Air Dry Bulb Temperature Research Articles

Thermo-economic analysis and comparison of novel desiccant air conditioning systems

Desiccant air conditioning (DAC) systems are considered an effective alternative to traditional vapor compression systems due to their ability to independently control temperature and humidity, coupled with their environmentally friendly design. Consequently, this paper deals with experimental and simulation study on DAC systems. The experiments were conducted on a reference system (RS) equipped with all necessary control and measurement devices. This reference system includes a traditional desiccant evaporative air-conditioning system with an additional heat exchanger placed after the desiccant wheel, functioning as an after-cooler. In addition, steady state and transient simulation models were developed using TRNSYS software to predict the performance of four different configurations of DAC systems and the reference system, under hot and humid climatic conditions.The experimental data verify the precision and relevance of the simulation results, with an average error of 2.57 % for the air temperatures. The steady state findings showed that Config-4 exhibited the best thermal performance compared to the other configurations. Also, Config-4 demonstrates a stable thermal cooling capacity despite fluctuations in outdoor air dry-bulb temperature. Transient results revealed that, Config-4 has levelized costs of CO2 emissions that are 64.2 % lower than RS, followed by Config-3, Config-2, and Config-1. Lower CO2 emissions result in a positive impact on mitigating climate change and improving air quality. Economic analysis revealed that the total levelized cost of cooling (LCOC) for Config-4 is 70.5 % lower than RS, demonstrating the most significant cost reduction. Configurations 3, 2, and 1 also showed lower LCOC compared to the reference system.

DESIGN AND ESTIMATION OF COOLING TOWER

A cooling tower is a device that rejects waste heat to the atmosphere through the cooling of a coolant stream, usually a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or, in the case of dry cooling towers, rely solely on air to cool the working fluid to near the dry-bulb air temperature using radiators. The natural draft cooling tower is an open, direct-contact system. It works using a heat exchanger, allowing hot water from the system to be cooled through direct contact with fresh air. To increase the heat transfer surface area (and optimize the cooling process), hot water is sprayed from nozzles within the tower. Cooling towers in the 19th century through the development of condensers for use with the steam engine. Condensers use relatively cool water, via various means, to condense the steam coming out of the cylinders or turbines. Keywords: Cooling tower, Cooling system, Evaporative cooler, Coolant system.

Applying indirect evaporative chillers for comfort cooling in Northern European commercial buildings: A case study in Sweden

Indirect evaporative chiller (IEC) can produce chilled water below the wet-bulb temperature of outdoor air. To evaluate the potential of applying indirect evaporative chillers for covering the high indoor sensible cooling loads in commercial buildings of Northern European countries, a case study based on a real commercial building in Stockholm was carried out assuming renovation of the existing air-conditioning system by replacing district cooling with an indirect evaporative chiller as cooling source. Numerical models were built for the indirect evaporative chiller as well as for the entire space cooling system, and techno-economic performance evaluation as well as sensitivity analyses were conducted with a validated numerical model to comprehensively evaluate renovation benefits. The simulation results show that, an indirect evaporative chiller fulfilling 80 % of the total sensible cooling load of the design outdoor condition with a dry-bulb outdoor air temperature of 26 °C and a relative humidity of 45 %, can produce chilled water below the wet-bulb outdoor air temperature when the relative humidity is lower than 0.4 for hours in July of year 2015 and 2018. Sensitivity analyses show that reducing the supply air flow rate of the ventilation system from the default setpoint of 1.2 L/(m2·s) to the minimum hygienically required level of 0.35 L/(m2·s) would double the seasonal energy efficiency rating of the air-conditioning system from 6.3 to 12.8. Compared to the original district cooling-based system, the operational expenditure of the renovated system can be saved for optimally 54 k SEK, justifying a capital expenditure of 588 k SEK assuming operation of 15 years. The case study shows that indirect evaporative chiller can potentially be applied for commercial buildings under the and climatic and market context of Sweden, providing an alternative cooling solution for similar applications.

