Design Of Air Conditioning System Research Articles

A review of the effect of climate change on malaysia's air conditioning system and dependability

The results of research on the impact of climate change on air conditioner performance and dependability in the tropics are presented in this article. The effect was primarily concentrated on three aspects: cooling or heating load, energy usage, and outside design conditions for the air conditioning system. The relevant articles were divided into three categories, and theoretical and experimental investigations were analyzed. Since the last few decades, many studies have been conducted on the effects of climate change on air conditioners in the tropics, but most of them have focused on current cooling as well as heating demands, regional overall electricity consumption, as well as existing outdoor design requirements for the air conditioning system rather than the potential impacts on heating, ventilation, as well as air conditioning systems. Based on the literature review, more extensive research is required to gain a clearer picture of the climate variation effects on air conditioning systems, so that a comprehensive guideline for future air conditioning system design in the tropics that takes into account possible climate change can be prepared.

Numerical study on indoor environment and thermal comfort in train station waiting hall with two different air-conditioning modes

With the increasing size of the waiting hall, the large-area use of transparent envelope materials makes the interior surface temperature of the envelope too high, which puts forward higher requirements for the control of environment and thermal comfort indoors. In this paper, the characteristics of indoor temperature distribution, relative humidity distribution and thermal comfort under the all air system (AAs) and the radiant floor cooling and wall cooling combined with air supply system (RC/ASs) were investigated in the large spaces. The computational fluid dynamics (CFD) method was used, and the performance of the CFD model was validated by comparing the measured results with CFD simulation results in the AAs. The numerical results clearly showed that the temperature and relative humidity indoors could satisfy the design requirement both in the AAs and RC/ASs. The indoor air distribution in most areas under the RC/ASs was more uniform based on the indoor heat and humidity requirements under the cooling load of measured day. In the AAs, the total cooling capacity of air conditioning unit was the highest when indoor thermal comfort was the best, that meant that to achieve the best working condition, the air-conditioning system need high energy consumption. Meanwhile, the RC/ASs addressed the problem that the temperature around the seated passengers in the waiting area was relatively high in the AAs. This paper will provide reference for the air conditioning system design in the similar large spaces in the future.

Design and performance analysis of a thermoelectric air-conditioning system driven by solar photovoltaic panels

Solar cooling technologies can play a vital role in renewable energy applications development. Thermoelectric systems have shown promising advantages over traditional refrigeration systems such as high thermal comfort, active adaptability, no moving parts, and refrigerants free. In this work, a novel thermoelectric air-conditioning system (TEACS) driven by photovoltaics (PV) is experimentally and theoretically investigated under the hot climate conditions of Sohag city (30°26′N, 42°31′E), Egypt for air conditioning of a typical small-size office room under different thermal loads. During day time, PV panels produce electricity which utilized to drive the TEACS directly and to charge batteries that store electricity to be exploited during nighttime. Moreover, a numerical model implemented in TRNSYS coupled with MATLAB software is developed to evaluate the performance of the proposed TEACS. The influences of varying the input electric current on the coefficient of performance (COP), cooling capacity, and average air room temperature are also studied. The results showed that a design point with an input current of 2.5 A for a cooling capacity of 30 W could be selected to maximize the cooling performance, in which the COP of the TEACS is found to be 2.2. Moreover, the daily average air temperature of the conditioned room was found to be 23.5, 25.5, 27.5, 28.5, and 30.5 °C for internal thermal loads of 0.0 W, 65.0 W,130.0 W, 195.0 W, and 260.0 W, respectively, at average air intake temperature of 36 °C, daily average input current of 4.28 A and air volume flow rate of 14.4 m3/h. It can be concluded that the TEACS powered by PV could be considered as a proper alternative to the traditional vapor compression systems.

Local and centralized conditioning systems

This article discusses two main types of air conditioning systems in office buildings: local and centralized systems. Since equipment developers, customers and users have different requirements for the design, installation and operation of air conditioning systems in office buildings, depending on the workload of buildings, location, external conditions, as well as space-planning solutions, air conditioning systems currently come in different types and configurations. Reliable knowledge of classification and the ability to distinguish one system from another is key when choosing the right air conditioning system for the customer. To form a proper understanding of the systems discussed, it is necessary to understand some of the basic terminology and principles of air conditioning systems. These include methods for system design criteria, load calculations (tangible and latent thermal loads, penetration loads, equipment and appliance loads, and air conditioning system requirements).

