Average Outdoor Air Temperature Research Articles

Thermal design of insulation on the outside of the cavity for a Trombe wall with phase change materials

A Trombe wall with a phase change material (TW-PCM) is a practical and low-carbon passive solar heating method. However, the heat efficiency is not high due to the large amount of heat loss at night. Insulation on the outside of the cavity is a suitable solution, but the design method has not been obtained, which hinders the realization of zero energy buildings. In the present study, we analyzed the thermal performance of a TW-PCM with insulation on the outside of the cavity at nighttime to develop the design approach. A mathematical model was established and validated based on experiments. This model was used to analyze the heat efficiency in different outdoor climates for a TW-PCM with insulation on the outside of the cavity. As well, the solar heating fraction (SHF) was analyzed. The results indicated that insulation on the outside of the cavity could significantly improve the thermal performance due to the reduced heat loss during the nighttime. The recommended additional thermal resistance due to the insulation on the outside of the cavity was negatively correlated with the average outdoor air temperature in January based on the analysis of various climates in China. The thermal resistance of the closed air cavity, formed by the TW-PCM and the insulation component, at the same wall emissivity was similar under the recommended additional thermal resistance in different outdoor climates. The SHF was improved significantly for the TW-PCM buildings with insulation on the outside of the cavity and it had a linear relationship with the solar heating load ratio (SLR).

Monitoring of a Living Wall System in Santo Domingo, Dominican Republic, as a Strategy to Reduce the Urban Heat Island

Given the current need to reduce the Urban Heat Island (UHI) worldwide, one of the strategies that can contribute to this mitigation is green façades. In this context, the aim of this research is to evaluate a Living Wall System (LWS) as a strategy to reduce the urban heat island in Santo Domingo, Dominican Republic, using outdoor test cells. This research was focused on the monitoring of two different façades, an LWS and a reference façade, during the warmer months. For the comparison, the parameters measured were air temperature, relative humidity, surface temperature and environmental variables. In addition, thermal images were taken. Results reveal that during the days selected, the average outdoor air temperature difference between the LWS compared to the reference façade was 5.3 °C, whereas during the day, the average was 3.3 °C. Concerning surface temperature, in the case of the LWS, the temperature was higher and had greater fluctuations than the reference façade. This behavior was confirmed by the results obtained with thermal images. In conclusion, using an LWS in a tropical climate helps the urban microclimate, which contributes to urban heat island effect mitigation during the warmer months.

Farklı Denge Sıcaklıkları İçin Isıtma ve Soğutma Derece-Saatlerinin Değişimi: Bandırma Örneği

Data on exterior temperature constitute one of the most important parameters in the calculation of energy needs in buildings. This study obtained the temperature distribution curves by analyzing the outdoor air temperature in Bandırma. Heating Degree Hour (HDH) and Cooling Degree Hour (CDH) for three different base temperatures were calculated. A 21-year data set between 2000-2020 obtained from the General Directorate of Meteorology was used. The incidence (%) of outdoor air temperature according to months was determined. In the calculation of the HDH and CDH values, base temperatures of (15, 18 and 20 °C) and (20, 22 and 24 °C) were considered respectively. The results of the analysis showed that the number of HDH changed between 31357 and 53037, while CDH numbers ranged between 10433 and 2669. The increase in the average outdoor air temperature with the effects of global warming was determined for heating and cooling season in a 21-year period according to year. It was determined that there was an increase of 1.68 °C in the heating season in the 21-year period and 1.80 °C in the cooling season in the 21-year period. In this study, the necessity of determining energy needs for heating and cooling purposes in a clear and up-to-date manner was emphasized once again. This is highly important to not only achieve energy savings but also reduce the air pollution effects of energy consumption. It is believed that this study will make a contribution to the literature in this sense.

