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Pervious pavement has been regarded as an effective technique for both water storm management and overheating prevention. However, compared with its widely recognized permeability capability, its solar evaporative cooling performance remains under debate after post-occupancy evaluation; thus, it is essential to predict the solar evaporative cooling ability before practical use. Hygrothermal properties (i.e., albedo, water absorption, and water retention properties) are key factors that affect the solar evaporative cooling effect of pervious materials and could be extracted as predictive indicators. However, an approach for assessing the water absorption and retention properties has not been well studied. Therefore, this study aimed at characterizing a feasible method for testing water absorption and retention properties of pervious materials as well as the influence of albedo on the solar evaporative cooling performance. Five widely used pervious materials were selected as research subjects, and three hydrological test methods, including the integral immersion test, partial immersion test, and rainfall simulation test, were conducted for comparing the feasibility of measuring water absorption and retention properties. Furthermore, the solar evaporative cooling performance of pervious materials with high and low albedo was also investigated. The results reveal that the partial immersion test has the highest accuracy for evaluating the water absorption and retention properties of pervious materials. Although the high albedo could weaken the evaporation rate, pervious materials with high albedo could also achieve better solar evaporative cooling performance. The results of this study support the proper selection of pervious materials to alleviate urban overheating.

Buildings on tropical islands in the South China Sea are facing an overheating challenge. High-water-absorbency unglazed porous ceramic (UPC) materials could counteract heat gain by evaporation. Salty humid air and seawater in the marine environment lead to evaporative cooling differences from inland conditions. This research replicated a salty humid atmosphere with a stable concentration similar to the actual environment in a dynamic hot-humid climate wind tunnel (DHWT). The influence of salt in gas-liquid media on evaporative cooling is discussed. The results showed that the salt concentration of humid air in the wind tunnel can be controlled by adjusting the atomization rate and the concentration of the atomized liquid. Humid air and liquid with salt reduced the evaporation rate of the UPC tiles. The influence of salty humid air was generally less than that of seawater. In 6 mg/m3 salty air, the total evaporative cooling effect decreased by 2.63% and 40.44% when saturated with fresh water and a 3.5% sodium chloride solution, respectively, relative to saturation with fresh water and evaporation in humid air without salt. In conclusion, sea salt in humid air and in the liquid phase reduced but did not eliminate the evaporative cooling effect of UPC materials. Seawater source utilization showed a significant benefit in cooling and water conservation aspects in coastal areas.

Pervious pavements are efficient in the mitigation of urban heat island effects. Many studies have revealed the water availability of pervious paving materials dominates the evaporative cooling effect. However, the water retention capacity of these materials is affected by the water absorption capability, which has scarcely been investigated in relation to evaporation. Therefore, this study investigates the water absorption capability of pervious paving materials and its influence on evaporative cooling performance. We examine the water absorption capability of three similar-coloured materials, including sintered ceramic pervious brick (CB), pervious concrete brick (PB), and open-graded pervious concrete (PC), as well as their evaporative cooling performance under a steady-state hot-humid environment in a climatic wind tunnel. The results indicate that: (1) CB had the highest water absorption coefficient of 2.04 kg/m2·s0.5, which is approximately about 30 and 200 times higher than that of PB and PC, respectively; however, these materials had similar water retention capabilities, with a capillary moisture content of 110 ± 10 kg/m3, revealing that CB could hold more water in a very short time; and (2) CB and PB could effectively reduce the surface temperature by up to 20 °C and 12 °C with a cooling period of 16 h and 12 h, respectively. In comparison, PC demonstrated a weak cooling effect of 2 °C, which only lasted for 4 h. Overall, materials with a high water absorption capability can maintain hydraulic continuity balance for a long time, which is beneficial to enhancing evaporation and further lowering the surface temperature.

The evaporative cooling of porous building materials is one of the passive strategies used for building energy conservation. The effect of evaporative cooling strongly depends on the evaporation rate, which is defined as the mass of water evaporated from a unit area of a porous material per unit time. In contrast to previous studies, which focused on the influence of material properties on the evaporation rate, the present work investigates the effects produced by climatic factors. In particular, porous clay tiles with pore sizes of 2.0–6.0 µm and porosity of 27.34% were selected as water storage media, and the impacts of four climatic factors (air temperature, solar radiation intensity, wind velocity, and partial pressure of water vapour) were examined at three different levels. The obtained results indicate that the evaporation process from porous tiles consists of constant evaporation rate, falling evaporation rate, and low evaporation rate stages. Moreover, by conducting range analysis, the studied factors can be ranked by their impact on the evaporative cooling process as follows: the intensity of solar radiation, air temperature, partial pressure of water vapour, and wind velocity.