Chillers of air-conditioning systems: An overview

In tropical and subtropical regions, air-conditioning commonly consumes the most energy in buildings. The chillers used in existing air-conditioning systems are largely based on thermodynamic vapour compression cycle because the cycle is highly effective, efficient and practical. Moreover, the system installation and operation are convenient when grid electricity is available. Popular vapour compression chiller types include air-cooled, water-cooled, seawater-cooled and oil-free chillers. In addition, thermal-driven absorption and adsorption chillers have become available in the market. Viable sources of thermal energy input include fuel combustion, renewable solar energy, waste heat, and so on. This paper provides an overview of different types of chillers and system configurations in terms of mechanisms, characteristics, energy efficiency, environmental performance and costs. The technical information and comparisons should help engineers select the chiller type in air-conditioning system design for achieving high sustainability.

Multi-objective optimization design of green building envelopes and air conditioning systems for energy conservation and CO2 emission reduction

Configurations of the building envelope and the air conditioning system have a considerable effect on annual building energy efficiency. Taiwan government proposed two green building indices, namely the Envelope Energy Load (ENVLOAD) and the Performance of Air Conditioning System (PACS), as energy performance models of building envelopes and air conditioning systems. Relatively few studies, however, have been mainly conducted, using multiobjective optimization design for building envelope and air condition systems, with a goal to treat both the building energy systems and the envelope. Consequently, this study is to make contribution to this related filed by proposing a multi-objective optimal building envelope and air conditioning system energy performance decision model (MOBELM).This model was used to design the optimal configurations of building envelopes and air conditioning systems based on the ENVLOAD and PACS constrictions and the two conflicting objectives. The first refers to the minimal construction cost when the building envelope and air condition system are built. The second is concerned with the minimal CO2 emission when the envelope materials are manufactured and used to form the building envelope. In the case study, the optimized configurations that dominated the original unoptimized design could validate the MOBELM.

Design of heat pump-driven liquid desiccant air conditioning systems for residential building

In this study, two workable designs of a heat-pump-driven liquid desiccant (HPLD) air-conditioning system were proposed for residential buildings. The proposed HPLD systems were designed to work as a multi-functional air-conditioning system without additional equipment which would solve the low practicality due to the large scale and complexity of the conventional liquid-desiccant-assisted air-conditioning system. The critical difference between the two systems is the sump design for containing the desiccant solutions: Case A has a single sump instantly mixing weak and strong solutions, whereas Case B has dual sumps containing weak and strong solutions separately. The thermal load of target space was estimated using TRNSYS 18, and energy performances of both HPLD systems for summer and winter operation modes were analyzed using EES by integrating several established models and theoretical analyses. Owing to decrease in solution cooling and heating loads, the results show that Case B, compared with Case A, saved 28% of energy consumption and improved mean energy-efficiency by 37.5% for summer operation mode, and saved 12% of energy consumption and improved mean energy-efficiency by 4.95% for winter operation mode. In conclusion, Case B has a better application potential for residences in terms of energy performance.

PERANCANGAN SISTEM TATA UDARA PADA RUANG NICU DI LANTAI 3 RUMAH SAKIT “X”

Salah satu upaya untuk mengurangi Hospital-acquired Infections (HAIs, atau yang biasa disebut dengan infeksi nosokomial) pada ruang NICU, adalah dengan merancang sistem tata udara khusus, yang ASHRAE HVAC Design Manual for Hospital and Clinics. Parameter-parameter yang perlu dikondisikan dalam sistem tata udara yaitu suhu, kelembaban udara relatif, tekanan ruangan, kebersihan udara, ventilasi, distribusi udara pada ruangan. Metode perhitungan kapasitas pendinginan yang digunakan dalam penelitian ini adalah dengan menggunakan Cooling Load Temperature Difference (CLTD). Sedangkan metode yang digunakan dalam merancang saluran distribusi udara adalah metode Equal Friction Loss. Dari hasil perhitungan, didapat kapasitas pendinginan yang dihasilkan oleh ruang NICU adalah sebesar 8,803 kW. Sedangkan kapasitas pemanasannya adalah sebesar 3,660 kW. Nilai total pressure loss untuk saluran udara yang dirancang adalah sebesar 44,85 Pa. Filter yang built-in dengan unit AC adalah pre-filter dan medium filter. Sehingga, HEPA filter diletakkan pada ceiling.

