Analysis of Heat Transfer Coefficient of Shell and Tube on Heat Exchanger Using Heat Transfer Research Inch (HTRI) Software

The heat transfer process in the industrial world is the most important thing to pay attention to, especially in industrial equipment that works at high temperatures, one of the heat exchangers commonly used in the industrial world is a heat exchanger which is used to exchange heat between fluids of different temperatures. Therefore, it is necessary to pay attention to the performance of the heat exchanger. In the shell and tube type heat exchanger, apart from using baffles which aim to direct the flow on the shell side, it also aims to increase the rate of heat transfer that occurs between the working fluids by causing flow turbulence on the shell side. The results of this study are to obtain the heat transfer that occurs in the shell and tube in the heat exchanger, and to obtain the total heat transfer coefficient

The heat transfer process in the industrial world is the most important thing to pay attention to, especially in industrial equipment that works at high temperatures, one of the heat exchangers commonly used in the industrial world is a heat exchanger which is used to exchange heat between fluids of different temperatures. Therefore, it is necessary to pay attention to the performance of the heat exchanger. In the shell and tube type heat exchanger, apart from using baffles which aim to direct the flow on the shell side, it also aims to increase the rate of heat transfer that occurs between the working fluids by causing flow turbulence on the shell side. The results of this study are to obtain the heat transfer that occurs in the shell and tube in the heat exchanger, and to obtain the total heat transfer coefficient

INTRODUCTION
Heat transfer is the transfer of energy due to a temperature difference between two different places. In the industrial world, especially in energy conservation, heat exchangers or heat exchangers are one of the most important tools. A tool used to transfer a certain amount of energy in the form of heat from one fluid to another that has a different temperature and keeps the fluids from mixing with each other. Hear exchanger tools are generally widely used in the process industry, because they can be designed to run at higher pressures and temperatures as found in the process industry. This Heat Exchanger can also be constructed from various materials. (Kreith, Frank & Prijono, Arko, 1994).
Heat exchangers have a variety of uses in a variety of industries and applications. Here are some common uses of heat exchangers: Heat Exchange: The main use of a heat exchanger is to transfer heat from one fluid to another without any interference between the two. This helps in heating, cooling or condensing fluids depending on the type of heat exchanger used. Examples include heating water in industry, cooling air in HVAC systems, and condensing steam in industrial processes.
Energy Efficiency: Heat exchangers are used to increase energy efficiency in systems. For example, in a power plant, a heat exchanger is used to heat water using the residual heat from exhaust gases or steam produced by the combustion engine. This helps in generating more energy from the same heat source. Heat Recovery: Heat exchangers can be used for heat recovery from flue gas or waste heat in industrial processes. The heat released by a system or process can be reused to heat other fluids or produce steam. By recovering previously wasted heat, heat exchangers help improve energy efficiency and reduce operating costs.
Calculating heat transfer in a heat exchanger has a significant influence on the design, performance and efficiency of the heat exchanger. Like an Optimal Design, Energy Efficiency, Performance Prediction, Identification of Potential Problems, and Design Optimization. In all, heat transfer calculations in heat exchangers provide important insights into heat exchanger performance, efficiency, and design. Using these calculations, heat exchangers can be designed and operated more efficiently and effectively, resulting in significant benefits in a variety of industrial applications.
In this study the heat exchanger used was of the shell and tube type, counterflow was chosen and used heating water fluid while for cold fluids it also used water. The baffle plate used was modified using copper. Shell and Tube Heat Exchanger consists of a shell (outer sleeve) and inside there are tubes (small tubes). Fluids that have different temperatures flow inside the shell and inside the tubes where the two fluids do not mix with each other. The flow direction of the two fluids can occur in parallel, counter, cross or mixed. Parallel flow occurs when both fluids enter from the same direction, flow in the same direction and exit in the same direction. for counter flow occurs when the two fluids enter from opposite directions, flow in opposite directions, and flow with opposite outlets, whereas for cross flow occurs when one of the fluids flows perpendicular to the other fluid. And for mixed flow, it is a combined flow of several types of these flows.

LITERATURE REVIEW
The following is a cross-sectional image of the shell and tube type heat exchanger that will be used in this study.

