Use Of Air Conditioning Research Articles

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.

Enhanced sub-cooling attained by using moisture condensate in-unit air conditioner

We live in a time of global warming. Global temperatures are rising almost every year as a result of climate change. In such a world, it is not hard to imagine that global cooling systems are more efficient than at any other time in human history. From our homes to our workplaces, from leisure centers to medical or laboratory purposes, it has become almost necessary for a person to be ventilated only for a variety of needs. We all know that air-conditioner use is very high during the summer and is followed by a small amount of reduced use during the rainy season. We also know that most air conditioning systems have an outlet for wastewater from machinery. The moisture present in the air when it comes in contact with the AC evaporator coil, turns into the water and will discharge from the system by passage. It means that AC in the coastal region, due to the high humidity in the air, will produce more polluted water than in the dry zone. It is therefore not uncommon to find people in many coastal areas reusing extruded water for other purposes such as flowering plants, washing dishes, etc. Cooling systems can work in both air conditioning and water cooling systems. Since it is very stable and has air-conditioning strategies, we often see air-conditioners installed as cooling methods unlike water cooling systems. Therefore in such 'tropical' countries, any efforts to increase AC efficiency will be welcomed. One way to achieve this goal is to provide a hybrid Cooling AC using the water it emits. In doing so, this test aims to reduce energy compensation and increase efficiency of the system. If successful, the whole project will help save energy and resources for the next generation. Global demand for Air conditioners will increase from 1.2 billion units today to 4.5 billion units by 2050. On an average, in India around six thousand trains use 7 to 15 tons of air conditioners every day. Thousands of liters of water that is being generated from the air conditioners is put to no use and let to be wasted, if we use that water to increase the efficiency of the refrigeration cycle we can reduce energy consumption. That will be for the benefit of future generations. With so much research going on around the world to make cooling systems more environmentally friendly, this small step is likely to change the future of ACs

Vulnerability of Affordable Housing to Global Warming in South Africa: Case Study of a Masonry House in Johannesburg

Global warming is expected to lead to longer and more intense heatwaves, which will have negative environmental and socioeconomic impacts around the world. South Africa is projected to experience significant warming, with surface temperatures possibly increasing by up to 3 °C by mid-century. This warming trend has implications for architecture, as the demand for cooling in buildings could rise dramatically. However, socioeconomic conditions in developing countries may limit the use of air conditioning to mitigate indoor overheating. In South Africa, research has shown that government provided low-cost housing structures are thermally inefficient, with temperatures occasionally exceeding outdoor levels. Residents often rely on natural ventilation and personal actions to cope with heat. However, the effects of climate change may render these strategies insufficient if energy poverty and housing improvement are not addressed. This study aims to examine the impact of global warming on a high mass, naturally ventilated, affordable housing structure in Johannesburg, South Africa. Measured operative temperature data from a long-term experimental study, alongside adaptive temperature limits to evaluate overheating, highlight the vulnerability of indoor spaces without adequate insulation and/or thermal mass. The results underscore concerns about the performance of low-cost and affordable housing in warmer future climates in the South African interior.

Living comfortably with heat in Australia – preferred indoor temperatures and climate zones

While the optimal mean annual temperature for people and nations is said to be between 13 °C and 18 °C, many people live productive lives in regions or countries that commonly exceed this temperature range. One such country is Australia. We carried out an Australia-wide online survey using a structured questionnaire to investigate what temperature people in Australia prefer, both in terms of the local climate and within their homes. More than half of the 1665 respondents (58%) lived in their preferred climatic zone with 60% of respondents preferring a warm climate. Those living in Australia's cool climate zones least preferred that climate. A large majority (83%) were able to reach a comfortable temperature at home with 85% using air-conditioning for cooling. The preferred temperature setting for the air-conditioning devices was 21.7 °C (SD: 2.6 °C). Higher temperature set-points were associated with age, heat tolerance and location. The frequency of air-conditioning use did not depend on the location but rather on a range of other socio-economic factors including having children in the household, the building type, heat stress and heat tolerance. We discuss the role of heat acclimatisation and impacts of increasing air-conditioning use on energy consumption.

