Hot Climate Zones Research Articles

Using a coupled heat pump desiccant wheel system to improve indoor humidity environment of nZEB in Shanghai: Analysis and optimization

To solve indoor high humidity problem in nZEB (nearly zero energy buildings) in hot and humid climate zone, a coupled heat pump desiccant wheel system is studied by adopting in a scenario of nearly zero energy residence with experimental and simulation method, for seasonal time scale. Dehumidification is achieved by pre-cooling evaporator, desiccant wheel and indoor evaporator. A heat recovery condenser is adopted for desiccant wheel regeneration. Firstly, the dehumidification rate proportion of the pre-cooling evaporator, desiccant wheel and the indoor evaporator is evaluated for three typical operation conditions. Secondly, with an innovative indicator, humidity energy ratio, the pre-cooling evaporator outlet air temperature is optimized in summer and dehumidification season. At last, the system performance is analyzed by comparing with a conventional air conditioner. The results showed that, compared with conventional air conditioners, the system has an overall performance improvement in indoor environment control and energy saving. With optimized pre-cooling evaporator outlet air temperature of 14 °C, indoor relative humidity is lower than 70% with 26 °C, for about 96% of the times. Around 9.4% and 14.9% of energy can be saved in summer and dehumidification season, separately.

Comparative Analyses Based on Simulations to Improve Energy Consumption in Office Buildings in Egypt. (Dept. A)

A growing attention has been paid to building envelope features for achieving lower energy consumption especially in large office buildings and hot climate zones, since these features and their variables are affecting energy consumption widely and with different sensitivity. Therefore, this paper conducts simulation-based comparative analyses between main envelope features with their internal variables; the selected features for this study are building geometry ratios, orientations and common envelope finishing materials (FMs). Two applications have been conducted (comparing cases with either a same or different building volumes), and more than 500 cases/simulations have been conducted and studied in total. Accordingly, sensitive features and variables have been determined to enrich design decisions for different cases, along with best variables' integrations that achieve best energy consumption through the proposed applications and cases. Cubic office buildings in Egypt have been used to demonstrate the study, and energy simulations have been achieved using eQuest (DOE-2). Results show that lower height with wider roof achieves best energy consumption if building volume is fixed via comparisons, and vice versa. Gravel and galvanized steel represent best studied roof and walls' FMs, while roofing shingles is the worst one. If building volume is varied via comparisons, horizontal dimensions are the most sensitive feature that affects energy consumption per m2, while FMs and height represent lowest sensitivity among studied features. Ranking of cases, features, variables along with sensitive features in details have been analyzed and discussed through the paper.

Impacts of temperature and humidity changes on air‐conditioning design load under the climate change conditions in different climate zones of China

AbstractMeteorological parameters, as the important basis for improving building energy efficiency, will show apparent changes under climate change conditions. In this study, outdoor design temperature and humidity for air‐conditioning system in 12 cities, representing major climatic zones of China, were analysed to determine the impacts of temperature and humidity on the design load of air‐conditioning system. The results showed that outdoor design temperature largely increased during the last few decades and relative humidity apparently decreased except for two cities belonging to the severe cold and hot summer and cold winter climate zones. The increase in temperature and decrease in humidity have made obvious changes in the design load of air‐conditioning system. The design loads for cooling increased 1.8%–10% in these selected cities during 1991–2017 compared with 1961–1990. By contrast, the design loads for dehumidification decreased 0.8%–7% in 1991–2017 relative to 1961–1990. When the cooling and dehumidification were considered together, the design loads changed from −1.5% to 4.1% in the two periods, depending on cities or climate zones. These results demonstrated that, under the condition of climate change, the combined changes of humidity and temperature rather than temperature alone should be fully considered to determine the design capacity of air‐conditioning system, especially for temperature and humidity independent control (THIC) air‐conditioning system, to save energy and improve indoor comfort.

