Hot-Humid Climate Zones Research Articles

Post-Occupancy Evaluation in Post-Disaster Social Housing in a Hot-Humid Climate Zone in Mexico

In Mexico, the national fund for disasters (FONDEN) spent up to USD 800 million yearly building low-income housing for victims of highly destructive disasters. Since 2002, a total of 34 thousand new houses have been built as a response to Hurricane Isidore. However, recent research suggests that most of the FONDEN houses have been either abandoned or repurposed, which questions their suitability. In this paper, the authors sought to gain insight into occupants’ perception of post-disaster social housing in Yucatan, southern Mexico, with views of understanding their use across this housing typology. The method employed in this study was a post-occupancy evaluation (POE), investigating occupants’ satisfaction levels and thermal comfort in the homes. This was conducted through questionnaires, observation through photographic documentation, and environmental monitoring. Results revealed that 52% of occupants reported extreme dissatisfaction during warm seasons and 28% experienced dissatisfaction during cold seasons. The most used electrical appliance (84%) was found to be fans for increasing air movement. This was consistent with the results of the environmental monitoring, which demonstrated that there was thermal discomfort 67% of the time in September and 19% in December. This accounts for a warm-humid period and cool period, respectively. The results suggested that thermal discomfort may contribute to the abandonment and repurposing of these houses.

Retrospective dynamic life cycle assessment of residential heating and cooling systems in four locations in the United States

Heating, ventilation, and air conditioning systems (HVAC) and water heaters are responsible for a relevant portion of the total Greenhouse Gas (GHG) emissions related to the building life cycle. A significant effort will be needed to substantially reduce building-related GHG emissions to meet the increasing demand to meet goals for energy use and GHG emission reduction. This study evaluates the GHG emissions of two alternative residential HVAC systems: natural gas furnace and electric air conditioning, and an electric heat pump, in a typical single-family house located in four different climate zones in the U.S. using a life cycle assessment model that includes spatial variations such as climate and electricity generation mix and temporal variations such as the changes in the generation mix and greenhouse gas emission factors for electricity generation over time. The locations selected are in very cold, cold, marine (temperate), and hot-humid climate zones in the U.S. The reduction in GHG emissions over time occurred due primarily to the changes in the electricity grid mix. As a result, the heat pump system had the greatest reduction in GHG emissions over time and had the lowest GHG emissions over the study period in two of the four locations. If the decarbonization of electricity production continues and refrigerants with low GHG potential are widely used, the heat pump can be the HVAC system with the lowest GHG emissions in all climate zones studied.

Recommendations for Improvement of the Thermal Performance of an Office Building Based on Retrofitting the Glazed Curtain Wall

Glazed curtain wall systems have become indispensable particularly in office buildings due to their light weight, aesthetic appearance, easy installation, and resistance to climate conditions. Curtain walls, however, also have problems in terms of thermal efficiency because of their wide, glazed windows and metal frames that have high thermal conductivity. The aim of this study is to offer proposals for improving the thermal performance of an office building with a glass curtain wall system built in a hot-humid climate zone. An office building constructed in Antalya, Turkey was modelled with the help of DesignBuilder energy simulation software, and various modifications were made to the model in order to improve the thermal performance of the building. With the improvements proposed in the study, it is possible to decrease the annual thermal loads of the whole building by 6.6%, and the annual thermal loads of the space with the curtain wall by 33.2%. The study revealed that applying an additional skin is more effective than lowering the U-value of the glass of the curtain wall in terms of thermal performance improvement.

Evaluating Spatial Identity Based on Climate Adaptation in Small Cities.

Urban spatial identity is declining in Chinese cities overall due to urbanization, which is attracting increasing attention from the government. Research gaps include systematically comparing urban identities based on causes and manifestations in small cities. We developed a framework for estimating spatial identity from the perspective of climate adaptation, which is based on the relationship between regional climate and spatial form. Five small cities were selected in China: Wu'an, Qingcheng, Jintang, Changxing, and Lianjiang. Our findings suggest that (1) typical indicators include impervious surface rate, green coverage rate, water surface rate, average story number, and total gross floor area, contributing to morphological characteristics influenced by climate drivers; (2) for the hot humid climate zones, the city with the highest level of spatial identity is in Jintang, followed by Lianjiang and Changxing; and for the cold climate zones, the level of spatial identity in Qingcheng was higher than in Wu'an. This can contribute to the understanding and methodology of spatial identity based on climate adaptation in small cities.