It is important to consider reducing energy use while improving occupants’ indoor thermal comfort. The actual thermal comfort needs and demands should be considered to determine the indoor thermal environment design. In previous studies, research has not been carried out on thermal comfort in karst areas. Thus, a long-term field investigation was carried out on multi-storey residential buildings in the karst area of Guilin city centre during summer (from August 2019 to September 2019) and winter (from December 2019 to January 2020). In this study, the indoor thermal environments of three categories of dwellings were analysed. A total of 77 residential buildings with 144 households were randomly selected, and 223 occupants from 18 to 80 years old participated. A total of 414 effective questionnaires were collected from the subjects. The results show that there was an obvious conflict between the predicted mean vote (PMV) and the thermal sensation vote (TSV). The neutrality temperatures calculated by the regression method were 24.2 °C in summer and 16.2 °C in winter. The thermal comfort range was observed at operative temperatures of 20.9–27.5 °C in summer and 12.2–20.1 °C in winter. The desired thermal sensation for people in the Guilin karst area was not always reflected in the thermal neutrality range. A preference for warmness was identified in the survey.

Outdoor thermal measurement is the most direct and accurate technique to investigate and assess urban overheating. Thanks to operational convenience and low costs, mobile measurements are regarded as more efficient than fixed measurements. However, the accuracy of mobile measurements has not been adequately studied, especially given the lack of a standardized method for “stop-and-go”. This paper aimed to develop an optimized method suitable for mobile measurements. By comparing data from mobile and fixed points, the settling time, the effective period, and the staying time of air temperature (Ta) and black globe temperature (Tg) were elucidated. Further verification and application of this optimized method was achieved. The results show that: (i) the spatial transformation caused initial differences for both Ta and Tg, which could be reduced by average settling times of 3.1 min and 4.6 min, respectively; (ii) elimination of the data in the first 5 min improved the result accuracy of Ta by 20 % and Tg by 30 %; and (iii) a staying time of 10 min could afford acceptable result accuracy. In short, through regulating the settling time and staying time, the optimized method for mobile measurements could achieve excellent result accuracy on thermal environments in complex urban spaces.

Urban pipe rack is a type of underground tunnel used for centralized laying of municipal pipelines in cities. In this study, the effort of using urban underground pipe rack to preheating or cooling ambient air for building thermal comfort as a new passive energy saving method was made. This is similar with the existing earth to air heat exchanger (ETAHE). In the research, a long-term static air temperature and humidity test and ventilation experiments in summer/winter were carried out in the underground pipe rack located in Guangzhou, the thermal performance of the pipe rack which includes temperature performance, cooling and heating potential was also made. The static air temperature in the pipe rack is lower than ambient temperature in daytime in summer and higher than ambient temperature all day in winter. After air flowed through 200-meter pipe rack, its maximum temperature drop and rise in summer and winter could reach 7.5 °C and 11.2 °C respectively. The daily average cooling potential in summer and heating potential in winter of the 200-meter pipe rack was 467.3 MJ and 1418.6 MJ respectively. The COP of the pipe rack was found to be 2.4 in summer and 2.7 in winter. Results show the potential of pipe rack in providing low energy cooling and heating.

Conventional outdoor dynamic and indoor steady-state experiments have certain limitations in regard to investigating the evaporative cooling performance of porous building materials. The present study investigated the evaporative cooling performance of a porous building material using a special wind tunnel apparatus. First, the composition and control principles of the wind tunnel environment control system were elucidated. Then, the meteorological environment on a typical summer day in Guangzhou was reproduced in the wind tunnel and the evaporation process and thermal parameters of specimens composed of a porous building material were continuously measured. Finally, the experimental results were analysed to evaluate the accuracy of the wind tunnel environment control system, the heat budget of the external surface of the specimens and the total thermal resistance of the specimens and its uncertainty. The analysis results indicated that the normalized root-mean-square error between the measured value of each environmental parameter in the wind tunnel test section and the corresponding value input into the environment control system was

The present study aims to further demonstrate the cooling benefits of an extensive green roof (EGR) and fill the gap existing in the literature in terms of a sensitivity analysis of an EGR, especially in subtropical areas. First, onsite measurements were performed. The results indicated that the peak air temperatures in the chamber with the EGR were 4.0 °C and 1.9 °C lower, respectively, compared to those in the chamber with a bare roof on sunny and rainy days. Moreover, the EGR decreased the daily electricity consumption from air conditioning by up to 16.7% on sunny days and 6.7% on cloudy days. Second, the measured values were employed to validate the green roof module (GRM) in EnergyPlus. The results demonstrated that the GRM yielded accurate results in quantifying the cooling benefits of the EGR. Finally, we selected 16 factors of the EGR, each with four levels, to perform the sensitivity analysis. Range and variance analyses revealed that the factors that most significantly impacted the EGR performance were the R-value of roof construction, substrate (soil) thickness, the thermal conductivity of dry substrate, the leaf area index, leaf emissivity, and the solar absorptance of the substrate. These factors contributed 90.8% to the performance index.

