Use Of Air Conditioning Research Articles

Design Automatic Air Conditioning System Control with Passive Infrared Receiver/motion sensor

Dr. Ferdinand Lumbantobing Airport faces serious challenges related to the waste of electrical energy in its operations. The quarterly report shows an inconsistent increase in electricity usage, which is largely due to human factors and some technical aspects. The biggest problem is the use of air conditioning and lights that do not need to be constantly active. This article takes a close look at the airport's efforts to address this waste of energy, focusing on the use of air conditioning and constantly burning lights in unused rooms. Measures such as monitoring, automation, sensors, employee extension, and smart appliance development are proposed to address these issues and achieve significant energy savings. This solution will help reduce airport operational costs, increase efficiency, and support environmental conservation.

The Financial Impact Potential as A Consequence of Thermal Discomfort in a Low-income Living Space: The Case Study of Rusunawa Pengadegan, Jakarta

The cost of electricity incurred for providing a thermally comfortable living space in big cities like Jakarta, by using fans and air conditioners, takes up to 32,41% of the overall utility cost per low-income household. The use of air conditioners by the low-income residents of a number of rusunawas in Jakarta, however, is clearly observable from the outside. This condition not only emphasizes the importance of a thermally comfortable living space but also the impact of the architects’ decisions in designing affordable vertical housings on the economy of the occupants. The aim of this study is to find the impact of the architect’s design decisions as reflected in the building shape and orientation as well as the opening dimensions on the thermal comfort as experienced by the residents and how it further affects their economy. This study uses rusunawa Pengadegan in South Jakarta as its research location. The study was conducted by developing a thermal comfort simulation and an observation on the evidence of use of air conditioners followed with a predictive calculation on the affected electricity cost. The aim is to examine the suitability of the rusunawa design toward the economic livelihood of the residents in the long run.

Deployment Strategies of EV School Buses with Vehicle to Grid (V2G) in the US School System

Governments across the world are pushing for speedier adoption of electric vehicles (EVs) in order to meet their target for transition to a greener and cleaner environment that has low or zero carbon emission. Transportation being one of the major contributors to environmental pollution because of incessant burning of fossil fuels. EVs are being considered to be the best possible solution to alleviate vehicular pollution. However, proliferation of EVs create additional burden on the power grids. The consumption of electrical power is steadily rising because of even-growing population and the demand is particularly higher during summer months due to higher use of air conditioners. To ease this pressure on the grid the novel vehicle-to-grid or V2G technology is being employed whereby idle electric vehicles can be put to use as giant batteries that can send power back to the grid to supplement its output. With the wide scale adoption of electrical buses is schools this turns out to be a feasible option. Battery driven school buses are best suited for this. These vehicles remain idle for major portion of the day and also during summer months and can be effectively utilized for generating electricity using their batteries. However, there are challenges involved in the implementation of this strategy. Besides lack of charging infrastructure and limited knowledge of owners about the nature and benefits of the implementation there are also problems of rapid battery degradation, lack of control on the vehicle and the process and high costs involved. Nevertheless, using literature review this article explains the rationale behind adoption of the technology and highlights, the strategies that can be adopted to effectively exploit this novel technology to make the most out of idle electric school buses to support public utilities. To an extent electric school buses and the v2g technology can be potentially helpful for stabilizing supply of electricity during peak hours and improve efficiency of supply chain management of several industries including the power sector.

Extensive green roofs thermal effect and energy saving indoor by cooling

This work analyzes the thermal effect of extensive green roofs (EGR), in different climatic conditions of eight cities in Mexico. A house is simulated and temperature, comfort sensation and air conditioning energy consumption are analyzed. The results show that the extensive green roof helps to decrease the maximum interior temperature, especially in the rooms located on the upper floor, where greater energy saving for air conditioning (cooling) is also observed. In all the cases studied, EGRs contribute to achieve thermal comfort conditions; in fact, their implementation under some climatic conditions avoids the use of air conditioning.

