Thoroughly revised, this book provides the reader with an understanding of the principles and practices of testing and balancing (TAB) heating, ventilating, and air conditioning (HVAC) air and water ...systems. For the novice and the experienced testing and balancing technician, it is a field reference book of procedures, equations, and information tables.
Divided into five parts, Part I has general and specific balancing procedures for constant air volume systems, variable air volume systems, return air systems, and fans and fan performance. Part II covers testing and balancing fume hood systems and cleanrooms, commissioning HVAC systems, centrifugal pumps and pump performance, analog and digital controls and water balancing procedures using flow meters, system components, and temperatures. Part III covers fans, pumps, air distribution, water distribution, motors, electrical, fluid flow, psychrometrics, refrigeration, and instrument usage and care. Part IV includes equations and tables. New to this edition, Part V has information and additional test and balance procedures and graphics for chapters 1-7 and 13-14. TAB Data and Test forms are in the new addendum as well.
Provides the readers with revised information about the principles and practices of testing and balancing (TAB) heating
Represents a field reference guide for both the novice and experienced testing and balancing technician
Includes a new section with information and additional test and balance procedures and graphics
Air Conditioning System Design summarizes essential theory and then explains how the latest air conditioning technology operates. Load calculations, energy efficiency, and selection of technology are ...all explained in the context of air conditioning as a system, helping the reader fully consider the implications of design decisions. Whether users need to figure out how to apply their mechanical engineering degree to an air conditioning design task or simply want to find out more about air conditioning technology for a research project, this book provides a perfect guide. * Approaches air conditioning as a system, not just a collection of machines * Covers the essential theory on fluid flow and the latest in A/C technology in a very readable and easy-to-use style * Explains the significance of factors, such as climate and thermal comfort as A/C design considerations * Addresses design using a range of air conditioning technologies, such as evaporative cooling, VRF systems, psychromatic software, and dessicant dehumidification
Globally, buildings are responsible for 40% of the total world annual energy consumption which is responsible for one-third of green house gas emissions around the world. A significant portion of ...this energy is used for lighting, heating, cooling, and air conditioning purposes in buildings. Increasing awareness of the environmental impact of green house gas emissions and CFCs triggered a renewed interest in environmentally friendly cooling, and heating technologies for buildings. Free cooling of buildings may be seen as an alternate to compressor based air conditioning systems used for the buildings. In free cooling, nighttime cold is accumulated in storage material and extracted when needed. Latent heat storage using phase change materials (PCMs) can be used for free-cooling purposes due to their high storage density. In free cooling, using PCM as storage material, cool air during night is used to solidify the PCM and the accumulated cold is extracted during the hot day times. In this article a detailed review of work conducted by different researchers on PCM based free cooling is presented. Major challenges being faced in the design of PCM based free cooling system such as phase change materials; their thermo-physical properties and the geometry of encapsulation are elaborated and discussed in detail. Also the parameters effecting the charging and discharging of PCM, effect of phase change temperature and climatic conditions on thermal performance of the free cooling system are also discussed. Potential reduction in CO2 emissions due to the applicability of free cooling systems in residential and commercial buildings is also discussed in this article. This paper also provides a comprehensive list of the PCMs currently being used and that can be used potentially for free cooling applications. At last, this paper also presents some current problems needed further research in this area.
► Investigation of occupancy information for energy efficient building climate control. ► Simulation study with different buildings, HVAC systems, seasons, and occupancy patterns. ► Adjusting ...lighting and ventilation to instantaneous measurements has large energy savings potential. ► Additional occupancy predictions do not provide significant energy savings potential.
This paper investigates the potential of using occupancy information to realize a more energy efficient building climate control. The study focuses on Swiss office buildings equipped with Integrated Room Automation (IRA), i.e. the integrated control of Heating, Ventilation, Air Conditioning (HVAC) as well as lighting and blind positioning of a building zone or room. To evaluate the energy savings potential, different types of occupancy information are used in a Model Predictive Control (MPC) framework, which is well-suited for this study due to its ability to readily include occupancy information in the control.
