Design and Manufacturing of Air Conditioning Coil

 

Jorwar Hrushikesh Dilip¹, Kharat Sunanda Bhavrao²

¹Student of Mechanical Engineering, SND College of Engineering and Research Centre Yeola, India.

ABSTRACT:

 

1. INTRODUCTION:

Dissipation process are normally practice in different ventures viz, food, refreshments, paper, petrochemical, and water treatment to eliminate moister from the items. As a variant technology, evaporator technology has been around for a long time. Variation in evaporator technology is primarily caused by a focus on pollution control and energy conservation. Engineers have had to fix a variety of issues with the evaporator system in the past by either changing the temperature and pressure at which it operates or completely changing the system to make it more effective. With the discharge of waste stream, the concentration of aggressive elements rises, resulting in corrosion and early system failure. Wiqas alam et al. (2020). This paper outlines the methodology used to choose the right material for the evaporator coil in an air conditioning system using the CES Granta design software¹. For an evaporator coil with an effective cooling system and pollution control by the process engineer, material selection is more important than ever. Although low-alloy steel has been utilized as an evaporator material, it must be upgraded to control corrosion. For evaporation purposes, stainless steels have been and will continue to be utilized in numerous industries. From very low to very high temperatures, stainless steel has excellent thermal properties and effective resistance to corrosion. Due to its resistance to high temperatures and corrosion, stainless steel is now used in a wider range of evaporating service applications.

 

In engineering design, material plays a crucial role. A design product that lacks the appropriate material results in premature failure during operation. Each material differs from another because of its unique properties. The process of selecting the best material for an engineering product is known as material selection. K. Kalyani Radha et al. (2012) through the development of storage periods, the experimental designs of an evaporator coil, condenser coil, and capillary tube are examined in terms of steady state and cyclic performance. In this review, the U factor is used to determine the ideal evaporator coil design². The fundamental tenet of the approach was to define function, constraints, objectives, and free variables for particular applications. All the materials present in the universe are considered as up-and-comer materials for the applications. Applying plan and utilitarian necessities screen out the bombed materials. Material indices were used to rank the remaining materials. The weighted property index method is used to calculate the material's performance value for each candidate who was shortlisted. The final option is the material with the best performance.

 

Aluminum and copper tubes were used in Heating, Ventilation and Air Conditioning (HVAC) coils because of their higher thermal conductivity and lower price. Stainless steel is a wise choice for corrosive environments due to its durability and corrosion resistance. Although stainless steel is very strong, aluminium tubes are better at transferring heat. In the future, it will be advised to combine stainless steel tubes with aluminum fins in evaporator systems for efficient heat transfer and lower cost. Utilizing stainless steel can reduce corrosion and leakage to the evaporator system caused by salty water or refrigerants because stainless steel has a higher corrosion resistance.  Faizan Ahmad et al. (2021) the use of nanofluid as an external cooling jacket for an air conditioner condenser is a novel concept presented in this paper. The effectiveness of an air conditioner was examined experimentally using two different types of nanofluids, namely copper and aluminum oxide nanofluids. By surrounding the condenser section with an external nanofluid medium, the nanofluids were used to improve heat transfer & Al2O3 nanofluid increased COP by a maximum of 22.1%, but copper nanofluid showed a more notable improvement by 29.4%³. It was discovered that the size of the components affects the ratio of cooling capacity to refrigerant charge; In addition, the volumes of the accessories—such as piping, accumulators, dryers, receivers, and filters—as well as the volumes of the heat exchangers have an impact on the amount of refrigerant charge. Accessories may have a significant impact on the volume of small refrigeration systems, while system architecture and refrigerant charge may also have an impact on system performance. Several experimental and modeling/simulation studies on the connection between the charge of the refrigerant and the system's performance can be found in the literature. The heat pump and air conditioning systems are the primary focus of these works, while chest freezers receive relatively little attention. In order to improve system performance, the current study investigates freezers that store frozen food at low temperatures and use fewer refrigerant charges in the evaporator coil¹⁰.