Low-altitude remote sensing platform has been increasingly applied to observing local thermal environments due to its obvious advantage in spatial resolution and apparent flexibility in data acquisition. However, there is a general lack of systematic analysis for land cover (LC) classification, surface urban heat island (SUHI), and their spatial and temporal change patterns. In this study, a workflow is presented to assess the LC&rsquo, s impact on SUHI, based on the visible and thermal infrared images with high spatial resolution captured by an unmanned airship in the central area of the Sino-Singapore Guangzhou Knowledge City in 2012 and 2015. Then, the accuracy assessment of LC classification and land surface temperature (LST) retrieval are performed. Finally, the commonly-used indexes in the field of satellites are applied to analyzing the spatial and temporal changes in the SUHI pattern on a local scale. The results show that the supervised maximum likelihood algorithm can deliver satisfactory overall accuracy and Kappa coefficient for LC classification, the root mean square error of the retrieved LST can reach 1.87 &deg, C. Moreover, the LST demonstrates greater consistency with land cover type (LCT) and more fluctuation within an LCT on a local scale than on an urban scale. The normalized LST classified by the mean and standard deviation (STD) is suitable for the high-spatial situation, however, the thermal field level and the corresponded STD multiple need to be judiciously selected. This study exhibits an effective pathway to assess SUHI pattern and its changes using high-spatial-resolution images on a local scale. It is also indicated that proper landscape composition, spatial configuration and materials on a local scale exert greater impacts on SUHI.

Accurate evaluation of the moisture effect on the thermal performance of building envelopes is essential to facilitate energy-saving building design in hot and humid climate areas. However, in extremely hot and humid climate areas, the coupled effect between the heat and moisture transfer is mostly neglected and a method to evaluate the moisture effect on the thermal performance has never been proposed. Thus, in this paper, a model is developed to simulate the coupled heat and moisture transfer inside an exterior wall subjected to extremely hot and humid climate. This model is validated using three benchmark tests and shows high accuracy. Based on the model, the effect of the moisture on the thermal performance of exterior walls in the tropical islands is firstly investigated quantitatively. The results show that moisture can substantially affect the thermal performance of an exterior wall. Neglecting the moisture effect, the total load is underestimated by 6.04–7.33%. Considering the moisture effect, the decrement factor is improved from 26.27–38.28 to 79.40–114.41 and the time lag is prolonged by 71–79 min. Finally, to clarify the spatiotemporal dynamic pattern of the moisture effect, a comparison between the four tropical islands and the continental city is performed.

Ventilated wall is considered as an effective technique for building energy efficiency retrofit in hot-humid areas, and the heat exchange inside the ventilated layer blocks the heat gain into the wall. Most current researches focus on the performance assessment of the wall system but lack the optimize design of the external board. Here we demonstrated a new type of ventilated wall, using the calcium silicate material as the cladding panel for its excellent physical properties and easy installation and maintenance. In particular, the aluminum foil was attached to the interior side of the board to further lower the emissivity for achieving a better insulation effect. Based on the field experiment in summer days, the thermal performance of the new type of ventilation wall was obtained and further compared with the conventional wall. Moreover, the equivalent thermal resistance of this novel ventilated wall was also calculated. The results revealed that: the interior wall surface temperature and energy consumption of the new ventilated wall proposed was about 3-5°C and 39.2% lower than those of the conventional wall, respectively. The low emissivity significantly insulated the heat transfer inside the cavity. In parallel, the calculated equivalent thermal resistance of the ventilation wall (0.971m2⋅K/W) was also 2.07 higher than that of the conventional wall.

Living walls are important vertical greening systems with modular prevegetated structures. Studies have suggested that living walls have many social benefits as an ecological engineering technique with notable potential for reconciliation ecology. Despite these benefits, there are currently no mature workflows or technologies for monitoring the health status and water stress of living wall systems. To partially fill the current knowledge gap related to water stress, we acquired thermal, multispectral, and hyperspectral remote sensing data from an indoor living wall in the Cloud Forest of the Gardens by the Bay, Singapore. The surface temperature (Ts) and a normalized difference vegetation index (NDVI) were obtained from these data to construct a Ts-NDVI space for applying the &ldquo, triangle method&rdquo, A simple and effective algorithm was proposed to determine the dry and wet edges, the key components of the said method. The pixels associated with the dry and wet edges were then selected and highlighted to directly display the areas under water-stress conditions. Our results suggest that the proposed algorithm can provide a reasonable overview of the water-stress information of the living wall, therefore, our method can be simple and effective to monitor the health status of a living wall. Furthermore, our work confirms that the triangle method can be transferred from the outdoors to an indoor environment.

