From geothermal, concentrated solar power and wind energy to air and water source heating systems, these technologies can be integrated into a shared low-carbon energy network, helping new developments make greater use of renewable and recovered energy while reducing reliance on fossil fuels. This innovative energy and power technology allows heat and electricity to be exchanged between homes, commercial and community properties within the network, greatly reducing CO2 emissions.

One major component of new build, energy networks is the heat transfer fluid and thermal fluid management. Energy must be transferred efficiently from the point of generation to the end users - this is where thermal fluid becomes a critical component. The fluid circulating through a heating or cooling network is responsible for transporting thermal energy between the source and the buildings it serves. Its properties can influence heat transfer, pumping requirements, frost protection, corrosion, system longevity and ultimately the efficiency and reliability of the entire installation. For a new development expecting to operate efficiently for decades, choosing the right fluid should therefore be considered part of the system design – not simply a commissioning decision.

The importance of heat network system design

Modern heat networks connect multiple homes and buildings to a shared source of heating, cooling or hot water. They can also make use of low-carbon and waste heat sources, including heat pumps, geothermal energy, ambient heat and recovered waste heat.

The UK Government expects heat networks to play a much greater role in decarbonising heat, with a target for heat networks to provide almost 20% of UK heat by 2050. Heat network zoning is also being introduced to identify areas where networks are expected to provide a low-cost, low-carbon heating solution. This creates significant opportunities for developers. A new eco-development can potentially combine highly efficient buildings with renewable or recovered energy sources and a centralised heat network, creating a more integrated approach to energy use across the community. But the efficiency of that network depends on more than the heat source alone.

Heat transfer fluids - important role in district heating

It is highly crucial that the correct heat transfer fluid is specified for each specific sector of the energy network, expert recommendations for the correct fluid and additive formulations ensures efficiency and optimised performance for the overall system operation.

The importance of fluid selection goes beyond simply choosing glycol - freeze protection, non-toxic fluid solutions, pump energy efficiency, corrosion protection and long-term performance are all important factors to also consider.

Heat transfer fluids operate continuously under demanding conditions, performance will be lost if not maintained correctly, potentially causing ...

  • Corrosion damage to pipework, heat exchangers, pumps and associated equipment.
  • Scale and deposits - reduction in heat transfer efficiency.
  • Fluid degradation resulting in changes to viscosity, pH and thermal performance.
  • Contamination contributing to fouling, blockages and reduced system performance.
  • Poor fluid condition increasing pumping requirements and energy consumption.
  • Freezing causing significant damage to systems operating in exposed or low-temperature environments.

The importance of pumping energy

One of the less obvious considerations when selecting a heat transfer fluid is viscosity. A fluid that is more viscous, particularly at lower operating temperatures, requires more energy to circulate around a system. This can influence not only the amount of heat being transferred, but also the energy required to operate it. This is particularly relevant for large developments where substantial volumes of fluid may circulate continuously through extensive pipe networks.

The range of glycol formulations can have significantly different viscosity and thermal characteristics. Hydratech manufactures a range of non-toxic, fully inhibited heat transfer fluids, with antifreeze function based on detoxified ethylene glycol. The fluid formulations provide high thermal conductivity and low viscosity even at sub-zero temperatures, this results in increased heat transfer efficiency and heat recovery with a reduction in pumping energy, energy consumption and equipment failure.

Protecting your infrastructure

A heat network can represent a significant long-term investment in infrastructure. Pipework, heat exchangers, pumps, valves and other components need to remain in good working condition throughout the operating life of the system. Corrosion, scale, deposits and biological activity can affect fluid quality and system performance.

Over time, these issues can contribute to reduced heat transfer, increased maintenance requirements, restricted flow, contamination, fluid degradation and damage to system components. An effective inhibitor package is therefore an important part of a properly formulated heat transfer fluid solution.

Hydratech’s advanced heat transfer formulations with inhibitors provide corrosion, scale and biological fouling protection. Whilst a team of expert engineers and in-house lab technicians provide a professional fluid monitoring program (FMP), offering chemical, technical and mechanical advice, and fluid analysis and testing, combined with ongoing fluid monitoring management to identify changes in system condition to help prevent larger operational problems and possible system failures.

For a new development, this is particularly important. The objective should not simply be to install a system that works on day one - it should be to install a system that continues to work efficiently years later.

The fluid behind system performance

Modern developments are becoming increasingly sophisticated. A community build project may incorporate heat pumps, communal heating, cooling systems, geothermal heating, concentrated solar thermal technology, wind turbine energy and water-source heating systems. These applications can have very different operating conditions. A fluid suitable for one operating network may not be the optimum choice for another. For example, geothermal systems may require long-term freeze protection, corrosion protection and environmental considerations, while solar thermal systems can operate at considerably higher temperatures and therefore require fluids formulated for those conditions. This is why heat transfer fluid selection needs to be based on the actual system, rather than simply selecting a generic glycol solution.

Hydratech’s range of products include, heat transfer fluids, inhibitors, additives and cleansers for district heating, geothermal, solar thermal, heat pump, wind and water-source energy, and all heating and cooling applications with formulations selected according to the requirements of the individual system.

Fluid management should begin before commissioning

One of the biggest opportunities for developers is to consider the fluid before the system is installed.

Fluid selection can be influenced by:

  • Heat source
  • Operating temperature
  • System materials
  • Required freeze protection
  • Hydraulic design
  • Pumping requirements
  • Environmental considerations
  • Maintenance strategy

Getting this right at the beginning can help avoid expensive system and equipment reconfiguration or adjustments at a later stage. It is also important to consider the pro-active monitoring of the condition of fluid throughout the life of the system (Hydratech FMP). Fluid concentration, pH, inhibitor levels, contamination, corrosion products and biological activity can change over time. Regular analysis will provide an early indication of developing problems and allow corrective action before system performance is significantly affected.

Future proofing your District Heating network

For developers delivering sustainable communities, the real measure of a heating or cooling system is not simply whether it passes commissioning - it is how efficiently, reliably and economically it performs throughout its operational life.

That means considering the entire system:

Energy source + heat pump + heat exchanger + pipework + pumps + controls + heat transfer fluid + ongoing monitoring. Every component contributes to the final performance.

A high-efficiency heat pump connected to a poorly designed or poorly maintained hydraulic system will not deliver its full potential. Equally, a well-designed network can still suffer if the fluid is incorrectly specified, inadequately inhibited, incorrectly concentrated, allowed to deteriorate or is not regularly monitored. The thermal fluid may seem as one of the smallest components of the overall system, but its influence can be much greater than you think.

Talk to the fluid specialists before the system is designed

Working on the next generation of low-carbon communities? Heat transfer fluid selection should form part of the conversation from the initial design stages.

At Hydratech, our engineers and in-house lab technicians are experts in heating, cooling and renewable energy systems, helping to determine the most appropriate fluid solution for each application.

From initial fluid selection and formulation through to system commissioning, balancing, analysis and ongoing fluid monitoring, the objective is the same: To provide efficient system heat transfer energy, protect the infrastructure and maintain high performance throughout the life of the district heating network.

Speak to Hydratech about thermal fluid selection for primary and secondary circuits for low-carbon, sustainable community developments.