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The experimental study of the thermal activity of single-phase flows through an automotive radiator is presented in this paper. In the engine, the radiator is a critical component of the vehicle cooling system. It is typically used as part of an engine's cooling system, with water serving as the heat transfer medium. The heat is extracted from the devices using a circulating coolant that surrounds them or enters the cooling channels in the devices. Because of their excellent thermal efficiency, nanofluids have gained traction as a new generation of heat transfer fluids in automotive cooling applications. This paper uses water-based Graphene nanofluids as a coolant to boost the heat transfer characteristics of a vehicle cooling device. The thermal efficiency of a nanofluid-operated radiator is compared to that of a traditional coolant-operated radiator. Reynolds number, there is a 50-70 percent increase in total heat transfer and overall heat transfer coefficient. With an increase in the volume concentration of Graphene particles in Base Fluid, Thermal Conductivity improved by 61.05 percent. [ABSTRACT FROM AUTHOR]

The energy consumption in the building operation stage accounts for about 20% of the total energy consumption of the building's whole life cycle, among the energy consumption, the air-conditioning system accounts for the largest proportion, significantly contributing to 50% of the energy consumption. In the conventional method in the air conditioning control system, a constant target temperature is usually set. However, due to the real-time changes in environmental parameters and personnel activities, the energy consumption of buildings and the comfort of users will also change accordingly. This paper studies the optimization of air conditioning energy consumption under dynamic conditions, comprehensively adopts technologies such as the Internet of Things (IoT), computer simulation, and meta-heuristic algorithms to adjust the control parameters of the air conditioner in real-time according to the on-site situation, to achieve the goal of reducing energy consumption and improving comfort. The building air-conditioning energy-saving optimization solution proposed in this paper takes into account real-time, adaptability and accuracy. According to the actual comparison, the energy consumption is reduced by about 10%, and the comfort satisfaction degree is increased by about 8%. [ABSTRACT FROM AUTHOR]

During the past almost two decades, the European Union launched and systematically updated Directives that aim to keep under control the use of energy in buildings. In this context, the "Strategy 20-20-20" (launched in January 2005), aimed to reduce greenhouse gases by 2020 with 20% and on the other hand, to increase the use of renewable energy consumption by 20%, in an effort to ensure the improvement of energy efficiency by 20%. It was followed in 2010 by the Energy Performance of Buildings Directive - that was revised in 2018 - and by the Energy Efficiency Directive in 2012, amended in 2019. Furthermore, in December 2021, the Commission proposed a revision of the Energy Performance of Buildings Directive, that sets new and ambitious targets regarding the buildings - either new or old - that match the provisions and expectation of the European Green Deal. "As of 2021, all new buildings must be nearly zero-energy buildings (NZEB) and since 2019, all new public buildings should be NZEB. When a building is sold or rented, energy performance certificates must be issued and inspection schemes for heating and air conditioning systems must be established" is stated on the Energy page of the site of the European Commission. However, as strange as it may seem, preoccupations for a fair energy management is probably almost as old as mankind as the building is the product with the longest life span: we have millennial buildings that not only stand but are still functioning. It was not a calculation or a direction that designed the buildings, it was the genius of architects. While not denying the political will and the strategies that it brings forth, it must be emphasized that energy efficient buildings were created long before the need to measure the building performance from the point of view of the energy it uses. And, as one of the greatest architects of the XX-th Century said "Architecture is the will of an epoch translated into space" (Ludwig Mies van der Rohe). And this epoch has the technological means of producing energy from alternative resources that can be embedded in building products. Hence, why not use them?! As means not as targets, in order for the building to continue to fulfil the Vitruvian triade: firmitas - utilitas - venustas (structural strength - utility - beauty). The paper is a plea for the prevalence of the architectural concept over rigid quantitative measures of energy efficiency. [ABSTRACT FROM AUTHOR]

Reaching the maximum level of the users' comfort in the building is an important role. At the same time, it is vital to have occurred minimum negative environmental effects. Having an atrium as a popular area in the building needs to investigate thermal performance. This paper finds out the effects of the floor heigh into the internal condition as the liner atrium with optimum shading device during the warm period. This paper illustrated the different results according to the atrium building height as floor numbers including 1, 3, and 5 floors in Famagusta, North Cyprus climate. As finding in all building height simulation models in August is the maximum discomfort condition month and maximum cooling loads as air-conditioning system, because of internal building gained and ventilation gains, (single floor Qz between 330 to-330 watts, Qv:-2000 to 2000 watts), (three floors Qz between 1200, 2200 watts to-1200,-2200 watts, Qv:-7000 to 7000 watts), and (five floors Qz between 2000, 4500 watts to-2000,-4500 watts, Qv:-12000 to 12000 watts) however, the optimum shading device as 35% over the south external facade of atrium applied but the fully air-conditioned is necessary especially from morning to afternoon time. It found that, while the floor height of the total building and atrium height increased, heat transferring massively occurred during morning time especially as passive performance. [ABSTRACT FROM AUTHOR]

The paper focuses on the relationship between architectural design and thermal comfort in the modern small lecture hall. Thermal comfort in modern small university lecture halls is usually provided by modern ventilation systems or modern air conditioning systems. Reconciliation of architectural design with the requirements of modern ventilation systems or modern air conditioning systems is inevitable to ensure the thermal comfort of students. Detailed analysis is devoted to the process of harmonization of architectural design with thermal comfort in a small university lecture hall. Abiding by the optimal parameters of thermal comfort is essential for students in a small university lecture hall. The adhesion of these parameters is fundamental for the physical and mental condition of students and directly relates to their performance. Experimental measurements were carried out in the winter season in the modern small lecture hall in Budapest to assess the parameters of thermal comfort. The Testo 480 device was used for the measurements. The measured values of thermal comfort are carefully presented on the charts. The architectural design and ventilation system of the modern small university lecture hall were evaluated based on measured thermal comfort. The conclusion of this paper presents the principles of modern harmonization of the architectural design of the new small lecture hall in relation to the design of the elements of the ventilation system. [ABSTRACT FROM AUTHOR]