© 2018 Elsevier Ltd Rainfall occurs frequently in subtropical regions of China, with the subsequent water evaporation from building roofs impacting the thermal performance and the energy consumption of buildings. We proposed a novel simulation method using actual meteorological data to evaluate this impact. New features were developed in EnergyPlus to enable the simulation: (1) an evaporation latent heat flux source term was added to the heat balance equation of the external surface and (2) algorithms for the evaporative cooling module (ECM) were developed and implemented into EnergyPlus. The ECM experimental results showed good agreement with the simulated results. The ECM was used to assess the impact of evaporation from porous roof tiles on the cooling load of a one-floor building in subtropical China. The results show that the evaporation process decreased the maximal values of the external and internal roof surface temperatures by up to 6.4 °C and 3.2 °C, respectively, while the lower internal surface temperature decreased the room accumulated cooling load by up to 14.8% during the hot summer period. The enhanced EnergyPlus capability can be used to evaluate the evaporative cooling performance of roofs with water-storage mediums, as well as to quantify their impact on building cooling loads.

Vertical green facades (VGFs) are one of the most promising technologies for reducing building energy consumption and mitigating the urban heat island phenomenon. Many studies have investigated the cooling effects of VGFs; however, research on the thermal behavior of VGFs and the impacts on indoor and outdoor thermal environments are scarce, which limits the understanding and application of VGFs. Therefore, field measurements were conducted in the subtropical city of Guangzhou, China, during hot days. First, the thermal balance of the vegetation canopy was investigated. In particular, the net photosynthesis and transpiration of foliage were measured to estimate the thermal effect of plant physiological activities. Moreover, the operative temperature (OT) and wet bulb globe temperature (WBGT) were measured to assess the comprehensive effects of the VGF on the indoor and outdoor thermal environments, respectively. The results indicated that transpiration could consume approximately 50% of solar radiation absorbed by the vegetation canopy. Furthermore, the thermal effect ratio of net photosynthesis to transpiration was less than 5.5%, suggesting that omission of the thermal effect of the net photosynthesis of climbing plants in thermal balance calculations could result in an error lower than 2.9%; such a low error may be acceptable for most engineering applications of VGFs. The VGF caused a decline in room air temperature and mean radiation temperature, resulting in a peak OT reduction of 3.6 °C. Moreover, the peak WBGT in the outdoor environment could be reduced by up to 2.7 °C due to the shading effect and transpiration cooling of the VGF. These findings help advance our understanding of the thermal transfer process of VGFs and extend the application of VGFs from a single cooling purpose to comprehensive improvement of the thermal environment.

We conducted a climate chamber study on the thermal comfort of people in the hot and humid area of China. Sixty subjects from naturally ventilated buildings and buildings with split air conditioners participated in the study, and identical experiments were conducted in a climate chamber in both summer and winter. Psychological and physiological responses were observed over a wide range of conditions, and the impacts of season, climate, and thermal history on human thermal comfort were analyzed. Seasonal and climatic heat acclimatization was confirmed, but they were found to have no significant impacts on human thermal sensation and comfort. The outdoor thermal history was much less important than the indoor thermal history in regard to human thermal sensation, and the indoor thermal history in all seasons of a year played a key role in shaping the subjects' sensations in a wide range of thermal conditions. A warmer indoor thermal history in warm seasons produced a higher neutral temperature, a lower thermal sensitivity, and lower thermal sensations in warm conditions. The comfort and acceptable conditions were identified for people in the hot and humid area of China.

Building evaporative cooling is an effective energy saving technology. With the aim to provide a reliable experimental method for the building evaporative cooling research, the dynamic evaporating and heat transfer process of two samples were studied by using the Climatic Wind Tunnel (CWT). The results of this study indicate the following: (1) The thermal resistance of the wet sample was two times that of the dry sample, which significantly improved the thermal insulation capacity of the wet sample. (2) The Penman–Monteith (P–M) model in Pedology was introduced to analyze the evaporation amount which was caused by the comprehensive effect of radiation term and aerodynamic term. The results displayed that the evaporation amount caused by radiation term accounted for 80.4% of the total evaporation amount. (3) The hourly evaporation data were used to calculate the heat balance equation on the facing layer of the wet sample. The calculation results demonstrated that the evaporating process can consume approximately 70% of the maximum incident solar radiation heat.

