Assign 26 - Airconditioning and Ventilation Systems -CODES AND STANDARDS USED IN HVAC -BASIC PDF

Preview

Summary

ASSIGNMENTCODES AND STANDARDS USED IN HVACEfforts to reduce energy use led to the development of energy codes and standards to establish minimum efficiency requirements for new-building construction, building additions, and renovations. Providing comfort cooling and energy efficiency in nonresidenti...

Description

ASSIGNMENT

CODES AND STANDARDS USED IN HVAC Efforts to reduce energy use led to the development of energy codes and standards to establish minimum efficiency requirements for new-building construction, building additions, and renovations. Providing comfort cooling and energy efficiency in nonresidential buildings is an ongoing task for engineers and designers as they increasingly have to focus on energy-efficient building codes and high-performance buildings. A building’s energy impact is determined by initial design decisions, operations, and the owner’s project budget. Energy codes and standards present designers with guidelines to enforce minimal energy savings through efficient design and implementing various equipment technologies. 1 These municipalities usually have an inspection department that sends inspectors out to inspect new HVAC air conditioning and heating system installations. A few municipalities apply their own mechanical code while many others use the International Mechanical Code or another code resource, which is applicable to air conditioning and heating installations. Some use a combination of inspections, and it is wise to find out before installing air conditioning and heating equipment to find out what your local municipality uses for inspections before installing any mechanical air conditioning and heating equipment. 2 Proper design and operation of HVAC Equipment and Systems not only requires a thorough understanding of relevant codes and standards, but also it requires one to stay up-to date with all frequent changes introduced in these codes and standards. This course enables participants to be knowledgeable with HVAC systems with respect to requirements of Part 5 (Environmental Separation) and Part 6 (Heating, Ventilation and Air Conditioning) of the Provincial Building Code. The course also covers information on applicable standards such as ASHRAE standards 55, 62.1, and 90.1. Case studies and workshops will be used to explore the prescriptive compliance options and the performance compliance options available in these codes/standards. 3

IMPORTANCE OF CODES AND STANDARDS USED IN HVAC Codes and standards dictate the design of HVAC systems; however, there are ways to improve the design of nonresidential buildings to achieve

1https://www.csemag.com/articles/hvac-codes-and-standards-cooling-and-energy-efficiency/ 2https://highperformancehvac.com/hvac-mechanical-code-overview/ 3https://www.epictraining.ca/course-catalogue/mechanical/13219/codes-and-standards-of-hvac-equipment-andsystems

maximum energy efficiency. Learning objectives: Examine owner and local codes for cooling system designs. Define HVAC codes and standards. 4 Inspection departments are common in these towns, and inspectors are dispatched to examine new HVAC (heating and air conditioning) When it comes to air conditioning and heating systems, a few towns have their own mechanical codes, while many others rely on the International Mechanical Code or another source Before installing any mechanical air conditioning and heating equipment, find out what your local government employs for inspections. 5 Proper design and operation of HVAC Equipment and Systems involves not only a complete grasp of applicable regulations and standards, but also the ability to keep abreast of all changes made to these rules and standards on a regular basis. It provides participants with a thorough understanding of HVAC systems and their compliance with the requirements of the Provincial Building Code Parts 5 (Environmental Separation) and 6 (Heating, Ventilation and Air Conditioning). As a result of case studies and seminars, these codes/standards will be explored in terms of prescriptive compliance alternatives and performance compliance. 6 ASHRAE

7

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE /ˈæʃreɪ/ ASH-ray) is an American professional association seeking to advance heating, ventilation, air conditioning and refrigeration (HVAC&R) systems design and construction. ASHRAE has more than 57,000 members in more than 132 countries worldwide. Its members are composed of building services engineers, architects, 4https://www.csemag.com/articles/hvac-codes-and-standards-cooling-and-energy-efficiency/ 5https://highperformancehvac.com/hvac-mechanical-code-overview/ 6https://www.epictraining.ca/course-catalogue/mechanical/13219/codes-and-standards-of-hvac-equipment-andsystems 7https://www.google.com/imgres?imgurl=http%3A%2F%2Fwww.ashraeasa.org%2Fimages %2FASHRAE_logo_rgb_transparent3.png&imgrefurl=http%3A%2F%2Fwww.ashraeasa.org%2Fmembers.html