The present paper investigates the heat load characteristics of Air Conditioned (A.C) coaches installed with Roof Mounted A.C Packaged Units (RMPU) in the Indian Railways. It has been observed in the available official documents that the parameters considered for the heat load calculations for the estimation of RMPU capacity requirements were inadequate. For example, the list does not include body heat generated by the on-board passengers and radiation from various gadgets and utilities which also contributes to the heat load on the RMPU. In addition, the humidity levels or passenger comfort were also not among the parameters which in turn provide a quantitative guideline for temperature settings of AC coaches. The inadequacy in the considered data clearly led to inaccurate assessment of the performance of RMPU and energy consumption. This study aims to improve the accuracy in predicting the heat load on the RMPU by including more parameters that are contributing to the heat addiction such as the opening and closing of the door, heat transfer through the partition between the wash basin area and sleeping berths, radiation from electronic gadgets and heat addition due to utilities. The calculations are relevantly based on various air conditioning systems in other applications. The results after the consideration of extra parameters showed that the revised required T.R per coach is 7.74 tons as opposed to the existing calculated results of 7 tons. The present work can motivate more efficient RMPU designs which in turn can inspire an improved approach towards the design of air conditioning systems of similar transportation modes and similar heating, ventilation, & air conditioning (HVAC) systems. [ABSTRACT FROM AUTHOR]

Due to the excess use of air conditioning systems led to significantly increase the demand for electric power in the household sector. Therefore, to decrease energy consumption, it can use an Earth-Air Heat Exchanger (EAHE); it has been demonstrated to be promising method for heating and cooling applications. In this paper, simulation study was performed using ANSYS FLUENT 19.0 (CFD) program as a numerical analysis on the impact of different pipe shape and air velocity on the performance according to the climatic conditions of Baghdad-Iraq in the summer and winter seasons. The pipes shapes in EAHE system that were used are spiral, wave and straight at the same length and diameter, and it has been studied their impact on performance at different speeds (5, 10 and 15 m / s). The results of numerical analysis showed that the shape of pipes and velocity of inlet air have an effect for the temperature of outlet air and performance of EAHE. Through the results obtained, it was found that the shape of straight tube presents the best performance compared to the other two shapes of spiral and wave. Therefore, the better performance for EAHE can be achieved on operating the system at low air velocity together with straight shape for the exchanger pipe. [ABSTRACT FROM AUTHOR]

Various types of cooling systems are widely used in Iraq to achieve comfortable conditions for occupants during the hot summer. Large amounts of energy are consumed due to the use of cooling systems in buildings for various activities. Improving the coefficient of performance for HVAC systems is an essential priority within sustainable energy management strategies. In the present paper, an experimental study was carried out to determine the effect of cooling the condenser in a split unit type air conditioner with a capacity of (1 refrigeration ton) indirectly through the passage of air over a wet filling. A different thickness of pads (3, 5 and 7 cm) was used. The pad was moistened with water at different volume flow rates ranging from (100, 125, and 150) liters / h. The rate of airflow passing through the condenser was fixed to determine the refrigeration system's performance and the energy consumed compared to the reference case at different factors. The results showed that the best increase in the coefficient of performance of the system is (25.2%) when the thickness of the pad is (5 cm) and volume flow rate (100) liters / h, and the percentage of energy saving is 13.2%. [ABSTRACT FROM AUTHOR]

The paper presents a bind of ways to improve indoor air conditions in the basement premises of the restored and reconstructed historical buildings. The features of the functional purpose of these basements are given and connected with religious architectural traditions of Russia. The measures are affecting the indoor air quality in the premises and building envelope conditions. [ABSTRACT FROM AUTHOR]

The efficiency of the refrigeration system, can be accomplished by dispersing numerous nanoparticles in the vapor compression refrigeration system's compressor oils and refrigerants, needs to be enhanced with regard to energy protection and environmental considerations. Similarly, the persistent every-day effort in the field of cooling and air- conditioning systems has involved the use of nana-refrigerants/nana-lubricants as one predominant set of applications and with the use of far more efficient eco-friendly fluids.the object of the analysis is to analyzethe effects of nanoparticles being applied to lubricants or refrigerants.this paper describes natural refrigeration fluids (refrigerants) as the perfect refrigeration fluids(refrigerants) that are environmentally sustainable and the ultimate response to ozone depletion and global warming issues. In refrigeration and air conditioning applications, hicks refrigeration fluids (refrigerants) are probably the most famous substitute to cfcs and huffs refrigeration fluids(refrigerants). This paper also explores the impact on tribological efficiency of the dispersion stabilization of nanolubricants and lubrication processes involved in improving tribological performance. Finally, it addresses the obstacles and prospects for future study. [ABSTRACT FROM AUTHOR]

In past several years, due to technology advancements, the costs of variable speed drives have come down sharply allowing the widespread applications of variable speed devices in building air-conditioning systems. This article presents the case study on application level of variable speed drives to the components of the air-conditioning system (VAV system) installed in Vivekanand Lecture Theatre Complex (VLTC) at MNIT Jaipur, India. After incorporating the variable speed drives to the air conditioning system, the proposed case energy performance index has been compared with the standard energy performance indexes of Energy Conservation Building Codes 2017(ECBC, ECBC+ and Super ECBC), developed by the ministry of power and Bureau of Energy Efficiency(BEE), India. The study of Hartman research paper on variable speed chiller plants has been used to learn existing algorithm for developing new operating strategies. Simulations are performed on EnergyPlusV8.8.0 (an energy analysis simulation program) for more than dozens of cases by making the variable a single and multiple combinations of HVAC equipment (AHU, Cooling Tower, Chiller, Pumps). The results show that the application of variable speed drives improved the performance of the air conditioning system substantially. At an average, the energy consumption of all variable chiller plant decreased by 40-45% compared to a constant speed chiller plant. All-variable speed chiller plant operating strategies have been developed based on the tailored specific performance characteristics of variable speed chillers and the variable flow characteristics of condenser pumps and cooling towers. The specific component-wise energy performance improvement after the incorporation of variable drives and ECBC compliance check for the proposed case has been presented in this paper. [ABSTRACT FROM AUTHOR]