 

2. METHODOLOGY:

2.1 Raw Materials:

There are many different kinds of metal used to make air conditioners. Plastic and other unconventional materials are frequently used to cut costs and weight. Tubing made of copper or aluminum, which is a crucial component in many parts for air conditioners, has better thermal properties and improves system efficiency. Depending on the application, different parts of an air conditioner may be made of stainless steel or other metals that resist corrosion. The refrigeration system in self-contained units is typically housed in sheet metal that is painted or powder-coated to shield it from the outside elements. Freon, hydrocarbons, ammonia, or water are all examples of liquids with strong thermodynamic properties that are used as the working fluid in the air conditioning system. Abhijit Samal (2021) use aluminum and copper as a first priority material has a good conductor of heat. A multi row evaporator was developed based on the requirement of cooling load with ambient air and exhaust air⁴.

 

2.2 Selection of Equipment:

According to Wufeng Jin et al. (2015) this paper provides an example of a split outdoor air conditioner machine in a semi closed space with optimal locations and louver forms. The study is conducted on an enthalpy differential laboratory platform to evaluate the effect of an outdoor unit installation and lover form on air conditioning energy and Energy Efficiency (EER). The air conditioners heat dissipation effect was better with larger louver spacing, and the optimal louver angle was about 30 ° when an outdoor wind was blowing in the lateral direction⁵. To have a cooling limit of 247.46 W from the rate run time, to keep a temperature of - 23 ºC in a 400 L chest cooler, we chose a blower from the blower cooling execution bends, drawn between dissipating temperature and cooling limit at 54 ºC gathering temperature. Coil need 255.81 W cooling capacities with a rated input power of 250 W to keep the freezer compartment temperatures at -23 ⁰C, which is more than the required cooling load. The compressor is a Tecumseh MLB 2410 series model with a rated input power of 250 W and a rated current of 2.53 A⁹.

 

 

2.3 Design:

There are four fundamental parts to every air conditioner: an expansion valve, an evaporator, a condenser, and a pump. There is also an opposing fluid medium and a working fluid in each. Despite their completely different sizes, shapes, and configurations, two air conditioners basically perform the same tasks. This is because there are so many applications and energy sources to choose from. The majority of air conditioners use an electrically driven motor and pumps to move the refrigerant fluid around. To produce significantly more torque, some natural gas-driven chillers pair the pump with a gas engine.J.Poliakina (2016) This work addresses the design and lie of limited scale even coils accompanying extreme number of turns (> 100) and self inductances until 32 μH appropriate for the augmentation of introductory sensors efficiencies. First, the reduced Wheeler’s rule is used to decide the optimum number of retires order to gain the maximal inductance⁶.

 

Through the pump, the working fluid or refrigerant moves through the air conditioning system at high pressure and enters an evaporator, where it changes into a gas and absorbs heat from the opposing fluid medium in a manner similar to a heat exchanger. The functioning liquid then moves to the condenser, where it radiates intensity to the air by gathering once more into a fluid. The working fluid returns to a low pressure state after passing through an expansion valve. Heat is drawn to the evaporator whenever the cooling medium, which can be air or a fluid. This method effectively cools the opposing medium, supplying the building with targeted cooling where it is needed. Freon was the operating fluid for early air conditioners; however, due to its potentially harmful effects on the environment, it has been phased out. While using a subpar replacement for Freon, recent designs have met stringent challenges to increase a unit's efficiency¹⁰.

 

2.4 Manufacturing Process:

Creating encasement parts from galvanized sheet metal and structural steel:

The majority of air conditioners begin as raw materials, consisting of structural steel shapes and sheet steel. Sheet metal is cut, formed, punched, drilled, sheared, and/or bent as it is processed into fabrication cells or work cells into useful shapes. The encasements or coverings, the metal that envelopes most open air private units, are made of stirred sheet metal that utilizes zinc covering to give insurance against erosion. An air conditioners bottom pan, face plates, and various support brackets are also made of galvanized sheet metal. When this sheet metal comes out of storage or inventory, it is sheared on a shear press in a fabrication cell. A band saw is used to cut and miter structural steel shapes into brackets and supports that are useful.