Study on productivity of office workers and power consumption of air conditioners in a mixed-mode ventilation building during springtime

The thermal environment in offices affects the productivity of workers; thus, it is important to adjust the thermal environment appropriately with heating, ventilation, and air conditioning. However, there is an urgent need to reduce the amount of energy used in the building sector for cooling, which has been rising. Mixed-mode ventilation has attracted attention as a means of decreasing air conditioning power consumption and improving the satisfaction of office workers. In the present study, a measurement survey and a questionnaire survey were conducted during springtime to investigate air conditioning power consumption during mixed-mode ventilation and to elucidate the relationship between the use of mixed-mode ventilation and productivity. The power consumption on the mixed-mode ventilation floors was less than that on the mechanical ventilation floors in the measurement period when the average outdoor air temperature was 21 °C, with savings ranging from 3.1% to 70.6%, although it varied widely with the weather conditions. The relationship between the use of mixed-mode ventilation and productivity was analyzed using multilevel analysis (hierarchical linear model), a method that considers the data hierarchy. Mixed-mode ventilation improved the productivity of male participants by about 9.1%, suggesting that mixed-mode ventilation could both decrease air conditioning power consumption and improve productivity during springtime. However, the increase in productivity of female participants was about 0.5%, indicating that there may be differences depending on gender. The present study has practical implications for promoting mixed-mode ventilation as a means to reduce air conditioning power consumption in offices and improve productivity.

Utilization of Thermally Activated Building System with Horizontal Ground Heat Exchanger Considering the Weather Conditions

The thermally activated building system (TABS) can reduce the peak load by integrating with the ground heat exchangers. When integrated, the cost of groundwork and stability of the ground temperature would counteract because the weather conditions would influence the ground temperature in shallow depth. However, previous studies on TABS assumed constant ground temperatures such as average outdoor air temperature. In this study, ground temperatures in different depths are simulated for their detailed investigations, and simulated results of ground temperature were applied to building energy simulations for observing the load-handled ratio (LHR), representing the peak load reduction by TABS evaluated in various weather conditions. Simulation results of ground temperatures from 1 m to 39 m depths show that the temperature stabilized at 2 m to 11 m depths depending on the characteristics of the outdoor air temperature. LHR increased as the ground depth increased because the ground temperature at shallow depths increased during peak hours. Ground depths of 8 m were found ideal for maintaining consistent LHR for all weather conditions. Detailed observation of ground temperature and its effect on LHR in various weather conditions can help system engineers design and operate the TABS with the ground system.

ORGANIZATION OF THE ENERGY MANAGEMENT SYSTEM ON THE BASIS OF THE UNIVERSITY KNOWLEDGE HUB

BACKGROUND AND OBJECTIVES. Energy efficiency and energy saving are the priority direction of science, technology and engineering development in Ukraine. The policy of energy saving, carried out all over the world, is directed to all branches and scientific researches in all spheres. The big consumer of energy resources is the higher school. Updating of normative-legal and technical base aimed at design and operation of buildings with low energy consumption and high energy efficiency class shows the necessity of short-term solution of the problem. At the same time, there is a lack of a systemic view of energy efficiency, which does not allow evaluating the level of energy costs throughout the life cycle of higher education institutions, which shows the need to find effective solutions to the problem.METHODS. Multiple regression equation was used to assess the influence of factors on electricity consumption and energy efficiency of Kyiv National University of Technologies and Design, statistical analysis of the obtained data was performed.FINDINGS. As a result it was found out that the data of electricity consumption do not obey the law of normal distribution, so it is difficult to build an accurate prediction of electricity consumption. The use of HAB knowledge on energy efficiency allowed a more qualitative analysis and highlighted the main factors affecting electricity consumption. The university has unregulated central heating, individual air conditioning systems, and central and individual lighting. In this regard, we selected the following main factors: average outdoor air temperature, average duration of daylight hours, heating period, average number of people working per day, during the month to conduct energy monitoring and energy audit of university buildings.CONCLUSION. Implementation of suggested scheme of structural organization of typical system of automatic accounting of university energy consumption on the basis of university HUB of energy efficiency knowledge: server, allowing to collect, store and process data; routers by means of various wire and wireless communication technologies; hubs, installed on the objects of energy consumption; workstations, which are personal computers with installed software of used HUB will allow to optimize energy consumption.