Integration of passive double-heating and double-cooling system into residential buildings (China) for energy saving

There are a substantial number of residential buildings situated in summer hot and winter cold climate zone of China, with tremendous energy consumption. In this work, we proposed a novel passive double-heating and double-cooling system, and integrated it into the residential buildings within this climate zone, aiming at improvement of the building energy efficiency. The proposed passive system includes a passive double-heating system (i.e., solar heating and water-to-air heating) and a passive double-cooling system (i.e., vegetation transpiration cooling and water-to-air cooling). Furthermore, a stand-alone residential building was selected as the study building, to evaluate its energy efficiency by applying the proposed passive system. Due to the passive system with double-heating and double-cooling functions, the indoor thermal comfort in the study building can be improved more significantly, in comparison with the base case. Moreover, a novel hydraulic-driven ventilation device was designed as an air-driven apparatus for the proposed passive system. Through air movement driven by the solar chimney and the hydraulic-driven ventilation device, the proposed passive system can be run without energy supply, under both the clear and rainy weather conditions. According to the numerical modeling, a total annual energy saving of 5523.42 kWh (i.e., energy saving rate of 39%) was achieved in the novel building, compared to the base case. This work focused on the passive double-heating and double-cooling system is expected to fill the knowledge gap in the building energy saving field.

Building envelopes toward energy‐efficient buildings: A balanced multi‐approach decision making

The worldwide environmentally friendly trend has focused the last decade on emphasizing the value of energy conservation and reducing the carbon footprint in buildings, achieving zero energy buildings. Presently, viable building techniques, in developing countries, are insufficient to achieve zero energy buildings. Thus, authorities should implement policies mandating new developments and renovations to establish “energy-efficient buildings”; nevertheless, design solutions should be properly evaluated and assessed preceding execution. The conservation of energy without jeopardizing human comfortability is a huge challenge for any designer. Occupants are less interested in making a major investment to save some expenses over the next two decades, especially nowadays that energy is still affordable. Therefore, improved indoor environmental conditions are perhaps another important parameter toward energy-efficient buildings. Through dynamic simulations, this study examines the energy efficiency and thermal comfort achieved by integrating retrofitting strategies in an institutional building in three different American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) hot climate zones represented by three cities of Egypt (Aswan, Cairo, and Alexandria). The built-up baseline model is validated using actual energy usage data. The validated baseline model is then subjected to local sensitivity analysis to determine the driving parameters influencing the building's energy demand. The study at hand focuses on a broader perspective on sustainability. With a multiapproach decision-making methodology based on the most recent measures, the study highlights the outcomes through an environmental–economic assessment and indoor thermal comfort depending on experts' weighting, responses, and recommendations. The outcomes postulate that the implementation of reflective paints solutions would achieve the highest percentages of whole-building energy savings with 21%, 19%, and 17% for Aswan, Cairo, and Alexandria, respectively, improving indoor thermal comfort levels.

Identifying household cooling savings potential in the hot summer and cold winter climate zone in China: A stochastic demand frontier approach

Cooling demand increases more than ten times over the past two decades in China. Especially, cooling in the Hot Summer and Cold Winter (HSCW) climate zone increases rapidly and becomes the fastest growing part in urban residential energy consumption. It will bring huge challenges to carbon emission cap control if effective and reasonable energy-saving and emission reduction measures are not taken. This study uses a data-driven method to identify cooling savings potential at household level using survey data from 1068 households in 2018 in Chongqing, China. A stochastic frontier analysis model is applied to decompose the actual cooling electricity consumption into minimum consumption based on fixed household characteristics and estimate the over-consumption (i.e. the amount of cooling consumption that could be saved). The results show that households have an average cooling efficiency of 65 %, which indicates that each household in the HSCW area has the potential to reduce its cooling electricity consumption by 35% while still maintaining the same level of cooling services currently produced. The study shows that the cooling savings potential is strongly influenced by level of household income, the level of building energy efficiency standards, cooling behavior characteristics and households’ energy-saving consciousness. Policy implications are derived.

Ambient temperature and hospitalizations for acute kidney injury in Queensland, Australia, 1995–2016