Wintertime patterns of residential electricity use and indoor temperature in the composite climate of India

Wintertime electricity use in India has received little attention due to the growth of residential air conditioning (AC) in the summer and monsoon seasons. This paper combines monitoring (time-series) and survey (contextual) data to examine the wintertime pattern of daily electricity current, indoor temperature, and relative humidity profiles across a sample of 64 dwellings in the city of Hyderabad representing the composite climate of India. Monitoring data were recorded for 31 days (December 2021 with a mean daily outdoor temperature of 25°C) using a CT clamp meter and Bluetooth enabled sensors. Contextual data covered dwelling and household characteristics, and use of appliances. The winter peak period of electricity use was found to occur from 6:30-10:30 in the morning, likely to be for hot water (geysers) and cooking. This is different to the late evening/night-time peak observed in the summer due to use of air conditioning (AC). Only one dwelling showed potential signs of using space heating. Higher electricity use aligned with lower peak temperatures in some homes particularly in the high-income group, indicating the potential use of AC during winter. The wintertime morning electricity peak in India could be managed using thermal stores in geysers through pre-heating which could also offer demand response opportunities.

Use of Inverter-Based Air Conditioners to Provide Voltage Regulation Services in Unbalanced Distribution Networks

The large-scale integration of photovoltaic generation and electric vehicles results in over-voltage, under-voltage, and voltage unbalance problems in three-phase distribution networks. The power consumption of the air conditioners (ACs) is large among the daily electrical appliances and can be regulated to provide voltage regulation services. To protect occupants' privacy and utilize the existing dispatch strategy of the battery, we propose a thermal battery equivalent model of the inverter-based AC to regulate the active power and provide a voltage regulation service. Moreover, an improved Newton-Raphson power-flow algorithm is developed to reduce the computational burden. The affinity propagation method is applied to cluster ACs according to different operating states. Thus, the ACs' operating frequencies are adjusted to reset the corresponding operating power. The feasibility of the thermal battery equivalent model and voltage regulation algorithm is verified based on case studies utilizing the revised IEEE 33-node three-phase power distribution network.

Enhanced sub-cooling attained by using moisture condensate in-unit air conditioner

We live in a time of global warming. Global temperatures are rising almost every year as a result of climate change. In such a world, it is not hard to imagine that global cooling systems are more efficient than at any other time in human history. From our homes to our workplaces, from leisure centers to medical or laboratory purposes, it has become almost necessary for a person to be ventilated only for a variety of needs. We all know that air-conditioner use is very high during the summer and is followed by a small amount of reduced use during the rainy season. We also know that most air conditioning systems have an outlet for wastewater from machinery. The moisture present in the air when it comes in contact with the AC evaporator coil, turns into the water and will discharge from the system by passage. It means that AC in the coastal region, due to the high humidity in the air, will produce more polluted water than in the dry zone. It is therefore not uncommon to find people in many coastal areas reusing extruded water for other purposes such as flowering plants, washing dishes, etc. Cooling systems can work in both air conditioning and water cooling systems. Since it is very stable and has air-conditioning strategies, we often see air-conditioners installed as cooling methods unlike water cooling systems. Therefore in such 'tropical' countries, any efforts to increase AC efficiency will be welcomed. One way to achieve this goal is to provide a hybrid Cooling AC using the water it emits. In doing so, this test aims to reduce energy compensation and increase efficiency of the system. If successful, the whole project will help save energy and resources for the next generation. Global demand for Air conditioners will increase from 1.2 billion units today to 4.5 billion units by 2050. On an average, in India around six thousand trains use 7 to 15 tons of air conditioners every day. Thousands of liters of water that is being generated from the air conditioners is put to no use and let to be wasted, if we use that water to increase the efficiency of the refrigeration cycle we can reduce energy consumption. That will be for the benefit of future generations. With so much research going on around the world to make cooling systems more environmentally friendly, this small step is likely to change the future of ACs.

Thermal insulation impact on overheating vulnerability reduction in Mediterranean dwellings

Heat waves are expected to increase the use of air conditioning (AC), deriving in higher energy consumption. This research aims to determine whether thermal insulation is an effective retrofit strategy for tackling overheating. Four occupied dwellings in southern Spain were monitored: two houses built prior to any thermal criteria and two with current thermal standards. Thermal comfort is assessed considering adaptive models and user patterns for the operation of AC and natural ventilation. Results show that a high level of insulation combined with a proper use of night-time natural ventilation can increase thermal comfort hours under heat waves, lasting 2–5 times longer than in poorly-insulated houses and with up to 2 °C temperature difference at nights. Long-term effectiveness of insulation under extreme heat presents a better thermal performance, especially in intermediate floors. Yet, the activation of AC usually occurs with indoor temperatures of 27–31 °C, regardless of the envelope’s solution.