Indoor Thermal Environment of Various Semi-Enclosed Atrium Configurations of Institutional Building in Tropical Climate

The consideration of local climate is essential for the application of atrium in building. Different strategies and approaches in atrium configuration are required for different climates in ensuring its effectiveness. Nevertheless, the final aim is still similar which is to provide a comfortable environment for the users. Hence, this study was executed to examine the effects of top and side configurations on the indoor thermal environment of semi-enclosed atrium in the tropical climate. The methodologies involved field measurement and questionnaire survey. The field measurements were executed at two different configurations of semi-enclosed atriums in the tropical climate of Malaysia. Meanwhile, the questionnaire surveys were executed simultaneously with the field measurements in obtaining the users’ thermal sensation and satisfaction. The findings indicated that the top configuration had more influence to the indoor thermal environment compared to the side configuration as it determined the amount of solar heat penetration into the atrium area. Meanwhile, the side configuration influenced the air velocity inside the atrium. The Faculty of Engineering and Built Environment’s atrium that has opaque top finishes was found to have the average indoor operative temperature of less than 30 °C throughout the day, though the average outdoor air temperature was more than 30 °C. It also had more hours with neutral thermal sensation felt by the users compared to the Faculty of Economics and Management’s atrium that has transparent materials for the top finishes. The study is useful in guiding the selection of appropriate strategy for an atrium in tropical climate

Scenario-based prediction of climate change impacts on building cooling energy consumption with explainable artificial intelligence

In this paper, we present a newly developed eXplainable artificial intelligence (XAI) model to analyze the impacts of climate change on the cooling energy consumption (Ec) in buildings, predict long-term Ec under the new shared socioeconomic pathway (SSP) climate change scenarios, and explain the underlying reasons behind the predictions. Such analyses and future predictions are imperative to allow decision-makers and stakeholders to accomplish climate-resilient and sustainable development goals by leveraging the power of meaningful and trustworthy projections and insights. We demonstrated that the XAI is capable of predicting the Ec under future climate scenarios with high accuracy (R2>0.9) and reveals the critical inflection points of the daily average outdoor air temperature (Ta) beyond which the Ec increase exponentially. We applied the XAI model for residential and commercial buildings in hot–humid and mixed–humid climate regions to quantify the incremental impacts of climate change on Ec under the different SSPs. The XAI-based analysis concluded positive and persistent incremental changes in the Ec from 2020 to 2100 under all future SSP scenarios, with the maximum incremental impact of 24.5%, 33.3%, 57.8%, and 87.2% in hot–humid and 37.1%, 47.5%, 85.3%, and 121% in mixed–humid climate regions under the sustainable green energy (SSP126), business-as-usual (SSP245), challenges to adaptation (SSP370), and increased reliance on fossil fuels (SSP585) scenarios, respectively. Potential increases in the Ec in future climates could have significant adverse impacts on the local and regional economy if necessary adaptation and mitigation measures are not implemented a priori.

Online Methodology for Separating the Power Consumption of Lighting Sockets and Air-Conditioning in Public Buildings Based on an Outdoor Temperature Partition Model and Historical Energy Consumption Data

Among sub-items of energy consumption in public buildings, lighting sockets play an important role in energy-saving analysis. So, the energy consumption data quality of lighting sockets is important. However, limited by the initial cost of energy monitoring platform, it is difficult to install electricity meters covering all branches and to retrofit the incompact classification electricity branches, which results in a mixture of the lighting socket energy consumption and other components. In this study, a separation methodology is proposed. First, the abnormal data in the energy monitoring platform are cleaned and screened using a clustering algorithm. Second, the average outdoor air temperature partitioning model (OATPM) method and the k-nearest neighbor (KNN) clustering algorithm method are proposed for identifying and separating the abnormal data. These two methods have complementary advantages in the best applicable scenarios, including calculation accuracy and other aspects. The verification results for three buildings show that the relative error of this separation methodology is less than 15%. Finally, this paper presents the optimization parameters of the KNN method. Through this methodology, building managers need only historical data in an energy monitoring platform to separate the combined power consumption of the lighting sockets and air-conditioning online, independent of detailed information statistics.