To examine the associations between ambient temperature and hospitalizations for acute kidney injury (AKI) in Queensland, Australia, 1995–2016. Data were collected on a total of 34 379 hospitalizations for AKI from Queensland between 1 January 1995 and 31 December 2016. Meteorological data were downloaded from the Queensland Government’s Department of Environment and Science. We assessed the temperature-AKI relationship using a time-stratified case-crossover design fitted with conditional quasi-Poisson regression model and time-varying distributed lag non-linear model. Stratified analyses were performed by age, sex, climate zone and socioeconomic group. Both cold and hot temperatures were associated with hospitalizations for AKI. There were stronger temperature-AKI associations among women than men. Cold effects were only positive in the ⩾70 years age group. Hot effects were stronger in the ⩽59 years age group than in the >60 years age group. In different climate zone areas, cold effects decreased with increasing local mean temperatures, while hot effects increased. In different socio-economic status groups, hot effects were stronger in the poor areas than the affluent areas. From 1995 to 2016, the magnitude of associations between cold temperature and hospitalizations for AKI decreased, while the hot effect increased. The associations between hot temperature and hospitalizations for AKI become stronger, while the magnitude of cold effect decreased from 1995 to 2016. This trend may accelerate over the coming decades, which warrants further research. More attention is needed toward susceptible population including women, people ⩾70 years, and the people living in hot climate zones and in low socioeconomic status areas.

NATURAL WIND DRIVEN SUSTAINABLE VENTILATION SYSTEM (PROTOTYPE) FOR INDOOR LIVING SPACES

One of the main design tasks of indoor space is to achieve human comfort. Cross ventilation systems are numerous but to propose a natural system that could be easily applied in different weather conditions is challenging. This study focuses on how to apply cross-ventilation by the direct and indirect driven wind. The research aims is to enhance design decisions by utilising venturi or stagnation conditions. This can be achieved by different openings and wall distributions that can help control wind velocities naturally in indoor spaces hence providing human comfort and at the same time save energy. By utilizing a simulation tool (ANSYS), it was found that in a moderately hot climate zone slightly windy, by a simple venturi proposed air velocity intervention air velocity can increase up to 42% of average outdoor air velocity between 2m/s and 8 m/s and by utilizing stagnation condition air velocity can reduce up to 55% of average outdoor air velocity between 2m/s to 8 m/s. The main aim of this research is to propose a design prototype for different types of indoor space such as hotel room prototypes to achieve natural comfortable ventilated living spaces.

Accelerated stress testing of potential induced degradation susceptibility of PV modules under different climatic conditions

Potential Induced Degradation (PID) is one of the severe failure modes observed in the field with high system voltage, high humidity and high operating temperature. PV module needs to be tested for PID susceptibility as per site conditions before installation in the field. In this paper the effect of temperature, humidity, and voltage on leakage current, as well as PID, has been analyzed for multi-crystalline silicon and HIT module technologies. Also, reported the effect of PID stress on PV modules in terms of electrical degradation and visual defects. For the studied multi-crystalline module, deviation of degradation between one cycle and three cycles of PID stress for the Isc is 98%, Voc is 18% and Pmax degradation is 87%. This paper also reported a case study about the designing of accelerated stress testing of the PID of the PV module for different climatic zones of India. The stress testing condition was designed at harsh conditions of temperature and humidity for representative sites of climatic zones. It was found that the required testing time for PV module in the case of Hot & humid climatic zone is more as compared to other climatic zones.

Pathogenicity of Pakistani isolates of Steinernema bifurcatum and S. affine (Rhabditida: Steinernematidae) in management of stored grain pests Lasioderma serricorne and Tribolium castaneum (Coleoptera: Ptinidae, Tenebrionidae)

BackgroundStored grain products suffer a considerable economic loss due to insect infestations. The resistance of pests to insecticide, and residues on crops are produced by the application of insecticide. Nowadays, incremental necessity has been occurred to find out alternatives to chemicals. As biological control agents, entomopathogenic nematodes (EPNs) attract attention increasingly in the research area recently.ResultsThe aim of the study was to evaluate the pathogenicity of Pakistani isolates Steinernema bifurcatum and S. affine against the stored grain pests, Tribolium castaneum and Lasioderma serricorne, under laboratory conditions. Suspensions of nematodes were applied at 4 different concentrations 0, 50, 100, and 200 IJs/ml and 3 variable temperatures 15, 30, and 45°C. Pathogenicity rate was recorded after 48 h of application. The larval stage is found more susceptible than the adult. At 200 IJs, S. bifurcatum showed high mortality of L. serricorne larva (92%) and T. castaneum larva (93%), whereas S. affine showed 90 and 95% mortality of L. serricorne and T. castaneum larva, respectively, at 200 IJs. The results revealed that both species of EPN were able to control and reproduce on L. serricorne and T. castaneum. Maximum mortality was recorded at 45 °C from S. bifurcatum whereas S. affine at 15 °C.ConclusionsTherefore, S. bifurcatum and S. affine could be suggested as a biological control agent for hot and cold climatic zones, respectively.