Porous face bricks on the outside of a building wall exhibit evaporative cooling after absorbing water. Thus, these bricks are promising for use as a passive energy-saving building technology. Artificial watering is an effective method to ensure a sufficient water supply for effective evaporative cooling. However, improper watering measures may result in the waste of water resources while failing to achieve the evaporative cooling effect. In this paper, studies were conducted on a composite wall composed of a facing layer and a base layer as follows. (1) The mass moisture content variations in the porous face brick with respect to soaking time were measured, and the feasibility of using this type of face brick as an evaporative cooling carrier was investigated. (2) The relationship between mass moisture content and the evaporation capacity of the porous face brick was determined under stable conditions. A critical mass moisture content for the porous face brick was determined through analysis of the measurement data. (3) A field measurement was performed to verify the feasibility of using the critical mass moisture content as a criterion for watering. The results indicate that the temperature and heat flows at the inner and outer surfaces of the composite wall were reduced significantly. However, when the mass moisture content exceeded the critical mass moisture content, the evaporative cooling capability tended to stabilize with further watering. Therefore, the critical mass moisture content of the porous face brick can be used as a criterion for watering to conserve water while facilitating the evaporative cooling effect.

The continuous Guangzhou expansion leads to more and more construction of the city road, which is a special underlying surface. In 2012, the total length of the road in Guangzhou is 9050.715 km. Among them, the total length of the highway is 652.6 km and the remaining 6044 km is urban roads. There are 47 main roads with a distance of 5685 km and area of 3953.63 million square meters. The roads are commonly constructed by asphalt and cement concrete whose heat absorption rate is higher than that of the green land and water body, while the thermal capacity of the asphalt and cement concrete is smaller than that of the green land and water body. This means that the roads with asphalt and cement concrete can absorb the solar radiation largely and cause the big temperature increase itself, which will increase the summer energy consumption of vehicles on the road and affect the outdoor thermal comfort of pedestrians. Nowadays, the construction of roads has become one of the main-reasons for urban heat island. In another hand, road provides the broad path for urban ventilation, which makes it become an important element for the construction of urban wind corridor. According to above negative impact on urban heat island and positive impact on urban ventilation, great difficulties still remain when urban planners attempt to design the urban roads to realize the comfortable outdoor thermal environment. The orientation of urban roads is an important element for the road design. Its relationship with the prevailing wind direction can somehow affect the city temperature distribution and ventilation efficiency. Fazia Ali-Toudert from University of Freiburg concludes that in urban street the roads with east-west orientation are less efficient in releasing heat compared with the north-south orientation (Fazia Ali-Toudert, 2006). Andreou concludes that, under the same condition of shade and solar energy, street geometry, height/width ratio, orientation and trees can affect urban canyon microclimate (Fazia Ali-Toudert, 2014). They do not have a detailed study of the relationship between the orientation towards the prevailing wind, as well as to the impact on the surrounding thermal environment This paper uses the method of numerical simulation to analyze the impact of road orientation on the thermal environment of Guangzhou Zhujiang New Town. Some implications for the urban road design are obtained. Orientation of the road has a great influence on the local thermal environment for example in windless area or with respect to high-rise buildings in low-lying areas.

An experimental study of human responses to step changes of temperature and humidity was carried out on people in hot-humid area of China. Thirty college students who were naturally acclimatized to local climate and well experienced with air-conditioned environments participated in the experiment. Their physiological and psychological responses were measured continuously under conditions of neutral-warm and neutral-cool. Psychological lead occurs in all conditions expressed as psychological responses reaching steady state in a much shorter time than physiological ones, and overshoot occurs under sudden heating and does not occur under sudden cooling. Validation test of the Two-Node model shows that the model overestimates the steady state skin temperature under conditions of 20, 23 and 29 °C, and underestimates the change rate of skin temperature at the initial time of step changes. Heat acclimatization is suggested to be taken into account while applying the Two-Node model in hot-humid area of China. Relationships between physiological and psychological responses under step changes of neutral-warm and neutral-cool are established, indicating that both skin temperature and its change rate over time have significant impacts on thermal sensation. The acceptable conditions for transitional spaces in hot-humid area of China are recommended as the upper limits of air temperature 29.2 °C at 50% RH and 28.0 °C at 70% RH for 90% percentage satisfied, and 31.0 °C at 50% RH and 29.5 °C at 70% RH for 73% percentage satisfied.

Thermal infrared cameras have been widely used to measure temperature as a non-invasive measuring instrument recently. To assess the temperature results of thermal infrared remote sensing, we compared them with the temperature obtained by traditional contact temperature measuring method. A ground remote sensing platform was designed to obtain the thermal infrared temperature of the underlying surface. Meanwhile, the traditional contact method was used to obtain surface temperature synchronously. Afterward, the two kinds of temperature were compared and analyzed. Our results indicate that for the four kinds of underlying surface studied in this paper, the two kinds of temperature all have strong correlation. Furthermore, the mean temperature difference ranges between 0.46 °C and 1.79 °C. Moreover, no significant difference can be observed between the two kinds of the temperature of grassland, tile, and permeable brick when the evaluation is at the level of P = 0.001.

