSF) layer is proposed as a more advanced envelope design compared to the single skin curtain walls (controlled ventilation, acoustic insulation etc.). A previous study based on thermal simulations in Tel Aviv, revealed that a ventilated DSF design with the LowE glazing as the exterior layer of the DSF reduced cooling loads by 15% on average, in comparison with a typical DSF design in temperate climates where the LowE glazing is on the interior layer of the DSF, and by an average of 50% from the option of single skin envelope with LowE glazing. This study draws from the conclusions of previous data, and tests the energy efficiency of different DSF cavities in the Mediterranean climate. Results revealed that by increasing the cavity width from 0.2 m to 0.5 m, cooling loads decrease significantly, while there are also substantial reductions, from 0.5 m to 1.0 m, and from 1.0 m to 2.0 m DSF cavity width.

The numbers of high-rise buildings around the world increase rapidly. However, this fast pace is not in tandem with the expertise gained on how to design this building typology to best adjust it to local climates. In addition, the increased transparency of the building envelope from the mid-twentieth century onwards, resulted in high-energy loads, especially prominent in high-rise construction. With planning policies moving towards targets for low carbon built environments, this challenging typology needs further research and experimentation. This study focuses on the building envelope, as a passive design strategy towards reduced energy loads. Simulations of different envelope scenarios in the Mediterranean climate are conducted with EnergyPlus thermal simulation engine, and comparisons are made on energy loads in relation to height. Initial simulations between three single-skin envelope scenarios and a ventilated double skin facade (DSF) revealed the importance of lowering the high cooling loads relevant to the hot and humid climate, while external shading performed better from a double-skin envelope with LowE glazing as the interior layer. The focus then shifted on increasing the energy efficiency of the DSF, as a more advanced envelope option (controlled ventilation, acoustic insulation etc.), by drawing comparisons between four DSFs. Simulations showed that the most energy efficient DSF in the Mediterranean climate is with LowE glazing as the outside layer. In the final step, the comparison between the building envelope with the proposed DSF and the one with external shading was in favour of the DSF option. Conclusions are drawn on the relationship of the building envelope with climate, with a preference on DSF towards a low carbon building design, while suggestions are made for further DSF research.

This chapter will present experimental data from studies in test cells, and from monitoring indoor temperatures in un-occupied and in occupied buildings, when data was available, regardless of the dates of the research, not just recent research. In many cases where sufficiently measured data of the outdoor and the indoor temperatures was available, formulas have been generated, expressing the indoor temperatures of the building or the test model as a function of the outdoor temperatures. In cases where long-term monitoring has been conducted, predicting formulas were generated: data from one period was used for the generation of the formulas while the data other period was used for their validation. All the formulas represent the experimental data and conditions of the various studies. They are not intended to be used for general prediction of the performance of the tested passive cooling system.

The paper presents the thermal analysis of a low-cost prototype consisting of plywood panels, which was designed and built by one of the authors within the scope of a program for subsidized low-cost housing. The object of analysis is a building prototype located in Canoinhas, in the South of Brazil (26°10′38″S, altitude 765 m above sea level). The present paper is concerned with evaluating the thermal performance of the prototype over given periods of the year by means of onsite measurements and indoor temperature predictions for the various rooms of the building prototype. From obtained results, the overall performance of the building as well as the individual performance of each room was evaluated.

This paper presents the findings of an outdoor thermal comfort study conducted in Hong Kong using longitudinal experiments--an alternative approach to conventional transverse surveys. In a longitudinal experiment, the thermal sensations of a relatively small number of subjects over different environmental conditions are followed and evaluated. This allows an exploration of the effects of changing climatic conditions on thermal sensation, and thus can provide information that is not possible to acquire through the conventional transverse survey. The paper addresses the effects of changing wind and solar radiation conditions on thermal sensation. It examines the use of predicted mean vote (PMV) in the outdoor context and illustrates the use of an alternative thermal index--physiological equivalent temperature (PET). The paper supports the conventional assumption that thermal neutrality corresponds to thermal comfort. Finally, predictive formulas for estimating outdoor thermal sensation are presented as functions of air temperature, wind speed, solar radiation intensity and absolute humidity. According to the formulas, for a person in light clothing sitting under shade on a typical summer day in Hong Kong where the air temperature is about 28°C and relative humidity about 80%, a wind speed of about 1.6 m/s is needed to achieve neutral thermal sensation.