Effects of temperature anomaly on health: A perspective from individual adaptation

We explore the causal relationship between temperature and health at fitness levels in this paper by constructing temperature anomalies using the Chinese General Social Survey (CGSS). The results indicate that for every 1 °C rise in temperature anomalies, the fitness level decreased by 0.255 units, a decrease of 7.081 % of the average. We use the order probit model and the traditional temperature bins to test the results, which are consistent with the benchmark results. The effect of temperature anomalies on health is considerably stronger for males, people over 85 years old, low education, and low-income groups. Further analysis shows that the use of air conditioning can avoid such effects. In addition to the direct impact of temperature, we found that rising temperatures will lead individuals to reduce outdoor activities, thereby affecting their health level.

Commercial HVAC system fault diagnosis using big data analytics: A case study

With the increasing use of heating, ventilating, and air conditioning (HVAC) systems nowadays, their energy consumption is receiving more attention. The study begins by trying available anomaly detection techniques, including KNN, COF, and isolated forests. The comparison reveals that these methods disregard some linear correlation results. Then, the pattern is summarized by analyzing data from 100 HVAC-equipped rooms. Next, the study uses correlation analysis and neural networks to identify abnormal HVAC data. Finally, it concludes by analyzing the factors that lead to the anomalies.

Influence of Occupants’ Space and Appliance Use Patterns and Behaviour during the Discomfort on Electricity Consumption in Mixed Mode Residences

Building characteristics, climate, socio-economic characteristics, and occupant behaviour influence the electricity consumption in buildings. In residential buildings, where people spend a lot of time and have high perceived control over their surroundings, electricity consumption for thermal comfort constitutes a higher proportion of overall energy consumption. Previous research studies mainly focused on the impact of building and household characteristics on electricity consumption in residences. In the Indian context, electricity usage in residential buildings may depend on lifestyle, family composition, daily routines and activity patterns, and consumption habits. In India, the space usage and sharing pattern of internal spaces depend on family composition and the number of rooms. In India, the usage of household appliances has been steadily increasing. During discomfort hours in humid conditions, people use fans with windows in the open position, switch on the air-conditioner or use the fan and air-conditioner together to attain thermal comfort. Therefore, the study aims to assess the impact of family composition, occupants' space and appliance use patterns and behaviour during the thermal discomfort on electricity consumption in Indian residential buildings. Information on the number of occupants, children, and elders; space usage at different hours of the day by the occupants; use of fans, air-conditioners, and other electrical appliances; and frequency and hours of opening of windows were collected through a questionnaire survey from 144 residences. Electricity consumption data for all 144 residences were collected from the utility bills. The variables influencing annual mean electricity consumption per unit area of residential buildings include the number of elders present, age of children, hours of air-conditioner use, space usage pattern, and occupants' behaviour during the discomfort

Cost-effective production of radiation shielding coatings using multilayers of titania and silica

The presence of visible and infrared (IR) radiations available from solar radiation causes the temperature in the atmosphere to rise. Because of the temperature disparity, glass-walled buildings typically utilize air conditioners, increasing the generation of green-house gases in the environment. As a result, the application of reflection coating is required to safeguard the environment and limit the danger of greenhouse emissions. We present here the fabrication of a thermal insulating coating utilizing a multilayer TiO2/SiO2 structure that can reflect visible and infrared light with fewer layers of the aforementioned combination. X-ray diffraction was used to examine the as-fabricated structure on the glass substrate and found the anatase phase of TiO2 with the strongest peak at Bragg angle 25O. Fourier transform infrared spectroscopy was used to investigate the presence of TiO2 and SiO2 functional linkages, which were found at 904 cm−1, and 763 cm−1 wavenumbers respectively. Cross-sectional field emission scanning electron microscopy examinations on the fabricated five-layer (TiO2/SiO2/TiO2/SiO2/TiO2) multilayer structure revealed the presence of TiO2 and SiO2 with thicknesses calculated around 186/300/273/218/131 nm respectively. Furthermore, reflectance analysis on the as-fabricated multilayer structure demonstrated 90 % reflectance in the infrared spectral region, and 100 % in the visible region. As a result, developed coatings for glass furnishings were advised in order to not only deflect visible and infrared radiations from the sun spectrum and keep indoor temperatures cool without the use of air conditioners, but also to act as visible light communication boosters.

Association between ambient temperature exposure and pregnancy outcomes in patients undergoing in vitro fertilization in Shanghai, China: a retrospective cohort study.