Performance Evaluation of Two Stages Parallel Flow Indirect Evaporative Cooling with Aspen Pads in Baghdad Climate Conditions

This study delves into the realm of advanced cooling techniques by examining the performance of a two-stage parallel flow indirect evaporative cooling system enhanced with aspen pads in the challenging climate of Baghdad. The objective was to achieve average air dry bulb temperatures (43 oC) below the ambient wet bulb temperatures (24.95 oC) with an average relative humidity of 23%, aiming for unparalleled cooling efficiency. The research experiment was carried out in the urban environment of Baghdad, characterized by high temperature conditions. The investigation focused on the potential of the two-stage parallel flow setup, combined with the cooling capability of aspen pads, to surpass the limitations imposed by conventional cooling methods. The empirical findings underscored the capacity of the two-stage parallel flow configuration to achieve air-dry bulb temperatures surpassing the ambient wet bulb temperature. Nonetheless, it was evident that an excessive application of water (exceeding 9 lpm) onto the aspen pads within the wet channels yielded adverse repercussions on the cooler's performance metrics, specifically in terms of wet bulb effectiveness and coefficient of performance. A range of air flows spanning from 150 CMH to 350 CMH was analyzed, revealing the influence of heightened air flow rates on the resultant dry bulb temperatures delivered by the cooling system. Notably, the peak wet-bulb effectiveness registered at 1.08, concurrently yielding a coefficient of performance measuring 7.8.

Spatiotemporal variability in human thermal comfort perception in open-air spaces: application to the state of Minas Gerais, Brazil.

The objective of this study was to propose bioclimatic zoning to classify human thermal comfort and discomfort in the state of Minas Gerais, Brazil; both historical and future scenarios are considered. Thus, historical series (1961 to 2017) of the effective temperature index as a function of the wind (ETW) were obtained as a function of the monthly average values of the minimum, mean, and maximum dry-bulb air temperatures (tdb,min, tdb,mean, and tdb,max, respectively), in addition to the mean relative humidity ([Formula: see text], %) and mean wind speed ([Formula: see text], m s -1). The data were obtained from 34 weather stations and subjected to trend analysis by using the nonparametric Mann-Kendall test, thus enabling the simulation of future scenarios (for 2028 and 2038). Then, to define the thermal ranges of the bioclimatic zoning, maps of ETWmin, ETWmean, and ETWmax were created from geostatistical analysis. Overall, the results show warming trends for the upcoming years in Minas Gerais municipalities. All climatic seasons showed an increase in the frequency of new classifications in the upper adjacent classes, which indicates climate warming. Therefore, when considering future scenarios for the autumn and winter seasons, attention should be given to changes in predicted thermal sensation, especially in the Central Minas Gerais, Belo Horizonte Metropolitan, South/Southwest Minas, Campo das Vertentes, and Zona da Mata.

Using a Model to Compare Cooling System Design Factors For Lactating Cows

Highlights Cow mass, milk yield, solar load, air velocity, dry-bulb and dew-point temperature impact lactating cow respiration rates. Modeled respiration rates align with published studies dealing with milk yield, solar load, and evaporative cooling. The model can be used to assess cooling systems for conditions that might be difficult to capture in field measurements. Abstract. The risk of lactating cows experiencing heat stress is increasing because of increased productivity. A steady-state process-based model described by Nelson and Janni (2023) and assessed by Janni et al. (2023) was used to compare additional combinations of environmental conditions (e.g., air dry-bulb and dew-point temperatures, air velocity, solar load) and lactating cow characteristics (e.g., body mass and daily milk yield) on modeled respiration rate. Respiration rate was linked to qualitative heat stress levels, based on work by Renaudeau et al. (2012). The model demonstrates how cows with greater body mass have larger inspired volumes of respired air (i.e., liters per minute) because they have larger tidal volumes (i.e., liters per breath) while they have lower respiration rates (i.e., breaths per minute) compared to cows with smaller body masses. The modeled results support previous studies that demonstrated heat stress increases with greater daily milk yields, solar load, and air dry-bulb and dew-point temperatures. The model finds conditions where increasing air velocity at cow level can help cows reduce heat stress levels due to solar load, and high air dry-bulb and dew-point temperatures. A comparison to a field study demonstrates the need to align field data collection and model input needs to explore the actual or potential impacts of mitigation methods like shade, evaporative cooling, and air velocity (i.e., via fans). This report demonstrates how the model can be used by engineers to investigate the impact of ventilation system designs on respiration rates using current and future technologies. Keywords: Air velocity, Cow mass, Dairy, Dew-point temperature, Dry-bulb temperature, Heat stress, Milk yield, Respiration rate, Solar load.