Vernacular architecture is still very popular and constructed widely in North-East India. In this paper, the result of long-term monitoring of two vernacular houses selected one in Tezpur (warm and humid climate) and other one in Cherrapunjee (cold and cloudy climate) are presented. Long-term monitoring work includes the measurements of temperature (inside and outside house), relative humidity (inside and outside house) and illumination level (inside and outside house) for 25 days in all the seasons (January: winter, April: spring/pre-summer, July: summer/monsoon and October: autumn/pre-winter) of the year 2008. Temperatures profile across all the seasons represents strong daily and seasonal fluctuations. Formulae have been developed based on part of the monitoring data to predict the indoor maximum, average and minimum temperatures inside the same house occupied by the same family. The predicted formulae were developed based on the measured data for the month of January and July and were validated with the measured data of April and October months. It is found that the correlation coefficient ( R 2 value) is above 0.96 for all the six formulae for the entire monitoring period.

In the warm and humid climate zone, air-conditioning (AC) is usually provided at working places to enhance human thermal comfort and work productivity. From the building sustainability point of view, to achieve acceptable thermal sensation with the minimum use of energy can be desirable. A new AC design tactic is then to increase the air movement so that the summer temperature setting can be raised. A laboratory-based thermal comfort survey was conducted in Hong Kong with around 300 educated Chinese subjects. Their thermal sensation votes were gathered for a range of controlled thermal environment. The result analysis shows that, like in many other Asian cities, the thermal sensation of the Hong Kong people is sensitive to air temperature and speed, but not much to humidity. With bodily air speed at 0.1–0.2 m/s, clothing level 0.55 clo and metabolic rate 1 met, the neutral temperature was found around 25.4 °C for sedentary working environment. Then recommendations are given to the appropriate controlled AC environment in Hong Kong with higher airflow speeds.

In this paper, we compare results of a long-term temperature monitoring in a building with high thermal mass to indoor temperature predictions of a second building that uses an indirect evaporative cooling system as a means of passive cooling ( Vivienda Bioclimatica Prototipo -VBP-1 ), for the climatic conditions of Sde Boqer, Negev region of Israel (local latitude 30°52′N, longitude 34°46′E, approximately 480 m above sea level). The high-mass building was monitored from January through September 2006 and belongs to a student dormitory complex located at the Sde Boqer Campus of Ben-Gurion University. VBP-1 was designed and built in Maracaibo, Venezuela (latitude 10°34′N, longitude 71°44′W, elevation 66 m above sea level) and had its indoor air temperatures, below and above a shaded roof pond, as well as the pond temperature monitored from February to September 2006. Formulas were developed for the VBP-1, based on part of the whole monitoring period, which represent the measured daily indoor maximum, average and minimum temperatures. The formulas were then validated against measurements taken independently in different time periods. The developed formulas were here used for estimating the building's thermal and energy performance at the climate of Sde Boqer, allowing a comparison of two different strategies: indirect evaporative cooling and the use of thermal mass.

Previous research on Urban Heat Island Intensity (UHI) in Hong Kong was limited to 4 weeks of field measurements during the summer in 3 major coastal housing estates. The current study extends this work to 6 months enveloping 3 “seasons” and 7 different locations within the coastal area. Variations in UHI in the range −1.3 ° to 3.4 °C were recorded. The study reveals seasonal changes are in general more influential on UHI than changes due to geographical characteristics. Among the seasonal models, the peak summer clear sky day's daytime and nocturnal models examined separately were found to provide the clearest indicators of the impact of urban design variables on UHI with R 2 value of 0.7 and 0.8 , respectively. Sky view factor, surface albedo, altitude, vegetation above 1 m in height, average height to floor area ratio, location quotient and proximity to sea are critical variables in mitigating both daytime and nocturnal UHI. Combining daytime and nocturnal data dilutes the impact of extreme values on UHI, by up to 50%, and is not useful for design solutions. Ideally design solutions may respond to the adverse impacts recorded in peak summer clear sky daytime at the concept design stage, and then have the design manipulated and validated for other seasons.

Urbanization brings several changes to the natural environment. First, vegetation is supressed and natural scenery is modified, in order to accommodate manmade buildings and streets. Consequences bring a direct effect on fauna and flora and, due to a modified environment, with heat fluxes having a different pattern from that of the original site, on climatic features, such as on air temperature and humidity, radiative and convective heat exchanges. Thus, one of the factors that can contribute directly to the creation of urban climate is land use. The present study investigates how land use influences local temperatures in Curitiba, Brazil (25°31′S, 917 m elevation). For that purpose, seven different locations of the city were analyzed during a 1-month period by monitoring air temperature and humidity. Also, land use patterns around each location were quantified, according to five different categories established for that purpose: water area, built area, free area, paved area and green area. The monitoring of climatic data occurred in winter (June/July) of 2002. Comparisons were made regarding averages of the minimum, average and maximum temperatures for each location, qualitatively and quantitatively. As a final step of this study, formulas were developed expressing the local temperatures as a function of air temperatures, solar radiation and the wind speed of the meteorological station, which was used as reference station.