Archive Depot Building, in general, serves as a place to store, safe-keep, and maintain archives. Therefore, archives located in this building should be treated in accordance with the Head of ANRI (The National Archives of Indonesia) Regulation No. 31of 2015 on Guidelines for Establishment of Archive Depots. For this type of paper archive, its recommended temperature setting is that of 15oC to 22oC with moisture of 55. This building has 4 floors, and is located at Margonda Raya Street No. 54 Depok. The geographical location of this building is South Latitude. The building is facing west, and the building area is of 3211,12 ft2. From the design and calculation results, we obtained cooling loads of 264929.11 Btu/hr or equivalent to 77.62 kW. The specifications of air conditioners selected to meet the cooling load based on the calculation results are: 1 Outdoor Unit; Nominal Cooling Capacity of 78,6 kW. 2 Indoor Units; Nominal Cooling Capacity of 2800 W. 3 Indoor Units; Nominal Cooling Capacity of 3600 W. 4 Indoor Units; Nominal Cooling Capacity of 4500 W. 1 Indoor Unit; Nominal Cooling Capacity of 8000 W. Lastly, 3 Indoor Units; Nominal Cooling Capacity of 14000 W. [ABSTRACT FROM AUTHOR]

The paper considers a thermostat unit that can be used in electronic devices operated at negative air temperatures. Operation of such a system makes it possible to use cheap electronic components designed for application in the temperature range of 0...+70 °C in the development of the device. An additional function of the thermostat is to ensure that the main device can be started only when positive temperatures are reached inside its housing. [ABSTRACT FROM AUTHOR]

In this paper effect of condenser inlet air temperature on actual cop is evaluated. Pure R134a is used initially, its performance is compared with mixing of nano particles. The temperature differential between the condensing refrigerant and the ambient air diminishes as the CIAT increases. This lowers the condenser's heat rejection rate, which increases liquid refrigerant buildup in the condenser and, as a result, rises the condenser pressure. The discharge temperature for both the refrigerant is slightly different. At 1600 rpm the discharge temperature of R134a at 37.5◦C is 99C which is 12% higher than nano refrigerant. The discharge temperature of nano refrigerant is always less than pure R134a refrigerant. The power consumption of nano refrigerant R134a+0.1nm at 1600 rpms and at 30◦C is 1008.0 watts which is 10% less than pure R134a refrigerant power consumption. The COP of nano refrigerant of R134a+0.1nm at 30◦C is 2.754 which is 12% higher than pure R134a refrigerant. [ABSTRACT FROM AUTHOR]

Special temperature conditioning systems are widely used to provide a special thermal regime of the payload of space rockets when the rockets are transported to the launch site. Most of these systems use air as the heat transfer medium. This air can flow either inside the payload fairing or between the fairing and a special temporary thermal cover installed on the fairing. However, for the case of ultralight (low payload) space rockets, these systems face difficulties in providing an acceptable temperature gradient under the payload fairing. Due to the relatively short fairing length, the difference between the air temperature in the cooling or heating cycle should be very small. As a result, the efficiency of the system also becomes relatively low. In this paper, an improved scheme of the air conditioning system for ensuring the temperature regime is proposed, which enables significant reduction of the temperature gradient under the payload fairing of the launch vehicle. Also, the proposed scheme enables significant increase of the efficiency of the thermal conditioning system for the payloads of ultralight launch vehicles. [ABSTRACT FROM AUTHOR]

In engineering practice, solving problems of convective-radiative heat transfer is of particular interest. As a rule, problems of this kind still do not have an analytical solution and are solved approximately, approaches based on numerical modeling techniques are often used. Considering the construction industry, it is worth noting that this class of tasks is of particular importance. Thermal panels are widely used in water heating and cooling systems (convectors, radiators, ceiling panels, floor panels). The most widely used plates belonging to the "convector" type, consisting of a set of a certain number of plates connected to each other by a pipeline with a heat or cold carrier circulating inside. In this regard, thermal panels are quite complex objects from the point of view of mathematical description. Such system is crucial in many heating, ventilation and air conditioning systems, including air conditioners, chillers, fan coils, heating equipment, etc. In this paper, for the first time, a mathematical model of a stationary temperature field in a rectangular plate with an arbitrary distribution of heat sources was developed, taking into account convective-radiative heat exchange with the external environment. The analytical model was tested on the problem of determining temperature fields in a heating device, for which a numerical solution was also obtained by the finite element method in the ANSYS Mechanical APDL software package. The resulting mathematical model will allow designers to determine the output integral parameters of the heating system necessary to ensure comfortable conditions for people to stay in heated rooms. [ABSTRACT FROM AUTHOR]

Green roofs have experienced an exponential interest for research in the past few decades in our attempts to attenuate the energy requirements of buildings to keep the interiors cool and comfortable. This review work is divided in two parts; the basic introduction of green roofs and evapotranspiration in them. This paper also intends to highlight the deficiency in research work with a perspective of India's climate and local vegetation. All major studies before are performed outside India in accordance with foreign climate and with the respective local vegetation. More studies need to be performed in India with its local vegetation taken into account. Another aspect pertaining to the modern cities' increased need for air conditioning is the effect of Urban Heat Islands (UHI). Utilizing the concept of green roofs is an excellent method to decrease the cooling required in the buildings by reducing the amount of heat absorbed by the surface of the buildings. Most of the benefits of GRs are mainly due to the cooling effect by Evapotranspiration (ET) which is basically evaporation (of water) and transpiration (a process carried out by plants). ET contributes towards the humidification process of the external ambient air. It reduces the surface temperature of the roof and helps to mitigate the urban heat island phenomenon. This review makes an attempt to bring research in Green Roofs as a major research field in India. [ABSTRACT FROM AUTHOR]

Advances in sensor technology have made the bridge security supervising system automated in real-time. Many long-span bridges in Korea and Japan have implemented this system of real-time security surveillance. In this, a new concept is implemented in the bridge security supervising system. TCP/IP wireless network is tested for a short distance (among bridge sensors) and CDMA is tested for long-distance (between bridge and management center) data communication. (3) A dynamic database which stores bridge condition data; (4) a cloud-based system that monitors and evaluates transmitted information from the control systems. This system consists of: (1) Bridge environmental control system installed; (2) Bridges management system connecting cloud-based communication systems as well as cloud-based servers. This technology monitors as well as monitors in real time the circumstances of a bridge as well as its environment, including local water flows, pipelines, air conditioning, as well as other safety conditions. For the real-time supervision of the bridge situations the data and images observed are transmitted to the server via cellular telecommunication systems as well as the database. [ABSTRACT FROM AUTHOR]