Optimization of energy use and academic performance for educational environments in hot-humid climates

Thermal comfort and air quality are important factors for indoor environment in school buildings owing to the strong relationship with students’ academic performance. However, the expense of achieving expected environment quality in classrooms is unaffordable by many schools; thus, this study aims to suggest optimal strategies for balancing energy use and indoor environment quality simultaneously. Through the field measurement and building energy simulation, we analyzed the influences of temperature set-point and ventilation rate on environment quality and clarified the optimal trade-off measures for Taiwanese primary school. The optimal combination of set-point and ventilation rate considered academic performance and cooling energy based on single-objective optimization is proposed and revealed the highest hourly average cost performance is 2.13%/kWh each hour in Taipei and 2.03%/kWh each hour in Kaohsiung, which respectively corresponding to the set-point and ventilation rate of 24 °C and 26 °C, 12.6 L/s-person and 22.05 L/s-person. Moreover, the optimal combinations concerning financial constraints are also confirmed by Pareto front through multi-objective optimization. The results indicated that to achieve the academic performance higher than 85% in primary school, the optimal solution sets are scattered between the set-point of 23 °C–25 °C and the ventilation rate of 20 L/s-persoñ25.2 L/s-person. Consequently, this study provides recommendations for policymakers to formulate strategies to maximize the academic performance in hot-humid climate zone.

Creating glazed facades performance map based on energy and thermal comfort perspective for office building design strategies in Asian hot-humid climate zone

Glazed facades are broadly applied in modern architecture especially office buildings. However, glass enables massive heat transmitted into buildings that leads to thermal discomfort and energy profligacy particularly in hot-humid climate zone. Considering the strategies of energy use and thermal comfort at initial design process is beneficial for building performance, while there is shortage of approachable method to easily involve in building energy modeling or thermal comfort assessment. To enhance the connection of architecture design and building environment, this study proposed a guide map to provide visualized information from the aspects of energy use and thermal comfort through simulating the performance of different composition of glazed facade parameters. Specifically, cases with various facade configurations located in Southeast Asia cities are set to demonstrate the cooling load and long-term thermal comfort evaluation, including Environmental Quality Index (EQI), Spatial Thermal Comfort Availability (sTCA), and Temporal Thermal Comfort Usability (tTCU). Furthermore, a comprehensive thermal parameter called facade solar aperture is suggested to describe the performance of solar gains from facade; eventually, correlation among facade parameters, energy use, thermal comfort, and geographic location is disclosed. The results also indicated that to eliminate the discomfort for maintaining the condition of PMV = 0.5, the setting temperature of air-conditioning needs to be decreased by 2 °C ∼ 3 °C which corresponding to the increasing cooling load of 142.5 MJ/m2 to 215.0 MJ/m2. Comprehensively, through the proposed method, architects can obtain optimal schemes of different parameters, then balance the energy conservation and thermal comfort through better glazed facade design strategies.

Dynamic simulation of hydrogen-based zero energy buildings with hydrogen energy storage for various climate conditions

Solar energy systems are an effective way to meet the needs of zone heating, cooling, electricity, and domestic hot water. However, to reach sustainability, and energy storage unit should be considered for installation. In this study, two combined cooling, heating and power (CCHP) systems are simulated and studied using TRNSYS software; both using natural gas engine generators and photovoltaics as prime movers and a hydrogen fuel cell/electrolyzer storage unit, one with absorption chiller and another with compression chiller cooling. For the study, a residential building is modeled for three major populated climate zones of the United States of America, namely, Hot-humid, mixed-humid and cold using DesignBuilder and EnergyPlus software. The energy demand for its HVAC operation and domestic electricity is obtained and used for system simulation in TRNSYS software. Due to choosing actual equipment for the CCHP arrangement, precise economic and environmental models are designed to further evaluate the possibility of execution of the system. The results show that absorption chiller-equipped CCHP has better performance both environmentally and economically. In addition, the outcome shows that the suggested systems show less favorability to be utilized in hot humid climate zones.

