Viscount Bridgeman Retirement Housing

Improving a poor system

Scheme:	System take over and upgrade of heating system installation
Boiler and plant:	2xETA PC70 kW pellet boilers with distribution to 36 individual properties
Fuel	Wood pellets
Fuel storage	Internal pellet storage built into plant room.
Grant /Funding	The installation was initially funded by the PSDS (Public Sector Decarbonisation Scheme)
Savings /Investment	The savings will come in the form of reliability and better efficiency from the boilers
Carried out	Aug 2024 and ongoing

Getting biomass right

Project overview.

Housing 21 are a large retirement and care housing operator, with over 25,000 properties throughout the UK. Dunster were asked to look at an install in Oswestry due to ongoing issues.

A biomass system was installed in 2021 but had proved to be really unreliable and a real headache for the onsite team. The boilers used were good, however the system design was very poor, causing the boilers to cycle constantly. This has resulted in serious damage to the internals of the boilers, new grates, new combustion chambers and dozens of breakdowns have resulted.

Dunster set up monitoring of the system using the ETA MeinETA system, recording what was happening in order to be able to identify the issues. It became very obvious that the hydronic design was the culprit and a new design was drawn up.

A re-piping of the plant room was required, adding control of the flow rates and ensuring distribution pumps were not starved. Heat meters were added, cascade controls to the boilers installed and ensuring everything was commissioned correctly was all undertaken in 1 day in January 2025 (as residents needed the heat back on).

So far the system has proved to be significantly more reliable, and fuel usage has gone down. It proves again that biomass is a reliable, efficient low carbon heat source, but it is essential that correct design and implementation is undertaken or else it can be a nightmare for the customer.

We received Housing 21’s contractor of the year certification for the works we have done, transforming the system by doing what was needed in the first place. Next on the list is replacement fuel stores to expand the capacity, reducing the fuel deliveries to site.

Corsham School Case Study

Two ETA Hack 350kW and district heating connections.

Scheme:	Replacement of 8 Gas boilers with Biomass Energy Centre
Boiler and plant:	Installation of 2x ETA Hack VR 350kW boilers, 2x 10,000 litre buffer tanks and full distribution network to 4 school buildings. Integration into existing heating systems and full control over thenetwork . Existing gas boilers were completely removed.
Fuel	The boilers are expected to use around 150 tonnes of wood pellet, producing over 525Mwh of heat per annum.
Pellet storage	Dunster designed and constructed underground Woodchip store, with sliding roof arrangement allowing easily tipped deliveries
Grant /Funding	The system was funded by the PSDS (Public Sector Decarbonisation Scheme) Savings
Savings /Investment	Switching from oil, the property is saving on energy bills and removing 94 tonnes of CO2 emissions. Additionally, the income from RHI payments will pay off the capital expenditure of the system.
CO2 saving	Compared to gas heating, our wood pellet system reduces CO2 emissions by over 95%, equating to
Commissioned	March 2024

Replacement of 8 Gas boilers with Biomass Energy Centre

Project overview.

The Corsham School is a large Secondary School in Wiltshire, which several 1960’s constructed buildings which had gas boilers coming to the end of their life.

The scheme was identified as eligible for the PSDS funding, and this application was successfully carried out by ReEnergise Projects. Dunster were successful in the tendering process, and detailed design works were carried out.

The system consists of and underground plant room and chip store, Biomass Plant, 500m of underground heat main & 4 heating interfaces with plate heat exchangers and flow control. Ground was broken in July 2023, with the system fully working by March 2024.

Fuel supply and handling

Of upmost importance to the project was the ease of fuel handling, and with this Dunster designed an underground plant room and fuel store. Although more expensive as a solution than the other submissions, the school saw the benefits of going into the ground.

The practicalities of this were difficult, a high water table and rock formations in the ground proved a challenge for the ground team, but a solid, accessible and discrete energy centre is the result.

