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The transformation of industries by the digital revolution is a story told many times over, and heating system design is no exception.

Expansion vessels are required in systems where a closed circuit is subjected to a fluctuation in temperature e.g. heating and cooling systems.

This 1/2 in lead-free thermostatic mixing valve is designed for residential, commercial or institutional environments for supplying baths or lavatories with tempered water. The double throttling design controls both hot and cold water supply to the mixed outlet. It consists of a lead-free brass body, solder union connections, solid wax hydraulic principle thermostat, integral filter washers and check valves with a locking mechanism for the temperature setting. The adjustable field range temperature at mixed outlet is 80 to 120 deg F. The maximum pressure rating is 150 psi (10.3 bar).

WATTS® Thermostatic Mixing Valve, Series: LFMMV Series, 1/2 in Nominal, Socket Connection, Solder Union End, 150 psi, 0.5 to 20 gpm Flow Rate, 4-13/16 in Inlet to Outlet Length, Cast Copper Silicon Alloy Body, Stainless Steel Disc, 80 to 120 deg F, 5-3/8 in H

"I would estimate over the length of this project, I have spent 50% less time designing than I would on our previous software.

This number will vary based on your geographical location and the associated climate but will likely be around 5°C (41°F) in the winter months.

Embracing the digital revolution in the form of heating design software, like that offered by h2x Engineering, is crucial for professionals who wish to stay competitive in the industry.

The expansion vessel provides the necessary ‘give’ in the system to handle this extra volume, preventing potential over-pressurisation damage.

They counterbalance changes in fluid volume, and consequently pressure fluctuations, which occur due to variations in temperature.

Ideally, they should be placed in a cooler section of the system, for instance, the return pipe close to the boiler or chiller.

– Incorrect positioning: this can disrupt the vessel’s primary function of accommodating fluid volume changes, potentially leading to dangerous pressure build-ups or operational inefficiencies.

CASE STUDIES Greengate, UK "I would estimate over the length of this project, I have spent 50% less time designing than I would on our previous software. The ability to output the design straight into Revit assisted clash detection and coordination." Read the full case study

Moreover, to avoid the issue of pump cavitation, installing the vessel on the suction side of the recirculation pump is recommended.

This level of detail ensured that the heating load accurately matched each space's requirements, minimising energy waste and maximising comfort.

Consider a system with a water volume of 500L, an initial temperature (T_initial) of 10°C, and a maximum operating temperature (T_max) of 80°C.

An expansion vessel, or expansion tank, is a device in a heating or cooling system that accommodates the extra volume of water produced when the system water is heated or cooled.

CASE STUDIES Award-Winning Heating Design "Using h2x was pivotal, allowing for precise heat loss calculations, pipe sizing and flow rates for each room. This level of detail ensured that the heating load accurately matched each space's requirements, minimising energy waste and maximising comfort. The strategic placement of heat pumps and careful sizing of pipework were crucial in maintaining minimal pressure drops over an 18-metre distance." Read the full case study

3 bar (300 kPa / 43.5 psi) is commonly used for this (recommended by CIBSE) but the manufacturer’s documentation is typically the best source for this information.

With the right software, like h2x Engineering’s Heating Design Software, you can drive efficiency and accuracy in your heating system projects.

The maximum allowable pressure is the peak pressure that a system can safely tolerate without causing damage to its components or risking a system failure.

"The software offers precision through detailed result outputs and advanced options for efficient pipe sizing, allowing heating engineers to optimise based on parameters like maximum velocity and pressure drop."

This data can usually be found within the system’s design specifications. In cases where it’s not readily available, a pressure gauge might be needed to measure this pressure.

As the water heats up, it expands, and without a place to go, this increase in volume can cause a dramatic rise in pressure.

CASE STUDIES Salon Republic, USA "The quality of the designs saw significant improvement with the adoption of h2x." "The software offers precision through detailed result outputs and advanced options for efficient pipe sizing, allowing heating engineers to optimise based on parameters like maximum velocity and pressure drop." Read the full case study

Gain a comprehensive understanding of expansion vessels inside this informative blog. Includes a calculation example for practical insights.

These vital components, also known as expansion tanks, are pivotal in maintaining system safety and operational efficiency.

The critical process of accurately calculating and correctly positioning an expansion vessel is crucial in designing and operating heating and cooling systems.

Having understood the crucial parameters, we now venture into the specifics of calculating the size of an expansion vessel.

The strategic placement of heat pumps and careful sizing of pipework were crucial in maintaining minimal pressure drops over an 18-metre distance."