Perancangan Sistem Tata Udara Ditinjau dari Aspek Energi dan Biaya pada Bangunan Hotel di Semarang

[Design of air conditioning system based on the energy and costs aspect of hotel buildings in Semarang] Indonesia’s economic growth has been above 5% for the past few years. Tourism industry is one of the sectors that shows a significant progress. The improvement in tourism industry has to be supported with good hospitality industry as well. Air conditioning system is one of the main utilities in a hotel building. The design of the air conditioning system for a hotel building must pay close attention to the thermal comfort factor for the guests, safety factor, and energy and cost efficiency aspect of it. Air conditioning system design consists of cooling load calculation for the hotel, air conditioning system selection, energy and cost calculation using the life cycle cost analysis. The maximum cooling load in this hotel is 3.279 kW. From that cooling load, three alternative systems are being considered, which are the central air conditioning system using chiller machine that has constant flowrate, the central air conditioning system using chiller machine that has variable flowrate, and the split air conditioning system using VRF machine. Energy analysis and life cycle cost analysis for 20 years was performed to be able to decide the best system. From that energy and cost analysis it can be concluded that the second alternative, which is three units of chiller with variable discharge with a capacity of 1,100 kW for each chiller, is the best system for the hotel. This system has an energy consumption intensity value of 118 kWh/m2 per year and total cost of Rp. 87,707,416,390 for a period of 20 years.

Design and Simulation of Air Conditioning System in a Large Auditorium Based on Computational Fluid Dynamics

Air conditioning system is an indispensable part of buildings today. The cost of this system increases with the rise in energy consumption which poses a challenge as well as air distribution in large auditoria. Analysis of results can also be daunting when designing this system. The study focuses on designing an air conditioning system in a large auditorium, applying Computational Fluid Dynamics (CFD) and visualizing the result in a Virtual Reality (VR) environment. The 3-dimensional model of the 520-capacity Technology Lecture Theatre, University of Ibadan, Nigeria was drawn with Autodesk Revit and modified into the geometry applicable for Displacement Ventilation (DV) and Mixed Ventilation (MV) for ease of numerical analysis with ANSYS Fluent. The building model and simulation results were then imported into Unity software for visualization in VR. The DV achieved better thermal comfort and air distribution in the computer simulation. At a supply temperature of 292.15 K, the DV system was able to keep the auditorium temperature at about 296.50 K, while the MV system at a supply temperature of 289.15 K was only able to maintain the temperature at 295.40 K. The temperature profile showed that the lower region where the students were seated was colder in DV compared to MV by at least 3 K. The results were also observed from a convenient position in VR. This study, with the aid of CFD and VR, was able to establish that displacement ventilation design has better air flow, lower energy consumption and is efficient for an air conditioning system in a large auditorium.

Design and Simulation of Air Conditioning System in a Large Auditorium Based on Computational Fluid Dynamics

Air conditioning system is an indispensable part of buildings today. The cost of this system increases with the rise in energy consumption which poses a challenge as well as air distribution in large auditoria. Analysis of results can also be daunting when designing this system. The study focuses on designing an air conditioning system in a large auditorium, applying Computational Fluid Dynamics (CFD) and visualizing the result in a Virtual Reality (VR) environment. The 3-dimensional model of the 520-capacity Technology Lecture Theatre, University of Ibadan, Nigeria was drawn with Autodesk Revit and modified into the geometry applicable for Displacement Ventilation (DV) and Mixed Ventilation (MV) for ease of numerical analysis with ANSYS Fluent. The building model and simulation results were then imported into Unity software for visualization in VR. The DV achieved better thermal comfort and air distribution in the computer simulation. At a supply temperature of 292.15 K, the DV system was able to keep the auditorium temperature at about 296.50 K, while the MV system at a supply temperature of 289.15 K was only able to maintain the temperature at 295.40 K. The temperature profile showed that the lower region where the students were seated was colder in DV compared to MV by at least 3 K. The results were also observed from a convenient position in VR. This study, with the aid of CFD and VR, was able to establish that displacement ventilation design has better air flow, lower energy consumption and is efficient for an air conditioning system in a large auditorium.