Does ambient temperature exposure affect outcomes including clinical pregnancy and live birth in women undergoing IVF? Both extreme cold and hot ambient temperatures were significantly associated with adverse pregnancy outcomes of IVF cycles. Heat exposure has been linked to adverse pregnancy outcomes worldwide. However, the effect of ambient temperature on infertile women undergoing IVF treatment is unclear. A retrospective cohort study was conducted from a database of 3452 infertile women who underwent their first fresh or frozen embryo transfer in the Shanghai First Maternity and Infant Hospital from April 2016 to December 2020. Daily mean ambient temperature exposure for each patient was obtained based on their residential address. Temperature-stratified multiple logistic regression analysis was performed to investigate associations between temperature exposure and pregnancy outcomes after controlling for confounders. Vulnerable sub-groups were identified using forest plots. The clinical pregnancy rate and live birth rate were 45.7% and 37.1%, respectively. Regarding clinical pregnancy, a higher temperature during cold weather was significantly associated with a higher pregnancy rate in the period about 11 weeks before ovarian stimulation (adjusted odds ratio (aOR) = 1.102, 95% CI: 1.012-1.201). Regarding live birth, an increased temperature during cold weather was significantly related to a higher live birth rate in the period after confirmation of clinical pregnancy or biochemical pregnancy, with the aORs of 6.299 (95% CI: 3.949-10.047) or 10.486 (95% CI: 5.609-19.620), respectively. However, a higher temperature during hot weather was negatively associated with the live birth rate in the periods after confirmation of clinical pregnancy or biochemical pregnancy, with the aORs at 0.186 (95% CI: 0.121-0.285) or 0.302 (95% CI: 0.224-0.406), respectively. Moreover, the decline in live birth rates during cold and hot weather was accompanied by increased rates of early miscarriage (P < 0.05). Stratified analyses identified susceptibility characteristics among the participants. Climate monitoring data were used to represent individual temperature exposure levels according to the patient's residential address in the study. We were not able to obtain information of personal outdoor activity and use of indoor air conditioners in this retrospective study, which may affect actual temperature exposure. This study highlights that the ambient temperature exposure should be taken into account during IVF treatment and afterwards. There is a need to be alert to extremes in cold and hot ambient temperatures, especially during the period of follicle development and pregnancy. With this knowledge, clinicians can scientifically determine the timing of IVF treatment and reinforce patients' awareness of self-protection to minimize adverse pregnancy outcomes associated with extreme temperatures. This work was supported by a grant from the Clinical Research Plan of Shanghai Hospital Development Center [SHDC2020CR4080], a grant from the Science and Technology Commission of Shanghai Municipality [19411960500], and two grants from the National Natural Science Foundation of China [81871213, 81671468]. B.W.M. is supported by a NHMRC Investigator grant (GNT1176437). B.W.M. reports consultancy for ObsEva, and research grants from Merck KGaA, Ferring and Guerbet. The other authors have no conflict of interest to declare. N/A.

Energy Performance of Room Air-Conditioners and Ceiling Fans in Mixed-Mode Buildings

Studies show that people can tolerate elevated temperatures in the presence of appreciable air movement (e.g., from using ceiling fans). This minimises the use of air-conditioners and extends their set-point temperature (Tset), resulting in energy savings in space cooling. However, there is little empirical evidence on the energy savings from using ceiling fans with Room Air-Conditioners (RACs). To address this gap, we analysed the energy performance of RACs with both fixed-speed compressors and inverter technology at different set-point temperatures and ceiling fan speed settings in 15 residential Mixed-Mode Buildings (MMBs) in India. Thermal comfort conditions (as predicted by the Indian Model for Adaptive Comfort-Residential (IMAC-R)) with minimum energy consumption were maintained at a set-point temperature (Tset) of 28 and 30 ∘C and a fan speed setting of one. Compared with a Tset of 24 °C, a Tset of 28 and 30 °C resulted in energy savings of 44 and 67%, respectively. With the use of RACs, a configuration with a minimum fan speed was satisfactory for an optimal use of energy and for maintaining the conditions of thermal comfort. In addition, RACs with inverter technology used 34–68% less energy than fixed-speed compressors. With the rising use of RACs, particularly in tropical regions, the study’s outcomes offer a significant potential for reducing space-cooling energy consumption and the resultant greenhouse gas (GHG) emissions.

