27/01/2023

3D Technical Design Ltd – Product Spotlight

3DTD are a specialist, practitioner-led, consultancy who serve a variety of public and private sector organisations, across the UK’s district energy industry. We draw our expertise from over 20 years of experience in designing, building, installing, operating and maintaining many of the UK’s largest city-centre district energy schemes. We have built an exceptional track record in offering design and consultancy at feasibility, detailed design and construction governance levels. Our track record demonstrates a highly effective assessment of key success and risk factors, which has enabled projects, in complex city-centre environments to rapidly progress, under control, into detailed design and procurement stages.

As part of our feasibility and detailed design services, we offer hydraulic and stress analysis for district heating networks which are crucial parts of a safe design of pressurised systems, driving decisions on piping specification, route layout, support arrangements and other project requirements.

Hydraulic analysis
Hydraulic design is essential to optimise the piping system, select adequate equipment parameters, determine the range of temperature losses and system pressures and compute the range of system pressure and temperature losses. It is important to simulate the behaviour of a piping system on three scale levels—the pipe cross section, the pipe/branch run, and the entire piping network—and then link and solve these models in order to examine them for hydraulic and thermal impacts.

Heat Loss
Heat loss occurs when a pipe carries hotter fluid than ambient temperature. Its amount depends upon several factors, i.e., insulation thickness of the pipe, ambient temperature (installation temperature), wind speed (for aboveground pipework), etc. Heat loss analysis allows the clients to make an informed decision when selecting insulation types that suit their technical and economical requirements.

Pipeline Sizing, Hydraulic Resistance, and Pressure Losses
Calculation of optimal pipeline diameter is a complicated problem requiring technical and economic assessments and consideration of numerous factors. This is attributed to the close interrelation between pipeline parameters under design and characteristics of the flow of medium pumped through it. Increasing the pumped water velocity makes it possible to reduce the pipeline diameter required to maintain a set flow rate, thus reducing the consumption of materials, and making system erection cheaper and more accessible. At the same time, velocity increase leads to head loss, which requires additional energy consumption for pumping. Excessive reduction of velocity also can result in unwanted aftermath. With our sophisticated design software and experienced engineers, we are able to model a variety of different operating situations, considering thermal effects and including all instruments and equipment that potentially have an impact on the system dynamics and thermodynamics in the model.

Water hammer effect
The water hammer effect (hydraulic shock) happens when a pipeline system shuts off suddenly (B). It is a result of a pressure surcharge when a valve shuts too quickly or a high-pressure shockwave that propagates through a piping system when a fluid in motion is forced to change direction or stop abruptly. As the system cannot withstand it, pressurised water builds up. As the water continues to hit the closed valve at total capacity, it sends a shockwave through the entire pipeline system which may damage pressure gauges, flowmeters, gaskets and other equipment, leads to leaks and ruptured pipes and could have a major impact on pipe support systems and pipe bridges. 3DTD can analyse the effect of valve openings/closings, the pumps switching on/off and the combination of these events. The loads generated by the water hammer effect are then transferred over to the stress analysis model for further assessment.

Stress Analysis

It is essential to determine stresses and strains in materials when subjected to forces and heavy loads to implement a safe, optimised design and prevent any material damage throughout the system lifecycle. 

During installation, commissioning, and operation of the District Heating pipes, stresses and thermal expansion/contraction can occur, affecting the environment in which the pipework is buried. To avoid any damage to it and the materials from which the network is built, a detailed analysis is required for the entire system.  

3DTD perform stress analysis for underground and aboveground pipe networks utilising a variety of advanced design software to determine expansion control positions (U-loops, Z-bends, compensators etc.), design expansion foam pad configurations and suitable pipe support systems.

Calculations for foam pads are carried out in house using the sisKMR software and to make it easier for the site team to interpret the design, 3DTD offers detailed drawings illustrating the number and size of the foam pads required at each directional change and branch connection.

Why choose 3D Technical Design?

3D Technical Design have extensive experience in modelling highly complex systems for below- and aboveground pipe works.

The stress analysis we perform uses our best knowledge, experience, and background to comply with the piping codes, national and international regulations, and guidelines.

3D Technical Design offers the complete package of stress and hydraulic calculations, sizing, and heat losses of the pipeline which will aid our clients to deliver optimised and cost-effective pipeline systems.

Visit 3D Technical Design Ltd at The Distributed Energy Show on stand 2009.