Performance Study of Dynamic Intake and Exhaust Fa鏰des in Hot and Dry Climates:Iraq Case Study

This paper is part of a series addressing the urgent need for effective technologies to reduce energy demand and mitigate climate impact.This study focused on the implementation and development of dynamic insulation technology for a sustainable and energy-efficient future in the region,especially in Iraq.The study assessed the energy efficiency of dynamic insulation technology by analyzing three wallmodels(static,dynamic,and modified)during thewinter season.This paper expands the analysis to include a hot,dry summer scenario,providing valuable insights into the year-round performance of dynamic walls and enabling sustainable and energy-efficient solutions for Iraq’s climate.The study evaluates the thermal efficiency of the dynamic intake and exhaust facades during the cooling season for the city of Baghdad.The finding indicated that the dynamic intake facade reduces energy consumption by 16.3%for the dynamic wall and 17.2%for the modified dynamic wall.In addition,the dynamic exhaust front reduces energy consumption by 46%during the cooling season,with the maximum permissible exhaust air level.Dynamic insulation is suitable for hot and dry climates,improving energy consumption.

EFFECT OF BUILDING PLAN FORM ON HUMAN THERMAL COMFORT IN NATURALLY VENTILATED OPEN-PLAN ENCLOSURES LOCATED IN HOT CLIMATES

This study aims to examine the effect of building plan form on internal thermal comfort conditions in naturally ventilated open-plan buildings located in hot climates.The study examined the square and the rectangular plan forms in relation to several values of wind direction,building plan depth,and climatic conditions.The study utilised CFD for ventilation prediction,DesignBuilder for thermal modelling,and the Tropical Summer Index(TSI)for thermal comfort assessment.These three tools were integrated in a quantitative approach to fulfil the study aim.The study concluded that the use of area-weighted average velocity magnitude is more accurate in the assessment of natural ventilation performance,as it accounts for both internal velocity magnitude and distribution.The study confirmed the common observation that the use of shallow building plans is more effective to increase internal air velocity and improve internal thermal comfort.At some point of increased plan depth,the internal air velocity magnitude dramatically decreases.In the three examined wind directions,this occurred when the plan depth exceeded 3H in the square cases and 2.5H in the rectangular ones,where H is the building height.This value is much less than the commonly recommended maximum value of 5H.The study also concluded that reducing building depth in the square cases has generally more potential to improve thermal comfort conditions when compared with the rectangular cases.The gross increase in Percentage of People Comfortable,PPC,in all the examined cases was 23%in the square cases,compared to 11%in the rectangular cases.

Optimisation of Thermal Comfort of Building in a Hot and Dry Tropical Climate: A Comparative Approach between Compressed Earth/Concrete Block Envelopes

Compressed earth blocks (CEB) are an alternative to cement blocks in the construction of wall masonry. However, the optimal architectural construction methods for adequate thermal comfort for occupants in hot and arid environments are not mastered. This article evaluates the influence of architectural and constructive modes of buildings made of CEB walls and concrete block walls, to optimize and compare their thermal comfort in the hot and dry tropical climate of Ouagadougou, Burkina Faso. Two identical pilot buildings whose envelopes are made of CEB and concrete blocks were monitored for this study. The thermal models of the pilot buildings were implemented in the SketchUp software using an extension of EnergyPlus. The models were empirically validated after calibration against measured thermal data from the buildings. The models were used to do a parametric analysis for optimization of the thermal performances by simulating plaster coatings on the exterior of walls, airtight openings and natural ventilation depending on external weather conditions. The results show that the CEB building displays 7016 hours of discomfort, equivalent to 80.1% of the time, and the concrete building displays 6948 hours of discomfort, equivalent to 79.3% of the time. The optimization by modifications reduced the discomfort to 2918 and 3125 hours respectively;i.e. equivalent to only 33.3% for the CEB building and 35.7% for the concrete building. More study should evaluate thermal optimizations in buildings in real time of usage such as residential buildings commonly used by the local middle class. The use of CEB as a construction material and passive means of improving thermal comfort is a suitable ecological and economical option to replace cementitious material.