Two approaches have been tested by the author for cooling soil in a given location to temperatures well below the “normal” temperatures in that location. The first approach has been tested in Sde Boqer Campus, in the Israeli Negev desert. The soil was covered with a layer of pebbles, about 10 cm. thick, and watered in the mornings. Substantial cooling of the soil was achieved. This cooling system was tested in test cells in Sde Boqer, Israel, and in a full scale room in Riyadh, Saudi Arabia, and has provided effective cooling. The second approach was tested at A&M University in Tallahassee, Florida. Temperature measurements were taken of moist soil under a wooden shack on stilts raised about 60 cm above the ground. Thus the soil under it was permanently shaded. The cooled soil temperatures were below the outdoors’ minimum temperatures, even during the peak of the summer, providing a potential heat sink for cooling buildings. The thermal performance of an earth covered building in the Negev arid region of Israel is also summarized.

Studies, around the world, have demonstrated that envelope colour has significant effect on building thermal performance and the use of thermal mass can usefully modify the thermo-physical signature of buildings. However, their influences under hot-humid climate have not been investigated in details. In view of the issue, a testing facility has been established in the Department of Architecture of the Chinese University of Hong Kong; the facility allows study of the effect of various building design features on indoor temperatures. This paper presents the results of investigation about the effect of envelope colour and thermal mass on indoor temperatures. The study reveals that the use of lighter surface colour and thermal mass can dramatically reduce maximum indoor temperatures. However, their applications in building design could be very different, and to a large extent, depend on the circumstance. Furthermore, the paper demonstrates the possibility to develop predictive formulas for daily maximum indoor air temperature.

The main purpose of formulating methodologies for building systems’ evaluation in low-cost housing is to find an effective solution for the huge Brazilian housing deficit of approximately five million housing units, mainly due to an accelerated population growth in urban centers. Low-cost housing programs are usually implemented in a broad sense, with no regard to local specific conditions. Thus, building systems of quite similar characteristics are employed in places with different climatic conditions, which leads to low-quality houses that do not respond to the users’ needs. In this paper, the results of the application of formulas to predict daily indoor temperatures in three monitored low-cost houses in Curitiba, Brazil, are presented. The houses were occupied by families having neither cooling nor heating devices and are built of different building materials with different thermal properties. The monitoring of the houses took place both in winter and in summer. Measured data were also compared with simulated data. In this case, the French software COMFIE was used. Finally, the results of the thermal simulations were compared with those of predictive formulas developed by Givoni.

The paper discusses methodological issues and carrying out problems in outdoor comfort research. It also deals with the relative effects of air temperature, solar radiation and wind speed, as well as with the relationship between thermal sensation and overall comfort sensation, as was found in the outdoor comfort research in Japan. The paper also summarizes several studies going on presently at Tel Aviv University in Israel and presents some of the actual experimental results from these studies.

Buildings with different mass levels were monitored in the summer of 1993 in Pala, South California, under different ventilation and shading conditions. The effect of mass in lowering the daytime (maximum) indoor temperatures, in closed and in night ventilated buildings, was thus evaluated. Night ventilation had only a very small effect on the indoor maxima of the low-mass building. However, it was very effective in lowering the indoor maximum temperatures for the high mass building below the outdoor maxima, especially during the ‘heat wave’ periods. On an extremely hot day, with outdoor maximum of 38 °C (100 °F), the indoor maximum temperature of the high-mass building was only 24.5 °C (76 °F), namely within the comfort zone for the humidity level of California. Comment: In 1994 the monitoring has been continued, first with the original dark color of the envelope and then with the buildings painted white, as well as under natural, all-day ventilation with open windows. The results of the 1994 experiments will be reported in Part II.

The paper summarizes experimental data from testing a new type of a passive cooling system developed by the author, the “Shower” tower, and compares its performance under three different climatic conditions: Los Angeles in California, USA, Riyadh (Saudi Arabia) and Yokohama (Japan).