Figure 1. Shell and Tube Type Heat Exchangers
This type of heat exchanger is a type of heat exchanger which according to its construction is characterized by the presence of a set of tubes attached to a cylindrical shell where two types of fluids exchange heat. This type is often used in the chemical industry.
The type of shell and tube type heat exchanger has components that are very influential in its construction. The components of this type of heat exchanger are: Before determining the heat surface area (A), the value of LMTD must first be determined. This is based on the difference in temperature of the fluid entering and leaving the heat. The LMTD approach with a heat exchanger is useful when the inlet and outlet temperatures can be determined easily, so that the LMTD can be easily calculated. Furthermore, the heat flow, surface area, and overall heat transfer coefficient can be determined. If we determine the inlet or outlet temperature, the analysis will involve an iterative procedure because the LMTD corresponds to a logarithmic function. The analysis will be easier to carry out by using a method based on the effectiveness of the heat exchanger in transferring a certain heat con.
To determine the maximum heat transfer rate in a heat exchanger, it must first be understood that the maximum value will be obtained if one of the fluids experiences a temperature change equal to the maximum temperature difference contained in the heat exchanger.

METHODOLOGY
This research was conducted by analyzing shell and tube type heat exchangers with manual calculations and HTRI (Heat Transfer Research Inch) software until accurate analysis results were obtained regarding the working conditions of the desired heat exchanger.
HTRI (Heat Transfer Research, Inc.) is a company and software package that provides tools and methods of calculating heat transfer for the design and analysis of heat exchangers.
The stages of the research to be carried out are: 1. Collect theory and data covering research such as literature studies on heat exchangers and specifications of heat exchangers. 2. Processing the data includes calculating LMTD, calculating the shell, calculating the pipe, impurities factor in the heat exchanger, and the effectiveness of the heat exchanger In this study we used the HTRI program, then we only need to enter known data such as mass flow rate of fluid, pressure, temperature, as well as design assumptions based on standards from TEMA, Perry's hand book from Pustaka kern.  In this study we used the HTRI program, then we only need to enter known data such as mass flow rate of fluid, pressure, temperature, as well as design assumptions based on standards from TEMA, Perry's hand book from the Kern Library.

RESULT
Because shell and tube is the most widely used type, it is necessary to standardize it in its manufacture. The standardization was made by the Tubular Exchanger Manufactures Association (TEMA) using a numbering system. The numbering system is made with 3 (three) letters of the alphabet. Each letter represents a part of the shell and tube where the first letter indicates the front header type, the second letter indicates the shell type, and the third letter indicates the end header type. (Gede, Tahdid, Candra, 2019) From this standardization, several types of shell and tube combinations can be created. However, there are 3 (three) main combinations that are often used, including fixed tube sheet heat exchangers, U-tube heat exchangers, and floating header heat exchangers.

The Process of Entering Data
In this process, we only enter the data needed by the HTRI program based on design assumptions, different from manual calculations, we don't have to enter all the data into the HTRI calculation process. The program only gives signs for data that must be entered and the rest of the program will process data automatically. As seen in the image below.

Figure 3. Data Input Process Data Processing Results
If the data processing process is complete, the data will be processed automatically by the program and it will be known whether the planning is successful or not. If planning fails, the program will give an error message and improvements must be made in entering data. If successful, the program will provide results in the form of a table as shown in the picture. Contains how data is collected, data sources and methods of data analysis, along with the flow of research conducted.

DISCUSSION
This study focuses on data collection on variations in baffle distances and variations in mass flow rates, to obtain optimum heat transfer conditions. The results of the calculations will be reviewed between the relationship between variations in baffle distance and the value of ΔPs and heat transfer effectiveness and a graph of the relationship between variations in mass flow rate and ΔPt and efficiency. Each will be discussed and reviewed for any trends trends and theories that support the graph results.

CONCLUSION
From the results of the comparison of the manual calculation and the HTRI calculation, a close value is obtained, only in the calculation of the pressure drop, a slightly different comparison value is obtained, this is due to the suspicion that there are different setups that need to be entered and changed in the HTRI software as well as differences in the reference values used in the calculations. manuals.
Calculation of heat transfer makes it possible to evaluate the energy efficiency of the heat exchanger. By understanding the magnitude of heat transfer that occurs, it can be identified how much heat is transferred and how well the heat energy is utilized. This helps in increasing energy efficiency and reducing unnecessary energy consumption