Optimization-informed Rule Extraction for HVAC system: A Case Study of Dedicated Outdoor Air System Control in a Mixed-Humid Climate Zone.

In the era of post-Coronavirus Disease 2019, the dedicated outdoor air system (DOAS), which provides 100% outdoor air for the building, is widely acknowledged as it can ensure acceptable indoor air quality by delivering fresh outdoor air to occupied space. The DOAS with a proper design and operation can provide sufficient ventilation and dehumidification while achieving energy efficiency. Nonetheless, there is limited guidance in determining the optimal control sequence of the DOAS for the designers and operators to implement in practice. Accordingly, in practice, a number of issues have been acknowledged in the design and control phases of DOAS, including insufficient ventilation and dehumidification, and increasing supply air dry-bulb temperature in fear of over-cooling, which might cause significant discomfort and energy waste. There have been efforts to develop high-performing DOAS controls for better energy efficiency. However, such controls are often complex, or difficult to interpret, for building designers and operators to consider in practice. In this regard, this paper explores a simulation-based framework for generating a supply air temperature control sequence of the DOAS not only to ensure improved energy-saving potential but also to guarantee the implement-ability of the control logic. The U.S Department of Energy prototype primary school with dynamic occupancy profiles was modeled with a whole building simulation program, EnergyPlus. The model consists of a DOAS with an exhaust air energy recovery system for ventilation and fan-coil units for space cooling and heating. Then, a Genetic Algorithm was adopted to find the true optimal supply air temperature control sequence in terms of minimizing the energy cost of the heating, ventilation, and air conditioning system operation. Lastly, Decision Tree was adopted to extract rules out of the optimums to derive an implementable sequence of operation for the DOAS supply air temperature. A total of 12 week-simulation including four weeks of heating, cooling, and shoulder seasons, separately, under the weather condition of New York City was conducted for the case study. This case study identified that the optimization-informed rule extraction-based control, when compared to conventional outdoor air temperature-based reset control, could save about 13% of energy cost and 25% of energy consumption throughout the heating, cooling, and shoulder seasons. It is notable that the energy-saving was mainly achieved by reducing the heating energy consumption. Importantly, it nearly corresponds to the true optimal control result, which reduces approximately 14% of energy cost and 27% of energy consumption. From the results, it can be highlighted that the optimization-informed rule extraction can be as energy effective as the optimal control, while significantly reducing the complexity of the control.

Monitoring and performance evaluation of a green wall in a semi-arid Mediterranean climate

Green walls are gaining popularity as a sustainable cladding solution for buildings, offering various advantages for the built environment and human well-being. However, there is a lack of research on plant selection guides and field data in semi-arid Mediterranean climates, limiting our understanding of green wall potential. To address these gaps, this study assesses the hygrothermal and sound insulation performance of a modular living wall in a semi-arid Mediterranean climate and develops a plant-selection guideline for green wall applications. The experiment involves a comparative assessment between the modular living wall and a bare-wall-reference facade. Measurements of air temperature, relative humidity, and sound pressure were taken, along with thermal imaging, to record the surface temperatures of the experimental facades. Results reveal that the modular-living wall significantly decreased dry-bulb air temperature (up to 8 °C) and reduced sound pressure by up to 5.1 dB. Additionally, relative humidity in the air cavity behind the modular living wall consistently increased by 6.6%, with a maximum absolute humidity differential of 8.6 g/kg. Thermal imaging showed a surface temperature difference of up to 27 °C, with foliage having a higher leaf-area-index proving more efficient in reducing the surface temperature of the green wall.Overall, the modular living wall effectively protected building walls from high solar radiation and temperatures, resulting in reduced energy requirements for space cooling. However, proper irrigation and plant health maintenance are necessary. This study fills important research gaps, providing valuable insights into the potential benefits and performance of green walls in semi-arid Mediterranean climates.