Quantifying the benefits of PV module shading for building heat gain reduction: A machine learning approach

This study investigates the indirect benefit due to the shading effect from PV rooftop systems installed on building envelopes by proposing a new method based on a machine-learning algorithm. The study gathered a year of data from a 25 kWp PV rooftop system installed on a metal sheet roofing. It classifies the dataset into four categories based on solar irradiance and ambient temperature to represent Thailand's climate. There evaluated the RTTV and case study from implemented projects with metal sheet roofing in Thailand to estimate the potential electricity bill savings from the PV module shade effect. The results reveal an inverse relationship between the percentage of heat reduction and heat gain reduction, with the most significant reduction occurring under high solar irradiance and ambient temperature conditions. The shading effect caused by the PV modules provides an indirect benefit of approximately 38 kWh/kWp/year from electricity bill savings. In contrast, the PV system production yields around 1401 kWh/kWp/year based on radiation of about 1839 kWh/m2/year. The study estimates that energy-saving possibilities range from 0.038 to 0.052 kWh/m2/day, depending on the weather conditions, equivalent to an electricity saving of approximately 6.33 kWh/m2/year from air conditioner use.

Mini air conditioning design with two levels of thermoelectric cooler module: cooling heat pipe

As the tropical country, the use of air conditioning (AC) in Indonesia is still high. This will affect energy consumption and global warming issue. This study aims to make solution of the AC issue with a design of the mini-AC using thermoelectrical cooler (TEC) technology and determine the output temperature result of the design, then to find out the coefficient of performance (COP) of the TEC cooler. The mini-AC design or method uses two TEC with additional heat sink, heat pipe, and fan to help release temperature to environment. The temperature measuring uses an 11-point thermocouple with real-time data collection using BTM-4208sd logger. The results of the study concluded that the mini-AC could work well even though one of the TECs was below its best performance. The use of heat pipes can help reduce heat quickly from TEC heat side. The best COP of TEC with ideal heat reduction is 0.69 from the upper position (72 W), and the highest at lower position (48 W) with 2.19.

Effect of ventilation patterns on indoor thermal comfort and air-conditioning cooling and heating load using simulation

Over the past three years, regulations have been implemented to combine natural ventilation (NV) and air conditioning to mitigate the risk of disease transmission, particularly in response to the COVID-19 outbreak. As we know, simultaneous use of NV and air conditioning can make it challenging to achieve indoor thermal comfort. This paper aims to analyze the effect of NV on the air conditioning`s cooling and heating load in a classroom through simulation. A simulation model was developed using EnergyPlus software with an OpenStudio interface software. Simulation results demonstrate that continuous use of NV alongside an air conditioner increases the cooling load from 1.06 to 1.75 times during summer and a 1.54 to 9.49 times heating load increase during winter. On the other hand, intermittent NV every hour results in a cooling load increase from 1.05 to 1.46 times in summer and a heating load increase from 1.13 to 4.63 times in winter. Moreover, employing NV based on the outside air temperature can reduce the cooling load at the air conditioner with set-point 26℃—28℃ from 0.94 to 0.88 times. The outcomes of this study are expected to serve as a reference for determining strategies that effectively combine NV and air conditioning to meet various needs without causing a significant increase in energy consumption. Additionally, the results are expected to be useful for reducing AC energy consumption in extremely hot and cold weather with some strategies of NV application.