Quantitative Analysis of the Outdoor Thermal Comfort in the Hot and Humid Summertime of Shenzhen, China

Outdoor thermal comfort has always been a major issue due to its irreplaceable role in maintaining good health and energy use. Thus,quantitative analysis of outdoor thermal comfort and discussions on influential factors seem very necessary to achieve the climate-conscious urban design. Therefore,an outdoor thermal comfort questionnaire survey and the simultaneous field measurement were conducted in six different places during the hot and humid summertime in Shenzhen. The results show that the overall weather conditions during the investigation can be expressed with high temperature and high humidity with strong solar radiation. The micro-meteorological parameters of six test sites vary greatly due to their different regional spatial layouts.Moderate range of air temperature( Ta) is between 28 to 30 ℃ while that of relative humidity( RH) mainly concentrates in 60%-70% with the thermal sensation votes. The main influential factors impacting outdoor thermal comfort are obtained and Tahas the greatest effect. The overall thermal comfortable ranges in Shenzhen are expressed by the range of 28. 14-32. 83 ℃ of PET and 24. 74-30. 45 ℃ of SET*. With the correlation analysis between the characteristic parameters of regional spatial layout and thermal climate and thermal comfort,it reveals that increasing the coverage ratio of water and green space( S) helps lower Taand increase RH. The global solar radiation( G) has a significant negative correlation with the height of buildings( H) and a positive correlation with sky view factor( SVF). Overall,reasonable configuration of the regional spatial layout contributes to providing a thermal comfortable environment.

The Extremely Hot and Dry Climatic Events and Potash Enrichment in Salt Lakes of the Jiangling Depression, Jianghan Basin

Objective A total of 820 million tons of potash reserves are predicted to exist in the Palaeocene-Eocene of the Jianghan Basin. However, the basin history is still unclear concerning the potash enriching conditions and mechanism. The Well SKDI is the first exploration well drilled in the Paleogene of Jianghan Basin with continuous coring, which was implemented in the south-central Jiangling Basin in 2013. It is essential to study the Palaeocene-Eocene paleoclimate, to further constrain the extreme draught events and the potash forming conditions.

Passive Cooling Strategies in Greening Existing Residential Building in Hot Dry Climate： Case Study in Bahrain

This paper will present several passive-cooling technologies and design features that can be adopted to reduce building heat gain without the need of excess energy consumption. A typical residential unit will be selected as case study and a three basic passive cooling strategies were selected to enhance the building envelop, as well as using appropriate shading devices and green roofing system that prove to be a good environment quality improver. IES energy simulation software will be used to evaluate the performance of the building. The study revealed a number of significant findings in reducing the energy consumption and enhancing the tenants＇ thermal comfort. American Society of Heating Refrigerating and Airconditioning Engineer （ASHRAE） standards specially via improving the performance of building envelop because it is the interface between internal and external environment. Moreover, improving the building envelope has recorded that overall energy and chiller energy consumption can be reduced up to 10.8% and 21.6% respectively, Therefore, it is anticipated that further reductions can be achieved via applying more passive cooling strategies. Finally, it could argue that the results of this paper will not only be applicable to Bahrain but also many countries that have similar climatic and environmental context.

Microclimate in Hot Dry Damascus： The Influence of the Urban Environment on Human Perception

There is a broad recognition that microclimatic conditions contribute to the quality of life in cities. A favorable microclimate has a positive influence on both commercial and social activities. The aim of this study is to investigate the relationship between the human being and the surrounding thermal environment in terms of thermal acceptability, physical quality of the place, emotional state and the usage of the urban space in hot dry Damascus, Syria. The study is based on questionnaire surveys during the summer and winter in six locations with different microclimates. It is shown that the urban design plays a significant role in improving the microclimate, especially during the summer. The study also illustrates that when people＇s thermal perception is within the thermally acceptable range （i.e., slightly cool, comfortable and slightly warm） they experience the urban design as significantly more beautiful and more pleasant than during thermally unacceptable conditions. The results indicate that there is an interactive relationship between the urban design and humans＇ emotional state. Our findings suggest that a new perspective is needed for determining urban microclimate requirements and incorporating them into the urban design process to enhance the thermal environment in outdoor urban spaces in Damascus.