We tested this system with objectives to plan and apply this system in Japan, and examined its cooling effectiveness and ir flow generation

The paper discusses the design objectives and the urban design elements which affect and can modify the urban micro-climate in hot humid regions. The design elements discussed are: Location of towns in a region; Density of the built-up area; Orientation and width of streets; Building design details affecting the comfort of people outdoors, and the Design details of public and private “green” areas. Urban design details are suggested for hot humid and for hot dry regions. The paper is based on a recent book of the author (Givoni 1994).

The paper discusses objectives and principles for building design, from the human comfort aspects, in regions with hot humid summers and mild winters . The issues discussed are: Building layout; Openings and ventilation; Orientation with respect to the sun and the wind; Thermal mass; Special problems in Hurricane regions.

An experimental mathematical model that calculates the performance of a passive evaporative cool tower (also known as downdraft evaporative chimney), has been developed by Cunningham and Thompson. The model calculates the tower's exit air temperature, flow rate and the speed of the air exiting from the tower, and the diurnal patterns of the indoor temperature of a lightweight building cooled by this system. Initial validation of the model, by comparing predictions with independent measurements of the indoor temperature of the test building, was done by Cunningham et al. In its present state the applicability of the model is limited to the use of evaporating pads of the type used in the Tucson study (CELdek) cooling a lightweight building (stud wall construction).

The paper describes the climatic characteristics relevant to urban and building design in hot-humid and in hot-dry tropical regions, respectively. It then discusses the different human comfort issues, the design objectives and the urban design elements which affect and can modify the urban microclimate. The design elements discussed in the paper are: location of towns in a region, density of the built-up area and building's configurations, orientation and width of streets, building design details affecting the comfort of people outdoors, and the design details of “green” areas. The appropriate (from the climatic aspect) design details of the above urban design elements, and some comments on building design in tropical regions, are discussed with respect to each climate type. Subjects of needed research on issues concerning comfort and design problems in tropical cities, on which more knowledge is needed, are suggested. The paper is based on a recent WMO Document (Givoni, 1989, WCAP-10, WMO/TD, No. 346).

The paper discusses issues of thermal comfort standards, including the ASHRAE comfort zone, techniques of graphical climate data analysis, as well as the uses of building bioclimatic charts in the formulation of building design guidelines, especially for hot climates. The problematics of applying the Olgyay bioclimatic charts and the ASHRAE comfort standards for unconditioned buildings, especially in developing hot countries, are discussed. Revised building bioclimatic charts are described for the first time in this paper. The boundaries of applicability of various building design strategies and passive cooling systems in different climates are discussed. These strategies are based on the expected indoor temperatures achievable with the different strategies and include daytime ‘comfort” ventilation, the utilization of the structural mass for thermal storage in conjunction with nocturnal ventilation, and direct and indirect evaporative cooling.

The paper reviews the performance characteristics of various passive solar heating systems for buildings, the main design factors affecting their performance, the relative advantages and main problems associated with them, and their applicability to different building types and climatic regions. Emphasis is placed on the architectural design issues associated with the different passive solar heating systems and to the problems that may be encountered when passive solar heating is applied in regions with hot summers.

The paper summarizes the state of the art of passive and low-energy cooling systems for buildings: comfort ventilation, nocturnal convective cooling, radiant cooling, direct and indirect evaporative cooling, and utilization of the soil as a cooling source for buildings. The factors which affect the performance of each cooling system, its design implications and its applicability for different building types and climatic conditions are discussed. Results are given of experimental studies, mainly by the author, evaluating the performance of various cooling systems.

The paper discusses the impact of urban planted areas: public parks and private planting around individual buildings, on various aspects of the quality of the urban environment. Specific issues discussed are: • functions and impacts of urban planted areas; • effect of plants on the climatic characteristics of an area; • climatic impacts of private planted areas around buildings; • experimental studies on the thermal effect of plants; • public parks and the urban climate; • range of the effect of urban parks; • impact of green spaces on air pollution; • planted areas as noise; • social functions of urban parks; • parks as social interaction areas between neighborhoods; and • summary: Climatic guidelines for parks design: ◦ Parks in hot, dry regions; ◦ Parks in hot, humid regions; and ◦ Parks in cold regions. Comment: This paper is based on a book by the author, published by the World Meteorological Organization (Givoni, 1989, Urban Design for Different Climates, WMO).