 

Fig.no.1 mfg process of ac coil

 

Punch pressing the sheet metal forms:

The sheet metal is loaded onto a CNC (Computer Numerical Control) punch press from the shear press. A drafting CAD/CAM (Computer Aided Drafting/Computer Aided Manufacturing) program or an independently written CNC program can provide the punch press with its computer program. The computer aided design/CAM program will change a drafted or displayed part on the PC into a record that can be perused by the punch press, telling it where to poke holes in the sheet metal. Kicks the bucket and other punching instruments are put away in the machine and precisely brought to the punching arm, where passing through the sheet can be utilized. Using a computer file to program it, the NC (Numerically Controlled) press brakes bend the sheet into its final shape. For various shapes and configurations, various bending dies are utilized, and they can be altered for each component.

In order to produce large quantities, some brackets, fins, and sheet components are outsourced to other facilities or businesses. Only when they are required for assembly are they brought to the assembly plant. Many of the brackets are made using a hydraulic or mechanical press, which allows for the continuous unrolling of brackets of various shapes and configurations from a coiled sheet into the machine. Because the press can frequently produce a complex shape with just one hit, it is possible to produce large quantities of parts.

 

Cleaning the parts:

Before being powder coated, each component must be thoroughly cleaned and devoid of any lubricants, oil, grease, or dirt. This essential task is carried out by employing a variety of cleaning techniques. Enormous arrangement tanks loaded up with a cleaning dissolvable shake and imitation the oil when parts are submersed. To get rid of grease and dirt, spray wash systems use pressurized cleaning solutions. Fume degreasing, suspending the parts over a cruel purging fume, utilizes a corrosive arrangement and will leave the parts liberated from oil based goods. The majority of parts that are outsourced arrive from a vendor having already been cleaned and degreased. Before entering a drying oven to prepare them for the application of the powder coating, many parts will be primed in a phosphate primer bath for additional corrosion protection⁷.

 

Powder coating:

A powder coating process is run on the brackets, pans, and wrappers prior to their final assembly. As the components pass through a booth on an overhead conveyor, the powder coating system sprays them with a dry powder that looks like paint. Robotic sprayers that are programmed to spray where needed as each component moves through the booth on the conveyor can accomplish this. The powder is drawn to the parts' deep crevices and bends by their statically charged nature. The parts that have been powder-coated are then fed through an oven, which typically uses the same conveyor system. Here, the powder is baked into the metal for good. In total, the procedure takes less than ten minutes.

 

Bending the tubing for the condenser and evaporator:

In air conditioning systems, the condenser and evaporator both serve as heat exchangers. They are made of copper or aluminum tubing that is bent in a coil shape to increase the working fluid's travel distance. As the working fluid removes heat from the evaporator, the opposing fluid, or cooling fluid, moves through the tubes. Guide rods and aluminum plates are used to anchor a number of small diameter copper tubes that have been bent into the same shape. The opposing fluid flows around the copper tubes and between the aluminum plates, passing through the copper tubes and the refrigerant. Using the same principle as the NC press brake, NC benders will frequently perform hairpin bends on the tubes. Every bend is the same as the previous one. A mandrel is fed through the inner diameter of the tubing that is being bent around a fixed die by the benders to prevent it from collapsing during the bend. The tubing has already been straightened. The mandrel is raked back through within the cylinder when the twist has been achieved⁸.

 

Before being fed through the bender, the coil of tubing that is supplied to the manufacturer goes through an uncoiled and straightener. An abrasive saw that can cut multiple small tubes at once will be used to cut some of the tubing into the desired lengths. In order to create divots or waves in the aluminum plates, they are punched out on a punch press and formed on a mechanical press. These waves augment the thermodynamic intensity move between the functioning liquid and the restricting medium. After the copper tubes have been finished in the bending cell, they are taken by automatic guided vehicle (AGV) to the assembly cell, where they are fed through the plates or fins by stacking them on guide rods.

 

Joining the copper tubing to the aluminum plates:

Joining the copper tubing to the aluminum plates is a crucial step in the assembly. By mechanically fusing the stacked copper tubing to the aluminum plates in their hairpin configuration, this assembly becomes the evaporator. The combining happens by taking a shot, or mandrel, and taking care of it through the copper tubing to extend it and push it against the internal piece of the opening of the plate. This gives a frugal, yet valuable connection between the tubing and plate, taking into consideration heat move.

