Including Air Conditioning Research Articles

Environmental Issues Related to Refrigeration Technologies

The impact of the refrigeration sector on climate change is important and growing, with four main issues: refrigerants used, energy consumption, food losses and the life cycle of materials. It is increasingly recognized at international level, but these environmental issues are complex, and most solutions are found at national and local levels. The issue of refrigerants is now well known; solutions have already been put in place, both for the stratospheric ozone layer and for climate change, even if these solutions are currently determined in a long-term perspective (mid-century). However, these timeframes may be shortened in the future. Conversely, energy issues (energy efficiency, use of renewable energies), which have so far been insufficiently addressed in most countries, have become an urgent challenge. The same applies to the implementation of cold chains in developing countries in order to reduce food losses and their carbon impact. The dramatic increase in the use of refrigeration, including air conditioning and the cold chain, makes truly sustainable development of this sector particularly important.

Utilization of Electrical Energy in Lecture Building at Universitas Bangka Belitung

Electrical energy has become necessary in supporting human life activities, one of which is in higher education institutions. Universitas Bangka Belitung, as one of the public universities in the Province of Bangka Belitung Islands, currently has 12 lecture buildings to provide the best academic services in the 20 available undergraduate programs. Through measurements carried out during lecture activity hours in a few weeks at the main panel in 12 lecture buildings, also obtained the average current, average voltage, and average real power in the R phase, S phase, and T phase. lecture building with sampling data every 15 minutes. Based on measurements, the entire lecture building’s electrical energy consumption is in the range 2-5 kWh with electronic equipment used, including air conditioning, LCD computer projectors, and room lighting

Contamination of Water Sources of Karaj Hospitals with Legionella pneumophila and Campylobacter jejuni

Background: One of the most common routes of infection development in humans is contaminated water. Legionella pneumophila and Campylobacter jejuni are the important causes of community- and hospital-acquired pneumonia and gastroenteritis that are transmitted to humans via the inhalation of contaminated water droplets and consumption of contaminated water, respectively. Thus, continuous monitoring of the water supply systems for these pathogens has great importance in public health. Objective: This study aimed to evaluate the water contamination of Karaj hospitals with these two bacterial species. Materials and Methods: In this study, 62 water samples were obtained from different parts of the hospitals of Karaj from April to September 2019, including air conditioning systems, dialysis equipment, ventilation tanks, and different wards of a hospital such as infectious diseases, pediatrics, gastroenterology, dialysis, and intensive and neonatal intensive care units. The samples were collected in sterile containers and immediately transferred to the laboratory for further analysis. The culture on specific media, staining, and biochemical tests were performed to identify the L. pneumophila and C. jejuni. Results: Out of 62 water samples, 25.8% (16 samples) were positive for L. pneumophila; 68.75% were observed in hot water samples, and 31.25% were attributed to cold water samples. Among 62 samples, 4.84% (3 samples) were positive for C. jejuni, which were all detected in hot water samples. Conclusion: Considering that the methods of water refinery of municipal water have no high efficiency, the quality improvement of the water sources of hospitals seems to be necessary.

Virtual energy storage model of air conditioning loads for providing regulation service

As the pressure of supply–demand balance increases with the high penetration of renewable energy resources, it is widely accepted that demand side resources including air conditioners (ACs) play an important role in providing ancillary services to the grid. In this paper, air conditioning loads are modeled as a kind of virtual energy storage device based on their inherent thermal storage capacity. It is investigated that air conditioning loads can provide regulation service with certain storage power output and ramping rate limits as a result of minimum on/off time requirements. Simulation studies demonstrate the effectiveness of the proposed method by coordinating ACs to track a regulation signal.