Adaptive Thermal Comfort for Occupants of Low-Cost Dwellings in a Hot Dry Climate

Adaptive models are based on the observation that there are some actions that people can and actually do take to achieve thermal comfort. Studies regarding thermal comfort conditions in economical dwellings were carried out simultaneously in seven Mexican cities, corresponding to warm dry and warm humid climates. In this article, case studies of low-cost dwellings in the city of Hermosillo （in northwest Mexico）, are presented and analyzed. Field surveys were carried out to obtain information about the physical characteristics of the dwellings and their occupants, as well as the indoor thermal environment. Neutral temperature was obtained from the applied survey. The high neutral temperature reveals the effect of inhabitants＇ adaptation mechanism to extreme climates. Occupant comfort votes as a function of indoor air temperatures were analyzed, and different characteristics such as age, size and gender were evaluated separately. The results show the variability of the neutral temperature and the tolerance to temperature changes, depending on the population＇s specific characteristics. In many cases where the population does not have access to artificial acclimatization devices, the neutral temperature values for specific climates and people can inform architects when choosing the most suitable thermal strategies for building design.

MASS FLOW RATE INDUCED BY COMBINED ROOF SOLAR COLLECTOR AND VERTICAL STACK IN A HOT HUMID CLIMATE

This paper presents the investigation of solar induced ventilation that utilizes roof solar collector and vertical stack. Three prototypes, namely A, B and C, were developed based on preliminary experimental work. They were then used in simulation study with the objective of determining the prototype that was able to induce the highest mass flow rate. The validation of simulation modelling against experiment indicated a good agreement between these two results. The findings showed that prototype A induced the highest mass flow rate. However, prototype C, which had obstructions at the stack outlets, was more appropriate for application in Malaysia due to various prevailing wind directions. In addition, the findings also indicated that besides solar radiation, the mass flow rate induced by the prototypes was also influenced by the local wind direction, the inlet and outlet positions as well as the outlet design. In summary, the findings highlighted the potential application of the proposed solar induced ventilation in a hot and humid climate.

Effects of water-cooled cover on physiological and production parameters of farrowing sows under hot and humid climates

The hot and humid climates,as encountered in the southern region of China with the open housing,can adversely impact the sows undergoing heat stress during the most vulnerable period at lactation.Hence,a water-cooled cover system(WCCs)for local cooling has essential practical value to improve productivity.The WCCs was developed for the sow crate of lactating sows separately,which performance was validated with the cooling efficiency in the sow occupied zone(SOZ)and physiological parameters.The results showed that the WCCs for the farrowing sows using aluminium plastic tubes connected in series could reach an appropriate cooling performance in adjacent units.The WCCs could decrease the SOZ air temperature by 3.0-4.5℃under the extremely hot climate when the indoor air temperature was 37℃,and maintain a suitable range(25-30℃)under the typical hot climate(<35℃).The respiration rate and skin temperature of farrowing sows had no significant difference between treatment group(WCC)and control group(sprinkle cooling)when the air temperature was below 30℃,but had a significant difference(p<0.05)when air temperature rose above 30℃.The control sows drank more during hot weather,and the feed intake was significantly lower than the sows with the WCCs(p<0.01).It was concluded that the WCCs could alleviate the heat stress of farrowing sows during typical hot climate.

Optimisation of the double skin facade in hot and humid climates through altering the design parameter combinations

Architects welcome double skin facade(DSF)due to its aesthetic quality.The first DSF structure was intended to prevent cold weather and strong winds.Nowadays,the application of DSF under different climates has been investigated in many previous studies.Fiowever,little work had been done on the behaviour of DSF in hot and humid climates.Therefore,this paper aimed to extend the application into this specific climate and Guangzhou was selected as the sample city.Both the climate and the design influence the performance of DSF.In this paper,rather than explore how each design parameter influences the performance,the design was evaluated from an overall aspect.The Designbuilder software was used to build the single skin facade(SSF)and double skin facade base model.Annual HVAC energy consumption for both the two models was calculated and compared.An optimisation process was conducted to figure out what kinds of parameter combination could make the design more energy-saving and thermally comfortable.The results indicated that it was possible to design an energy-saving DSF system applied in hot and humid climates compared with the SSF model.The efficiency of the DSF could be further enhanced with a better parameter combination.The optimised options had some features in common,which could provide some inspirations for the application of DSF in hot and humid climates.