An MPC controller, which controls the building based on a standard fixed occupancy schedule, is used as a benchmark. The energy use of this benchmark is compared with three other control strategies: first, the same MPC controller which uses the same schedule for control as the benchmark, but turns off the lighting in case of (an instantaneous measurement of) vacancy; second, the same MPC controller which uses the same schedule as the benchmark for control, but turns off lighting and ventilation in case of (an instantaneous measurement of) vacancy; and third, the same MPC controller as the benchmark but using a perfect prediction about the upcoming occupancy.
This comparison is carried out for different buildings, HVAC systems, seasons and occupancy patterns in order to determine their influence on the energy savings potential.
The aim of this review is to describe variation in standards and guidelines on 'heating, ventilation and air-conditioning (HVAC)' system maintenance in the intensive care units, across the world, ...which is required to maintain good 'indoor air quality' as an important non-pharmacological strategy in preventing hospital-acquired infections. An online search and review of standards and guidelines published by various societies including American Institute of Architects (AIA), American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), Centers for Disease Control and Prevention (CDC), Department of Health Estates and Facilities Division, Health Technical Memorandum 2025 (HTM) and Healthcare Infection Control Practices Advisory Committee (HICPAC) along with various national expert committee consensus statements, regional and hospital-based protocols available in a public domain were retrieved. Selected publications and textbooks describing HVAC structural aspects were also reviewed, and we described the basic structural details of HVAC system as well as variations in the practised standards of HVAC system in the ICU, worldwide. In summary, there is a need of universal standards for HVAC system with a specific mention on the type of ICU, which should be incorporated into existing infection control practice guidelines.
Rotary desiccant air conditioning system, which combines the technologies of desiccant dehumidification and evaporative cooling, is advantageous in being free from CFCs, using low grade thermal ...energy and controlling humidity and temperature separately. Compared with conventional vapor compression air conditioning system, it preserves the merits of environment-friendly, energy saving, healthy, comfortable, etc. Ongoing research and development works suggest that new desiccant materials and novel system configurations have significant potential for improving the performance and reliability and reducing the cost and size of rotary desiccant dehumidification and air conditioning system, thereby increasing its market competitiveness and breaking out the current fairly small niche market. For the purpose of providing an overview of recent efforts on these issues and showing how rotary desiccant air conditioning systems can be designed and coupled to available thermal energy, this paper presents and analyzes the status of rotary desiccant dehumidification and air conditioning in the following three aspects: the development of advanced desiccant materials, the optimization of system configuration and the utilization of solar energy and other low grade heat sources, such as solar energy, district heating, waste heat and bioenergy. Some key problems to further push forward the research and development of this technology are also summarized.
Air conditioning system is used for various application, in passenger car it gives comfort to the passenger. Now a days huge advancement have been included in the air conditioning system, especially ...automatic air conditioning system plays a vital role in passenger car. These air conditioning systems are performing well and have the capability of maintaining the temperature for long time with energy consumption. However, in some vehicle the performance of these air conditioning system is not achieved, while some vehicle achieved better performance. In later study it is found that, the structure of vehicle body also influence the performance of air conditioning system. In some structure the air conditioning air-flow a long distance in short time and have the capability to enhance the air conditioning performance. It is also found that the air conditioning performance can be improved by the structure of vehicle body. In this paper, we considered an Indian small budget car. The structure of the car is slightly modified and replaced the position of the air conditioning outlet. Then the residual temperature inside the car is analyzed with and without air conditioning. Here the CFD is used to analysis the temperature inside car at various position.
The world is facing a pandemic of unseen proportions caused by a corona virus named SARS-CoV-2 with unprecedent worldwide measures being taken to tackle its contagion. Person-to-person transmission ...is accepted but WHO only considers aerosol transmission when procedures or support treatments that produce aerosol are performed. Transmission mechanisms are not fully understood and there is evidence for an airborne route to be considered, as the virus remains viable in aerosols for at least 3 h and that mask usage was the best intervention to prevent infection.