The climate in hot-moist regions like Guangdong is characterized as short in summer and long in winter, which imposes high insulation requirements on the roof of houses. In this case, this paper proposes a roof greening overhead structure, which is developed by making a bracket under the existing planting box after reinforcing the bottom thereof, thus there will be an overhead layer with a height of 300mm between the planting box and the roof. The study used three office rooms with identical conditions on the top floor of the office building as the test rooms. The roofs of the three rooms were set as the roof with the overhead planting box, the roof with the existing planting box and the reference roof, respectively. The temperatures of the structural layers in the three test rooms were measured under the non-air-conditioning closed conditions in summer. The hourly power consumptions of the air-conditioners in the three test rooms were measured under the air-conditioning closed conditions in summer. The results indicates the natural ventilation formed by the overhead structural layer can improve the overall insulation effect of the roof. The energy saving rates of the air conditioners in the room with the overhead planting box on the roof reached 28.2%.

This study examined the effects of personally controlled air movement on human thermal comfort and perceived air quality (PAQ) in warm-humid environments. At temperatures 26, 28, and 30 °C, and relative humidity (RH) 60% and 80%, sixteen human subjects were exposed to personally controlled air movement provided by floor fans in an environmental chamber. The subjects reported their thermal sensation, thermal comfort, and PAQ during the tests. Two breaks periods with elevated metabolic levels were used to simulate normal office activities. Results show that with personally controlled air movement, thermal comfort could be maintained up to 30 °C and 60% RH, and acceptable PAQ could be maintained up to 30 °C 80% RH, without discomfort from humidity, air movement or eye-dryness. Thermal comfort and PAQ were resumed within 5 min after the breaks. The 80% acceptable limit implicit in comfort standards could be extended to 30 °C and 60% RH. The average energy consumed by the fans for maintaining comfort was lower than 10 W per person, making air movement a very energy-efficient way to deliver comfort in warm-humid environments.

The effects of air movement from ceiling fans on subjective thermal comfort and perceived air quality (PAQ) were examined for warm-humid environments. In a climate chamber controlled at three temperatures (26 °C, 28 °C and 30 °C) and two relative humidity (RH 60% and 80%), sixteen subjects (8 males and 8 females) dressed in summer clothing (0.5 clo) were exposed to 7 levels of air speed ranging from 0.05 m/s to 1.8 m/s. The subjects were asked to rate their thermal sensation, comfort, PAQ, air movement acceptability, humidity sensation, eye-dryness during the 2-h and 15 min long tests. Air movement significantly improves the subjects' thermal comfort, PAQ, and humidity sensation without causing dry-eye discomfort. Without air movement, the 80% acceptable limit established by the ASHRAE standard 55 was reached at 26 °C/60%RH, 26 °C/80%RH, and 28 °C/60%RH. With air movement, more than 80% of the subjects perceived the environments acceptable at 28 °C/80%RH, 30 °C/60%RH, and 30 °C/80%RH. The preferred air speeds for ceiling fans were in many cases higher than the limit specified in ASHRAE Standard, which is 0.8 m/s when users have no control over the fan.

Presently, there have been few studies on the outdoor thermal environment and thermal comfort of campus clusters in subtropical climate urban areas. In this study, first we investigated the influence of various types of design elements on the outdoor thermal environment around campus clusters in subtropical urban areas, such as pilotis, squares, and teaching building blocks. Second, we conducted a questionnaire survey on thermal sensation and thermal comfort in campus clusters to study the subjective response of young students to the outdoor thermal environment in subtropical urban areas. Assessment of thermal comfort by the SET∗ index suggests that the neutral SET∗ of young students is about 24 °C in an outdoor environment in subtropical urban areas in the summer. A 0.9 K temperature difference is observed between teaching building blocks and a grass-covered surface square, indicating the influence of the sky view factor (SVF) and heat capability of ground surface on air temperature distribution at night-time. Owing to a large SVF, more short-wave and long-wave reflections and long-wave radiations are incident on the square: attention should be paid to this fact, which may create an extremely hot outdoor thermal environment in the daytime. Influenced by MRT, the SET∗ around teaching building blocks is higher than those of the square and pilotis in the afternoon, which is expected to reduce the acceptable rate of the outdoor thermal environment. Pilotis can reduce SET∗ by 6–10 °C; therefore, the use of pilotis is encouraged to create an outdoor thermal environment of well-being in subtropical cities.

Human responses to thermal environments in naturally ventilated (NV) buildings in hot-humid area of China were systematically investigated in the present study. Thirty local inhabitants long-time living in NV buildings participated in the study and reported their thermal sensations and perceptions and adaptive behaviors while all physical and personal variables were collected. Based on a year-long survey, a close match of indoor physical variables and occupants’ clothing insulation with outdoor climate was found as an important feature of NV buildings. Integrated indices can capture more thermal contexts in the NV buildings in hot-humid area of China than simple indices. Thermal sensation was found to be a good linear function of SET* with the thermal neutrality of 25.4 °C and the 90% (80%) acceptable range of 23.5–27.4 °C (22.1–28.7 °C) in SET*. The adaptive evidences were obtained for clothing adjustment, window opening and using fan respectively and the modified PMV model was validated to be applicable in NV buildings in hot-humid area of China with an expectancy factor of 0.822. Comparisons with other field studies indicate that people can develop various human-environment relationships through thermal adaptation to local climate, resulting in different thermal neutral temperatures in various climates. The subjects in hot-humid area of China are more acclimated and tolerable with hot and humid environments and more uncomfortable and intolerable with cold environments while compared with those in temperate climates.