Study on the comprehensive energy performance of different shading systems in China

This study evaluates the impacts of different shading systems on the comprehensive energy performance of buildings in China. Firstly, simulation models for four shading systems were developed using THERM, WINDOW and EnergyPlus. Then, four shading systems with different qualities, setting modes and baseline window systems were defined and simulated. Two cities, Beijing and Guangzhou, were selected as representative cities for heating-dominated and cooling-dominated regions in this study. Finally, the comprehensive energy performance, including cooling electricity consumption, heating electricity consumption and lighting electricity consumption for buildings with different shading systems were analysed. The results show that in Beijing, the most suitable shading system is roller shade with D quality (the combination of performance parameters), H (half shading) setting mode and low-e glazing system, while in Guangzhou, the most suitable shading system is roller shade with A quality, F (Full shading) setting mode and low-e glazing system. Besides, buildings in Beijing with suitable shading systems can achieve at least 20% energy saving potential (including air conditioning and lighting electricity consumption) compared with buildings without shading systems and the corresponding figure for Guangzhou is 50%. The conclusions of this study provide a reference for design and selection of shading systems in different regions in China.

The Impact of Japan Heatwave on Community Emergency Medicine in 2018

Introduction:Due to the heatwave in Japan, the number of patients with heatstroke transported via ambulance hit the highest record according to the Tokyo fire department in 2018. Now, heatwaves are thought to be a natural disaster. Emergency medical professionals located in a Tokyo suburb covering 40,000 individuals experienced a wide range of challenges in patient care with heatstroke.Aim:To assess the impact of the 2018 Japan heatwave on community emergency medical service.Methods:Patients (aged ≥ 16 years) with heatstroke and who were transported to our hospital by ambulance from June to September of 2018 were included. Data were derived from prehospital records and electronic medical records. Weather data was referenced from a Japanese meteorological agency.Results:The number of all-cause cases was 1,764, and the total number of heatstroke cases was 51 (2.9%). Heatstroke cases were concentrated in July and August of 2018. The rate of males was 69%. The average age was 63 ± 23 years. Physical labor was associated with 31% of cases, such as sports in 7.8%. Hospitalization was required in 24%. ICU admission was required in 9.8%. There was no fetal case directly caused by heatstroke in this survey.Discussion:The risk factors of heatstroke considered to be male and elderly. About one-half of heatstroke patients were over 70 years old, and it may have been related to regional characteristics. As mentioned in the Heatstroke STUDY 2012 (Miyake, 2014), most cases which occurred inside residences were found that there was no air conditioner use. There was also an increased number of patients with heatstroke who made emergency visits by themselves. Further investigation is needed annually to estimate the effect of climate change. It is important to make a strong recommendation from public health agency about heatstroke prevention, including air conditioner use during hot weather.

Thermal performance evaluation of a vertical closed-loop ground heat exchanger according to rock type in Korea

Geothermal heat pump systems have a variety of uses including air conditioning and heating for buildings and greenhouses, hot water supplies, and crop drying applications. The installation environment and conditions of operation can have a large influence on the performance of the system and need to be considered. In this study, we applied the line-source method to different types of rocks and borehole depths in order to analyze the characteristics of effective thermal conductivity. We conducted thermal performance tests for a geothermal heat exchanger in accordance with initial ignoring times (5, 7, 9, and 12 h) and analyzed the stability of effective thermal conductivity and the relationship between the heat injection and slope of k in λeff = Q/4πHK according to variations in appropriate heat injection levels. The analysis of effective thermal conductivity according to the rock type and borehole depth for 40 boreholes showed that the value of effective thermal conductivity was generally high at the borehole depth of 200 m. This seemed to be due to the increase of underground space for energy storage. Consequently, we determined that the aquifer had the largest effect on the effective thermal conductivity.

State of the art and kinetics of refrigerant hydrate formation

This study aims to introduce suitable hydrate forming-refrigerants well-suited for air-conditioning systems through a kinetic study. The formation of clathrate hydrates is a time-consuming process. Hence, in an air-conditioning system, which uses refrigerant hydrate as a media for storage of cold energy, the knowledge of the hydrate formation rate, is crucial. In this experimental study, the rate of hydrate formation of four refrigerant blends, including R404A, R406A, R408A and R427A have been investigated. The induction time for hydrate formation, apparent rate constant of the hydrate reaction, water to hydrate conversion during hydrate growth, storage capacity, and the rate of hydrate formation of these refrigerants at various pressures and temperatures have been obtained using a kinetic model. The effect of sodium dodecyl sulfate (SDS) on the hydrate nucleation rate was also investigated. This study also aims to prepare a review on gas hydrates applications and characteristics in the power generation systems and cold storage applications including air conditioning systems. The advantages and disadvantages of this compound over traditional storage media and phase change materials (PCMs) including water, ice, salt hydrates, eutectic salts, paraffin waxes and fatty acids, slurries and phase changed emulsions have been reviewed.