Effect of Inlet Air Humidity Control on a Novel Indirect Condensative Cooling Performances in Achieving Air Thermal Comfort

The objective of this research is to investigate the effect of controlling inlet air relative humidity on the performance of solid dry pad based indirect condensative cooling (SDP-ICC) system, in an effort to have a better air thermal comfort. The main evaporative cooling parameter such as cooling efficiency, cooling capacity, and temperature drop, condensation rate and energy efficiency ratio would be observed, together with the final dry and wet bulb air temperature and relative humidity in respect to reach the standard air thermal comfort. During the experiment test, the inlet air would be heated respectively using 1.0 kW, 1.5 kW and 2.0 kW heater in a climate chamber before it passed through to the solid dry pad, to be cooled indirect condensatively. The air velocity would be set on 11.3 m3/. The test results indicate that to achieve an air thermal comfort significantly in the evaporative and or condensative cooling system, the air should need to be treated with more than one thermal process, rather than cooling only. In this research, the SDP-ICC has only achieved the air thermal comfort in respect to its relative humidity of 67.3%, 55.65% and 44.3% respectively for heating capacity of 1.0 kW, 1.5 kW and 2.0 kW. The highest SDP-ICC cooling performance has been achieved on 1.5 kW heating capacity, in which it has reached 1.9 kW, 1.83, 3.4oC and 0.237 m3/hr respectively for cooling capacity, energy efficiency ratio, temperature drop and condensation rate. It can be concluded that by heating the inlet air relative humidity in evaporative and or condensative cooling system, it can be resulted the product air which has met the standard air thermal comfort.

Experimental study on the operating performance of the air source heat pump (ASHP) with variable outdoor airflow rate under the standard frosting condition

Frosting is a common phenomenon of the ASHP under the heating mode in winter, and the outdoor air flow rate flowing through the evaporator of the ASHP was always thought to be a major contributor. In order to validate its contribution, effects of outdoor fan airflow rate on the performance of air source heat pumps (ASHPs) were investigated under the winter heating condition. The experiment was conducted in a laboratory at the standard 2 °C air dry bulb temperature (DB)/ 1 °C air wet bulb temperature (WB) frosting condition, which enabled the analysis of the operating performance, frosting performance, and heating performance of the ASHP unit by changing the airflow rate of the outdoor fan. Results showed that as the airflow rate of the outdoor fan reduced from 100% to 36%, the operating performance decline and the elevated frosting-defrosting loss were observed. Meanwhile, both the frosting rate and the operating efficiency during frosting-defrosting cycles showed an increasing trend then followed by decreasing tendency. The maximum frosting rate and operating efficiency were 0.92 g/m2.min and 2.92, respectively, which were observed at 74% airflow rate of the outdoor fan of the ASHP unit. The observation implied the existence of the “minimum frosting suppression airflow rate”. At 36% airflow rate of the outdoor fan of the ASHP unit, however, the performance of the ASHP unit was attenuated greatly, with the frosting-defrosting efficiency loss coefficient of 0.47, the heating capacity and COP reduction by 51.5 and 38.8%, respectively. These findings provided significant references to the optimization of ASHPs performance with variable airflow rate of the outdoor fan under frosting conditions.

6 Comparison of Ammonia Concentrations Between Flush and Pull-Plug Waste Management Systems in Wean-Finish Swine Barns

Abstract Pig manure contains a wide variety of corrosion-inducing chemicals such as ammonia. Ammonia production and its release are influenced by temperature and moisture in the barn environment. Increased concentrations of ammonia can negatively affect pig health and growth, as well as pose a risk to human health. Additionally, even at decreased concentrations, ammonia reacts with humidity and causes premature corrosion of barn equipment and is a threat to the structural integrity of livestock buildings. In this study, ammonia concentrations were monitored and compared between two 880 head wean-finish swine facilities with different types of waste management systems. Both facilities had shallow manure pits, one containing a flush system and one containing a pull plug system to remove manure from the barns into the lagoon. Ammonia, dry-bulb air temperature, and relative humidity levels were measured every0 min for an entire wean-finish cycle (approximately 20 weeks). Data will be compared between the facilities to evaluate the impact of the waste management systems on indoor air quality conditions. Potential implications for pig health and growth and facility maintenance will be explored. Results will provide information on best management strategies for swine facilities.