Smart system for controlling and monitoring electronic facilities in budget hotel rooms

The fundamental attribute of a budget hotel is the provision of essential services at a low cost due to reduced services and facilities. Several services at budget hotels that affect customer choice are related to limitation of accommodation and entertainment services which include the use of television, air conditioning, and other electrical devices. The purpose of this research is to develop a smart system that is used to control and monitor electronic facilities in budget hotel rooms. This system provides budget hotels with the ability to select the electronic facilities that guests want to use in their rooms according to their needs and budget. This system also provides a feature to monitor the use of electronic devices in each room via a web application. The system was developed by using microcontrollers, sensors, radio frequency identification (RFID) devices, a database server, and a web application. The developed system can perfectly provide the room electronic facilities requested by the guest. The system can also monitor the service hour and power consumed by the devices with an accuracy of 99.1% for the service hour and 99.4% for the power consumed.

Current prospects of building-integrated solar PV systems and the application of bifacial PVs

Building-integrated solar photovoltaic (BIPV) systems have gained attention in current years as a way to recover the building’s thermal comfort and generate sustainable energy in building structures. BIPV systems can provide shade against sunshine while generating ancillary electrical power. Over the last decades, engineers have been trying to improve the efficiency of BIPV systems. BIPV systems with various installation types, including rooftop, balcony, curtain, sunshade, and wall façade types, are being constantly researched and intensively presented for improving power efficiency and reducing air-conditioning use. This work provides an overview of solar BIPV systems and focuses particularly on existing applications of the bifacial type of BIPV systems. The motivation and an overview of BIPV systems are first introduced, followed by the study methodology considered and the contributions. This work discusses PV technologies of bifacial PVs (monocrystalline and polycrystalline bifacial modules), BIPV installation [curtains, rooftop, flat rooftop, transparent faced, balcony windows (transparent), wall opaque facade, flat roof-faced, and skylight sunshade types], simulation and optimization software (simulation software and future trends), zero-energy BIPV technology, and optimization techniques of BIPV systems. Last, suggestion amendments to the current BIPV design that possibly contribute to growing the system’s effectiveness, reliability, and cost as future design theories for the whole system are presented.

Preparation and characterization of waterborne polyurethane based coating resins including near infrared blocking compound

Near infrared (NIR) rays, which account for 53% of sunlight, act as the strongest heat rays at 800–1,200 nm. Due to this heating action, the temperature inside a building or vehicle rises, which increases the use of air conditioners, energy consumption, and carbon dioxide generation increase. In order to solve this problem, a NIR blocking compound was prepared and introduced into the waterborne polyurethane (WPU) coating resin to prepare a WPU based coating resins including NIR blocking compound. As a result, a new absorption peak appeared around 870–910 nm which is the NIR region and a NIR blocking rate of 58.3% was confirmed.

Development of CFD simulation model of earth air heat exchanger for space cooling of a 36 M2 house in tropical climate Banda Aceh, Indonesia

The global warming makes the ambient temperature hotter and greater efforts are made to reach a comfortable temperature. The continuous use of air conditioners that consume electricity is also unsustainable for the surrounding environment. Several studies on thermal comfort have been conducted by various researchers. Earth-air heat exchangers (EAHE) with air-working fluids can be used as a passive contribution to reduce building energy requirements for heating or cooling purposes. It should be noted that there is very little information in the literature on the development of a CFD (Computational Fluid Dynamic) simulation model of an EAHE for space cooling of a 36 m2 house in a tropical climate, such as Banda Aceh, Indonesia. Therefore, this study aims to examine the performance of EAHE with several variations in design parameters, such as pipe length, pipe diameter, number of pipe bends, and the type of soil where the EAHE is installed, as well as the thermal regime of a 36 m2 house either with or without the use of EAHE. The simulation in this study was conducted with CFD ANSYS Fluent software. The inlet air temperature of EAHE was set to be the same as the ambient air temperature, namely 31.4oC. The simulation results reveal that for variations in pipe length, the highest drop in outlet air temperature was yielded by the 47 m pipe length, which is 26.8°C. In which an increase in pipe length causes a decrease in air outlet temperature. The variation in pipe diameter does not significantly affect the outlet air temperature. Where the average air temperature drop at the EAHE exit is 0.046oC. The variation in number of turns shows that the drop in outlet air temperature is identical, namely 28.2°C, despite the fact that their pressure drop values are different. In addition, it was found that the performance of EAHE buried under different types of soil is distinct. The highest drop in outlet air temperature was generated when the EAHE was buried in silty soil, namely 26.1°C. A case study on a 36 m2 house shows that the utilization an underground heat exchanger can reduce the house’s indoor temperature by 2°C, with an average house temperature of 30.4°C compared to that with a natural ventilation.