Use of standalone photovoltaic system for office building: the case study of national centre for hydropower research and development, Nigeria

This paper presents the design of a cost effective energy system for National Centre for Hydropower Research and Development (NACHRED) building to supply its daily energy requirements. The daily hourly load demand of the building was measured with FLUKE 434 Series II Energy Analyzer. The measurement was grouped into two namely: category 1 and category 2. In category 1, the essential electrical load demand excluding air conditioner system was measured for 3 consecutive days while in category 2 the total daily load demand including air conditioner system was also measured for three consecutive days. HOMER pro3.2 was used to size and simulate photovoltaic system required for the two categories. The system in category 1 with the load of an average consumption of 36.34kWh/d, is considered as a cost effective system for the building, as compared to one in category 2 with the load of an average consumption of 198.1kWh/d. http://dx.doi.org/10.4314/njt.v36i4.30

A Time-Varying Potential-Based Demand Response Method for Mitigating the Impacts of Wind Power Forecasting Errors

The uncertainty of wind power results in wind power forecasting errors (WPFE) which lead to difficulties in formulating dispatching strategies to maintain the power balance. Demand response (DR) is a promising tool to balance power by alleviating the impact of WPFE. This paper offers a control method of combining DR and automatic generation control (AGC) units to smooth the system’s imbalance, considering the real-time DR potential (DRP) and security constraints. A schematic diagram is proposed from the perspective of a dispatching center that manages smart appliances including air conditioner (AC), water heater (WH), electric vehicle (EV) loads, and AGC units to maximize the wind accommodation. The presented model schedules the AC, WH, and EV loads without compromising the consumers’ comfort preferences. Meanwhile, the ramp constraint of generators and power flow transmission constraint are considered to guarantee the safety and stability of the power system. To demonstrate the performance of the proposed approach, simulations are performed in an IEEE 24-node system. The results indicate that considerable benefits can be realized by coordinating the DR and AGC units to mitigate the WPFE impacts.

Numerical analysis of temperature field and structure field in horizontal continuous casting process for copper pipes

To efficiently utilize energy, refrigeration industries, including air conditioning, have put forward higher and higher requirements for the performances of copper pipes used for heat exchangers. Horizontal continuous casting of pipe blank is a key process in production of copper pipes, and optimization of its technological parameters has positive effects on improving the structure uniformity of casting blank. The stability of the performances of pipe blank also directly influences the quality of subsequent machining process. In this paper, numerical analysis was carried out for the temperature field and structure field during solidification of pipe blank in the crystallizer for horizontal continuous casting, and the steady-state sump depth and morphology in the crystallizer for continuous casting, which could be used to evaluate production safety, were obtained. Quantitative analysis was conducted for the laws of influence of different casting technological parameters, such as cooling water flow rate, withdrawal speed, and casting temperature, on the sump morphology in the crystallizer for casting blank and the final distribution of structure field in casting blank. Metallographic experiment was carried out for casting blank, and the results were compared visually with the structure field from simulation calculation, to provide measurable reference bases for further optimizing the horizontal casting technological parameters for copper pipes.

Does Marketing Widen Borders? Cross-Country Price Dispersion in the European Car Market

Pricing-to-market (PTM), the practice of differentiating the price of a good across markets, is commonly attributed to differential distribution and border costs. In this paper we show that some of this price differentiation is sustained by manufacturers selling different versions of an otherwise identical good in different markets. We study price differences across countries in the European car market, using a rich data set which includes detailed technical information on each car model. Relative car prices show no sign of convergence during the period 2003-2011. PTM is pervasive in this market: model-specific real exchange rates for mechanically identical cars differ significantly from unity. They also vary significantly across countries and, within countries, across car manufacturers. We find strong evidence that car manufacturers price discriminate by manipulating the menu of included car options and features available in each country, e.g. by including air conditioning as a standard feature as opposed to pricing it separately. We find that such bundling decisions sustain cross-country price differences of 10% and more.