This paper analyzed the energy balance of extensive green roofs and presented a simple but practical energy balance model. Field experiment justified the validation and accuracy of this model. Experimental results demonstrated that within 24 h of a typical summer day, when soil was rich in water content, solar radiation accounted for 99.1% of the total heat gain of a Sedum lineare green roof while convection made up 0.9%. Of all dissipated heat 58.4% was by the evapotranspiration of the plants–soil system, 30.9% by the net long-wave radiative exchange between the canopy and the atmosphere, and 9.5% by the net photosynthesis of plants. Only 1.2% was stored by plants and soil, or transferred into the room beneath.

Taking a certain housing in Guangzhou as an example, we conduct the field measurement of the microclimate at fixed points for air temperature, relative humidity, black globe temperature and wind speed, etc. We investigate the effects of manmade lake, shade of trees and ground surface character on outdoor thermal environment, and make a quantitative analysis on the weighting position of the landscape design factors in design behavior. The study intends to explore a method to improve the thermal environment of residential quarters by changing the corresponding factors.

Solar penetration through the transparent envelope can severely deteriorate indoor thermal environment inside an atrium building particularly in tropical climates. This paper reports the application of two low-cost measures, namely high level internal solar blinds and water spray, to minimise overheating problems on the three levels inside the atrium of a guesthouse in Southern China, where summer is hot and humid. The blinds reduce direct solar penetration at the top of the atrium whilst the evaporative spray system cools down the glazed surfaces of the atrium envelope. A site test was undertaken over 10 consecutive days covering both overcast days and clear days in July 2004. Measurement of indoor thermal environmental parameters was conducted on three levels in the atrium and the recorded data represent the internal conditions: with and without internal blinds protection from solar, and with and without water spray. This study has shown that on hot and clear summer days, with water spray and without blinds the average air temperature difference from 1200 to 1800 h between both first floor and second floor, and second floor and external were 5.7 and 1.7 K, respectively; whilst with blinds and without water spray the average air temperature differences were 8.7 and 4.8 K, respectively.

Telecommunication base station (TBS) buildings have large numbers, high energy consumptions and great potentials on energy conservation. Through field investigation of a typical TBS in Guangzhou, the basic information of TBS was achieved, the key factors influencing energy consumption of TBS were determined and several energy efficient envelope designs were proposed. The effect on annual cooling load was analyzed for each energy efficient design and the combined effects were achieved for several combinations of the designs by thermal simulation. The energy efficient design strategy of building envelope for TBS in Guangzhou was proposed.

In uncomfortably warm areas and seasons of the year, passive cooling effects resulting from natural rainfall evaporation can greatly cut down on building energy consumption. To simulate the passive evaporation cooling effect and evaluate the relevant energy-saving potentials, hourly rainfall data are needed. However, in currently used building energy simulation software, such as DOE, EnergyPlus and DeST, no rainfall information is provided in the climatic database. This paper uses a limited set of monthly and daily rainfall distribution data in Guangzhou area to identify and model monthly, daily and hourly rainfall patterns. For a current weather database used by building energy simulation software, rainy days and rainy hours are distinguished using distance discriminant analysis, which uses measured data samples for rain identification. According to an autocorrelation analysis of rain sequences, a one-order AR model is suitable for monthly rainfall estimation by AIC criterion judgment. Distribution of daily rainfall month-by-month shows a Gamma distribution model agrees well with daily rainfall distribution. Using a Gamma distribution model and monthly total rainfall, daily rainfall is assigned stochastically. Analysis shows distribution patterns of hourly rainfall percentage, both in the rainy season and non-rainy season, coincide well with the Beta distribution. Using a Beta distribution model and daily total rainfall, hourly rainfall is assigned stochastically. A comparison of statistics features of simulated data to that of measured data validates the method.

