More
When a heating installation company in Cornwall wanted to proceed with its first ground source heat pump installation, it was natural to turn to Sentinel - a company whose products they had used for years and that they trusted implicitly, to offer support.
Dave Ewins and Neil Orient, of Davanna Heating Ltd of Truro have an excellent track record of installing renewable heating systems in the county – modern heating technology that doesn’t rely on traditional fossil fuelled heating and contributes to reducing CO2 emissions in the UK. In the main, they have been installing solar thermal systems - which take heat from the sun through panels on the roof and convert it into heat for hot water - and air source heat pumps that take the latent heat from the air and turn it into heat for heating and hot water systems in the home.
Having installed these systems for a while, they had the opportunity to install their first ground source heat pump, a source of heat for the home that sees the latent heat in the ground captured by a glycol based heat transfer fluid circulating in pipe loops under the ground.
The drillers had installed three 90 metre 40mm Ground Loops, and Dave and Neil installed the headers to the property and the Nibe Heat Pump that drives the system. The Ground Loops had been installed six months prior to Sentinel’s involvement, at the time the foundations had been dug for the property and left for that time, whilst the building was built.
As you might expect from a system left that long, the first flush of the heat pump pipes resulted in a horrific ‘bad eggs’ smell that saw the plant room evacuated and left to ventilate for a couple of hours before it was possible to return to the job. It was immediately clear that there had been significant bacterial growth in the loops – exactly the kind of problem that has caused problems in ground source heat pump installations in the past. And exactly why Sentinel has developed its renewables range of water treatment products and its bespoke glycol-based heat pump fluids.
The smell highlighted the very real need to sanitise ground loops before filling them with glycol based fluid. Unless the bacteria and debris that has accumulated in the loops is flushed out and the system sanitised, the bacteria which ‘eat’, thrive and multiply rapidly on the glycol in the fluid, will rapidly degrade the glycol mix and at best reduce the energy efficiency of the system significantly and at worst cause the system to block, freeze and fail to deliver the energy efficient heat the system has been designed to deliver. In addition, it will be far more difficult to flush out the degraded glycol mix and clean the system at that stage – far better to start off with a squeaky clean system that only needs regular upkeep.
The Cornish GSHP installation was still not clean to go after flushing with clean mains water. High levels of bacteria were measured by Sentinel that showed that the six months of standing dormant had seen a major infestation of micro-bacterial growth and more attention was needed to return it to a state where the installation could safely be continued. Sentinel R700 – a sanitiser and biocide product that eliminates the problems caused by bacteria and fungi in Heat Pump Systems - was added to the system by Dave, Neil and the Sentinel team and the bacterial activity reduced to very low levels over just an hour. Each of the three loops was dosed independently to clear the problems and ensure it was practical to continue the glycol based thermal fluid fill, using Sentinel R500C which gives freeze protection down to -15ºC and the bacteria level was again tested. Based on ATP Assay, the activity was now zero - a job well done by the Sentinel team and Dave and Neil’s team on site.
Dave said: 'It was really eye opening and encouraging to see a supplier showing so much interest in training installers. Sentinel has been really helpful and I will certainly be using their products whenever we install Ground Source Heat Pumps in the future. We witnessed quite graphically the problems associated with GSHP installations – and smelt them too! It’s clear to me that the Sentinel renewables range has been designed with a very high understanding of the issues involved and with a product for every need in the installation process from flushing the system, sanitising it and filling it with a robust glycol based fluid that will deliver the high efficiency heating that people investing in heat pump technology expect. I’ve been very impressed with the whole process.'
Sentinel is a company with a clear goal: we offer water treatment products and services that provide the best lifetime protection for heating and hot water systems. Originally launched in the UK by Grace Dearborn in 1988 and subsequently a subsidiary of the leading multinational General Electric, Sentinel has operated independently since 2005, expanding its international reach and range of innovative solutions. As of 2021, Sentinel is owned by Aalberts N.V., and sits in the hydronic flow control cluster.