Urban sound event classification based on local and global features aggregation

The automatic content-based classification of complex and dynamic urban sound is an important aspect of various emerging applications, such as surveillance, urban soundscape understanding and noise source identification, therefore the research topic has gained a lot of attention in recent years. The aim of this paper is to develop efficient machine learning-based scheme for urban sound classification in real-life noise conditions. Unlike conventional sound event classification methods that mainly address local temporal-spectral patterns, we propose an aggregation scheme to combine both local and global acoustic features. For characterizing local patterns, we employ feature learning method to extract class-dependent temporal-spectral structures; on the other hand, long-term descriptive statistics are employed to exploit global features of sound events, e.g. variability and recurrence, which also carry rich discriminant information. In order to aggregate the heterogeneous acoustic information for classification, we introduce mixture of experts model (MoE) which effectively formulates relationship between local and global information. At validation stage, we conduct experiments on UrbanSound8K database which consists of 10 categories of urban sound events with 8732 real-world clips. It is noteworthy that the 10 classes of crowdsourced recordings, including air conditioner, car horn, children playing, dog bark, drilling, engine idling, gunshot, jackhammer, siren and street music, are most common urban sounds closely related to urban life. According to experimental results, the proposed scheme achieved superior performance compared with 3 other latest approaches and it can be a fundamental building block of various urban multimedia information processing systems that help to improve quality of life.

A multilevel analysis to explain self-reported adverse health effects and adaptation to urban heat: a cross-sectional survey in the deprived areas of 9 Canadian cities.

BackgroundThis study identifies the characteristics and perceptions related to the individual, the dwelling and the neighbourhood of residence associated with the prevalence of self-reported adverse health impacts and an adaptation index when it is very hot and humid in summer in the most disadvantaged sectors of the nine most populous cities of Québec, Canada, in 2011.Methods The study uses a cross-sectional design and a stratified representative sample; 3485 people (individual-level) were interviewed in their residence. They lived in 1647 buildings (building-level) in 87 most materially and socially disadvantaged census dissemination areas (DA-level). Multilevel analysis was used to perform 3-level models nested one in the other to examine individual impacts as well as the adaptation index.ResultsFor the prevalence of impacts, which is 46 %, the logistic model includes 13 individual-level indicators (including air conditioning and the adaptation index) and 1 building-level indicator. For the adaptation index, with values ranging from -3 to +3, the linear model has 10 individual-level indicators, 1 building-level indicator and 2 DA-level indicators. Of all these indicators, 9 were associated to the prevalence of impacts only and 8 to the adaptation index only.ConclusionThis 3-level analysis shows the differential importance of the characteristics of residents, buildings and their surroundings on self-reported adverse health impacts and on adaptation (other than air conditioning) under hot and humid summer conditions. It also identifies indicators specific to impacts or adaptation. People with negative health impacts from heat rely more on adaptation strategies while low physical activity and good dwelling/building insulation lead to lower adaptation. Better neighbourhood walkability favors adaptations other than air conditioning. Thus, adaptation to heat in these neighbourhoods seems reactive rather than preventive. These first multi-level insights pave the way for the development of a theoretical framework of the process from heat exposure to impacts and adaptation for research, surveillance and public health interventions at all relevant levels.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-2749-y) contains supplementary material, which is available to authorized users.