Study on wind environment of semi-open space in hot-arid and hot-humid climate zones in rural areas

To explore the coupling effect of open space temperature and air velocity in hot-arid and hot-humid climate regions in rural China, 1690 valid data were obtained by long-term field tests and questionnaires were carried out in hot-arid and hot-humid regions. Results indicated that when the operative temperature is below 33.5 °C, the mean thermal sensation decreases with the increase of air velocity in the hot-humid region. When the operative temperature rose to greater than 33.5 °C, the mean thermal sensation could be significantly reduced only when the air velocity is over 1.0 m/s. However, increasing air velocity in hot-arid regions can significantly improve the thermal sensation. In addition, residents in hot-humid regions were more willing to increase airflow than those in hot-arid regions. These results support the theory of climate adaptation and can provide a reference for the design of semi-open space buildings in rural regions.

Energy performance analysis of a historical building using cost-optimal assessment

The energy efficiency concept has attracted significant attention over the last few years and has taken a prominent role in the development goals of countries. Considering that buildings have a high share in total energy consumption, it is crucial to improve their energy performance both in environmental and economic terms. Although efforts in increasing buildings’ energy efficiency have primarily focused on new buildings, existing buildings still retain their importance. Historical buildings are included in the existing building stock. It is essential to increase their energy efficiency to achieve carbon–neutral building targets set from EU Directives. In this paper, we proposed measures to improve the energy efficiency and determine cost‐optimal levels of a public historical building located in a hot-humid climate zone of Turkey. An integrated approach based on in situ measurements and building energy simulations was used to create a building energy model that was calibrated by using real measurements. Then, 365 energy-efficient measures are applied to the building and conducted an economic feasibility study by utilizing a cost-optimal envelope, lighting, heat pump and photovoltaic panel. A sensitivity analysis is performed to determine the impact of investing on optimal cost-of-energy level calculations with focus on the inflation rate, different interest rates, and calculation periods. Sensitivity analysis of discount rate has shown when the discount rate increases, global costs decrease. It is observed that the changes in economic parameters that could cause a decrease in annual costs reduced the cost effectiveness of the scenarios with high initial investment costs.

A Multi-Facet Retrofit Approach to Improve Energy Efficiency of Existing Class of Single-Family Residential Buildings in Hot-Humid Climate Zones

Targeting existing residential buildings for retrofit improvement presents significant prospects for global reduction of energy-usage and carbon footprints. Energy consumption of the existing single-family building in the hot-humid climate zone needs to be targeted for improvement due to their potential energy-savings and sizeable market share. This paper proposes and evaluates energy savings and cost-effectiveness of a whole building retrofit package for single-family residential buildings built between 1950 and 1970. The study outlined a survey conducted using the clustering data mining technique on Florida Single-Family Residential (SFR) homes to determine the essence of the building envelope, patterns of construction, and Heating, Ventilation, and Air-Conditioning (HVAC) systems. The evaluation of the energy efficiency measures (EEMs) effectiveness is performed utilizing Autodesk Revit and a Six-Step modeled framework. This framework consists of baseline model development, validation of the model with an actual case study building, identification of potential EMMs, evaluation of EEMs individually and incorporating the selected EMMs into retrofit package and maximizing the energy-saving and cost-effectiveness of the proposed retrofit package. The study develops proposed retrofit improvement package detailing replacement & improvement EEMs, implementation cost, annual energy savings (kWh), cost-saving ($), and payback period (years) for each individual EEM as well as the combined/total energy improvement package. The paper further explored the usage of solar photovoltaics (PV) energy generation options to offset the remaining energy-use after the implementation of the proposed retrofit package.

Performance assessment of a solar thermal combisystem in different climate zones

As one of the largest energy consumers, the residential buildings have a worthy potential for energy saving. Solar thermal combisystems, which provide the required energy for both domestic hot water and space heating, play a key role in reducing the building energy consumption. The purpose of this paper is to investigate the effect of the climatic conditions on the thermal performance of a solar combisystem using a dynamic simulation by TRNSYS. To this aim, the system performance is considered in five different climate zones including Hot-Dry, Cold-Dry, Moderate-Humid, Hot-semi-Humid, and Hot-Humid. Based on the obtained results, the required energy for domestic hot water is supplied by solar energy in all climate zones, except Moderate-Humid and Cold-Dry climate zones. For providing the required energy for space heating, it is necessary to use the auxiliary energy in all climate zones and all months, except Hot-semi-Humid and Hot-Humid climate zones, which has the small space heating loads because of the high ambient temperature in cold months. The annually total solar fraction of 74%, 61%, 47.8%, 87.9%, and 92% is obtained in Hot-Dry, Cold-Dry, Moderate-Humid, Hot-semi-Humid, and Hot-Humid, respectively. The findings confirm that the building energy consumption decreases considerably using the solar combisystem as a heating system, which resulted in significant energy and economic savings.