The impact of meteorological changes on the quality of life regarding thermal comfort in the Amazon region

The meteorological imbalances in Brazil have a strong impact on the lives of the population across the country, especially in the Amazon region. These impacts extend to meteorological phenomena, such as extreme rainfall, droughts, and an increase in temperature in several regions, as well as impacts on health, the economy, and, as the object of this study, the quality of life. This study presents the impact of meteorological changes on the quality of life in the Amazon region, based on (i) the thermal discomfort index (TDI), (ii) the temperature and humidity index (THI), and (iii) the effective temperature index as a function of the wind (TEFW). For this, meteorological data from the years 2003–2021 were used, in which the variables include total precipitation, global radiation, air-dry bulb temperature, the maximum temperature in the previous hour, the minimum temperature in the previous hour, relative humidity, and wind speed. This analysis indicates that for this tropical region, the sensation of mild discomfort was predominant in about 70% of the measurements, indicating a certain level of impact on the population's quality of life, in addition to the fluctuation of levels of discomfort during periods of winter in that there are high rates of precipitation. The data control was performed with the removal of null data and calculation of monthly and annual averages, by using the compression (average) empty data frames in order to receive the values without losing the indexing of dates. At first, it was considered to use the kriging process to fill in the missing data; however, due to the existence of microclimates in the regions, the data could characterize remote regions in a generalized way, which would make it difficult to understand these data in comparison with the data from the National Institute of Meteorology (INMET, in Portuguese).

Experimental Study on Heat Recovery of Air Dryer from Waste Heat Energy of Condensing Unit from VCRS Air Conditioner

Heating, Ventilating, and Air Conditioning (HVAC) is a system to condition indoor air by cooling or heating to achieve thermal comfort for a human being. The HVAC system operates based on the refrigeration cycle, where heat is dissipated from the condensing unit in the warm air arrangement. This represents an ironic foundation of heat that might be recovered for further schemes or applications. In this paper, experimental work was developed to validate the proposed heat recovery system using heated air released from the condenser unit of the HVAC system as a source for the air dryer for the drying rack. Four different output parameters are to be observed in this research: the dry-bulb temperature of the air exit from the condenser unit, the dry-bulb temperature of the air inflowing the dryer, and the drying time and the relative humidity of the air leaving the dryer. These experimental works were conducted using a domestic application of a 1.0 hp air conditioning (AC) system with R-22 refrigerant gas and based on the following factors: The three-variant mass of wet clothes, the three-stage of mechanical fan speed for releasing warm air from the condenser, and the effect of variable ambient or surrounding air dry-bulb temperature were studied. A physical prototype of the dryer was constructed for proof-of-concept purposes. The experimental output was then analyzed to obtain precision and accurate data. To determine the system behavior, a refrigeration cycle analysis was conducted. It has been shown that an AC system of 1.0 hp can cover wet clothes drying of weights 1950 g, 4255 g, and 6350 g at 55, 80, and 110 min with a constant air velocity of 0.34 m-3.s-1 in an ambient temperature of 33°C. The significant contribution of this research is the proposed heat-recovery-based air dryer system with the capability to increase the Coefficient of Performance (COP) of the AC unit from 2.36 to 2.70. Hence, the energy-saving was received using the heat-recovered-based air dryer instead of a commercial electric air dryer system that uses high power consumption from their heater element.

기존 주택용 창문 부착형 현열교환 환기장치 제안 및 성능 평가

Purpose: Air pollution is becoming serious around the world, and indoor air quality in buildings is also deteriorating. For energy-saving ventilation and good indoor air environment, this research proposed and made a window type heat exchange ventilation system that can be installed easily in an existing house, and examined its performance. A plate type heat exchange element for ventilator was made by a 3D printer. Method: According to the Korean Industrial Standard KS B 6879:2020 Test Method for Heat Recovery Ventilator, the ventilator was tested four times in a real environment. Two experiments were measured for 10 minutes, and the remaining two were measured for 11 hours and 10 hours, respectively. Ventilation, supply air, exhaust air, and outside air dry-bulb temperatures were measured every 5 seconds. After that, the temperature exchange efficiency was calculated for ventilation, supply air, exhaust air, and outside air average temperature using the temperature exchange efficiency formula described in KS B 6879:2020. Result: The performance was 70.97% in the first experiment, 68.11% in the second experiment, 56.47% in the third experiment, and 64.16% in the fourth experiment.