Prevalence of dry eye disease among visual display terminal office users in Uyo, Nigeria

Context: Dry eye disease (DED) results from loss of tear film homeostasis. Increase use of visual display terminals (VDT) by individuals and professionals increases the risk of DED.&#x0D; Objective: This study is aimed to determine the prevalence of dry eye disease among office workers who use visual display terminals in Uyo.&#x0D; Methods: A descriptive, cross-sectional study of VDT office workers aged 19-65 years. Multi-stage sampling technique was used to recruit participants. Self-administered Impact of Dry Eye on Everyday Life (IDEEL) questionnaire and ocular examination was done to gather data; such data was analyzed using SPSS version 22.0&#x0D; Results: Prevalence of dry eye disease (DED) was 5.8% (95% CI 3.44 - 8.16). Mean Schirmer’s 1 was 21.60 ± 9.29mm, mean TBUT was 9.74 ± 2.48s, mean IDEEL score was 76.15 ± 25.47. There was a statistically significant association between DED and educational level 7.56(p-value 0.02), hours of visual display terminal use per day 10.72(p-value 0.013), and use of air conditioning 7.66(p-value 0.006). Multivariate regression analysis to identify predictors of dry eye was statistically significant for module 1(Symptom bother) of the dry eye questionnaire (p-value 0.01, odds ratio 12.71,), tear break up time in the left eye (p-value 0.00, odds ratio 38.67), and Schirmer 1 test in the right eye (p-value 0.00, odds ratio 30.83)`.&#x0D; Conclusion: The prevalence of DED increases with the number of hours spent on VDT Periodic medical and psychological evaluation of VDT users to identify office workers most at risk should be carried out by employers of labour.

Implications of the COVID-19 Pandemic on the Family Structural Dimensions: A Correlational Study.

The COVID-19 pandemic caused changes in the families' social support network, employment status, and family income, which are the focus of attention of family health nurses. This study aims to describe the pandemic's repercussions in the areas of attention of the structural dimension of families according to the Dynamic Model of Family Assessment and Intervention, as perceived by Portuguese families, and to relate the changes in their employment status according to the variables of the structural dimension. A quantitative, descriptive, and correlational study was conducted using snowball sampling. A questionnaire of sociodemographic characterization and assessment of the family structural dimension according to the model's operational matrix was applied to 235 family members. Changes were found in their employment status; family income; intensity and frequency of contact with family, friends, and coworkers; frequency of contact with educational/health/religious institutions and community groups; cultural activities; and housing comfort conditions such as the use of heating/air conditioning, gas, and water consumption. Changes in employment status were related to family income, interaction with friends, frequency of cultural activities, and use of air conditioning and heating. Knowing the implications of the pandemic on the family's structural dimension results in a nursing intervention more focused on family needs.

Sustainability of Traditional, Historical Roofs in the Mediterranean: A Rediscovered Opportunity for a Carbon Neutral Future

As the world grapples with the effects of climate change, there is an urgent need for sustainable solutions to help reduce carbon emissions. Historic urban centres can indicate one possible way forward, and this is because of the way traditional buildings (in this paper centring on the Mediterranean) are built. Their materials and technologies are usually well chosen and adapted to hot climates, while the layout of historic centres, often with quite narrow, winding streets, provide shading and frequently also appropriate direction of cooling winds, especially in marine locations. These often result in these urban cores being cooler than more modern city centres. Traditional roofs, in particular, have over the centuries proved to be reliable and sustainable (when given appropriate maintenance), with layers of porous materials providing inbuilt breathable (evaporative) properties. These lead to a degree of passive cooling and ultimately to less energy consumption (less use of air conditioning for example), thus creating a smaller carbon footprint for each building, and hence also for the urban centre when a number of these buildings are present. This paper is based on a three-year pilot study, where an innovative methodology using a combination of remote data (obtained from Unmanned Aerial Vehicle (UAV) and satellite) with in situ measurements, allows for the remote identification of traditional and modified roofs, as well helping understand the thermal behaviour of such roofs, with this study concentrating on historic centres in the Island of Malta, in the Mediterranean. Ultimately aimed at promoting preservation of these traditional roofs, this study provides data to help address, at least in part, current climatic concerns, whilst also potentially providing some adaptation strategies to address climate change (in particular increased ambient temperatures). Our studies on the behaviour of traditional deffun mortar roofs have shown that they are effective in protecting the internal environment from the external one. This can lead to a reduction in carbon emissions and help create a more carbon-neutral future over an entire historic centre. Therefore, in the long term, with the right management policies in place, traditional roofs on traditional buildings can provide an excellent and cost-effective way of moving towards carbon neutrality in historic urban centres.