mechanical contractors, building owners, equipment manufacturers' employees, and others concerned with the design and construction of HVAC&R systems in buildings. The society funds research projects, offers continuing education programs, and develops and publishes technical standards to improve building services engineering , energy efficiency, indoor air quality , and sustainable development. 8 The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is the premier authority on sustainable building practices. Through extensive and up-to-date reports, courses, training, and conferences, ASHRAE dominates the sustainable building industry. Any professional in the HVAC industry should familiarize themselves with ASHRAE’s key handbooks, guidelines, and toolkits to ensure their personal knowledge remains on the cutting edge of healthy building technologies. 9 SMACNA

10

SMACNA, the Sheet Metal and Air Conditioning Contractors’ National Association is an international trade association and ANSI-accredited standards developing organization representing 1,834 member firms in 103 chapters throughout the United States, Canada, Australia, and Brazil. SMACNA standards and manuals address all facets of the sheet metal industry, from duct construction and installation to air pollution control, energy recovery, and roofing. 11

8https://en.wikipedia.org/wiki/ASHRAE 9https://yellowbluetech.com/hvac-codes-and-standards/ 10https://www.google.com/url?sa=i&url=https%3A%2F%2Ftwitter.com 11https://law.resource.org/pub/us/cfr/ibr/005/smacna.duct.1995.html

This Second Edition of the SMACNA commercial metal and flexible duct construction standards is another in a long line dating from the 1950s. A quick overview of the changes is provided in the front of this manual. Meanwhile, a Committee has already begun work on what will be either addenda or a new edition. Subjects being investigated are ribbed round duct, fatique testing of tie rodded metal, new flat oval duct standards, duct liner pin lengths, more double wall casings, sealant specifications and more performance specifications for joints and reinforcements. And, indirectly related to these standards, significant progress is being made by major mechanical code writing agencies in developing one uniform, consensus-supported code for the entire nation. SMACNA expresses appreciation to the many who have offered suggestions for constructive improvement in the fabrication and installation of duct systems. Suggestions for future improvement are welcome. Special thanks is given to those who volunteered their time, gave their special knowledge and struggled with development of a consensus that would reflect the needs of a diversified industry. Although standardization intrinsically involves selection, no intention of discrimination against the use of any product or method that would serve a designer’s need equally or better exists. 12 NFPA

13

NFPA 90A covers construction, installation, operation, and maintenance of air conditioning and ventilating systems, including filters, ducts, and related equipment, to

12https://webstore.ansi.org/sdo/smacna 13https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.safetysign.com%2Fnfpa-hazard-rating

protect life and property from fire, smoke, and gases resulting from fire or conditions having manifestations similar to fire. 14 I. NFPA Standard 90A, Standard for the Installation of Air Conditioning/ Ventilating Systems, 2002 Edition This Standard states that "Class 1 rigid or flexible air ducts tested in accordance with UL 181 Standard for Safety, Factory-Made Air Ducts and Air Connectors, and installed in conformance with the conditions of listing, shall be permitted to be used for ducts when the air temperature in the duct does not exceed 121˚C (250˚F) or when used as vertical ducts up to two stories in height." This Standard also requires that supplementary materials including duct coverings, duct linings, vapor retarder facings, adhesives, fasteners, and tapes "shall have, in the form in which they are used, a maximum flame spread index of 25 without evidence of continued progressive combustion and a maximum smoke developed index of 50 when tested in accordance with NFPA 255, Standard Method of Test of Surface Burning Characteristics of Building Materials." The Standard further requires that air duct, panel, and plenum coverings and linings "shall not flame, glow, smolder, or smoke" when tested in accordance with ASTM C 411, Standard Test Method for Hot-Surface Performance of High Temperature Thermal Insulation, "at the temperature to which they are exposed in service." In no case shall the test temperature be below 121˚C (250˚F). 15