Cooling performance and optimization of a tubular indirect evaporative cooler based on response surface methodology

To optimize the cooling effectiveness of the tubular indirect evaporative cooler (TIEC), an experimental design was conducted using the response surface methodology (RSM). In this work, the wet-bulb effectiveness was selected as the response value, while the influencing factors included six operation parameters, namely, the spray water flow rate (Qw), secondary-to-primary air flow rate ratio (Rsp), primary air resistance (R1), secondary air resistance (R2), inlet air dry bulb temperature (tg1) and air relative humidity (RH). The operation conditions of a TIEC with a tube diameter of 10 mm were optimized. The second-order model fitting of the RSM was used to obtain the polynomial regression equation between the wet-bulb effectiveness and each factor. The wet-bulb effectiveness can be achieved up to 78 % under the optimized conditions with Qw of 1.2 m3/h, Rsp of 0.5, R1 of 89 Pa, R2 of 100 Pa, tg1 of 17.3 °C, and RH of 79.6 %.

Dairy Cow Thermal Balance Model During Heat Stress: Part 2. Model Assessment

Highlights The thermal balance model body temperature and respiration rate results compared well with published data. Model results were commonly within one standard deviation of reported averages. Research that measures more model inputs, coefficients, and results is needed. The thermal balance model can be used to identify heat stress factors and assess mitigation practices. Abstract. A steady-state process-based lactating cow thermal balance spreadsheet model developed by Nelson and Janni (in press) was compared to mean measured body temperatures, respiration rates, and skin temperatures from two published studies (Gebremedhin et al., 2010; Chen et al., 2015). Model body temperatures were also compared with reticular temperatures from cows standing in unshaded paddocks that were part of a solar shade study (Sharpe et al., 2021). Gebremedhin et al. (2010) reported measured mean rectal temperatures, 39.4 ± 0.5 C and 40.6 ± 0.4 C for hot and dry conditions with and without a solar load; model body temperatures for similar hot and dry conditions were 39.7 C and 40.6 C with and without a solar load, respectively. Model respiration rates were within one standard deviation of measured mean respiration rates (Gebremedhin et al., 2010). The model body temperature for a baseline condition was 39.1°C, which was within 0.1°C of the mean baseline temperature of 39.2 ± 0.6°C (Chen et al., 2015). The model respiration rate was 63 breaths per minute (bpm); much lower than the reported baseline respiration rate of 88 bpm (Chen et al., 2015). Model body temperatures were 0.1°C to 0.7°C lower than the measured mean reticular temperatures of standing cows in non-shaded paddocks with solar loads when ambient temperatures ranged from 24.4°C to 26.5°C. Model results compared well with mean measured parameters from three studies. The model can be used to assess the impact of factors affecting heat exchange (e.g., body mass, milk yield, solar load, air dry-bulb temperature, dew-point temperature, and air velocity) on heat exchange flux, cow respiration rate, and body temperature. Keywords: Body temperature, Dairy, Heat stress, Lactating cow, Respiration rate, Thermal balance model.

Performance evaluation of ventilative cooling systems for buildings under different control parameters and strategies

Ventilative cooling is an energy-saving technology to diminish thermal discomfort and overheating risk of buildings, meanwhile achieving high indoor air quality (IAQ). However, there is still no optimal control strategy in practice, which considerably limits its application. This study developed a typical office building model to evaluate the performance of ventilative cooling systems with different control parameters and strategies for five typical cities in different climatic zones of China. Results showed that, when the control parameter was selected as the upper limit of satisfied comfortable zone by 90% of the occupants, the adaptive thermal comfort (ATC) model, which outperformed the other models in terms of outdoor air utilization, was not necessarily optimal in terms of energy efficiency. The outdoor air utilization potential based on the indoor dry-bulb air temperature (Td) and indoor operative temperature (Top) control was similar, but the energy usage varies considerably, especially in the hot climatic zones. When the overheating period controlled based on the thermal comfort models was the same, the energy usage would be underestimated by 16%–38% without considering the effect of radiant temperature. The ATC-based control could have up to 37% of energy-saving compared to thermostatic control, but inappropriately low limits could make it less advantages to achieve energy-saving. The energy-saving potential associated with the PMV and ATC controls showed a completely opposite trend in the different climatic zones. The analysis results indicate that eliminating the drawbacks of the lower limit in the ATC model is an effective way to demonstrate energy-saving effectiveness. The findings of this study will contribute to the effective improvement of the application potential of ventilative cooling in different climatic zones.