Impact of Energy Efficient Design Parameters on Energy Consumption in Hot-Humid Climate Zones

Impact of Energy Efficient Design Parameters on Energy Consumption in Hot-Humid Climate Zones

Evaluation of the ENVI-Met Vegetation Model of Four Common Tree Species in a Subtropical Hot-Humid Area

Urban trees can significantly improve the outdoor thermal environment, especially in subtropical zones. However, due to the lack of fundamental evaluations of numerical simulation models, design and modification strategies for optimizing the thermal environment in subtropical hot-humid climate zones cannot be proposed accurately. To resolve this issue, this study investigated the physiological parameters (leaf surface temperature and vapor flux) and thermal effects (solar radiation, air temperature, and humidity) of four common tree species (Michelia alba, Mangifera indica, Ficus microcarpa, and Bauhinia blakeana) in both spring and summer in Guangzhou, China. A comprehensive comparison of the observed and modeled data from ENVI-met (v4.2 Science, a three-dimensional microclimate model) was performed. The results show that the most fundamental weakness of ENVI-met is the limitation of input solar radiation, which cannot be input hourly in the current version and may impact the thermal environment in simulation. For the tree model, the discrepancy between modeled and observed microclimate parameters was acceptable. However, for the physiological parameters, ENVI-met tended to overestimate the leaf surface temperature and underestimate the vapor flux, especially at midday in summer. The simplified calculation of the tree model may be one of the main reasons. Furthermore, the thermal effect of trees, meaning the differences between nearby treeless sites and shaded areas, were all underestimated in ENVI-met for each microclimate variable. This study shows that the tree model is suitable in subtropical hot-humid climates, but also needs some improvement.

Opportunities to improve indoor temperatures and electricity use in remote Australian buildings

Abstract: Adaptation to climate change and mitigation of the rising costs of electricity are key incentives for improving building energy efficiency. The need is particularly acute in remote communities in Far North Queensland and Central Australia. Electricity is expensive, incomes are relatively low and maintenance services are difficult to access. At the same time buildings have to provide an environment that is safe and productive while coping with extremely challenging climates. We report eight case studies that investigated community buildings and their associated electricity consumption, temperatures and relative humidities over a nine month period. The study focused on two building construction types: i) concrete block and ii) steel frame, in the hot arid and hot humid climate zones of northern Australia. Key findings are described relating to i) improving building thermal efficiency, ii) reducing the electricity consumption by appliances, particularly standby consumption, iii) the potential for adapting the energy efficiency rating tool AccuRate for use in remote communities in arid and tropical northern Australia.

Field study on adaptive comfort in air conditioned dormitories of university with hot-humid climate in summer

This study aims to investigate adaptive comfort in air conditioned dormitory rooms in hot-humid climate zone. A field survey was carried out in air conditioned dormitories in Changsha, a big city in south-central China in summer. This survey included indoor environment measurements, questionnaires and interviews. The obtained results indicated that the experience of long-time living in regions with hot-humid climate in summer enhanced subjects’ adaptability to higher temperature, which can be explained by psychological and behavioral processes. Such kind of adaptability still existed in air conditioned environment even though it was not as strong as that in naturally ventilated environment due to increased expectation, psychological and behavioral dependencies on air conditioners as well as possible weaker physiological adaptation. Moreover, the experience of long-time living in humid regions also strengthened the adaptation to high humidity, which probably mainly came from psychological adaptation process. Nevertheless, the adaptation process to humidity was slower than that to temperature because less adaptation approaches were available. This paper also provided references for both adaptive comfort researches and application of air conditioners in dormitory environment.

