UK & Europe: +44 (0)1925 747 101 - Global: +1 778-895-1990

Changing the properties of water to improve energy efficiency.

Water is used in chiller systems as it is a good cooling transfer medium that is abundant and low-cost.

EndoCool optimises water to influence chiller system performance.


EndoCool 10L drum

Although water is abundant and low cost, its thermophysical properties can be improved upon.

EndoCool interacts with water’s hydrogen bond network to improve its thermophysical properties to maximise the ability of chiller systems to deliver cooling to the locations required at the times it is needed.

These changes can increase the rates at which rooms reach temperature and improve the ability of the chiller system to respond to changes in demand.

This allows systems to better deliver cooling to the right places, and at the right times to maximise system efficiency.

How much energy it takes to cool the buildings in which we live and work depends not only on how efficiently we can convert the energy source into cooling, but also on how and when that cooling is delivered to the spaces in which it is needed.

Fluid properties play an important role in how well hydronic chiller systems can meet the demands of buildings and their occupants.

Many thermophysical properties of water relate to the network of hydrogen bonds between the individual molecules.

EndoCool interacts with this hydrogen bonding network influencing both the amount of bonds and how they alter with changing temperature, thereby improving a number of properties of the fluid such as rheology and specific heat capacity.

These changes can impact on rates of cooling and energy required to cool the hydronic fluid, the response behaviour of the system to controls such as thermostats, and the amount of wasted energy once demand is met.

Such changes have cumulative effects throughout the system which contribute to improving the ability of the chiller system to deliver cooling at the right time and right place, maximising system efficiency as well as component efficiency.


Using EndoCool we can influence water systems in the following ways…

Andrew Williams
PhD, MEng

Manager of Research & Development

Dr Andrew Williams holds a first class Masters degree in Mechanical Engineering and PhD from Loughborough University.

Dr Williams has been an active researcher in the areas of energy and thermofluids since 2001, including co-leading a UK Fluids Network Special Interest Group and academic advisor for the Energy Technologies Institute.

In roles as Senior Lecturer at Loughborough University and Visiting Research Fellow at University of Chester he applied his expertise in energy and thermofluids to the challenge of heating system de-carbonisation and hydronic heat transfer modifiers.

Interested in EndoCool for your building? Get in touch...

Bubble Behavior: Surface &

Bubbles within the fluid can occur because of entrained gases as well as degassing during heating or pressure changes. The presence of surface bubbles can inhibit cooling transfer significantly. The presence of entrained air bubbles changes the flow behaviour, pump performance and heat transfer.

Surface bubbles are more easily removed with EndoCool, and entrained bubbles tend to be significantly smaller. Internal surfaces remain clear during degassing as surface scratches are no longer preferential nucleation sites.

Changing Heat Capacity

The specific heat capacity of a liquid is the amount of cooling required to decrease the temperature of a given amount of the liquid by one degree.

Changing heat capacity affects fluid temperatures, fluid embedded energy and cooldown rates and delays.

Improving Rheology

The rheology of a liquid refers to the study of its flow and deformation characteristics. It is the science that deals with the behavior of liquids under the influence of applied stresses or strains.

Rheology helps us understand how a liquid responds to changes in its environment, such as temperature, pressure, and shear rate.

Changing the rheology of cooling system fluid can improve heat transfer and change pipe system flows. 

Surface Affinity

Liquid surface affinity, also known as surface wetting, refers to the degree to which a liquid spreads out or adheres to a surface.

It is determined by the balance between the adhesive forces between the liquid and the surface, and the cohesive forces between the liquid molecules.

EndoCool molecules can be better thermally coupled with surfaces than water alone.

Better thermal coupling improves heat transfer and efficiency.

Temperature Dependent Bi-phasic Behaviour

Liquid temperature-dependent bi-phasic behavior is observed in some liquids where their physical properties change abruptly with temperature as a result of the formation of two distinct phases.

The presence of two phases with different physical properties such as density and viscosity influences turbidity and rheology.


Analysis of EndoCool’s effect on common system materials of construction (including steel, copper and aluminium) showed less corrosion detected with EndoCool dosed water than hard and soft water alone.


Tested over 1,008 hours EndoCool dosed water showed minimal to no impact on EPDM rubber.

EPDM rubber is commonly used for sealants in a heating or cooling system.


EndoCool has been tested and approved to be compliant with freeze protection and corrosion inhibitor products.

All products, including EndoCool continue to function as expected. 

EndoCool is not regarded as hazardous waste as defined by EU Directive 91/689/EEC (No Discharge Requirements)

Get in touch with the EndoCool team

UK & Europe

Telephone: +44 (0)1925 747 101

USA, Canada & Rest of the World

Telephone: 778-895-1990

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EndoCool is part of the EndoTherm product family and a registered product of Endo Enterprises (UK) Ltd.
EndoTherm is an energy saving additive for heating systems
Endo Enterprises (UK) are experts in water treatment solutions.
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