Dominic Wish, HMX UK Technical Director, shares with LABM how a pioneering new approach to reducing energy use and carbon emissions is seeing the heating bills of eight schools in Essex drop by up to 47% and carbon emissions cut by around seven tonnes per year per site.
The Chelmsford Diocese schools are the first in the country to have Hydromx, a cutting-edge heat transfer fluid, installed in their central heating systems. It utilises nano technology to speed up heat transfer from boilers into the radiator system, reducing the energy required for rooms to reach the required temperature and extending boiler lifespan due to decreased cycling.
Its installation into one school has proved so successful that Headmaster Iain Gunn was astounded at how quickly the building heated up and it led to the management team requesting the retrofitting of thermostatic radiator valves to better control the heat and realise the energy, cost and carbon savings that are possible.
“The very first day after installation everyone said how hot the school felt,” says Iain Gunn, Head of St Peter’s Church of England Primary School in South Weald, Essex. “The radiators were hot rather than being luke warm and every classroom had windows open. It really has made an incredible difference to our school.”
Hydromx was installed into St Peter’s during October half term last year. Installation involved draining/flushing the heating system and re-filling with 50% water and 50% Hydromx. Post-installation the concentration was measured with a refractometer to ensure the optimum mix had been achieved. Energy and carbon savings are achieved from day one.
Building challenges
Like many schools, St Peter’s presented the challenge of a building added to over many years, with some parts dating back to 1957 and others much more recent. It has a diverse range of radiators and fittings and some TRVs in newer parts of the premises but not throughout. Because the school is linear — around 100m long — its extremities had proved difficult to heat. Hydromx solved this, as Iain explains: “My office never really got warm and was always on ‘five’ on the TRV. Now I have it on one.”
With TRVs fitted throughout the building, staff now have complete control of comfort levels. Boiler sequencing and timing has been adjusted to take into account the increased efficiency of the system.
Energy savings
St Peter’s, which has a roll of 413 pupils, was one of five schools selected to participate in the initial Hydromx pilot project due to its eco credentials — it already has solar panels generating electricity.
Of the five pilot project schools, three have so far reported their before and after energy usage statistics, revealing gas consumption savings of between 37.5% and 47% in November/December 2022 and January 2023 when compared to the previous year (with an HDD — Heating Degree Day — calculation applied). ROI ranges from 1.42 years to 2.18 years. It should be noted that the schools have TRVs fitted to ensure optimum savings and, coupled with the Hydromx installation, there has been a significant focus on energy saving within each, leading to these outstanding results.
For Iain Gunn the energy savings represent a significant boost to school coffers ( just a 30% saving represents his school’s entire book budget for one year), but that’s not the only benefit, as Iain explains: “The school is hotter, it’s the entire school. It’s such a great product. Everybody I have spoken to can’t quite believe how good it is.”
He’s now looking forward to bringing the school swimming pool online with Hydromx: “It will make a huge difference,” Iain says. “We are hoping it will save us even more money.”
Due to the success of the pilot project the solution has been installed into three more schools and the diocese, working with supply partner HMX UK, is now rolling it out to its remaining 30 controlled schools. Peter Palmer, School Buildings and Organisation Officer for the Chelmsford Diocese, explains: “Specifying Hydromx into our school estate is a key component of the Diocese’s Net Zero objective. The pilot project has delivered significant savings in energy consumption, cost and carbon emissions and we now intend to roll out Hydromx across the remainder of our voluntary aided schools, providing them with energy-efficient and highly effective heating systems which also deliver meaningful cost and carbon emission reductions.”
Efficient
Hydromx is suitable for any commercial or domestic closed loop hydronic HVAC system. It is a non-invasive, easy-to-install energy, and carbon saving solution, which works by improving heat transfer, making heat exchangers more efficient and requiring less energy input to do so. It provides complete system protection against corrosion, calcification and bacteria and includes anti-freeze. The solution is inert, recyclable and guaranteed for 20 years. Depending upon the application and system characteristics, it will normally deliver energy, carbon and cost savings of between 20-35%.
Installation
There are two key elements of installation — assessing the system volume and ensuring it is clean (which may mean flushing. This can also help ascertain volume if it’s unknown). The heating system needs to be in reasonable condition, ideally with no history of leaks. Any remedial work required — including the fitting of TRVs — should be carried out prior to installation. Post installation the building will get significantly hotter more quickly and boiler sequencing/thermostats will need turning down significantly.
Suitability
The solution is suitable for most systems — including swimming pools — and buildings, for both heating and cooling. Savings vary by system characteristics, however with the school heating systems the older design boilers and large surface area of cast or pressed steel radiators made the savings achieved considerable.