An Empirical Study on Time Lag Phenomenon Regarding Summertime Indoor Thermal Environments in the Domestic Buildings of Different Construction Types in Hot-Humid Climate Zone

In the empirical case studies of the seven detached house buildings situated in Yilan, Taiwan in a hot and humid climate, this research conducted the actual measurements and analysis of the Summertime Indoor and Outdoor thermal environment parameters in order to accomplish the research of Time Lag Phenomenon of Summertime Indoor Temperature and Humidity in the Buildings of Light (Composite) Constructions and Heavy (Reinforced Concrete) Constructions. Firstly, it indicated that given the condition of doors and windows in closed positions, there would be Time Lag Phenomenon for both of the indoor Temperature and Humidity measurements in domestic buildings. The Temperature Time Lag for Heavy Construction Buildings had a duration of around three hours, almost as twice that of the figure for Light Construction Buildings. There was a significant correlation between Quantity of Interior Finishes and Humidity Time Lag inside domestic buildings, whereas the bigger the Quantity of Interior Finishes, the longer the Humidity Time Lag. Secondly, it also showed that given the condition of doors and windows in opened positions, there was almost zero Time Lag for both of the domestic indoor Temperature and Humidity measurements. Last but not least, generally speaking, the Ratio of Indoor/Outdoor Diurnal Temperature Range of Light Construction Buildings were higher than that of Heavy Construction Buildings. In particular, given the condition of doors and windows in opened positions with natural ventilation in summertime, it was slightly cooler inside the Light Construction Domestic Buildings than the Heavy Construction Domestic Buildings.

Specifying residential retrofit packages for 30 % reductions in energy consumption in hot–humid climate zones

The purpose of this research was to demonstrate the application of energy simulation as an effective tool for specifying cost-effective residential retrofit packages that will reduce energy consumption by 30 %. Single-family homes in the hot–humid climate type of the Southeastern USA were used to demonstrate the application. US census data from both state and federal studies were used to create 12 computer simulation homes representing the most common characteristics of single-family houses specific to this area. Well-recognized energy efficiency measures (EEMs) were simulated to determine their cumulative energy reduction potential. Detailed cost estimates were created for cost-to-benefit analysis. For each of the 12 simulated homes, 4 packages of EEMs were created. The four packages provided home owners options for reducing their energy by 30 % along with the estimated up-front cost and simple payback periods. The simple payback period was used to determine how cost-effective a measure was. The packages are specific to a geographic area to provide a higher degree of confidence in the projected cost and energy savings. The study provides a generic methodology to create a similar 30 % energy reduction packages for other locations and a detailed description of a case study to serve as an example. The study also highlights the value that computer simulation models can have to develop energy efficiency packages cost-effectively and specific to home owner’s location and housing type.

Thermostat strategies impact on energy consumption in residential buildings

This paper identifies the impact of thermostat strategies on heating and cooling energy consumptions in buildings, thus suggesting the importance of a database for understanding the effect of thermostat settings and for deciding energy-conscious strategies. Using computer simulation, diverse thermostat strategies – change of setback period, change of set-point temperature, and change of setback temperature – were tested parametrically in a typical USA single-family homes, located in two climate zones, namely cold (Detroit, Michigan) and hot-humid (Miami, Florida). Analysis revealed that heating and cooling systems were significant energy-consuming components in each climate zone. Accordingly, heating energy in cold climate zones and cooling energy in hot-humid climate zones have potential for matchingly significant saving. Diverse thermostat strategies (changes of setback period, of set-point, of setback temperature) demonstrated their obvious impacts on such saving. In the cold climate in particular, the heating system showed the most significant energy-saving effect via proper thermostat strategies. Proper setback period, set-point and setback temperature need to be established to achieve energy efficiency in residential buildings.

Air movement acceptability limits and thermal comfort in Brazil's hot humid climate zone

In hot humid climates, natural ventilation is an essential passive strategy in order to maintain thermal comfort inside buildings and it can be also used as an energy-conserving design strategy to reduce building cooling loads by removing heat stored in the buildings thermal mass. In this context, many previous studies have focused on thermal comfort and air velocity ranges. However, whether this air movement is desirable or not remains an open area. This paper aims to identify air movement acceptability levels inside naturally ventilated buildings in Brazil. Minimal air velocity values corresponding to 80% and 90% (V80 and V90) air movement acceptability inside these buildings. Field experiments were performed during hot and cool seasons when 2075 questionnaires were filled for the subjects while simultaneous microclimatic observations were made with laboratory precision. Main results indicated that the minimal air velocity required were at least 0.4 m/s for 26 °C reaching 0.9 m/s for operative temperatures up to 30 °C. Subjects are not only preferring more air speed but also demanding air velocities closer or higher than 0.8 m/s ASHRAE limit. This dispels the notion of draft in hot humid climates and reinforce the broader theory of alliesthesia and the physiological role of pleasure due to air movement increment.