Development of window opening models for residential building in hot summer and cold winter climate zone of China

This study monitors the open/closed states of the windows in 16 residential apartments in representative cities of the hot summer and cold winter zone of China, along with outdoor air temperature, outdoor relative humidity and outdoor PM2.5 concentration in 2017, to investigate the window opening/closing behavior. Three window opening models are developed. All the models are validated by modeling a typical residential apartment to compare the predicted indoor CO2 concentration with monitored data. It is found that the window opening probability is negatively correlated to both outdoor PM2.5 concentration and outdoor relative humidity, and the probability of window opening reaches the peak value when the outdoor air temperature is 23.7 °C. In terms of season, the shortest window opening duration occurs in winter due to the cold outdoor air temperature and high outdoor PM2.5 concentration. Finally, by comparing the correlation between the measured date and simulation results of indoor CO2 concentration, this study provides an appropriate window opening model for reference.

Condensation-free radiant cooling with double-skin infrared-transparent membranes

Radiant cooling has been well acknowledged as high-performance space cooling technique owing to the advantages of thermal comfort and energy efficiency. However, there are two problems (viz., condensation risk, and insufficient cooling capacity) which hinders their application in hot and humid climate zones. Herein, a condensation-free radiant cooling was demonstrated by covering cooling source with double-skin infrared-transparent membranes (DIMs). The DIMs' surface instead of the cooling source surface served as the air-contact surface while maintaining infrared radiant transfer from cooling source to cooling load. Therefore, the DIMs’ surface temperature was maintained above the dew point for condensation-free safety while the cooling source temperature could be lower for improving cooling capacity. A heat transfer model was presented to predict the cooling capacity. The calculated results were validated with the measured data on a reduced-scale radiant cooling setup by using commercial polyethylene for the DIMs with an error smaller than 5%. The results indicated that the cooling capacity with DIMs at cooling source temperature of 7 °C was 104.0 W/m2, 48% improved compared to conventional radiant cooling. It will be of great guidance for high-performance radiant cooling design without condensation and improved cooling capacity. Concerning size difference of the reduced scale demonstration in this work with real scale application more accurate and detailed investigations (e.g. cooling capacity, air-tightness and mechanical strength) on the condensation-free radiant cooling should be carried out in further work.

Numerical investigation of optimal wall materials for effective thermal performance in warm and hot climatic regions

Purpose Heat gain in buildings occurs due to heat transfer through the building fabric or envelope, especially the walls and roof. The purpose of this paper is to identify and recommend the suitable wall materials for better thermal performance in buildings in warm and hot climatic zones of India. As India lies between the tropic of cancer and the equator, the solar radiation from the sun falls more on the walls than the roofs of the buildings. Thus, it is imperative to protect the walls from heat gain to promote thermal comfort in naturally ventilated buildings and reduce the energy loads due to artificial cooling systems in air-conditioned buildings. Design/methodology/approach In this paper, an investigation of heat flow characteristics in steady-state and the transient state for five different uninsulated wall structures using computational fluid dynamics (CFD) software has been carried out. The climate conditions at Madurai, India have been considered for this study. Findings The findings of the study revealed that aerated autoclaved concrete (AAC) and hollow clay blocks (HCB) for external walls in naturally ventilated buildings in warm climatic regions could improve the building’s thermal performance index and reduce peak indoor operative temperature by about 6°C–7°C. The results of steady-state and transient state analysis were found to be in good agreement with the results of the reviewed literature. Research limitations/implications Over the past few decades, only very few architects and builders have been successful in influencing their clients to accept alternate materials such as AAC blocks, HCB, stabilized earth blocks, adobe blocks, fly-ash bricks as an alternate to conventional bricks in an attempt of highlighting their benefits, such as; materials that are easily available, more energy-efficient, can withstand the extreme weather conditions, promote thermal comfort and cost-effective. This paper provides strong evidence that AAC and HCB blocks are the most appropriate materials for improving the thermal performance of envelope walls in regions where the outdoor temperatures are above 40°C. Originality/value This paper has made an attempt to identify the appropriate wall materials for effective thermal performance in warm and hot climates. A comparative analysis between five different wall types under the existing solar conditions has been analyzed using CFD simulation study in steady-state and transient conditions under summer conditions and the appropriate wall materials have been suggested. There has been no attempt carried out so far to analyze the thermal performance of different walls using 24 h transient approach in CFD.

