A central heating additive that can save energy?

[RandomGrinch]

This thread may not last very long, but here goes...

There was a recent thread on here questioning the efficacy of a central heating additive called EndoTherm; that according to their website:

EndoTherm is a unique, multi-award winning energy saving additive independently proven to save up to 15% on space heating energy consumption.

It works by:

• • Due to the surface tension of fluid and imperfections in materials inside heating systems optimal thermal contact is not made.

  • When dosed EndoTherm stably changes the surface tension of the fluid by over 60% whilst remaining non-corrosive.

  • This increases the thermal contact which improves heat transfer rate and efficiency.

The previous thread has since been deleted, possibly due to a post by a representative of the company.

Which may be fair enough. However, I just wanted to compare some of the website claims with my understanding of the science - and here I may be wrong, but...

I can not find any constants relating to this claim:
What temperature is the water?
Is the surface tension calculated at a water/air boundary, or water/solid boundary?
What does a 60% "Change" mean? (Presumably reduction!)

For example, the surface tension of water (at an air/water boundary) can be reduced by 10% simply by raising its temperature from 20 to 60°C (i.e. by turning the C/H on)

Surface Tension - Water in contact with Air

Surface tension of water in contact with air for temperatures ranging 0 to 100 degC (32 to 212 degF) - in imperial units (BG units) and SI units.

www.engineeringtoolbox.com

...and a greater than 65% reduction in surface tension from 0.073 to 0.025N/m (at an air/water boundary at 20°C) can be gained by making the water soapy (adding a simple surfactant).

Surface tension

Their website has a case study section detailing case studies and highlighting the effectiveness of the product.

And I am not disputing these.

However, all the tests listed in the independent testing section seem to make the claims of a 15% energy reduction, based on a comparison with a system using water only (no inhibitor), for example:

The endotherm product is not an inhibitor. An inhibitor will need to be used in addition to it. And as I mentioned in the now deleted thread - the MSDS for Sentinel X100, lists nitrilotriethanol (a surfactant) as a constituent

To conclude, why can't we have some scientifically rigourous comparisons with properly inhibited systems, so we can judge for ourselves whether a product with EDIT (misspelt) Glucoside as the only listed chemical on the MSDS, and costing £30-£70! Per 500ml -

EndoTherm Energy Saving Additive 500ml 10-01-000

EndoTherm is an award winning energy saving additive which can be installed into any wet heating system. It improves the properties of water to increase the performance of boilers, whilst allowing systems to be more reactive to changes in heat demand. EndoTherm has independently proven to use up...

www.cityplumbing.co.uk

is a product that can be trusted to save us energy and money in these difficult times.

 

[JohnD]

Never mind magic additives making water wetter.

The only way to get 3kWh of heat out of your heating system

Is to put 3kWh of heat into it

And to pay for the energy you consume.

Does anybody seriously believe that you can get an extra 15% of heat out of it? Without paying for it?

 

[RandomGrinch]

The only way to get 3kWh of heat out of your heating system

Is to put 3kWh of heat into it

Good point.
The amount of energy required to raise the room to a set temperature will remain constant.

So, with an 'A' rated boiler having to have an efficiency of over 90% (and for example a Viessmann Vitodens 200-w having an ERP of 98%), any additive can only help the boiler creep closer to achieving its theoretical maximum efficiency, rather than gaining a blanket 15% improvement.
Which, with a well set-up, modern boiler, may mean a negligible efficiency improvement.