In this paper, a Self-learning Artificial Neural Network (ANN) controller has been implemented for Heating, Ventilation and Air-Conditioning (HVAC) system, which has solved the issues of stability and efficiency observed in traditional systems. Though the traditional systems like Proportional, Integral and Derivative Controller (PID), On-Off controllers etc are in use, they fail to provide the intelligence and causes mathematical complexities in implementation. They consume more time to reach the high level of stability, large energy consumption and create oscillations and peak overshoots. This paper, spotlights on scheming the air conditioning system using Self-learning ANN based intelligent controller. It derives its inputs from the user and predicts the speed of the fan and water flow to achieve comfort at minimum energy consumption and least settling time. The kind of practice investigated here, is valid to a wide variety of non-linear control problems. The Back Propagation (BP) algorithm has been applied in the neural topology. The Self Learning ANN controller has been compared with PID controller and the outputs have been shown in MATLAB Simulink. A real time hardware has been implemented for the HVAC system through the Self Learning ANN controller topology and has been compared with the PID controller. [ABSTRACT FROM AUTHOR]

In this paper, experimental and analytical studies of the energy consumption of rolling stocks in real operational conditions have been carried out. The Human factor, which significantly affects the consumption and recuperation of electrical energy, is minimized, as well as the influence of the railway profile. The measurements provide data on the energy consumption and on the total energy recuperated to the traction grid. The main indicators used in the analysis of the energy consumption have been calculated: relative operating energy consumption for acceleration and traction, relative energy recuperated to the traction grid during regenerative braking and relative net energy consumption. A comparative analysis of the energy indicators in terms of energy consumption with on and off air conditioning systems of the studied trains has been done. Digitization of the results has been made by two approaches – depending on the time range (peak, off-peak and night schedule) and the specifics of the route (the distance traveled). Recommendations have been done in various aspects in order to increase the efficiency of transport and optimize energy consumption. [ABSTRACT FROM AUTHOR]

One of the oldest techniques used by men to cool their homes was evaporative cooling. It has only recently been placed on a stable thermodynamic foundation. Different from conventional air conditioning systems that employ vapor-compression or absorption refrigeration cycles is evaporative cooling. Evaporative cooling offers comfort by filtering and circulating the cooled air; it does not perform all the duties of genuine air conditioning. In this paper we tried to synchronize the discharge water with fan speed, using the fine coconut coir as a cooling pad material, design and fabrication of the air cooler in order to dismantle it into parts for easy carrying and maintenance purposes. The efficiency of the fabricated air cooler has been improved compared with the existing air cooler. The detailed mechanism and working principle of the air cooler has been discussed in the following sections. [ABSTRACT FROM AUTHOR]

The paper presents an analysis linked to sustainable energy alternatives in terms of the use of refrigerants in air conditioning equipment, with the aim of achieving compliance with the energy agreements that will allow avoiding and reducing the risk of pollutant emissions into the atmosphere, saving energy, and contributing to more efficient methods in this equipment. A bibliographical analysis was carried out to contextualize the research, in addition to the experimental method through systematic observation in the reconversion processes, in this context, measurements of the experimentation carried out were taken, in addition to carrying out different tests to obtain the desired results. The conversion processes were evaluated as an alternative to the substitution of R-22, through the use of R-290, which resulted in a decrease in condensation pressure between 4 and 6%, a decrease in pressure drops between 13 to 19% in the condenser, and between 24 and 43% in the evaporator, contributing to a 6 to 10% decrease in the demanded power, directly affecting the energy consumption of the equipment, resulting in a decrease of the cooling capacity between 5 and 8%, this being insignificant for premises with commercial and domestic use. [ABSTRACT FROM AUTHOR]

Occupancy detection is critical during building operations, particularly in energy efficiency, space utility, heating, ventilation control, and air conditioning (HVAC) to optimize user comfort. However, applying occupancy sensors to detect occupants can violate a person's privacy, and the resulting data could be more precise. Therefore, this study aims to detect occupancy through environmental sensors by utilizing the accuracy of machine learning-based classification results. The ultimate goal of this study is to detect whether there are people in a room based on the benchmarks studied. Benchmarks for classifying whether people are in a room include CO2, humidity, lighting, temperature, and occupancy. This paper presents a method for comparing and evaluating a set of different machine learning techniques based on a given performance measure (for example, precision, accuracy, f1 score, and algorithm recall) and then using the algorithm with the best performance. This study uses five machine learning classification algorithms: K-Nearest Neighbors, Support Vector Machine, Decision Tree, Naive Bayes and Random Forest, and the method used to evaluate the results is cross-validation. Experiments were conducted using occupancy detection datasets from the UCI Machine Learning Repository. After performing the experiment, the predictive results of the five algorithms are high. That is, each has an accuracy value of more than 90%. Support Vector Machine has the highest accuracy value compared to other algorithms, namely 98.5%, and Decision Tree has the lowest accuracy value, namely 91.9%. The results show that selecting the right features and the suitable classification model can significantly impact prediction accuracy. [ABSTRACT FROM AUTHOR]

A performance analysis of a solar photo voltaic system based cascade refrigeration system is conducted in this paper using engineering equation solver simulation software. Solar-electric set up is considered for the analysis of the system. Different refrigerant pairs have been chosen for analyzing the cascade vapour compression refrigeration system. Coefficient of performance (COP) and refrigerating effect values are evaluated and characteristic curves are plotted with the variation in hourly global irradiance data of Visakhapatnam, Andhra Pradesh, India. The effect of variation in hourly irradiance values in the month of April has been studied here. With the aim of lower environmental degradation, refrigerants with low GWP values are considered for this study. Also the evaporating temperature of the lower refrigerating unit on the COP has been varied and possible effects have been noted on the parameters. Highest COP was obtained by R744-R600 pair with a value of 0.6754 at 12pm, at -10°C as the evaporating temperature. The overall highest COP was obtained by R744-R600, when the evaporating temperature is 5°C. The result shows that proposed system is definitely a good alternate choice for fulfilling air conditioning expectations of human beings and for promoting healthy environment. [ABSTRACT FROM AUTHOR]