Analysis of phase change materials for regulating the thermal environment of greenhouses in different climatic conditions in Highland areas

Phase change materials have good peak-shaving and valley-filling effects, which are effective for improving the thermal environment of passive thermal storage buildings. In this paper, phase change materials were applied to a solar greenhouse in the plateau area, and the indoor temperature is measured and analyzed under different meteorological conditions. It was concluded that when phase change materials were applied in the central region of Yunnan, where the temperature difference between day and night was large, it had a significant improvement effect on the thermal environment inside the solar greenhouse. The average outdoor air temperature, the maximum outdoor temperature difference between day and night, and solar radiation were the main factors affecting the temperature in the greenhouse. By analyzing and evaluating the effect of using phase change materials in solar greenhouses under different outdoor climate conditions, the advantages and limitations of using phase change greenhouses in different areas of the plateau were discussed.

Design Corrections in Spanish Office Buildings to Improve Energy Efficiency in the Face of Climate Change

The majority of buildings in Europe are at present naturally ventilated and do not use heating or cooling equipment throughout the summer. However, this idea is changing and as a result heating ventilation air conditioning (HVAC) related energy consumption has been rising in the recent years. On the other hand, predictions published by the intergovernmental Panel on Climate Change (IPCC) indicate an annual warming rate ranging between 0.1 and 0.4 °C. In the present study, the ISO 13790:2011 standard has been employed to analyze the effect of building design corrections over the energy saving of a real building during its mean life and under climatic change predictions. In this sense, the effect of climate change, ventilation rate and its energetic and carbon dioxide emissions implications are obtained for the next 15 years. The results obtained indicate that an increment in the air changes by natural ventilation will be more effective than changing the wall structure and, in consequence, the thermal inertia. In particular, it was obtained that an increase of natural ventilation will always reduce the energy consumption and that this consumption will be lower with time due to an increment of an average outdoor air temperature. This modification will allow reduced cooling energy peak demands during the summer season and improve indoor ambiences in mild regions and the energy efficiency.

Field experiments on the effects of an earth-to-air heat exchanger on the indoor thermal environment in summer and winter for a typical hot-summer and cold-winter region

An earth-to-air heat exchanger (EAHE) is a shallow geothermal energy utilization technology, which can significantly reduce the building energy consumption. This study aims to investigate the effects of an EAHE on the indoor thermal environment in hot-summer and cold-winter regions. A full-scale experiment was conducted for a continuous 24 h period using two identical buildings (with and without an EAHE) exposed to the same outdoor conditions on typical summer and winter days. Experimental results show that the EAHE provides an average outdoor air temperature reduction of 9.12 °C under cooling conditions and increase of 5.53 °C under heating conditions. Moreover, the average outdoor air relative humidity increases by 46.89% and decreases by 27.41% in the cooling and heating conditions, respectively; the corresponding average EAHE coefficients of performance (COP) are 7.03 and 4.26, respectively. Compared to that of the building without EAHE, the average indoor air temperature of the building with EAHE decreases by 5.9 °C in summer and increases by 4.29 °C in winter, and the average walls’ internal surface temperature decreases by approximately 6 °C and increases by approximately 5.8 °C. Moreover, the EAHE system reduces the average building cooling and heating loads by 55.4 and 40.43 W/m2, respectively.