The underground nature of the design allows tipped deliveries of woodchip, no need for expensive, slow and noisy blown or auger fed systems, a 30m3 delivery can be deposited in less than 10 minutes, which is a huge advantage in the operation of the whole system
for its lifespan.

The Corsham School Biomass Storage and Boiler housing

Deanfield Study Centre

ETA PC100 Pellet Boiler

Scheme:	Replacement of end of life oil boiler with ETA 100kW pellet unit
Boiler and plant:	IETA PC100kW pellet boiler with external buffer tank. Full system control using the ETA in built controllers, two hot water cylinders and integration into open vented existing radiator circuits.
Fuel	The boiler is expected to use around 35 tonnes of wood pellet, producing over 150Mwh of heat per annum.
Pellet storage	External pellet silo.
Grant /Funding	The system was funded by the PSDS (Public Sector Decarbonisation Scheme) as it is part of Bristol Council Net Zero targets.
Savings /Investment	Switching from oil, the property is saving on energy bills and removing many tonnes of Carbon Dioxide over its life span.
CO2 saving	Compared to gas heating, our wood pellet systemreduces CO2 emissions by over 95%, equating to1611 kg CO2 saving per year
Commissioned	January 2024

Replacement of end of life oil boiler with ETA 100kW pellet unit

Project overview.

Deanfield Study Centre is a Council owned property in the Forest of Dean, offering a range of outdoor activities for large groups of children. The centre was originally the engine house for the coal mines, but now is repurposed to offer young people a chance to explore the outdoors.

The oil boiler used for heating the site was well beyond its expected life span and was unreliable and in-efficient. The PSDS (Public Sector Decarbonisation Scheme) provided a chance to receive funding to replace this as well as help with the Councils commitment to Net Zero.

Space in the existing plant room was very limited, so an external pellet store and buffer tank were specified and the installation carried out during the school holidays to minimise any downtime of the heating system. Water treatment was added in the form of an IWTM Chemical free system which keeps the pH and dissolved Oxygen in check, extending the life span of the system.

Resolve Care Home

ETA PC80 Pellet Boiler

Scheme:	Upgrade of unreliable pellet boiler with new ETA system
Boiler and plant:	ETA PC80 kW pellet boiler replacement. Full system control using the ETA in built controllers, two hot water cylinders and integration into existing radiator circuits.
Fuel	The boiler is expected to use around 28 tonnes of wood pellet, producing over 120Mwh of heat per annum.
Pellet storage	Internal pellet storage built into plant room shipping container. ETA flex auger extract system
Grant /Funding	The installation will receive the remainder of the non domestic RHI which was with the existing installation, this will cover the extra costs of investing in new.
Savings /Investment	The care home was already on biomass as a heating system, but this was proving to be unreliable and costly to run. The new system attracts a 5 year warranty and will give many years service.
CO2 saving	Compared to the alternative of reverting to oil heating, our wood pellet system reduces CO2 emissions by over 95%, equating to circa 1300 kg CO2 saving per year
Commissioned	October 2024

Upgrade of unreliable pellet boiler with new ETA system

Project overview.

The Resolve Care group run a series of care homes for young people in the North of England, and have always wanted to embrace renewable energy as part of their Corporate responsibility. Highview House is one of their homes, and a biomass boiler has been installed for the last ten years. Unfortunately, this has proved to be an unreliable and expensive to run system, with no thought to system design and control being made.

Dunster proposed replacing with a new ETA 80kW system, modifying the fuel store to suit and controlling flow rates through the plate heat exchanger to maximise the efficiency and comfort within the home. The plant room was a shipping container, which is not an ideal
option in which to house boiler, buffer and fuel store, but with careful layout planning and location of the mechanical install we have everything in there and accessible for service and repair.

The installation was all very tight, and our in house mini telehandler proved itself invaluable to getting the old boiler out and new boiler in what was a very tight access path.

A fast turnaround was essential and from de-commissioning the old system we have heat back into the building in under three days, which was a huge positive to the residents.

Resolve Care Home Biomass boiler housing