 

The condenser is made in a similar way, with the exception that air typically serves as the opposing medium, cooling the copper or aluminum condenser coils without the plates. They are connected to the evaporator via fittings or couplings and held in place by brackets that support the coiled tubing. Most of the time, the condenser is just one tube that can be turned in a series of hairpin turns. A complete component, the expansion valve, is purchased from a vendor and installed in the piping following the condenser. It allows the working fluid's pressure to drop and return to the pump⁹.

 

Installing the coil:

A third party is used to acquire the pump in its entirety. The pump is attached to the system via fittings and held in place by support classes and a base. Its purpose is to increase the pressure in the system and circulate the working fluid. The wrapper, also known as the distance essence sheath, covers it and holds it in place alongside the other structural components of the air conditioner. In order to provide sufficient protection for the internal components, the sheath is either concentrated or bolted together¹¹.

 

3.     QUALITY CONTROL:

Each component's quality is always checked at different points in the manufacturing process. Before they can be used in the finished product, outsourced parts must pass a quality assurance representative's incoming dimensional inspection. Normally, every creation cell will have a quality control intend to confirm layered trustworthiness of each part. When assembly is finished, the unit will be put through a performance test to make sure it works right.

 

4.     PARAMETER STUDIED: -

4.1 Coil Construction Parameters

 

4.2 Moist air Conditions 

 

4.3R-134a

 

Inlet Air Condition

 

Outlet Air Condition

 

 

 

 

5. CONCLUSION:

Air conditioning coil for a specific room. This work provides Very important for the development of new technologies Energy saving that realize shot air and cold air No purchase cost, no harmful effects and safer for the environment side. Therefore, more attention is needed in this area. Work must be carried out based on their background. Originality, status and research.

 

6. REFERANCES:

1.      Wiqas Alam et al. Methodology of Material Selection for Evaporator Coil in Air Conditioning System.   International Journal of Engineering Works. 2020; 7(4): 217-220.

2.      K. Kalyani Radha et al. Development of A chest Freezer – optimum design of an Evaporator coil. International Journal of Automotive and Mechanical Engineering (IJAME). 2012; 5: 597-611.

3.      Faizan Ahmed et al. Efficiency enhancement of an air-conditioner utilizing nanofluids: An experimental study, Published by Elsevier Ltd. 2021; 7: 575-583.

4.      Abhijeet Samal. Design of Evaporator Cooling Coil for Cooling Load. International Journal of Engineering Research & Technology (IJERT). 2021; 10(11).

5.      J. Poliakine et al. Design and manufacturing of high inductance planar coils for small scale sensing applications, Published by Elsevier Ltd. 2016; 168: 1127 – 1130.

6.      Wufeng Jin et al. Experimental study of factors affecting the performance of a semi enclosed outdoor air-conditioning Unit, Ors. Published by Elsevier. 2015; 121: 1713–1720.

7.      Reddy, G. Peasant, and Navneet Gupta. Material selection for microelectronic heat sinks: an application of the Ashby approach. Materials and Design. 2010; 31(1): 113-117.

8.      Zupan, Marc, Mike F. Ashby, and Norman A. Fleck. Actuator classification and selection—the development of a database. Advanced Engineering Materials. 2002; 4(12): 933-940.

9.      Shanteahwar.I. Kumbhar et al. A Review paper on Experimental Investigation for Air Conditioning Condenser to Increase the Heat Transfer Rate by Varying the Tube Arrangement. IJIES. 2019; 4(10).

10.   N. Balaji, P. Suresh Mohan Kumar. Eco Friendly Energy Conservative Single window Air Conditioning System by Liquid Cooling with helical inter cooler. 2012; 76(3): 455-462.

11.   P. Sathiamurthi, R. Sudhakaran. Effective utilization of waste heat in air conditioning. Proc. 2003: 13-14.

 

 

 

Received on 22.05.2024            Accepted on 14.06.2024 ©AandV Publications all right reserved Research J. Engineering and Tech. 2024; 15(1):7-12. DOI: 10.52711/2321-581X.2024.00002