Vapor compression refrigeration system is commonly used for air-conditioning and refrigeration. It is also used in domestic & commercial refrigerators and cold storage applications. Industrial sectors like refinery, petrochemical, chemical, pharma & pulp also benefit from it. The refrigeration system cools the process fluids to the desired temperature. The most commonly used process fluids are water, air, and brines. Irrespective of size and application of the system, all of them operate on common thermodynamic cycle called 'Vapor compression refrigeration cycle'. Oil is used in compressors of refrigeration systems for lubrication, sealing, cooling, reducing pressure pulsations (leading to silencing effect) and for auxiliary functions like capacity control in screw compressors. Oil gets mixed with refrigerant and is discharged out from the compressor along with refrigerant at high pressure & temperature. Oil, if not separated from the discharge gas, can deteriorate heat transfer in heat exchangers in the refrigeration system. In extreme cases, if oil does not return back to compressor then compressor damage can happen. Therefore, separation of oil from refrigerant before the condenser is important. In this paper the conditions when oil separators are necessary in refrigeration systems are discussed. The paper presents a review of variety oil separation technologies used in different types of refrigeration systems. These technologies are based on fluid flow mechanisms involving velocity reduction, change of direction, gravity settling, centrifugal motion, demister pad, impingement separation and coalescing separation. Every technology has unique advantages and limitations. Construction and operation of commonly used oil separators, employing different technologies for oil separation are explained. Though article focuses on refrigeration systems, the concepts discussed are also applicable to any oil-gas separation systems [ABSTRACT FROM AUTHOR]

This paper investigates the implementation of heat pipe in the air conditioning system, specifically in an air circulating room. The use of air conditioning system in an air circulating room may increase the cooling load of the evaporator. In this experiment, the heat pipe is utilized for reducing the inlet air temperature in order to reduce the cooling load of the evaporator. Thermal analysis of the Heat Pipe Air Conditioning System (HPAC) is conducted with variation of vertically-installed adiabatic and initial air cabin temperature of 30°C with Air Conditioner (AC) setting temperature of 20°C; 18°C; 16°C. The thermal analysis is then compared with the HPAC without the adiabatic. The result shows that the utilization of vertically-installed adiabatic in the heat pipe of the HPAC decreases the inlet air temperature with cooling load of 5,981 kW; 6,978 kW; 7,477 kW, respectively to the AC setting temperature, compared to the HPAC without adiabatic with the result of 6,48 kW; 7,477 kW; 8,474 kW. The HPAC with vertically-installed adiabatic shows a lower energy use within the range of 29,1% – 37,7% for the AC compressor and 16,6% – 23% according to the cooling rate. The results indicate that the implementation of heat pipe with vertically adiabatic in the air conditioning system in a circulating room is more effective compared to without using the adiabatic. [ABSTRACT FROM AUTHOR]

The development of electric railway train has been growing rapidly in the last few years. Comfort is one of the important aspects in electric railway cabin, including the acoustic comfort. İn this paper, noise reduction efforts for air conditioning system of electric railway trains are discussed. Air-borne noise and structure-borne noise are considered while finite element analysis is used to study the contribution of each path to the total sound pressure level found in the passenger area. The air-borne noise control is realized by using the acoustic liner on the internal wall of the ducting where fibrous porous absorbers are used. This approach decreases the sound pressure level as much as 29.3 dB. Meanwhile, the structure-borne noise is reduced by placing a set of a parallel stiffener at the ducting wall. This approach can reduce the sound pressure level up to 28.9 dB at low-frequency range. Combining both of the acoustic liner and stiffener altogether can reduce the sound pressure level up to 37.1 dB by which the overall sound pressure level at passenger area is around 51.2 dBA. [ABSTRACT FROM AUTHOR]

Following the energy strategy until 2035 of the Russian Federation, obsolete generation facilities are replaced with new promising combined-cycle power units with higher energy efficiency indicators. The difficulties of operating combined-cycle power units, particularly gas turbine units, are primarily related to the working fluid preparation quality. This article discusses the elaborate practice of the air supplied to the compressor, including its cooling and filtration. The paper presents an engineering solution for the technical re-equipment of an integrated air purifier by installing panels for the air's evaporative cooling. The porous structure of the panel material also allows for air filtration. The article presents the dependence of the power of a gas turbine installation on the temperature of the outdoor air in the climatic conditions of the Republic of Tatarstan (Russia). The economic effect of introducing the proposed technology is calculated, which is associated with eliminating lost profits from the under-development of electric energy and the quality of preparation of the working fluid for a gas turbine installation. [ABSTRACT FROM AUTHOR]

Non-standard situations in monitoring systems are associated with changes in time series describing the parameters of the monitored system. A grid cluster for processing physical data is a complex system that includes various physical equipment - air conditioning systems, uninterruptible power supplies, computing servers and data storage systems. To control the operation of such systems, it is important to monitor the condition of the equipment and detect hardware malfunctions in time. The paper presents the main results on the development of software for searching for anomalies in the operation of the computing cluster equipment, as well as on the determination of the optimal parameters for it to prevent false alarms. The architecture of such a system includes an indexing cluster (a cluster of nodes that receives data), nodes for storing real data, and a search cluster for performing searches on stored data. The system allows you to automatically find shift anomalies in time series, combine the found anomalies into a JSON data array for subsequent sending to Elasticsearch. As a result, the system can reduce the time it takes to perform daily operations for analyzing time series for anomalies. When developing the system, the following software products were used: RStudio, Elasticsearch, Kibana. [ABSTRACT FROM AUTHOR]