Analysis of Daylight Performance of a Courtyard House: A Case Study of Prototype House in Riyadh City, Saudi Arabia.(Dept.A)

The Introverted design concept is widely applied in hot dry climatic zones. From the environmental point of view, the main purpose of having a courtyard house is to control the thermal performance as well as to provide daylight for spaces that have not an opening on the external walls. Many courtyard houses are designed with less consideration for daylight performance. This study focuses on the investigation of the daylight performance in a typical- prototype- courtyard house in Riyadh, Saudi Arabia. The study contains an overview of solar characteristics of Riyadh city. Then it focuses on the selected design, collection of Riyadh city solar and end up with a daily and annually picturing of a three dimensional model in order to record the existing daylight performance of the building. The study concludes with a general observations and recommendations of the daylight performance for the selected design.

Heating Demand with Heterogeneity in Residential Households in the Hot Summer and Cold Winter Climate Zone -A Quantile Regression Approach

Heating in the Hot Summer and Cold Winter (HSCW) climate zone in China increases rapidly and becomes the fastest-growing part of urban residential energy consumption. It will bring huge challenges to carbon emission cap control if effective and reasonable energy-saving and emission reduction measures are not taken. This study employs the quantile regression method to explore the heterogeneity in consumer response between groups by using survey data from 1,075 households in 2016 in Chongqing, China. We identify the characteristics of high heating electricity-consuming households in the HSCW zone. Households with larger household sizes, more elderly family members and high-income would tend to consume higher electricity. In terms of building characteristics, a greater number of rooms and detached houses contribute to higher heating electricity consumption. Additionally, we find that high-performance residential buildings are much more efficient for high-consumption households than lower-consumption households. Households adopt central heating systems for heating contribute to higher household heating electricity consumption. Finally, strategies for reducing heating demand with respect to high heating-consuming households are given in this research.

Review on integrated management of brinjal shoots and fruit borer, Leucinodes orbonalis (Guenee)

Eggplant Solanum melongena is one of the most important vegetables of south Asia. It is the most important vegetable of hot and wet climatic zones. It is commercially very profitable vegetable crop to farmers. It has a wide range of bio chemicals, minerals, vitamins, proteins, calcium and phosphorus. Several insect pests attack the brinjal crop among those, Leucinodes orbonalis is the most obnoxious, destructive damaging pest to the brinjal .It is a key pest of brinjal, causes damage to shoots buds stems and fruits. Larva of this pest is the damaging stage to brinjal crop. Larvae bore inside the shoots petioles and fruits and reduce the crop yields up to 80% damage to fruits has been identified. This sitsuation has posed a hindrance to the farmers in commercial cultivation of eggplant; hence relevant literatures were collected, studied and reviewed regarding biology and management of borer. Available management tools are not being enough to control the population of this pest and in such condition it is needful to have a holistic approach towards IPM practices. In this article, several control measures for L. orbonalis including resistant varieties, cultural methods, physical and mechanical barriers, sex pheromones, bio-pesticides and bio-control agents; chemical and botanical means are outlined and evaluated with supportive facts and figures with reference to previous works and researches in this area.

Energy Renovation of Residential Buildings in Hot and Temperate Mediterranean Zones Using Optimized Thermal Envelope Insulation Thicknesses: The Case of Spain

One of the greatest challenges facing the European Union is the conversion of the existing residential building stock into nearly zero-energy buildings (NZEBs) by 2050 through energy renovation, given that the residential sector is one of the largest consumers of final energy and that approximately two-thirds of existing dwellings were built before 1980. The objective of this study is to assess the energy, environmental, and economic impacts of the energy renovation of thermal envelopes of existing multi-family buildings in the hot and temperate climate zones of Spain by using life cycle cost analysis (LCCA) to determine the optimal thicknesses of insulation to be added to the walls, roof, and first floor framework of the buildings and replacing existing building openings to achieve NZEBs. Four thermal insulation materials are considered with four different heating and cooling systems and ten different models. With the methodology developed, the best energy renovation solutions are estimated and then thermally simulated. In total, 67 of the 576 proposed energy renovation solutions achieve NZEBs. This study fills in the gap between LCCA estimates and reality.