Heating, Ventilation and Air Conditioning Systems (HVAC) are used as a primary infection disease control measure. However, if not correctly used, they may contribute to the transmission/spreading of airborne diseases as proposed in the past for SARS.
The authors believe that airborne transmission is possible and that HVAC systems when not adequately used may contribute to the transmission of the virus, as suggested by descriptions from Japan, Germany, and the Diamond Princess Cruise Ship. Previous SARS outbreaks reported at Amoy Gardens, Emergency Rooms and Hotels, also suggested an airborne transmission.
Further studies are warranted to confirm our hypotheses but the assumption of such way of transmission would cause a major shift in measures recommended to prevent infection such as the disseminated use of masks and structural changes to hospital and other facilities with HVAC systems.
Air conditioning is essential for maintaining thermal comfort in indoor environments, particularly for hot and humid climates. Today, air conditioning, comprising cooling and dehumidification, has ...become a necessity in commercial and residential buildings and industrial processes. It accounts for a major share of the energy consumption of a building or facility. In tropical climates, the energy consumed by heating, ventilation and air-conditioning (HVAC) can exceed 50% of the total energy consumption of a building. This significant figure is primarily due to the heavy duty placed on cooling technologies to remove both sensible and latent heat loads. Therefore, there is tremendous potential to improve the overall efficiency of the air-conditioning systems in buildings.
Based on today’s practical technology for cooling, the major components of a chiller plant are (1) compressors, (2) cooling towers, (3) pumps (chilled and cooling water) and (4) fans in air handling units. They all consume mainly electricity to operate. When specifying the kW/Rton of a plant, there are two levels of monitoring cooling efficiency: (1) at the efficiency of the chiller machines or the compressors which consume a major amount of electricity; and (2) at the overall efficiency of cooling plants which include the cooling towers, pumps for moving coolant (chilled and cooling water) to all air-handling units. Pragmatically, a holistic approach is necessary towards achieving a low energy input per cooling achieved such as 0.6kW/Rton cooling or lower by considering all aspects of the cooling plant.
In this paper, we present a review of recent innovative cooling technology and strategies that could potentially lower the kW/Rton of cooling systems – from the existing mean of 0.9kW/Rton towards 0.6kW/Rton or lower. The paper, broadly divided into three key sections (see Fig. 2), begins with a review of the recent novel devices that enhances the energy efficiency of cooling systems at the component level. This is followed by a review of innovative cooling systems designs that reduces energy use for air conditioning. Lastly, the paper presents recent developments in intelligent air-control strategies and smart chiller sequencing methodologies that reduce the primary energy utilization for cooling.
The energy efficient cooling technology, innovative systems designs, and intelligent control strategies described in the paper have been recently researched or are on-going studies. Several have been implemented on a larger scale and, therefore, are examples of practical solutions that can be readily applied to suit specific needs.
Free cooling of data centers: A review Zhang, Hainan; Shao, Shuangquan; Xu, Hongbo ...
Renewable & sustainable energy reviews,
07/2014, Letnik:
35
Journal Article
Recenzirano
The growing demand for electricity and the increasing size of the carbon footprint of data centers worldwide bring a severe challenge to sustainable development of human civilization. The cooling ...energy consumption takes up around 30–50% of the total consumption of data centers due to the inefficient cooling system. Free cooling is an effective solution for reducing the power consumption of cooling systems. This paper reviews the advancements of data center free cooling mainly focusing on configuration features and performances. Three kinds of free cooling methods, airside free cooling, waterside free cooling and heat pipe free cooling are discussed and performance characteristics of each are analyzed. Further, the criteria of performance evaluation for free cooling of data centers are summarized, and an overview of free cooling systems based on these criteria is demonstrated in order to help researchers acquire the latest developments in this area.
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