A survey of high school students' clothing in classroom

In this study, a thermal-environment survey focusing on clothing behaviors of students in high-school classrooms was performed during summer. Subsequently, statistical analysis was performed to estimate the realizable limit level of adaptation to the thermal environment by adjusting clothing behavior. Additionally, a questionnaire-based subjective-vote and thermal-environment surveys were conducted in a naturally ventilated high school in Nagano city, Japan, during summers of 2017 and 2018. Nagano city is characterized by a humid subtropical climate (Cfa), per Köppen climate classification. The study involved 59 male and 21 female participants aged between 15 and 18 years. Five hundred and two subjective votes were collected in this study with 365 and 137 votes being cast by male and female participants, respectively. The average outdoor air temperature measured 23.9 °C during the survey period, whereas the average indoor operative temperature equaled 28.0 °C. The insulation level of clothing worn by participants varied in the 0.29–0.77 clo range. Results of regression analysis reveal that both male and female participants reduced their clothing insulation level in response to an increase in indoor operative temperature. However, at operative temperatures exceeding 29 °C, the median value for clothing insulation was observed to be in the 0.31–0.37 clo range. This result reveals limitations that exist with regard to clothing adjustments that can be made by participants in hot environments. Additionally, thermal sensation votes were observed to increase at operative temperatures exceeding 29 °C, thereby confirming the existence of a limit to thermal-environment adaptation realizable via adjustment of clothing insulation levels.

Analytical model to study the heat storage of phase change material envelopes in lightweight passive buildings

Integrating phase change materials (PCMs) into building envelopes can improve the heat storage ability of buildings and prevent overheating when the outdoor air temperature and solar radiation are high. However, simply adding a PCM to a building does not ensure that the temperature of a room can be controlled; hence, a suitable design method is necessary. Nevertheless, the heat storage mechanism of PCM envelopes is very complicated because it is affected by several factors, including the climate, building parameters, and the properties of the PCM employed. This study develops a mathematical model for passive buildings, and the factors affecting the heat storage process of PCM envelopes in summer are analyzed to determine an efficient method to control the temperature of the room with PCMs. A theoretical analysis demonstrates that PCMs reduce the indoor temperature, but not the average room temperature. The effectiveness of PCMs in buildings is influenced by both climate and building parameters. If the average outdoor air temperature is higher than the boundary of the humans' comfort level, overheating will occur even when using PCMs. Before using PCMs, the average room temperature should be calculated and previewed using the proposed theoretical model. If the effectiveness of PCM is limited, the average room temperature is reduced via ventilation.

Microbiome in an Office Building Using a Cooling Trench as an Outdoor Air Duct

Subterranean temperature at a depth of 10 m is almost equal to the average outdoor air temperature of the same area. Therefore, if a building cooling trench is used as an outdoor air duct, outdoor air can be cooled in summer and warmed in winter. This energy-saving technique is often used in Japan. However, since the relative humidity in a cooling trench is high, microbe numbers tend to increase in summer. The present study sought to characterize the microbiome status in the cooling trench of such an office building in Japan. Specifically, we performed a metagenomic analysis in which we analyzed DNA directly upon collection from the environment, without intervening cultivation. The results showed the presence of bacteria of the genera Pseudomonas, Lactobacillus, Nesterenkonia, Staphylococcus, Deinococcus, Acinetobacter, Enhydorobacter, and Corynebacterium. Bacteria of the genera Nesterenkonia, Deinococcus, Enhydorobacter, and Corynebacterium predominated on the surface of the trench. Notably, bacteria of the genus Nesterenkonia constituted >50% of the organisms on the surface of the downstream end of the cooling trench. Principal coordinate analysis was used to compare bacterial inhabitants of outdoor air, indoor air from 2nd- and 3rdfloor offices, and the region downstream of the cooling trench. The results suggested that the microbiome of air in this cooling trench influenced indoor air within the building.