Evaluation of energy performance of dynamic overhang systems for US residential buildings

A novel dynamic overhang system is evaluated in this paper when applied to control solar heat gains through windows of US residential buildings. In particular, the energy performance of the dynamic overhangs is compared to static systems using various operation scenarios. The main objective for the control strategies evaluated in the analysis is to minimize annual heating and cooling energy consumption when dynamic instead of static overhangs are applied to US residential buildings. The operation of the dynamic overhangs is adjusted to account for the range of positions allowed as well as the setting frequencies. In particular, the dynamic overhangs can be set on hourly, daily, and monthly basis depending on the window orientation and the time of the year. The analysis has indicated that the performance of the dynamic overhangs depend on their design specifications as well as on the window glazing type. However, the energy saving potential for the dynamic overhangs compared to static devices depend largely on the window size and the climate with significant reduction in cooling energy use achieved in hot and mild US climatic zones. Indeed, the dynamic overhangs can save over 45% of the air conditioning needs for US homes with window-to-wall ratio of 30% located in Phoenix, AZ, and San Francisco, CA, when automatically operated on hourly basis.

Envelope performance of residential building in cool, warm and hot climatic zones: Results from self-designed in-situ monitoring campaigns

Climatic conditions can exert significant impacts on energy demand of residential buildings. Therefore, case-based evidence is necessary for aiding local policy making on building energy performance. By designing and carrying out in-situ monitoring campaigns respectively in Cambridge, Hong Kong and Shanghai, we present in this paper a cross-regional analysis of actual building envelope performance in these three climatic regions that operate under different energy efficiency policies. Compared with conventional tabulated data, information gleaned from the method of in-situ monitoring shows lower uncertainty and higher precision, especially when the wall has good thermal properties. By comparing practices in different regions and with accurate post-occupancy thermal data, the analytical results further show that the effectiveness of building-related policies on energy performance varies across regions. This is one of the pioneering studies that make interactive policy recommendations based on the evidence obtained from cross-regional, in-situ monitoring campaigns.

Vine performance benchmarking of indigenous Cypriot grape varieties Xynisteri and Maratheftiko

Aim: The aims of this study were to (1) formulate a baseline understanding of the performance of the indigenous Cypriot white grape Xynisteri and the red grape Maratheftiko (Vitis vinifera L.), and (2) compare these varieties to Shiraz and Sauvignon blanc grown in a Cypriot vineyard.Materials and results: The investigation involved multiple dry grown vineyards from the Krasochoria region of Lemesos, Cyprus, during the 2017, 2018 and 2019 vintages. Vine performance measurements, including midday stem water potential, stomatal conductance, chlorophyll content, stomata density, vine phenology and vegetative and reproductive measurements, were taken at flowering, veraison and pre-harvest. Xynisteri had the greatest stomatal density, more shoots, more leaves, heavier bunches, greater yield, higher leaf water potential at harvest, and a stomatal conductance equal to Maratheftiko, but greater than that of both Shiraz and Sauvignon blanc. Maratheftiko had the longest shoots, largest shoot diameter and the greatest chlorophyll content out of all four varieties.Conclusions: This study identified the ability of the indigenous Cypriot grape varieties, Xynisteri and Maratheftiko, to better tolerate hot and dry conditions when compared to more commonly cultivated varieties grown in the same environmental conditions.Significance and impact of the study: The changing climate of wine growing regions worldwide is placing great pressure on the resources for sustainable viticulture. Many vineyards in hot climate zones base their businesses on European grape varieties traditionally grown in regions with abundant water resources. It is therefore necessary for the global wine industry to investigate grape varieties that are indigenous to hot climates. The eastern Mediterranean island of Cyprus is one such place, with more than 10 indigenous grape varieties that grow well in a hot climate without irrigation. Consumer studies have demonstrated that wines made from these Cypriot varieties are equally, if not more, acceptable than wines made from more traditional European grapes; therefore, the potential for their use in other hot wine growing regions is promising.