Comparative study of Pressure Vessel Design Software – Case Study for a Heat Exchanger

Objective
The purpose of this study is to perform a detailed comparison of heat exchanger design workflows using two different software tools – VCLAVIS and a leading industry-standard software (latest available as of April 2025). The focus is specifically on the design of tubesheets, which involve verifications under multiple design conditions, as outlined in ASME VIII DIV.1 standard for unfired pressure vessels.

Designing of heat exchangers presents unique challenges. These include modeling of tubesheet geometry (implicating calculations for tube un-laned areas, outer tube limits, tube to tubesheet joints e.t.c), calculating shell and tubes differential expansions and verifying shell, tubes and tubesheet components under design or operating cases, as defined in standards such as ASME VIII DIV.1 and TEMA. Traditional software often falls short in these areas, leading to increased engineering hours.

This study evaluates how each software platform handles:

• Setting up Tube and Shell side design data
• Tubesheet geometry modeling
• Tubesheet calculations
• Workflow automation

By applying the same design scenario across both tools, the study quantifies the time required for each task, identifies workflow bottlenecks, and evaluates each tool’s usability. The goal is to assess not only time efficiency but also the reliability and user-friendliness of each software when designing heat exchangers.

Sample heat exchanger specifications
Type BEM heat exchanger with expansion bellow on shell. Tubesheets are connected on shell and bare a flanged extension for connection with channel. There are 4 tube passes, 90° layout at 23.81 mm pitch. The heat exchanger has been thermally calculated using Commercial Software and only relevant TEMA datasheet is provided to the manufacturer (no native files shared, which is typical).

Design Data
	Shell Side	Tube Side
Internal Design Pressure:	1 MPa	2 Mpa
Internal Design Temperature:	100°C	450°C
External Design Pressure:	0.1 Mpa	0.1 Mpa
External Design Temperature:	250°C	120°C
Corrosion Allowance:	1 mm	1 mm

Dimensional Data
Component	Diameter	Thickness	Length	Material
Shell	OD=610	T=9.52	L=5940	ASME II: SA106-B
Belllow	Stainless steel, DN600, PN25, with butt welding ends for shell connection
Tubes	OD=19.05	T=2.11	L=6096	ASME II: SA179
Shell Flanges	OD=914	T=75		ASME II: SA266-2
Channel (bonnet)	OD=610	T=12.7	L=500	ASME II: SA106-B
Channel Flanges	Standardized per ASME B16.5, 300# WN			ASME II: SA105

Example Nozzle Index (Nozzles with Pads)
Tag	Description	Dimension	Make	Nozzle material	Flange Rating	Flange material
S1	Inlet	DN100	Pipe 8.56mm	ASME II: SA106-B	150#	ASME II: SA105
S2	Outlet	DN100	Pipe 8.56mm	ASME II: SA106-B	150#	ASME II: SA105
T1	Drain	DN100	Pipe 8.56mm	ASME II: SA106-B	300#	ASME II: SA105
T2	Vent	DN100	Pipe 8.56mm	ASME II: SA106-B	300#	ASME II: SA105

Design Execution Time: Industry Software vs. VCLAVIS
Industry software (2025 edition)
Examination Point		Time	Issues spotted
1	Model main heat exchanger components and nozzles	30 min	No problems spotted in modeling shell, channel, channel flanges and nozzles.
2	Find how to input the heat exchanger shell side and tube side design data	20 min	There is no clear input for heat exchanger design data, separating the shell and tube side. User needs to watch tutorial videos in order to learn how to model a heat exchanger.
3	Design tubesheet geometry	30 min	Poor tubesheet layout assistant.
4	Set design load case scenarios and operation load case scenarios	60 min	Load cases are not automatically set as per ASME. User needs to set input case by case
5	Check material elasticities	30 min	Can be specified by user (however this requires checking with Code properties and performing interpolations). Software does not provide the direct value for user checking, user needs to run the module and check with output reports.
6	Check thermal expansion data	30 min	Can be specified by user (however this requires checking with Code properties and performing interpolations). Software does not provide the direct value for user checking, user needs to run the module and check with output reports.
7	Set expansion bellow data	30 min	There are no sketches representing the bellow, so user needs to check with Code sketches.
8	Connect the tubesheet on the heat exchanger	10 min	The tubesheet needs to be modeled on the correct position. This is time consuming since the attachment method is complicated.
9	Implement channel flange loads on the tubesheet	20 min	The implementation of the flange loads for each tubesheet examination scenario is not automatically set per Code dictations
10	Design of saddles	10 min	No particular specifications apply, so saddle modeling is simple
Aggregate time:			270 min (4.5hrs)

Design Execution Time: Industry Software vs. VCLAVIS
VCLAVIS
Examination Point		Time	Solutions adopted
1	Model main heat exchanger components and nozzles	30 min
2	Find how to input the heat exchanger shell side and tube side design data	0 min	Specify design data on the starting menu. Heat exchanger is built just as it is manufactured, placing all components in clear attaching points.
3	Design tubesheet geometry	10 min	Powerful layout assistant
4	Set design load case scenarios and operation load case scenarios	10 min	Load cases automatically set as per ASME.
5	Check material elasticities	5 min	Directly selected by user
6	Check thermal expansion data	5 min	Directly selected by user
7	Set expansion bellow data	10 min	Dedicated geometry sketches are provided. Expansion bellow GUI is not within the tubesheet, making it much easier to create.
8	Connect the tubesheet on the heat exchanger	5 min	The tubesheet is connected in line with shell component, just as it would be manufactured.
9	Implement channel flange loads on the tubesheet	5 min	Load cases automatically set as per ASME.
10	Design of saddles	10 min
Aggregate time:			90 min (1.5hrs)

Results
The comparative analysis highlights a pronounced efficiency gap between the two software tools. While the traditional industry software remains functional, it demands extensive effort to perform the overall heat exchanger modeling and analysis. In contrast, VCLAVIS significantly enhances workflow with its integrated tubesheet generator and automated load case set up.
By reducing design time from 4.5 hours to just 1.5 hours—a 66.67% improvement—VCLAVIS Software for Pressure Vessel Design not only accelerates the process but also minimizes the risk of human error, ensures consistent code compliance, and reallocates engineering effort toward more critical design decisions. In today’s high-stakes engineering environments, where precision, speed, and regulatory adherence are essential, adopting a comprehensive and modern tool like VCLAVIS is more than advantageous – it is a strategic imperative.

Author: Dassa Isaak

Co-Founder & Lead Engineer at VCLAVIS O.E. Experienced Mechanical Engineer with a strong track record in the pressure vessel industry, specializing in the design and analysis of heat exchangers. Proficient in leading engineering tools including VCLAVIS.com, Autodesk Inventor, PVElite, VVD Ohmtech, and HTRI. Highly knowledgeable in international design codes and standards, including ASME, AD2000, PD5500, and EN13445. Holds a Master’s degree in Mechanical Engineering from the Aristotle University of Thessaloniki. Lead Engineer and Co-Founder of VCLAVIS.com, a specialized software platform for pressure vessel calculations.