In the cooling industry, micro-channel heat sinks are regarded a revolutionary technology since they allow for the evacuation of a great quantity of heat through a little space. As a viable alternative to the traditional method of heat exch ange that relies on conventional finned tube heat exchangers, micro-channel heat exchangers have swept the world by storm, owing to the numerous advantages they provide. Micro-channel heat exchangers are now employed in automotive, air conditioning, and refrigeration sectors. Thermally conductive heat sinks like silicon or copper have micro-channels carved into their surfaces. Coolant is forced to flow via a large number of parallel micro-channels that are generally present on the cooling surface in order to remove heat from a heated surface. When compared to the qualities of a base fluid, nano-fluids have the potential to increase the thermal conductivity and convective properties of the base fluid. This paper introduces the principle of heat transfer enhancement of micro-channels and reviews some of the experimental, numerical and analytical works done by researchers on this technique in recent years, also it focuses on the various methods or geometries used to produce laminar flow and its eff ect on the heat transfer rate. [ABSTRACT FROM AUTHOR]

Nowadays, solar powered air conditioning machines have made increasing progress as air conditioning systems are almost a must in every building in Indonesia. Indonesia is a tropical area that can receive sunlight all year round. This study examines the design and performance of a solar-powered air conditioning system that is integrated with a photovoltaic (PV) system consisting of PV panels, solar chargers, DC power controllers/inverters and batteries. This air conditioning system can be used in non-electrical areas. The first step in this research is the calculation of the cooling load for the space to be conditioned and obtained about 1 ton of refrigeration (3.52 kW). Based on this cooling load, a photovoltaic (PV) system has been estimated and constructed with the necessary connections. Data logging systems have been used to measure the temperature of the main components in the cycle such as the compressor inlet and outlet as well as the evaporator and condenser. The input power for the system as well as the coefficient of performance (COP) for the system under Indonesian climatic conditions are measured throughout the day. The coefficient of performance varies from 2.9 to 8.5 for the system and this result is compared with the performance of the conventional system. [ABSTRACT FROM AUTHOR]

As social requirement of power supply reliability keeps rising, distribution network working with power uninterrupted has been widely carried out, while the high - temperature operating environment in summer can easily lead to physical discomfort for the operators, and then lead to safety incidents. Aiming at above problem, air-conditioning suit for distribution network working with power uninterrupted has been putted forward in this paper, and the structure composition and cooling principle of which has been explained, and it has been ultimately put to on-site application. The results showed that, cooling effect of air-conditioning suits was remarkable, and improved the working environment for the operators effectively, which is of great significance to improve Chinese level of working with power uninterrupted, reduce the probability of accidents and enhance the reliability of power supply. [ABSTRACT FROM AUTHOR]

This paper presents the comparative experimental results of an automotive air conditioning (AAC) system charged with refrigerants R1234yf and R134a which were analyzed to find the effect of increasing ambient temperature using energy and exergy-based approaches. The urgencies for such investigation are due to the demand of finding refrigerant both satisfy the performance and also compatible with Kyoto Protocol and EU f-gas regulation. For this aim, a bench-top experimental AAC system was constructed and tested at four different compressor speeds, namely 1000, 1500, 2000, and 2500 rpm. For each compressor speed, the temperatures of the air streams at the inlets of the inside duct was 30 °C and varies the outside duct, i.e. Tcond,ai, of 30, 35, and 40°C. It was revealed that the AAC system with R1234yf yield comparative performances shown by the higher mass flow rate, comparably less cooling capacity and COP than that of with R134a. The mass flow rates and power absorbed in the compressor get higher as Tcond,ai increase. The biggest contributor to the total exergy destruction of the system is always the compressor and the heat exchangers, i.e. evaporator and condenser, respectively. Thus, in order to improve the system performance, those components should be enhanced. [ABSTRACT FROM AUTHOR]

Residential air conditioning (AC) systems commonly use R-410A refrigerant for the new systems. The R-410A refrigerant has high global warming potential (GWP 100 years) of 2100 and it is not environmentally friendly. Moreover, energy consumption of AC systems also indirectly contributes to the GWP. Thus, energy performance of AC system becomes important. This paper aims to investigate seasonal energy performance of residential AC system using R-32 as refrigerant. R-32 has much lower impact to the environment compared to R-410A. The investigation applied a thermodynamic simulation using EES (Engineering Equation Solver) distributable program. The energy performances of the AC system were evaluated in one year based on Bali-Indonesia weather conditions. The performance evaluations include power and energy consumption, coefficient of performance, and seasonal energy efficiency ratio (SEER). For comparison analysis, the investigation was also performed on AC system using R-410A. The results indicated that the AC system using R-32 could provide better seasonal energy performance than a such system using R-410A. Therefore, R-32 becomes supplementary promising refrigerant for residential applications. [ABSTRACT FROM AUTHOR]

The paper describes the development of a digital model of the cooler to calculate in advance the technical characteristics of refrigerating units. The simulation method is used to compare and present the measurement and calculation results through the simulation model. The mathematical model of refrigerating units has been studied and improved. It was concluded that technical characteristics of refrigerating equipment can be specified by means of computational methods. The model developed can be used during the energy audits of enterprises by the experts. [ABSTRACT FROM AUTHOR]

This paper deals with the improving performance of air conditioning system by reducing the compressor work. The copper tube with the cold-water supply reduces the temperature of the compressor and water is sprayed on the condenser coil. This reduces the temperature of condenser coil because specific heat capacity of water is 4.187kJ/kg, it is higher than that of air (0.718kJ/kg). Therefore, heat rejection can be carried out by both air and water. Spraying the water on the condenser coil also helps in cleaning its surface from the dust. When the temperature of condensing coil is reduced the work done by the compressor is also reduced. This reduction of heat is achieved by circulating the condensed water from the indoor system of an air conditioner. The waste water from the evaporator is used to cool the condenser; due to this additional cost for coolant is eliminated. The condensed water will have the temperature below the room temperature. So, the heat rejection can take place at faster rate. The compressor is prevented from overheating and other failure due to heat. There is continuous generation of water from the indoor unit, hence the cooling happened continuously. [ABSTRACT FROM AUTHOR]

In day to day life, global warming is the major challenge for survival. Nowadays lots of new inventions are produced with the output of waste hot gases. This waste hot gases can be reused means the global warming produced in the world is under control. In order to control the global warming thermo electric generator can be used. Thermoelectric generator is an eco friendly equipment and to produce the electric power by using the temperature difference. In this thermoelectric generator there are two junctions are available, one side is known as hot side and the other side is known as cold side. For this hot junction, hot gases from exhaust pipe is used and for cold junction condensate water from the air conditioning unit can be used. The main aim of this paper is to reuse the hot gases and condensate water and by using this above source to generate electrical power and at the same time the heat liberation is reduced and the global warming can be controlled with the limited amount. [ABSTRACT FROM AUTHOR]