In this paper, we present the results of a long-term monitoring of a passive solar house. Formulas were developed for predicting indoor air temperatures in the monitored building. As such formulas are based on climatic data, commonly registered at meteorological stations, the issue of adopting site-specific outdoor temperatures instead of those gathered at the meteorological station for evaluating comfort and cooling demand is also addressed in the paper. The formulas were here used for estimating the building’s thermal performance in summer, taking into account 1) air temperature data gathered at the adjacent meteorological station and 2) measured canyon air temperature.

(1981). Earth-Integrated Buildings—An Overview. Architectural Science Review: Vol. 24, No. 2, pp. 42-53.

Cooling of buildings by natural energies can be effected either by solar energy, although only with ‘active’ sophisticated systems, or by the utilization of other natural energies which can also be applied in a passive way. The natural energies which can be utilized for passive cooling are: • - nocturnal longwave outgoing radiation • - night convection • - water evaporation Combinations of these cooling sources are also possible, such as combining convective and evaporative nocturnal cooling or combining nocturnal longwave radiant initial cooling of air with subsequent super-cooling or water evaporation. The applicability of the various natural cooling sources (besides solar energy) depends greatly upon the climatic conditions prevailing in summer at night in a given region, and in particular on the dry and wet bulb temperatures of the nights in summer. This is because the low level to which a thermal storage system can be cooled is close to the dry or wet bulb temperatures at night, for convective or evaporative cooling, respectively. This paper discusses the applicability of various cooling systems utilizing the above-mentioned natural energies and some of the problems involved. Quantitative comments are related to the climatic conditions prevailing in Israel.

The paper summarizes the various heat sinks available for passive cooling of buildings; night ambient air for convective and evaporative cooling, the sky for radiant cooling and the earth. Different techniques for utilizing these options are discussed.

Previous experimental studies have dealt with the earth's surface and subsurface temperature profiles. The results from these studies have been summarized and analysed jointly, making it possible to derive some generalizations. It appears that the temperature range decrement factors for the different studies fit within a narrow range, and that they suggest a classification by climatic type. The values for the time lag in the annual temperature wave were also found to fall within a narrow range. Simplified equations are presented for determining soil temperatures and time lags as a function of depth. Different approaches for estimating the surface temperature are presented and discussed.

The state-of-the-art of passive and low energy hybird cooling systems is established through an examination of the various channels for cooling. Building components and design are discussed as elements that may enhance cooling. Impacts of earth-coupling are investigated.

The paper presents a mathematical model of the expected indoor temperatures in buildings cooled by different types of shaded roof ponds. Initial validation, by comparing predictions with experimental results of test cells, show good agreement.

This paper summarizes recent research works of the author on passive solar heating and cooling of buildings. The studies summarized are: Experimental validation of the LASL predictive formulae for Direct Gain; Extention of the LASL correlational formulae into a generalized model; Nocturnal Radiant Cooling; Convective Cooling; Roof-pond cooling; Earth Cooling. The paper presents the methodologies and summarizes the results of these studies.

One of the objectives of the design of the built environment is to provide comfort, while minimizing energy demand. In order to account for the attributes of a climatic region, the designer needs to adapt the built form to the natural environment. Within the constraints of declining nonrenewable resources, achievement of the objective of comfort requires sensitivity to an integrative perspective of the individual built form within the urban space. Such integration recognizes that there is no optimal design; rather, there are certain features of the physical environment and a set of human needs which seek satisfaction. It is the responsibility of the designer to plan so as to satisfy these needs. Such planning requires a clear understanding of design to ‘best fit’ the built environment to human physiology and behavior.

The performance of four passive cooling systems, nocturnal convective cooling, nocturnal radiative cooling, direct evaporative cooling and conductive earth‐coupled cooling, is evaluated for representative environmental conditions in the temperate, hot‐humid and hot‐arid climatic zones of the United States. The analysis indicates that substantial portion of the cooling load of a typical energy‐efficient single family residential building can be eliminated with any of these passive systems. Depending on system type and climatic zone, the building cooling load can be reduced by 1/3 to over 4/5 of its original value. The corresponding energy savings would amount to a minimum of 25 TWh/yr and could potentially exceed 50 TWh/yr, if proper passive cooling systems were to be employed throughout the country. Incorporation of passive cooling models in building energy analysis codes will be necessary to determine more precisely the potential of each system. Field testing will also be required to further evaluate this potential. Moreover, the extension of analytical modeling to include additional passive cooling systems and the research of advanced building—natural environment coupling systems and materials constitute tasks requiring further effort.

This paper presents some results of the research project “Domestic Violence and Architectural Space”, sponsored by several Mexican Governmental Offices and Citizen Organizations. One of the...