FLUID CONTROL
System water quality products integral to ground-breaking large-scale GSHP project
Plymouth Marjon University is well on the way to becoming one of the UK’s most environmentally friendly universities following the completion of one of the largest ground source heat pump heat installations in England.
T
he second phase of the project known as ‘Marjon Zero’ was completed in September last year and, within the revamped domestic services provision, is a product from Spirotech, specialists in the field of system water quality in closed HVAC systems. The SpiroCombi deaerators/dirt separators - designed for the simultaneous removal of air and dirt from water systems – help improve cost control and energy efficiency and effectively removes circulating air and microbubbles. Dirt can be discharged whilst the system is in operation and no shut-off valves or bypass is required. The university’s new ground-breaking system was designed by Kensa Contracting, the specialist delivery partner for mass ground source heat pump installations. Will Yapp, non-domestic design engineer at Kensa Contracting, takes up the story. “It was a very fast-paced project due to the public sector decarbonisation scheme deadlines being utilised to facilitate the project which involved stripping out the gas boilers serving large parts of the university and replacing them with new ones, before the next stage involving the installation of ground source heat pumps as part of Marjon’s push to become net carbon zero by 2030. (This will save an estimated 617 tonnes of carbon each year). “The design work for the plantroom started in July last year and decommissioning the old boilers began in December. One plant room served both the north and west wings of the campus with its boilers being replaced with 560kw of heat pumps as part of a two- stage system. The requirement was to reach a temperature of up to a 70 degrees flow – with one set of heat pumps able to achieve 45 degrees, whilst another heat pump set added an additional 30 degrees to take the system to target temperature.
“A single heat pump on the West Wing delivers a load of 50kw; whilst 45 Kensa Shoebox Heat Pumps were also installed to serve the accommodation blocks. “Spirotech’s SpiroTrap filtration dirt separators
are very effective and were installed in line with the LTHW return in order to provide excellent levels of filtration to protect the new plant as we were unable to provide physical separation between the distributed heating system and the new heat generating plant due to spatial constraints” he said. A SpiroVent was proposed to be installed on the flow from the boilers and heat pumps at the hottest point in the system, which in a heating system, is the point where the system water leaves the heater. In a cooling system, it should
be installed in the return line, just before it enters the cooler. Due to the tight time frames this wasn’t available and so a SpiroCombi was deployed instead, adding a second pass at filtration in addition to deaeration of the system.
Kensa Contracting commissioned Peak Mechanical Services to undertake the installation and, according to Peak director Ben Walker, the project was originally envisaged as a ‘stand- alone’ one. He commented: “However, the decision was taken to split the work into two phases, which was deemed to be a better approach to the work. The university system was between 20 and 30 years old and there were a number of challenges that we faced. “We were told at the outset that we would have 10 days on site in which to complete the job, but we were able to complete it in just seven by working 14-hour days. Two weeks prior to going on-site, we started the planning process of organising and structuring the onsite activity and the overall plan of attack.
“The work involved emptying the whole of the plant room, carrying out the decommissioning of the existing gas fired boilers and then installing the new Hamworthy boilers and pipework before connecting to the existing pipework and the distribution pumps. One of the key elements of the project was the decarbonising and installation of heat pumps.
“Those connections entering the plant room had to be cryogenically frozen – initially six of them, but at the final count 10. There were no major issues needing to be resolved during
28 BUILDING SERVICES & ENVIRONMENTAL ENGINEER MAY 2023
the commissioning of the equipment. One of the key elements in the process is undertaking water quality testing and it is vital to flush, clean and dose before and after to ensure that no contaminants are pulled through the pumps resulting in damage to the pipes.” The first development stage of the ‘Marjon’
project was completed in 2020 and involved the installation of some 2000 solar panels, which are estimated to reduce annual carbon emissions by a very substantial 300 tonnes. In addition to this, the University has commissioned a number of electric vehicle charging stations, as well as turning to energy efficient LED lighting. A spokesperson for the university said: “This
project involving Kensa and Salex has been incredibly efficient and successful. We are striving to become one of the greenest universities in the UK through research and our passion for a more sustainable world. Our Marjon Zero project has targeted carbon emissions from structural features to operational matters such as waste disposal and suppliers. “We are working to provide a safer environment and greener place for our current and future students and are thankful to Kensa and Salex for helping us take leaps towards our 2030 carbon Net Zero goal. The university will now go on to retrofit its current buildings and continue to enhance our carbon-saving project.” The project has been funded by PSDS grant which is administered by Salex, which delivers the government funding scheme for the public sector and aimed at reducing carbon emissions.
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