Estimates of dry eye disease in Saudi Arabia based on a short questionnaire of prevalence, symptoms, and risk factors: The Twaiq Mountain Eye Study I.

To estimate the prevalence and associated risk factors of dry eye disease (DED) among the citizens of Saudi Arabia. A cross-sectional prevalence survey was administered to 4066 healthy adults from the five main regions of Saudi Arabia. Initial estimates of the prevalence and associated risk factors of DED were calculated for the general population and then stratified by demographic characteristics such as age, sex, and location. DED was assessed by a short, validated dry-eye questionnaire. The overall prevalence of DED was 49.5% (n=2016), including 33.1% (n=1347) of participants who reported a previous DED diagnosis and 16.4% (n=669) who reported severe symptoms; 14.7% reported severe symptoms and a previous DED diagnosis (n=598). The DED prevalence among men was 49.8% (n=1005) compared with 50.2% (n=1011) for women. The multivariate model analysis confirmed the increased prevalence of DED in women (OR 1.48; 95% CI 1.30-1.88), those ≥60years of age (OR 1.99; 95% CI 1.60-2.81), those who had undergone refractive surgery (OR 1.79; 95% CI 1.50-2.59), those having undergone acne treatment (OR 1.51; 95% CI 1.34-1.97), contact lens wearers (OR 1.77; 95% CI 1.40-2.48), those having taken antiallergy drugs (OR 2.23; 95% CI 1.55-2.78) or antidepressants (OR 1.60; 95% CI 1.14-2.44), and those who reported computer use of >6h per day (OR 1.66; 95% CI 1.41-2.52). Dry eye is a common disease among the Saudi Arabian population. Prevalence is found to be high and vary significantly across the country. DED could be attributed to dry weather, low annual rainfall, low humidity, widespread use of air conditioners, air pollution, high temperature, and exposure to sunlight.

كفاءة الطاقة لأنظمة التكييف التقليدية في ظل تغير المناخ

The energy used in a country's economy is very important to its development. Over the years, the electricity and ventilation consumption of buildings have increased. People's concerns about the quality of their indoor environment are also increasing. Most buildings have air conditioning and ventilation systems that are designed to provide an environment that’s comfortable and healthy for the occupants. This is done through the use of ventilation. In addition to improving the indoor air quality, it can also help prevent people from experiencing discomfort. Studies have shown that about 60% of office buildings' energy consumption is attributed to the use of air conditioning systems. These systems provide cool air to the spaces while keeping the temperature controlled. A VAV system can meet the health criterion and the IAQ by supplying enough fresh air to meet national standards. A conventional AC system requires a refrigeration plant and a network of pipes to deliver cold water to the spaces. Since air-cooled chiller systems have a flexible design, they are commonly used in commercial buildings. They can provide a cooling effect that's significantly higher than that of water-cooled units. Compared to water cooling systems, air-cooled units are more energy-efficient. This is because the head pressure control of the system ensures that the pressure is kept high. The use of air conditioning has been one of the biggest sources of electrical energy consumption worldwide. It has contributed over 10% of the total energy produced, and it contributes to the harmful effects of climate change. Climate change is a growing concern that will require the production and use of more air conditioning units. This has necessitated the development of a comprehensive research to address this issue.

Application-driven level-of-detail modeling framework for occupant air-conditioning behavior in district cooling

Occupant behavior (OB) contributes significantly to uncertainties in the results of building performance simulation (BPS). However, a consensus regarding the appropriate level of detail (LoD) for OB modeling in BPS is yet to be reached. Hence, this study focuses on district cooling simulation applications. A systematic technical framework for determining the most appropriate LoD for modeling occupant air-conditioning (AC) use behavior is proposed herein. The framework includes three steps: defining applications and the key performance indicators (KPIs), defining comparable LoDs for AC use behavior modeling, and selecting LoDs based on KPI analysis. Appropriate LoDs for different applications are concluded. For the application related to total cooling demand evaluation, LoD O-1, representing average occupant with stochastic models, is recommended. For the design (sizing) of cooling equipment, LoD O-2, considering the diversity behaviors of occupants, is recommended. For the design of district thermal energy storage (TES) system, LoD O-2 is appropriate. For electricity pricing strategy-making, the most detailed LoD O-3 is recommended. The proposed analytics framework of modelling different LoDs of AC behavior can inspire researchers and modelers on understanding and determination of OB modeling LoDs for various future projects.