At present, the outdoor thermal environment research methods mainly include two types: the measurement and simulation, the limitation of the field measurement only makes an objective record and reflect on the existing environment of microclimate, it can't make predictions; while the software whether can simulate thermal environment of the scene or environment to make quantitative predictions, to make up for any deficiencies in the study of the measured is a concern. ENVI - met is considered to be the best fluid mechanics simulation software of the outdoor thermal environment, which is mainly in the application of high latitude and cold regions. Based on the research of subtropical country park outside environment thermal comfort, this paper analyzed three seasons of climate data through the experimental research of the east gate entrance area of Guangdong Tianlu Lake Country Park for spring, summer, autumn; and combined with simulation software ENVI-met to build the model, respectively for spring, summer, autumn three season of simulation experiment, then the authors work out the comparative study of the measured and simulated data, and analyzed the change rule to find out the following four conclusions:(1) with the actual measurement of meteorological data as boundary conditions, ENVI-met can simulate microclimate condition of the subtropical hot and humid region country parks outdoor environment; the change trend of simulated data and measured data is identical within the scope of the instrument error.(2) compared with the simulated data and the measured data, it can more reflect the general trend of change, and is not affected by the measured specific emergency on that day.(3) the variations in the data of simulation generally less than the measured data.(4) the hard ground and artificial facilities compared natural tree shade field simulated results is more close to the actual measurement results. Thus this paper could confirm that the simulation software ENVI-met, which began in the high latitudes, is also could be used in the simulative study of subtropical hot and humid area of outdoor thermal environment, and as a aided designing tool; the authors preliminarily found a certain rule for the background parameter setting in the simulation experiment to set up a foundation for further research in the future.

Rooftop shading is an effective green building design strategy in subtropical areas; it can create an ecological rooftop space and produce energy savings for rooms on the top floor. This article describes the rooftop shading system of the Humanities Building at SCUT (South China University of Technology). A shading calculation software developed by the Building Energy Efficiency Laboratory (BEEL) of SCUT is used to calculate and analyze the rooftop shading effect in summer and winter. The actual performance of this rooftop shading system was evaluated by measuring the wet bulb globe temperature (WBGT) in the shaded and unshaded areas under the shading system on July 2, 2003.

Climate chamber study, was performed by using 30 subjects living in the hot-humid area of China in the summer of 2009. The subjects dressed with the standard 0.6clo clothing were exposed to 6 transient conditions in the range of cool to warm and their subjective and physiological responses were collected. The results show that the subject's psychology should react than physiology faster, shorter Stable time. The rate of change in thermal sensation skin temperature are related to varied range of air temperature and humidity .the humid sensation is neutral and the mean skin temperature is 33.2℃ when the thermal sensation is neutral. Mean skin temperature predict thermal sensation well

Telecommunication base stations (TBSs), which are the basis of the telecommunications network, consume more energy than other public buildings due to their high inner heat density and special operating schedule. The number of mobile phone users in China exceeds 500 million, and the telecommunications network has become the largest in the world, consisting of more than 100,000 TBSs. The annual energy consumption of the network is 20 billion kWh, one third of which is used by TBSs. Guangzhou, as one of the fastest developing cities in China, has more than one thousand existing TBSs and the total annual electricity bills are in the tens of millions of RMB, 25% of which is the cost of air conditioning. With the rapid growth of telecommunications, energy conservation for TBSs is gaining greater attention in China. Previous studies on energy conservation in TBSs mainly focused on improvement of efficient air-conditioning systems (Nakao et al., 1988; Maeda et al., 2005; Choi et al., 2007), indoor airflow optimization (Hayama & Nakao, 1989; Dan & Matti, 2000), use of renewable energy (Makhkamdjanov, 2006), and other energy saving and monitoring techniques (Schmidt & Shaukatullah, 2003). There are very limited studies on building energy efficiency design of TBS. Building energy efficiency design, which is known as passive cooling technology, is very popular in the traditional buildings and well inherited and applied in the modern buildings in Southern China. Compared with the active one, such as airconditioning, passive cooling technology has notable advantages on utilizing natural cooling capacities with no or few energy consumption. Many studies report building energy efficiency designs of walls, roof, glazing, shading and natural ventilation for residential buildings (Feng, 2004), institutional buildings (Athanassios et al., 2007) and high rise apartments (Cheung et al., 2005), however, no such studied were performed on TBS buildings. Nakao et al. (Nakao et al., 1988) studied a thermal control wall for TBS, which can lose heat by using a two-phase loop-type thermo-siphon system integrated inside the wall. The heat transmission coefficient of the wall was found to be one to ten times of the ordinary wall and the annual energy saving was estimated to be 20%. The study proposes a new energy efficiency design of wall for TBS, however, no other designs, such as shading or natural ventilation were mentioned. 26

The between blinds glass is a new product which installs aluminium blinds between the hollow glasses. It is mainly used in the developed country nowadays. The purpose of this article is to discuss the adaption of between blinds glass in different climate regions of China. The heat load in winter and cooling load in summer of the residential buildings using three kinds of window glass such as ordinary hollow glass, low emissivity glass and between blinds glass in different climate regions of China are calculated. The thermal performances of three kinds of glass are compared. The results show that between blinds glass is fit for the residential buildings in different climate regions of China.