It is undeniable that the world's climate conditions are experiencing a significant quality decrease where the air around our homes, including Jakarta, are not feasible anymore where there are a lot of dangerous Particulate Matter 2.5 in the air that we breathe daily. Not only the air condition, the high demand for processed petroleum such as gasoline and diesel causes Indonesia to import where in 2018 there are 393,000 barrels per day. Of course, the budget spent to meet the fuel needs is not small, and will not decrease for the next few years, given that Indonesia's petroleum stock has also decreased. Based on these problems, Universitas Indonesia is committed to build an environmentally friendly transportation, called Electric Bus. This Electric Bus has prime mover in the form of a 3 phase induction motor. Author on this paper is doing the research to build an electric motor design used on The Bus, so that the motor can produce performance in accordance to the design specifications that is 100 kW, where three motors will be combined to produce 300 kW of power with 1200 Nm of torque. This research focuses on motor construction, as well as the selection of materials where the material used is from Indonesia so that all components of the motor are originally made in Indonesia, with the best quality and specifications. This design has been successfully made resulting a weight of 298 kg and dimensions of 630 mm x 470 mm. The results of this research are expected to be able to electrify The Yellow Buses at Universitas Indonesia. [ABSTRACT FROM AUTHOR]

The performance of air-handling systems in buildings needs to be improved. Many of the deficiencies result from myths and lore and a lack of understanding about the non-linear physical principles embedded in the associated technologies. By incorporating these principles, a few important efforts related to diagnostics and controls have already begun to solve some of the problems. This paper illustrates three novel solutions: one rapidly assesses duct leakage, the second configures ad hoc duct-static-pressure reset strategies, and the third identifies useful intermittent ventilation strategies. By highlighting these efforts, this paper seeks to stimulate new research and technology developments that could further improve air-handling systems. [ABSTRACT FROM AUTHOR]

During the repeated braking, it will generate high amount of heat on the braking disc and braking pads. The value of the generated heat depends on many factors such as the vehicle speed, materials properties, disc brake construction, as well as the number of braking cycles. The aim of this paper is to investigate the effect of repeated braking on the temperature distribution of the braking pads and disc. It was performed the experimental approach under the laboratory conditions without air flow. It was found that the temperatures of disc and pads increase significantly with each new cycle of braking. It was found that magnitude of the friction coefficient has great influence to reduce the braking distance. The obtained experimental results can be applied in the design and manufacture the brake system of the automotive vehicles based on the safety factor of passengers. In the other words, keep the heat generation within the limit. [ABSTRACT FROM AUTHOR]

This paper presents the performance of a solar hybrid desiccant air-conditioning system that was tested in a humid and hot weather of Malaysia. The system is consisted of a desiccant wheel, a solar thermal collector, a vapour compression refrigeration cycle and a heat pipes heat exchanger. In this system, the latent heat load of supply air was removed by a silica-gel desiccant wheel which was regenerated by a 31.5 m² evacuated tube solar collector assisted by an auxiliary heater. The sensible heat load was removed by pre-cooled the supply air using vertical heat pipes (act as a heat recovery system) before the air temperature is further reduced by a cooling coil connected to a conventional vapour compression cycle. Through the test, the supply and exhaust (regeneration) mass flow rate of air were maintained at 450 m³/hr. The Coefficient of Performance (COP), effectiveness of desiccant wheel and heat pipe were 1.42, 0.61 and 0.54, respectively. Reduction in energy consumption was estimated at 62% relative to a system without a desiccant wheel and heat pipe heat exchanger. It can be concluded that this system can provide supply air at a temperature of 23.4 °C and specific humidity of 0.011 (kg/kg) with a significantly less energy consumption in a hot and humid weather of Malaysia. [ABSTRACT FROM AUTHOR]

Over the last century, fresh water and cooling demand have been increased tremendously due to improved living standard, industrial and economic development. The conventional air-conditioning and refrigeration processes consume 15% of total global electricity and it is expected to increase any fold due to harsh weather conditions. In terms of fresh water supplies, the current 38 billion m3 per year desalination capacity is projected to increase to 54 billion m3 per year by 2030, 40% more compared to 2016. The current business as usual trend of cooling and desalination is not sustainable due to high energy consumption and CO2 emissions. In contrast, the adsorption (AD) cycle operate at low-grade waste heat or renewable energy and produce fresh water and cooling simultaneously. The major bottleneck of conventional thermally driven AD cycle is its large foot print and capital cost due to complex packed bed arrangements. We proposed pressure swing adsorption cycle (PSAD) that can utilize low-pressure steam (2-5 bar) for regeneration using thermal vapor compressor (TVC). The proposed system has best thermodynamic synergy with CCGT plants where low-pressure bleed steam can be utilized more efficiently to produce cooling and water. In this paper, a preliminary experimental investigation on PSAD has been presented. It is successfully demonstrated that 2 bar primary steam can regenerate silica gel at less then 0.5 kPa through TVC with compression ratio 3-4 and entrainment ratio around 1-1.5. The discharge steam can be re-utilized to operate the desalination cycle, maximizing the bleed steam exergy. The proposed system will not only reduce footprint but also CAPEX and OPEX due to simple design and operation. [ABSTRACT FROM AUTHOR]

There is a common misconception that all central systems are only operating in full-load conditions where in fact, most central systems are have the control system that can adjust the operating condition with the cooling loads. Customers tend to choose the air conditioning systems based only on full-load ratings despite a system may have different ratings on different load profiles. These differences can result in more expensive annual energy cost. The goal of this research is to develop an equation to provide customers with the part-load efficiency ratings of central air conditioning system (chiller) as an addition to full-load efficiency ratings provided by air conditioner companies. Non-standard Part Load Value (NPLV) is an equation to obtain part-load efficiency of a system which coefficients vary with location of interest. In this paper, NPLV for city of Jakarta, Bandung, Pontianak, Kupang, and Palembang were determined by Degree-Hours Method and Radiant Time Series Method. The results are compared and discussed. [ABSTRACT FROM AUTHOR]