Electrospray-printed nanostructured graphene oxide gas sensors

We report low-cost conductometric gas sensors that use an ultrathin film made of graphene oxide (GO) nanoflakes as transducing element. The devices were fabricated by lift-off metallization and near-room temperature, atmospheric pressure electrospray printing using a shadow mask. The sensors are sensitive to reactive gases at room temperature without requiring any post heat treatment, harsh chemical reduction, or doping with metal nanoparticles. The sensors’ response to humidity at atmospheric pressure tracks that of a commercial sensor, and is linear with changes in humidity in the 10%–60% relative humidity range while consuming <6 μW. Devices with GO layers printed by different deposition recipes yielded nearly identical response characteristics, suggesting that intrinsic properties of the film control the sensing mechanism. The gas sensors successfully detected ammonia at concentrations down to 500 ppm (absolute partial pressure of ∼5 × 10−4 T) at ∼1 T pressure, room temperature conditions. The sensor technology can be used in a great variety of applications including air conditioning and sensing of reactive gas species in vacuum lines and abatement systems.

Increasing concentrations of dichloromethane, CH&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;Cl&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;, inferred from CARIBIC air samples collected 1998–2012

Abstract. Atmospheric concentrations of dichloromethane, CH2Cl2, a regulated toxic air pollutant and minor contributor to stratospheric ozone depletion, were reported to have peaked around 1990 and to be declining in the early part of the 21st century. Recent observations suggest this trend has reversed and that CH2Cl2 is once again increasing in the atmosphere. Despite the importance of ongoing monitoring and reporting of atmospheric CH2Cl2, no time series has been discussed in detail since 2006. The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) has analysed the halocarbon content of whole-air samples collected at altitudes of between ~ 10–12 km via a custom-built container installed on commercial passenger aircraft since 1998, providing a long-term record of CH2Cl2 observations. In this paper we present this unique CH2Cl2 time series, discussing key flight routes which have been used at various times over the past 15 years. Between 1998 and 2012 increases were seen in all northern hemispheric regions and at different altitudes, ranging from ~ 7–10 ppt in background air to ~ 13–15 ppt in regions with stronger emissions (equating to a 38–69% increase). Of particular interest is the rising importance of India as a source of atmospheric CH2Cl2: based on CARIBIC data we provide regional emission estimates for the Indian subcontinent and show that regional emissions have increased from 3–14 Gg yr−1 (1998–2000) to 16–25 Gg yr−1 (2008). Potential causes of the increasing atmospheric burden of CH2Cl2 are discussed. One possible source is the increased use of CH2Cl2 as a feedstock for the production of HFC-32, a chemical used predominantly as a replacement for ozone-depleting substances in a variety of applications including air conditioners and refrigeration.

Повышение эффективности производства холода

The paper is dedicated to the use of renewable energy in cold production, particularly to recycling low temperature heat (below 160&#x0D; °C) by the absorption chiller (AС). In most, it is a secondary energy resource, which eliminates carbon emissions and thermal pollution.&#x0D; The possibility of increasing the efficiency of cold production for different consumers (including air conditioning) is considered. The&#x0D; result is achieved by using a seasonal cold accumulator, which is also a renewable source. Structural diagram and description of&#x0D; the workflow are proposed. The example of a single-stage water-ammonia AС illustrates the effect of external temperatures on the&#x0D; workflow. Results of thermodynamic calculations prove efficiency of combined AС and seasonal cold accumulator.

Dermatophytes contamination of wrestling mats in sport centers of Isfahan, Iran.