Analysis of the Criteria for Selecting Heating Systems for Residential Buildings in Cold Climate

How to choose a heating system a residential building? That is an important question builders and owners of the buildings in Lithuania. The heating season in Lithuania starts by October 15th and ends on April 15th. During this period, the average outdoor air temperature is about 0°C. Many of the new single-family buildings in Lithuania are sold not completed as the new owners want to be free in choosing interior materials and engineering equipment. For this reason, many engineering decisions must be taken by the owner of the building, who is usually not a professional in the field of engineering. When choosing a heat source, it is always necessary to distinguish between many for and against arguments. Every heating option has both advantages and disadvantages. There is also a striking balance: the same heating method can never be either very comfortable and at the same time very cheap. When making a final decision, it is always recommended to compare the ratio of heat to the price and comfort, of course, taking into account energy and fuel price forecasts. The article provides information that helps the building owner to navigate in the field of different engineering solutions that affect the future maintenance costs, efficiency, environmental aspects and comfort level of the building. DOI: http://dx.doi.org/10.5755/j01.sace.23.2.21359

Children's residential exposure to organophosphate ester flame retardants and plasticizers: Investigating exposure pathways in the TESIE study

BackgroundFollowing the phase-out of polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs) have been increasingly used in consumer products and building materials for their flame retardant and plasticizing properties. As a result, human exposure to these chemicals is widespread as evidenced by common detection of their metabolites in urine. However, little is known about the major exposure pathways, or factors that influence children's exposure to OPEs. Furthermore, little data is available on exposure to the novel aryl OPEs. ObjectivesTo examine predictors of children's internal exposure, we assessed relationships between OPEs in house dust and on hand wipes and levels of their corresponding metabolites in paired urine samples (n = 181). We also examined associations between urinary metabolites and potential covariates, including child's age and sex, mother's educational attainment and race, and average outdoor air temperature. MethodsChildren aged 3 to 6 years provided urine and hand wipe samples. Mothers or legal guardians completed questionnaires, and a house dust sample was taken from the main living area during home visits. Alkyl chlorinated and aryl OPEs were measured in dust and hand wipes, and composite urine samples were analyzed for several metabolites. ResultsTris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), 2-ethylhexyl diphenyl phosphate (EHDPHP), triphenyl phosphate (TPHP), and 2-isopropylphenyl diphenyl phosphate (2IPPDPP) were detected frequently in hand wipes and dust (>80%), indicating that these compounds were near-ubiquitous in indoor environments. Additionally, bis(1-chloro-2-propyl) 1-hydroxy-2-propyl phosphate (BCIPHIPP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPHP), mono-isopropyl phenyl phenyl phosphate (ip-PPP), and mono-tert-butyl phenyl phenyl phosphate (tb-PPP) were detected in >94% of tested urine samples, signifying that TESIE participants were widely exposed to OPEs. Contrary to PBDEs, house dust OPE concentrations were generally not correlated with urinary OPE metabolite levels; however, hand wipe levels of OPEs were associated with internal dose. For example, children with the highest mass of TDCIPP on hand wipes had BDCIPP levels that were 2.73 times those of participants with the lowest levels (95% CI: 1.67, 4.48, p < 0.0001). Of the variables examined, hand wipe level was the most consistent and strongest predictor of OPE urinary metabolite concentrations. Outdoor air temperature was also a significant predictor of urinary BDCIPP concentrations, with a 1 °C increase in temperature corresponding to a 4% increase in urinary BDCIPP (p < 0.0001). ConclusionsOPE exposures are highly prevalent, and data provided herein further substantiate hand-to-mouth contact and dermal absorption as important pathways of OPE exposure, especially for young children.

Optimum Insulation Thickness for the Exterior Walls of Buildings in Turkey Based on Different Materials, Energy Sources and Climate Regions

Thermal insulation improves the strength and longevity of buildings by reducing energy consumption, and as a related result, improved energy use. The selection of insulation material is governed by important parameters, including the average outdoor air temperature, the thermal conductivity of the buildings and the cost of the insulation material. Increases in the thickness of the insulation material will gradually decrease the energy consumption for heating; however, the insulation thickness has an optimum value that minimises the total investment cost, and determination of this optimum value is critical for economic analysis. In this paper, a life-cycle cost analysis is presented to show the optimum insulation thickness, energy savings over a lifetime of 15 years and payback periods for six different fuels and insulation materials for four cities in Turkey selected from climate regions identified by the Turkish Thermal Insulation Standard (TS 825). Mugla (1st region), Kocaeli (2nd region), Ankara (3rd region) and Ardahan (4th region) were selected for analysis of a sandwich-type wall constructed from the following six insulation materials: extruded polystyrene, expanded polystyrene, glass wool, rock wool, polyisocyanurate and polyurethane. The calculations were also made on the basis of six different fuels, such as motorin, natural gas, propane (LPG), electricity, coal (imported), and fuel-oil No. 4. As a consequence, results demonstated that the optimum insulation thickness vary between 2.8 cm and 45.1 cm, with energy savings between 16.4 ₺ /m 2 and 479 ₺ /m 2 , and payback periods fluctuating between 0.078 and 0.860 years, depending on the city, the insulation material, and the cost of fuel.