IEEE

16

The incorporation of advanced sensor data acquisition techniques, concepts of cyber physical systems, and the Internet of Things (IoT) devices into infrastructures and building energy management systems is enabling the smart city deployments. The main 14https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail? code=90A 15https://guides.co/g/a-guide-to-insulated-hvac-systems/136710 16https://www.google.com/url?sa=i&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki %2FInstitute_of_Electrical_and_Electronics_Engineers

emphasis of this paper is to design and implementation of energy efficient controls into the heating, ventilation, and air conditioning (HVAC) systems of the commercial buildings. These systems are responsible for providing acceptable indoor air quality and thermal comfort to the occupants. By tuning and implementing advanced control systems into the existing HVAC systems, energy consumption can be reduced by 2030%. The traditional control techniques are compared with two advanced control techniques: Pattern Recognition Adaptive Controller (PRAC) and Model Predictive Control (MPC). The salient features of the advanced control techniques are presented. By utilizing the existing hardware and software systems, the proposed control techniques are implemented on one of the academic buildings of the Texas Tech University campus. The preliminary results obtained in the minimization of simultaneous heating and cooling and energy savings of the HVAC systems are presented in the paper. 17 Making buildings more energy efficient while keeping thermal comfort has been an important topic in last decades, including improving efficiency of Heating, Ventilation and Air Conditioning (HVAC) systems. One approach to this goal is to use better control methods. This paper presents a review of methods which have been researched in scientific papers in last couple of years. Most papers focus on one of the following trends: improving “classical” control methods; use of predictable control based on models; use of intelligent control methods. 18 PSME

19

This case study will evaluate the feasibility of data center free cooling in the Middle East using indirect evaporative cooling (IEC). General •

1MW

Data

Center

IT

Assumptions: LOAD

17https://ieeexplore.ieee.org/document/8373615 18https://ieeexplore.ieee.org/document/7321372 19https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.facebook.com%2FPSMEQCnorth

• Cooling demand at 100% IT LOAD • The data center is pressurized, with no infiltration of outside air into the white space • The analysis focuses on the white space only • Energy consumption of cooling requirements of other spaces are not part of this case study • Data center cabinets are in hot and cold aisle configuration with containment Evaporative Cooling Evaporative cooling uses water as a medium to cool the air through its evaporation. The adiabatic evaporation of water provides the cooling effect which requires less energy than the typical vapor compression system used for air conditioning. There are two types of Evaporative Cooling - Direct and Indirect. According to ASHRAE HVAC Systems and Equipment Handbook, “With direct evaporative cooling, water evaporates directly into the airstream, reducing the air’s drybulb temperature and raising its humidity. Direct evaporative equipment cools air by direct contact with the water, either by an extended wetted-surface material (e.g., packaged air coolers) or with a series of sprays (e.g., an air washer).” On the other hand, according to ASHRAE: “With indirect evaporative cooling, secondary air removes heat from primary air using a heat exchanger. The water does not make any contact with the primary air, in this case, the data center air. In one indirect method, water is evaporatively cooled by a cooling tower and circulated through a heat exchanger. Supply air to the space passes over the other side of the heat exchanger. In another common method, one side of an air-to-air heat exchanger is wetted and removes heat from the conditioned supply airstream on the dry side.” 20

BASIC COMPONENTS OF AIR CONDITIONING REFRIGERATION CYCLE The refrigeration cycle starts and ends with the compressor. The refrigerant flows into the Compressor where it is compressed and pressurised. At this point, the refrigerant is a hot gas. The refrigerant is then pushed to the Condenser which turns the vapour into liquid and absorbs some of the heat. The refrigerant then proceeds to the Expansion Valve where it expands, losing pressure and heat. The refrigerant coming out of the expansion valve is cold and slow due to the loss of pressure. It enters the Evaporator in a liquid state where the exchange of heat takes place thus cooling the load inside the refrigerator. As the gas cools down the load,