Klima Sistemlerinin Yanlış Montajının Elektrik Tüketim Maliyetine Olan Etkilerinin İncelenmesi

Changes in air temperatures with the effect of global warming are seen with increasing temperatures especially in summer months. Due to temperature increases, the use of air conditioners is increasing in order to provide the desired comfort conditions. As a result of the researches, it was determined that the air inlets were closed as a result of incorrect installation or use of the condenser unit of the air conditioning systems and the electricity consumption increased because the desired amount of air passage could not be achieved. Within the scope of this study, the authors examined the cost of electricity consumed by the air conditioning system in case of incorrect installation or use for 12 different countries. As a result of the analysis made for Turkey, the cost of electricity consumption as a result of incorrect installation practices of the air conditioning system caused an annual cost of approximately 56-62.78 $ more than the electricity consumption cost of the reference system.

A detailed view of the Adaptive-Comfort-Control-Implementation Script (ACCIS): The capabilities of the automation system for adaptive setpoint temperatures in building energy models

Recent research has looked into the potential for energy savings from adopting setpoint temperatures based on adaptive comfort. The recently suggested Adaptive-Comfort-Control-Implementation Script (ACCIS), a computational method that expands the use of air conditioning to adaptive comfort, can be used to accomplish this. The user's setup and an Input Data File (IDF) are used by ACCIS to convert PMV-based EnergyPlus models into adaptive setpoint models. The Adaptive Comfort Control Implemented Model (“accim”) Python module has been used to nest ACCIS, which was originally an Energy Management System (EMS) script. This research focuses on the creation of ACCIS and offers a more in-depth understanding of how the computational method functions based on the connections between the objects that compose it. Since all weather file quantity constraints have been overcome and studies can now be generated based on millions of simulations, ACCIS opens up new opportunities for performing energy simulations on a worldwide scale rather than only on a national or continental level. This potential is increased considering that, until recently only international models ASHRAE Standard 55 and European standard EN16798-1 were considered in ACCIS, but now a recent update allows to select local comfort models developed for specific areas. As a result, this potential is firstly demonstrated by means of the study of the 3 arguments that have the most important impact on the setpoint temperatures: the thermal comfort model, the acceptability levels and the behaviour of setpoint temperatures when adaptive comfort models are not applicable; and secondly by means of an actual example of use of accim.

The influence of the climate of the urbanized territory and the main parameters of building

The article deals with the peculiarities of the organization of the urbanized territory, the influence of the territory on changes in climatic parameters, the protection of buildings from negative weather phenomena and the extension of the service life, the influence of anthropogenic and natural nature.
 The research method is the main problem of construction in urbanized areas – protection and improvement of the environment, increasing the service life of buildings and structures. An urbanized area can have a significant impact on changing climatic parameters, in particular on increasing air temperature and higher humidity. This is influenced by various factors, such as intensive construction, traffic flows, emissions of harmful substances, use of air conditioners and other devices. One of the important aspects of the urbanized area is to ensure its effective protection from negative weather phenomena. Buildings located in urban areas often experience significant damage from natural disasters such as floods, earthquakes, winds, and other weather phenomena. One of the possible solutions is the introduction of new construction technologies that provide a high level of protection of buildings against these phenomena. These aspects are the main part of the design and planning work at all stages of the design and operation of the city territory. This is a problem of increasing the effectiveness of forecasting the consequences of climate change for the natural environment and society. The biggest issue in the study and prediction of climate change is the question of the causes that cause these changes.
 Conducted studies have shown that modern construction standards, with the allocation of insufficient attention to the natural and climatic influence on construction and structures. Usually uses typical construction projects throughout the country. Thus, the emergence of a research issue necessitated the structuring of the main climatic indicators that have an impact on the urbanized area. Based on this, a method of balancing the negative impact of climatic parameters is proposed.
 The use of architectural and climatic analysis from architectural climatology makes it possible to balance climatic conditions at the design stage with the help of architectural and urban planning and engineering solutions.