SMOKE DETECTION DESIGN USING MQ-2 SENSOR AND EXHAUST FAN BASED ON MICROCONTROLLER

Clean air is a very important requirement for life on earth, especially for humans. Nowadays people are competing to maintain air quality in their environment by using Air Conditioners (AC). The use of air conditioning in the home environment without us knowing that the air we breathe is contaminated with smoke. The smoke in the air-conditioned room cannot escape because the room is always closed. As a result, the smoke content that cannot escape is very dangerous, so a prototype of an indoor smoke detector is made using the Arduino microcontroller and the MQ-2 sensor as a smoke sensor. If smoke is detected by the MQ-2 sensor, Arduino will turn on the bazzer and fan.

Computational intelligence for residential electricity consumption assessment: Detecting air conditioner use in households

This article presents an approach applying computational intelligence for detecting the use of air conditioners in households. The main objective is determining the intensive use of air conditioning with a high level of confidence. Unsupervised (k-means) and supervised (Artificial Neural Networks) approaches are developed for classifying consumers for a case study in Uruguay, using data collected by a smart meters network and open weather data. Data from 29 Uruguayan cities were considered in the period from January 1, 2022, to December 31, 2022. Two thermal models are developed for estimating the temperature inside households. The main results indicate that the proposed approach is able to reach a high classification accuracy, up to 94.5% and a high classification recall, up to 95%, for the considered real case study. The final scope of the work is developing smart tools for classifying consumers, to design and suggest specific commercial products that promote energy efficiency.

A systematic review on thermal environment and thermal comfort studies in Chinese residential buildings

Amid the backdrop of the energy crisis, thermal comfort is crucial to achieve energy savings. Residential buildings are characterized by a wide range of adaptive comfort opportunities. However, there has been a lack of systematic refinement and review of residential thermal comfort field studies in China to provide valuable recommendations for energy conservation. We systematically reviewed studies on thermal environment and thermal comfort in Chinese residential buildings published in peer-reviewed journals up to 2020. A total of 34 studies were deemed to have provided sufficient information on both the thermal environment and thermal comfort. We found that in winter, there were obvious differences between urban and rural dwellings in Severe Cold (SC) and Cold (C) zones, with regard to their indoor air temperature (urban: 19.8 ∼ 25.0 °C v.s. rural: 11.3 ∼ 17.8 °C) and neutral temperature (urban: 17.6 ∼ 25.1 °C v.s. rural: 11.9 ∼ 23.45 °C). While in summer, the indoor air temperature in urban dwellings were slightly lower than those in rural areas due to their prevalent use of air conditioner (urban: 26.1 ∼ 28.9 °C v.s. rural: 29.5 ∼ 34.9 °C). Indoor air temperature and neutral temperature varied considerably in different climate zones in winter. In SC zones, the indoor environment was overheated, which could lead to energy wastage and overheating discomfort for residents. Residents in Hot-Summer and Cold-Winter (HSCW) zone were the most tolerant to the variation of thermal environment (the median coefficient of MTS or TSV equation: SC: 0.18; C: 0.20; HSCW: 0.13; HSWW: 0.23).

Evaluating the household-level climate-electricity nexus across three cities through statistical learning techniques

As the climate crisis intensifies, rising temperatures and increased frequency of extreme events are likely to strain the electricity system. This will be particularly disastrous if the grid is unprepared for the climate-induced shifts in electricity demand that will result from increased temperatures. Recently, the use of data-driven modeling has emerged as a way to predict these climate-induced changes in electricity demand, however, much of the work has focused on entire sectors or regions. Here, we focus on the impact of climatic variables on hourly household electricity use for air conditioning. Our goal was to determine the best model for predicting the air conditioning use based on climate variables, as well as use that model to extract insights related to the household-level climate-electricity nexus. Using smart meter data from three US cities (Austin, Texas, Ithaca, New York, and San Diego, California), we tested seven different models of varying complexity. Ultimately, Bayesian additive regression trees (BART) was selected as the best model across all three cities (NRMSE ranged between 0.085 and 0.250). Additionally, we found that while the majority of the climate variables were important, relative humidity was the most important variable in each city. Given that air conditioning tends to drive non-base electricity demand in the summer, understanding these nuances in the climate-electricity nexus as it applies to air conditioning is critical for building a resilient grid.