A Semi-Automatic Data Management Framework for Studying Thermal Comfort, Cognitive Performance, Physiological Performance, and Environmental Parameters in Semi-Outdoor Spaces

Semi-outdoor space can be used as an alternative to short-term office activities to save office energy consumption and promote a healthy and nature-based working environment. This study evaluated the suitability of semi-outdoor space in four aspects including environmental measurements, physiological measurements, subjective measurements and cognitive performance tests. However, the manual processing and analysis of such multidimensional data can be time-consuming and error-prone. Hence, the objective of this study was to develop a semi-automatic method to manage and analyze the data from different instruments and platforms and two open-source applications (a stroop color and word test and a digit span test) for cognitive performance tests. These codes were critical to the success of the project, providing an effective framework for data extraction, data pre-processing, data analysis and performance tests. Eighty-nine people participated in the experiment of evaluation of thermal comfort, cognitive performance, physiological performance and environmental parameters in semi-outdoor spaces in a tropical setting. Each participant received cognitive tests to assess their selective attention, short-term memory, concentration and creativity quotient. Concurrently, qualitative measurements were conducted to assess thermal sensation, thermal comfort and thermal acceptability. The heart rate, skin temperature, and skin conductance of participants were measured throughout the experiments. Microclimatic variables such as illuminance, noise levels, dry-bulb air temperature, global temperature, relative humidity, air speed, and air direction were monitored simultaneously. To understand the effects of semi-outdoor spaces on participant performance, this study recorded participant performance in different environments through controlled experiments. Data related to participants in different settings include those shared (e.g., environmental measurement), and data unique to each participant (e.g., physiological performance). The results revealed that the subjects’ cognitive and physiological performance did not change significantly after switching to the semi-outdoor space due to the availability of natural and mechanical ventilation, suggesting that short-term office activities in the semi-outdoor space are feasible in the tropics.

The Effect of the Number of Cooling Pads on the Output Air Condition and Effectiveness of Air Cooler

To get comfortable air, it can be done by using an air conditioner or air cooler. The electrical power used for the air cooler is relatively lower. This research aims to see the effect of the number of cooling pads on the output air condition and on the effectiveness of the air cooler. The research was conducted experimentally. The research was conducted by varying the number of cooling pads used, thick. The distance between the cooling pads is 1.5 cm. The air temperature inlet of the air cooler has a dry bulb air temperature of 30𝑜𝐶 with an air humidity (RH) of 60%. The lowest dry bulb air temperature achieved was 24,04𝑜𝐶 when the number of cooling pads was 6 pieces. The highest air cooler effectiveness achieved was 0.99. Research has given satisfactory results. However, research can be developed by varying the cooling pad material or cooling pad pattern in order to obtain a small number of cooling pads.

Feasibility of condensate water recycle of split air handling unit in Chinese University buildings

Recycling the condensate water of the air conditioner could be explored as an alternative water source to contribute to building the green campus. This paper explored the condensate water production through actual measurement based on a split air handling unit (SAHU) in a university building. Then, the statistical analysis was used to analyze the recycling feasibility and the impact factors of the condensate water production in 31 Chinese provincial capital cities to obtain the recycling potential map of the condensate water generated from a SAHU. Results showed that: (1) In the measurement, the amount of condensate water produced by a single split air conditioner was 1.6 kg from 12:40 to 13:40. Therefore, the daily output of condensate water of the air conditioner with the university operation schedule could reach 52.99 kg during the main air-conditioning season. (2) Among the 31 provincial capital cities in China, the largest condensate water outputs could be found in the Hot Summer and Warm Winter zone and the Hot Summer and Cold Winter zone, with an average monthly output of 1600 kg and 1100 kg, respectively. (3) Regression analysis showed that the dry-bulb temperature and dew point temperature of outdoor air had the highest positive and significant influence on condensate water production. The objective of this study is to provide theoretical guidance for the design and energy conservation evaluation of the feasibility of SAHU condensate water recycling in universities.