20https://psme.org.ph/blogpost/1224421/TG-HVAC

it absorbs the heat which turns it into a gas. The gas is then pushed back into the Compressor where it can start the cycle again. 21 a refrigeration cycle's mission is heat absorption and heat rejection. As any HVAC instructor will tell you (emphatically), you can't make cold, you can just remove heat. The refrigeration cycle, sometimes called a heat pump cycle , is a means of routing heat away from the area you want to cool. This is accomplished by manipulating the pressure of the working refrigerant (air, water, synthetic refrigerants, etc.) through a cycle of compression and expansion. 22 COMPONENTS OF AIR-CONDITIONING SYSTEM (USES AND FUNCTION) An air conditioning system is an electrical device that is purposely installed for the removal of heat and moisture from the interior of an occupied space. It is a process that is commonly used to achieve a more comfortable environment, basically for human and other animals. Air conditioning system is also used to cool and dehumidify rooms that contain heatproducing electronic devices, such as computer server, power amplifiers. It also used in space that contains delicate products like artwork. Cooling is generally achieved in the air conditioning system through a refrigeration cycle, but sometimes evaporation or free cooling is employed. The system can also be made based on desiccants (chemicals that eliminate moisture from the air). Most AC system stores and rejects heat in pipes called subterranean. 23

AIR CONDITIONER PARTS & FUNCTIONS 







Blower: Air flowing from supply registers is the work of the blower. This component, which also works with your furnace, circulates cooled air into your home and pulls room-temperature air back for re-cooling. Evaporator coil: This indoor component, located near the blower, is responsible for extracting heat and humidity from the air. This is possible thanks to the refrigerant running through the coil. Compressor: Once it has absorbed heat, the refrigerant is in a gaseous state. It passes through the compressor, where the gas is pressurized and heated even more. This important step prepares the refrigerant to give up its heat. Condensing coil: This is the outdoor equivalent to the evaporator coil. As refrigerant travels from the compressor to the condenser, it expels the heat

21https://www.fridgefreezerdirect.co.uk/knowledgebase/latest-news/commercial-refrigeration-101-how-does-therefrigeration-cycle-work 22https://www.superradiatorcoils.com/blog/4-main-refrigeration-cycle-components 23https://studentlesson.com/air-conditioning-system-definition-functions-components-types/







collected from indoors to the outside. Once the refrigerant is cooled to a liquid, it circulates back inside to collect more heat in the evaporator coil. Fan: The outdoor condensing unit becomes very hot with all that overheated refrigerant running through it. A fan and fins that act as heat syncs draw the heat away so the unit doesn’t overheat. Air filter: While an air conditioner can function without the air filter, dust and dirt in the air would quickly collect on A/C components and possibly damage them without the filter in place. Install an efficient enough filter and you can even improve indoor air quality while the air conditioner operates. Thermostat: This is the control center of the entire air conditioning process, reading the indoor temperature and telling the air conditioner when to turn on and off. You change temperature settings here based on your needs. The higher you set the thermostat, the lower your cooling bills will be. 24

REFRIGERANTS

25

A refrigerant is a substance used in a heat cycle to transfer heat from one area, and remove it to another. Usually a gas at room temperature. Found in pretty much everything that cools, and sometimes in things that heat, most commonly air conditioners, fridges, freezers, and vehicle air conditioners. Traditionally, fluorocarbons, especially chlorofluorocarbons (CFC’s), were used as refrigerants, but they are being phased out because of their ozone depleting effects. Other common refrigerants used in 24https://www.roth-heat.com/blog/2015/may/7-important-components-for-air-conditioner-funct/ 25https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.albertair.com%2Fblog%2Fhvac%2Fsigns-thatyour-air-conditioner-has-too-much-refrigerant

various applications are ammonia, sulfur dioxide, and non-halogenated hydrocarbons such as propane. Most refrigerants found in end of life devices are ozone depleting and global warming inducing compounds. 26 Without refrigerant, there would be no air conditioning, refrigeration or freezing technology. Air conditioners contain refrigerant inside copper coils. As refrigerant absorbs heat from indoor air, it transitions from a low-pressure gas to a high-pressure liquid. Air conditioning components send the refrigerant outside where a fan blows hot air over the coils and exhausts it to the exterior. The refrigerant then cools down and turns back into a low-pressure gas. Another fan located inside the home blows air over the cool coils to distribute the resulting cold air throughout the building. Then the cycle repeats. 27 A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated due to their toxicity, flammability and the contribution of CFC and HCFC refrigerants to ozone depletion and that of HFC refrigerants to climate change. 28

PROPERTIES AND CHARACTERISTICS OF REFRIGERANTS The ideal refrigerant would be: non-corrosive, ...