Analysis on the Operation of Ice Storage Air Conditioning System in Practical Engineering

Cold storage technology is one of the effective means to alleviate the imbalance of power load during peak and valley period. Based on a practical project, the operation of the ice storage air conditioning system was monitored for 26 days. Temperature, pressure, ice storage and other parameters were recorded. Through the analysis of the operation data and air temperature, it is found that the operation of the ice storage system is stable and consistent with the design condition. But there are still some shortcomings in the operating strategy. This paper provides some suggestions for the design and operation of air conditioning system in future projects.

Energy performance analysis on segmented liquid desiccant air-conditioning system for bus spray-paint booths

A paint booth is the dominant energy consumer in a manufacturing plant. Large amount of conditioned air with accurate temperature and humidity is required in the spray-paint booth to guarantee constant product quality, which implies huge energy consumption for air-conditioning. However, there has been limited research on energy-saving design for air-conditioning systems applied in the spray-paint booth. In this study, a novel segmented liquid desiccant air-conditioning system is proposed for energy conservation in the spray-paint booths of a bus manufacturing plant. A mathematical model is built to simulate the performance of the proposed system during the cooling season. The advantages of the proposed system can be summarized in terms of the following two aspects: first, the segmented and cascaded configuration of the proposed system helps to reduce the cooling load from 2844.4 to 1078.0 kW under basic conditions when compared with the separated configuration; second, the adoption of the liquid desiccant dehumidifier helps to avoid reheating, and a reheating capacity of 630.8 kW in the current operating system could be saved by operating the proposed system under basic conditions. When operating the proposed system, a yearly primary energy saving rate of 40.7% can be achieved, while a yearly running cost saving rate of 35.6% can be achieved in this plant as compared to the current operating system. This study would provide valuable reference for energy-efficient air-conditioning system design for applications in spray-paint booths.

Study on the calculation of unsteady radiant heat transfer load with stratified air distribution based on harmonic reaction method

The stratified air conditioning systems are widely used in large space buildings. Stratified air conditioning load (SACL) is the basis for determining the cooling capacity of air conditioning system, and it is also the key to assess its energy savings of stratified cooling. Calculation of the radiant heat transfer load (RHTL) is the difficult point to determine the SACL. In recent years, there have been many researches on the calculation of SACL. Most of them are steady-state calculation processes, and there are few studies on dynamic calculation processes. Therefore, the RHTL is taken as the research object, a novel calculation method is proposed according to the harmonic reaction method (HRM) and verified by the experiments. Experimental radiant heat transfer load can be received through convection and radiation separating method. The experimental and theoretical values of RHTL were compared and it was found that the theoretical values were in good agreement with experimental values. Therefore, the proposed method can be used to predict the unsteady RHTL accurately. Based on the verified calculation method, the effects of outdoor climatic conditions, building types and stratified heights on RHTL of an actual large space building are analyzed, which will contribute to the design and optimization of stratified air conditioning system for large space buildings.

Revisión general sobre sistemas de acondicionamiento de aire en edificios ecológicos e inteligentes.

The aim of this paper is to present a general bibliographic review about recent scientific papers focused on the design and operation of air conditioning systems in green and smart buildings.The suggested review is developed using tools offered by the Scopus academic research directory, with a defined search criteria. Furthermore, the VOSviewer science bibliometric analysis software has been used. This paper has several reviews of cooling and heating systems existing or under development available for residential buildings (green and smart buildings) and some initiatives and research projects from recent years. The present paper is an academic research guide for engineers, architects, and students interested in designing, constructing and efficiently managing the cooling processes of green and smart buildings. Economic powers characterized by large megacities of countries such as the United States of America, China, Italy, Malaysia, Germany and Australia; Nowadays, increasing energy efficiency and decreasing carbon footprint of current and future buildings, both green and smart is considered more important. The most frequent fields of research in scientific contributions related to the cooling of green buildings are: sustainable development, energy efficiency and the construction industry; while in smart buildings they are: energy efficiency, smart grids, energy management .