Demand of high performance heat exchanger in industrial application is increasing since the depletion of energy resources such as in food processing plant, air-conditioning system and power plant. One of the ways of saving energy is by enhancing heat transfer performance, which in return will give a high performance heat exchanger. Existing enhancing techniques can be classified into three different categories which are active method, passive method and compound method. Spirally corrugated tube is one of the passive heat transfer enhancement method which involve surface extensions. The type of surface extension used in heat transfer performance will contribute to heat transfer coefficient and pressure drop, and directly affected the heat transfer performance. Traditionally, experimental studies were carried out to get the desired results but with the help of technology, numerical simulation is one of the promising alternatives in predicting reliable results for real application. For reliable numerical results, experimental studies are still necessary for the validation process and the verification process which comes before it is also mandatory. Thus, this paper focus on verification the numerical simulation of flow in a double-pipe heat exchanger with spirally corrugated internal tube. It was done for laminar flow with Reynolds number of 1000. Numerical simulation model using commercial CFD software were run with different mesh sizes to determine the grid independent solution and to choose which mesh is suitable to use for the whole simulation process. Minimizing and choosing the right mesh were done through Grid Convergence Index (GCI). Solutions of three different grids with their residuals convergence are also presented to fulfil the verification steps. The level of grid independence is evaluated using a form of Richardson extrapolation and the study shows that the finest grid solution has a GCI of less than 5%. [ABSTRACT FROM AUTHOR]

Compact heat exchangers are commonly used for many refrigerating and air-conditioning applications due to features like high performance and less space consumption. The objective of this paper is to provide an overview of the salient features of tube-fin and plate-fin compact heat exchangers and hint at conditions when to select either of them as per the application demand. A sample air-conditioning unit of heat capacity 2.63kW is used to perform an experiment in order to collect 40 sample readings. These readings are used to develop the system's Pressure-Enthalpy chart to calculate the condensing heat load, and then only the condenser is redesigned from tube-fin to plate-fin configuration. The final result in terms of the sizes and weights of both the condensers are compared and the conclusion is derived. The pressure loss in the tube-fin condenser is determined using Lockhart-Martinelli and Geary's equations, which are validated against a renowned air-cooler design software- Unilab Coils. During the design of the new proposed plate-fin condenser, suitable correlations are used to find the heat transfer and pressure loss coefficients. These coefficient values are also verified against another popular software named Aspen EDR which falls within an acceptable range. The results of this comparative study could not be generalized, as it requires more investigation to be conducted over wide heat load capacities, however, it proves salient features of studied heat exchanger types. It also improves the decision-making capability of thermal engineers or related field practitioners on the type of selection of exchangers for certain applications. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation on the system performance of a residential air conditioner using condensate as a compressor discharge cooler. The condensate is water produced by the evaporator surfaces. The use of condensate is to reduce the energy consumption and improve the performance of the air conditioning system. The experimental investigation has been carried out on a split-type air conditioner with cooling capacity of 2.5 kW. The utilization of condensate as a discharge cooler decreased the compressor discharge pressure and consequently, reduced the compressor power consumption by 6.3%. In addition, the effect of the decrease in the compressor discharge pressure resulted in the decrement in the temperature of condenser outlet by 2.2°C. The decrease in temperature of condenser oulet leads to the increment in the subcooling and increases in the cooling capacity. [ABSTRACT FROM AUTHOR]

The paper is concerned with the analysis of the two dimensional model of incompressible, viscous, stationary flow through a radial blade machine. This type of turbine is sometimes called Kaplan’s turbine. In the technical area the use is either to force some regular characteristic to the flow of the medium going through the turbine (flow of melted iron, air conditioning) or to gain some energy from the flowing medium (water). The inflow and outflow part of boundary are in general a concentric circles. The larger one represents an inflow part of boundary the smaller one the outflow part of boundary. Between them are regularly spaced the blades of the machine. We study the existence of the weak solution in the case of nonlinear boundary condition of the “do-nothing” type. The model is interesting for study the behavior of the flow when the boundary is formed by mutually disjoint and separated parts. [ABSTRACT FROM AUTHOR]

The Adsorption heat pump is a technology for cooling and heating by using hot water as a driving heat source. It will largely contribute to energy savings when it is driven by solar thermal energy or waste heat. The system is available in the market worldwide, and there are many examples of application to heat recovery in factories and to solar cooling systems. In the present system, silica gel and zeolite are popular adsorbents in combination with water refrigerant. Our study focused on activated carbon-ethanol pair for adsorption cooling system because of the potential to compete with conventional systems in terms of coefficient of performance. In addition, activated-ethanol pair can generally produce larger cooling effect by an adsorption-desorption cycle compared with that of the conventional pairs in terms of cooling effect per unit adsorbent mass. After the potential of a commercially available activated carbon with highest level specific surface area was evaluated, we developed a new activated carbon that has the optimum pore characteristics for the purpose of solar or waste heat driven cooling systems. In this paper, comparison of refrigerants for adsorption heat pump application is presented, and a newly developed activated carbon for ethanol adsorption heat pump is introduced. [ABSTRACT FROM AUTHOR]

A building is an assemblage that is firmly attached to the ground and provides the performance of human activities and need to be considered in the daily operation in that building. The improvements in building performance are focused on improving the energy efficiency of buildings. This is approach by designing heating, ventilation and air conditioning (HVAC) duct system due to one of the most utilized energy in maintaining building performance and environment. The objectives of this research is to calculate the air (CFM) supply in office building, to characterize the velocity and head loss in a round and rectangular HVAC ducting system at various duct thickness and to optimize the thickness of the duct in HVAC system according to ASHRAE Standard. The increasing of velocity in duct system shows the increasing of head loss. The round duct design gives the lowest velocity and head loss in HVAC system approximately around 9.35% as compared to rectangular duct at 0.06 inches thickness. Hence, the trends of the head loss and duct thickness has influenced in reducing noise in HVAC duct system in order to select the best design concepts which is round shape design. [ABSTRACT FROM AUTHOR]