Sprinkler flow rate affects dairy cattle avoidance of spray to the head, but not overall, in an aversion race

Spraying cattle with water elicits behavioral responses ranging from willing use to avoidance of wetting the head or entire body. This variation may be partly explained by sprinkler flow rate, as higher flow rates result in greater heat abatement and spray impact. An aversion race can be used to evaluate the emotional valence cows associate with treatments, based on the prediction that they will approach negative (vs. positive) stimuli more slowly and require greater pressure from a handler. Our objective was to evaluate how heat load affects the degree to which dairy cattle show reluctance to approach sprinklers with different flow rates in an aversion race. We compared unsprayed treatments (n=8 with feed, n=16 without) to 0.4L/min (n=14) and 4.5L/min (n=17) sprinklers, which differed eight-fold in spray impact (1.1 vs. 8.9kPa, respectively). Over 10 trials, cows were required to approach treatments in a covered, narrow raceway (average outdoor air temperature, mean±SD, 31±3.8°C). We compared time to complete the race (transit time), the pressure handlers applied, and head posture. Overall, handlers applied pressure half as often when feed was offered but there were no other treatment differences in handling pressure or transit time. Thus, we excluded the feed treatment when examining interactions with heat load and sprinkler flow rate. In warmer weather, transit time increased (by 13s per 10°C increase). As their respiration rate increased, unsprayed cows moved more slowly (by 7s per 10 breaths/min increase), whereas sprayed cows did not. Handling pressure was not affected by heat load or spray application, but head posture depended on sprinkler flow rate. When cows approached 4.5L/min, they lowered their heads nearly five times as often compared to 0.4L/min or no spray (proportion of trials±SE, 0.81±0.05, 0.17±0.06, and 0.15±0.05, respectively). This may have been an attempt to reduce exposure of sensitive body parts to higher-impact spray. Indeed, when we applied von Frey monofilaments to the ear and shoulder (n=56), the ear had a lower response threshold (greater sensitivity) than the shoulder [mean (95% confidence interval), 0.2 (0.1 to 0.4) vs. 1.2 (0.5 to 2.5) g of force, respectively, back transformed from natural log values]. In conclusion, each measure provided different insights about reluctance to approach treatments. Transit time increased in response to heat load rather than aversion. Handling pressure reflected willingness, as it was needed less often when cows were offered a feed reward, but this measure did not differ among sprinkler treatments. Therefore, although cows lowered their heads to avoid exposing sensitive areas to 4.5L/min spray, they did not show overall aversion to higher-impact spray.

Simulation Analysis on the Solar Heating System Combined with Tabs in Lhasa, China of Annex 59

Lhasa, at high altitudes, in the west of China, is in a cold region, but with an annual total solar radiation as much as 7.2GJ/m2. Conventional water solar collectors and water pipes have the risk of burst in the severe cold. In this paper, a building heating system combining solar air collector with thermally activated building system (TABS) is proposed in Lhasa, China. To analyze the performance of the solar heating system in intermittent operation, a numerical model was built using the finite difference method for TABS and the state-space method for the reference building in Lhasa. The systematic simulations show that the indoor air temperature could be maintained at 17-24°C for 24hours with the TABS in intermittent operation at an average outdoor air temperature of -3°C. The air solar collector of an area of 1m2 could undertake the heat load of a building area of 3-4 m2 in Lhasa without any other heat source.