Optimization of the Electric Vehicle HVAC Duct System Based on Gradient Method

Our study describes the optimization of the part of heating, ventilation and air conditioning (HVAC) system of an electric car. The geometry of the air duct connected to the heater unit on one side and the dashboard on the other. From the point of view of aerodynamics, it is necessary to change the geometry of the air duct so as to minimize the loss of air pressure and ensure a more uniform flow from the exit holes to improve the efficiency of windshield heating. In order to optimize the initial geometry of the air duct, approach of using gradient methods was applied. According to the results of the study, detailed concept of optimizing the air duct of an electric car is presented. The optimized geometry was tested with the use of methods of computational aerodynamics. Calculations were made as part of the interior model of electric car with the output of temperature fields on the windshield. The results can be applied to the design of heating, ventilation and air conditioning systems of vehicles in a short time.

Design and Thermo-Economic Comparisons of an Absorption Air Conditioning System Based on Parabolic Trough and Evacuated Tube Solar Collectors

Solar absorption cycles for air conditioning systems have recently attracted much attention. They have some important advantages that aid in reducing greenhouse gas emissions. In this work, design and thermo-economic analyses are presented in order to compare between two different collector types (parabolic trough and evacuated tube) by water–lithium bromide absorption systems, and to select the best operating conditions. Generally, the system consists of three major parts. The first part is the solar field for thermal power conversion. The second part is the intermediate cycle, which contains a flashing tank and pumping system. The third part is the water lithium bromide absorption chiller. A case study for a sports arena with 700–800 kW total cooling load is also presented. Results reveal that a parabolic trough collector combined with H2O–LiBr (PTC/H2O–LiBr) gives lower design aspects and minimum rates of hourly costs (USD 5.2/h), while ETC/H2O–LiBr configuration give USD 5.6/h. The H2O–LiBr thermo-economic product cost is USD 0.14/GJ. The cycle coefficient of performance COP was in the range of 0.5 to 0.9.

Design and Thermo-Economic Comparisons of an Absorption Air Conditioning System Based on Parabolic Trough and Evacuated Tube Solar Collectors

Solar absorption cycles for air conditioning systems have recently attracted much attention. They have some important advantages that aid in reducing greenhouse gas emissions. In this work, design and thermo-economic analyses are presented in order to compare between two different collector types (parabolic trough and evacuated tube) by water–lithium bromide absorption systems, and to select the best operating conditions. Generally, the system consists of three major parts. The first part is the solar field for thermal power conversion. The second part is the intermediate cycle, which contains a flashing tank and pumping system. The third part is the water lithium bromide absorption chiller. A case study for a sports arena with 700–800 kW total cooling load is also presented. Results reveal that a parabolic trough collector combined with H2O–LiBr (PTC/H2O–LiBr) gives lower design aspects and minimum rates of hourly costs (USD 5.2/h), while ETC/H2O–LiBr configuration give USD 5.6/h. The H2O–LiBr thermo-economic product cost is USD 0.14/GJ. The cycle coefficient of performance COP was in the range of 0.5 to 0.9.

Feasibility of hybrid renewable heating system application in poultry house: a case study of East Midlands, UK

Abstract Currently, there has been an obvious lack of innovation within poultry houses heating, ventilation and air conditioning (HVAC) system design that deals with both energy efficiency and poultry welfare issues. This paper presents an innovative and renewable heating system for poultry house application to meet the welfare living environment requirement for breeding, to improve the energy efficiency of HVAC system and to decrease fossil fuel consumption and harmful gas emissions. The purpose of this study is to design, develop and test the highly efficient hybrid heating system via an integrated photovoltaic/thermal array with polyethylene heat exchanger coupled to geothermal heat pump system based on the East Midlands’ climate conditions in the UK. The numerical model is established based on finite volume method and solved by using Engineering Equation Solver, and a good agreement with less than 15% difference between the numerical and experimental results is achieved. The results indicate that the annual electrical and thermal output are 11867 kWh and 30245 kWh, respectively, which not only could fulfil the poultry house electrical need, but also can provide ~43.5% electricity demand of the heat pump compressor operating.

Design of Central Air-conditioning Partition Scheduling System Based on WLAN Positioning

A partition scheduling system of central air-conditioning based on Wireless Local Area Network (WLAN) positioning is designed. The system can quickly update the personnel density of the partition by WLAN positioning algorithm, and obtain the actual load by integrating the temperature and humidity and the surrounding partition information. Therefore, the rotating speeds of the fans and water pumps of the air conditioning in this area are automatically adjusted, so as to realize the intelligent scheduling of the air conditioning in different areas based on personnel density. At the same time of regional differentiation, the overall cooperative operation can truly achieve the energy-saving effect of distribution on demand.