Anatomy of a eustatic event during the Turonian (Late Cretaceous) hot greenhouse climate

Sequence stratigraphic studies consider relative change in sea level(as regulated by eustasy,local tectonics and sediment supply)as the main builder of the stratigraphic record.Eustasy has generally been considered as a consequence of the growth and decay of continental ice sheets that would explain large,rapid changes in sea level,even during periods of relative global climatic warmth.However,such a mechanism has become increasingly difficult to envision during times of extreme global warmth such as the Turonian,when the equator-to-pole temperature gradient was very low and the presence of polar ice seems improbable.This paper investigates the timing and extent of sea level falls during the late Cenomanian through Turonian,especially the largest of those events,sequence boundary KTu4,which occurred during the middle to late Turonian peak of the Cretaceous hot greenhouse climate.We conclude that the amplitude of the widespread third-order sea level fall in the middle Turonian that is centered at^91.8 Ma varies at different locations depending on the influence of dynamic topography on local tectonics and regional climatic conditions.Ice volume variations seem unlikely as a mechanism for controlling sea level at this time.However,this causal factor cannot be ruled out completely since Antarctic highlands(if they existed in the Late Cretaceous)could sequester enough water as ice to cause eustatic falls.To ascertain this requires detailed tomographic imaging of Antarctica,followed by geodynamic modeling,to determine whether high plateaus could have existed to accumulate ephemeral ice sheets.Other mechanisms for sea level change,such as transference between ground water(a small amplitude shorter time scale effect)and the ocean and entrainment and release of water from the mantle to the oceanic reservoir(a potentially large amplitude and longer time scale process),are intriguing and need to be explored further to prove their efficacy at third-order time scales.

Exploring building's envelope thermal behavior of the neo-vernacular residential architecture in a hot and dry climate region of Algeria

It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this point of view,it is interesting to quantitatively assess the effectiveness of the vernacular strategies to improve the environmental performance of the building's envelope under desert climate conditions.The research tries to address this issue and was undertaken in southern Algeria where a very hot and arid climate prevails.The effect of some selected passive cooling strategies on enhancing the building's envelope climate performance was examined.These strategies are inspired from the local vernacular architecture,and they are expected to provide satisfactory indoor thermal comfort for users and to reduce the energy cooling demand from residential buildings.Applying field and computational investigations,two existing residential buildings were tested:a typical residential unit and a contemporary vernacular(neo-vernacular)building.In the latter,climate responsive strategies inspired from vernacular architecture were applied.A comparison based on site measurements was carried out on the two selected buildings which differ from their envelope design properties and components.

Cooling load characteristics of indoor spaces conditioned by decoupled radiant cooling unit with low radiant temperature

Decoupled radiant cooling units(DRCUs)are capable of increasing the cooling capacity without increasing condensation risks even using a much lower cooling temperature than conventional radiant cooling units(CRCUs).However,it is unclear whether DRCUs using low radiant cooling temperature will increase the cooling load of the conditioned indoor spaces.In this study,the cooling load characteristics of a thermal chamber conditioned by a DRCU was investigated through developing a steady-state analysis model suitable for both DRCUs and CRCUs.The total/radiative heat flux,as well as the heat exchange with a thermal manikin and walls were analysed under different surface temperatures of DRCUs.The effect of the emissivity of the thermal chamber’external wall on the cooling load was also investigated.Results indicated that the cooling load under the DRCU was slightly smaller than that under the CRCU when the same operative environment was created.Decreasing the infrared emissivity of the exterior wall’s inner surface could lead to a significant decrease in the cooling load for both the DRCU and CRCU.By decreasing the wall emissivity from 0.9 to 0.1,the total cooling load of the DRCU can be decreased by 8.4%and the heat gain of the exterior wall decreased by 21.6%.This study serves as a reference for developing the analysis model and understanding the load characteristics when DRCUs are used to create the thermal environment for indoor spaces.