Sir, Dermatophytes are fungi causing one of the most common infections in the medicine. These pathogens will spread through two ways: direct contact with other people, animals, and soil; or indirectly from fomites.[1,2] Direct contact during exercise or competitions with infected athletes or contaminated equipments is the reason of being infected by Tinea gladiatorum (dermatophytosis or ringworm in wrestlers).[3] Prevalence of dermatophytes in wrestlers is reported in a wide range of 20%-77%.[4,5] Some studies have reported that wrestling mats will be a source for the fungal infections as it is reported that 44% wrestling mats were contaminated.[6,7] We aimed to assess the prevalence of wrestling mats contamination with dermatophytes in the sport centers of Isfahan city of Iran. To achieve this aim a cross-sectional study was conducted. All the sport centers in Isfahan city that had the wrestling club were enrolled into this study. Demographic of the club including air conditioning, temperature, and exercise time per day were obtained from the directors. Also history of any fungal infections during the previous month was obtained. For each club, three samples from two wrestling mats (six samples for each club) were taken. To collect the samples, 2.5 × 2.5 sterile carpet pieces were used. The differentiation of dermatophytes was carried out based on colony morphology on mycosel agar and on their microscopical appearance. Statistical analysis was done using SPSS version 16. Descriptive analysis and Chi-square test were used to describe and compare the distributions, respectively. Statistical significance was assessed at the 0.05 probability level in all the analyses. In this study, seven wrestling clubs were included. Temperature of all the clubs was lower than 25°C and 1.5 h was the exercise time during a day for all of them. Table 1 shows the result of culturing and dermatophytes determination. As table 1 is reporting, only two dermatophytes of Trichophyton rubrum and Trichophyton mentagrophytes were detected in wrestling mats in Isfahan. Of the 14 mats, eight (57.1%) of them and of the clubs, six (85.7%) clubs had at least one positive result for dermatophytes contamination. Of all the 21 samples, 13 (61.9%) were contaminated (52.4% and 9.5% were T. rubrum and T. mentagrophytes, respectively). Our data showed negative results for one of the clubs (club C). In clubs A, B, D, E, and F, T. rubrum (71.4% of all clubs) and in club G, T. mentagrophytes (14.2% of all clubs) were detected. Of the seven clubs, five (clubs A, B, C, E, and G) had air conditioning and two of them (clubs D and F) had not, and there was no significant difference in the type of dermatophytes between clubs with and without air conditioning (P = 0.571). Also one club (club D) had positive history of fungal infection during last month. There was no significant difference between distribution of type of dermatophytes in clubs with and without a positive history of fungal infection during the previous month (P = 0.792). Habibipour et al., in their study in Hamadan city of Iran, reported that a mat (10%) was infected with dermatophytes. Dermatophyte that was isolated from wrestling mats was Trichophyton tonsurans.[8] Another study by Aghamirian et al. revealed that of 24 wrestling mats that were surveyed, 33.3% were heavily contaminated with T. tonsurans (the only dermatophyte detected in mats).[9] Ahmadinejad et al. have reported that 44% of wrestling mats were contaminated with different fungal organisms, including Epidermophyton floccosum, T. mentagrophytes, and T. rubrum.[10] Kohl et al. determined that it is unlikely that wrestling mats be a source of dermatophyte infections in wrestlers. In Kohl et al.'s study, none of the mat samples produced any dermatophyte growth.[7] Hedayati et al. in a study from Sari, Iran, showed that all the wrestling mat samples were positive for T. tonsurans and have suggested that contamination of wrestling mats with dermatophytes has a crucial role in the infection of wrestlers.[10] Some other studies have suggested that transmission of T. gladiatorum occurs only by skin-to-skin contact and not by contact with contaminated wrestling mats.[11,12] According to previous studies and also our results, wrestling mats will be contaminated with dermatophytes and can be potentially a source for transmission of ringworm diseases. Table 1 Dermatophytes detected from samples of different wrestling clubs mats of Isfahan, Iran As T gladiatorum in Iran is a common phenomenon among wrestlers and this infection can disqualify the athletes from matches and exercise; appropriate preventive programs must be designed to reduce the incidence of fungal skin infection and transmission among wrestlers. This aim will be reached by finding the sources and disinfecting them.

知的生産性向上を考慮した多様なワークプレイスの環境性能の空調設備計画と性能検証

In recent years, research has been promoted into the improvement in workplace performance by the Workplace Productivity Research Consortium in IBEC,1) 2) and awareness of workplace productivity in offices has been increasing in Japan as a technically advanced country. The O building 3), which was completed in 2011, is a research office, in which various workplaces are configured to improve productivity; the dwelling environment including air conditioning systems is designed for application to that “location,” and verification is carried out in the operational stage. An outline of this work is presented as our knowledge of the importance of workplace productivity in the future.

Analysis on Performance Test Methods of Particle Cleaning Capacity for Large-scale Air Cleaners including Air Conditioners

Analysis on Performance Test Methods of Particle Cleaning Capacity for Large-scale Air Cleaners including Air Conditioners