53% Reduction in Resident Heat Tariff
87% Reduction in Heat Losses from the Network
47% Reduction in Total Carbon Consumption
Background
The project consists of a residential development for a local authority on the south coast of the UK. The development contains a heat network that integrates across 10 blocks, serving a total of 274 dwellings. This network is built on a 2-pipe system, which is fuelled by gas boilers. It is designed to provide both space heating and domestic hot water through its bespoke single plate Heat Interface Units (HIUs). A unique feature of this system is the direct provision of heating via radiators from the network, eliminating the need for a hydraulic separation between the individual radiators in the dwellings and the main distribution network.
Challenge
The local authority engaged with FairHeat as gas and electricity consumption was found to be higher than expected at the scheme. Also, the resident experience of the heat network was sub-optimal when considering factors such as reliability and overheating. FairHeat proposed collaborating with the local authority by undertaking an optimisation study, which was underpinned by a site audit, a meticulous performance analysis, and a comprehensive technical and financial analysis report.
The development was facing significant heat losses, which amounted to 8,700 kWh per dwelling. This is considerable when compared to buildings of a similar type and age. The inefficiency identified was traced back to a series of factors. The HIU pipework and plate heat exchanger was not sufficiently insulated, the function of a control valve was inadvertently causing bypassing, and the radiator return temperatures were high.
The system’s gas and electricity consumption were found to be higher than desired. This was attributed to the issues identified with the high heat losses. In addition, the boiler shunt pumps and recirculation pumps operating at a fixed speed. This operational pattern also led to a rise in boiler inlet temperatures, frequent boiler cycling, and a lack of stability in flow temperatures.
Another oversight was the absence of equipment dedicated to the continuous maintenance of water quality.
FairHeat Solution
In response to the challenges identified, FairHeat proposed a few options to improve the performance of the system work packages, so an informed decision could be made on the package of works to proceed with.
Using the information and analysis from the study, the local authority was able to build a case internally on the package of works to proceed with. This involved insulating the HIU pipework and plate heat exchanger in alignment with the CP1 2020 standards and replacing the existing DHW plate. An upgraded control valve sensor accelerator was proposed, and both the space heating system and the HIU were proposed to undergo thorough recommissioning. The internal riser pipework and the accessible external pipework were also proposed to be reinsulated to meet the CP1 2020 standards.
To further enhance the system’s efficiency, several additional measures were proposed: the external pipework weatherproofing, AAVs were installation on all riser tops, pump de-commissioning/removal and a 3-port valve across the network flow and return.
To optimise the control and operation of plant, BMS amendments were proposed boiler and pump control methodology. Additionally, an isolation valve was proposed to be strategically placed in the header, isolating the flow and return connections, and the plantroom pipework was to be reinsulated, adhering to the CP1 2020 standards.
Results
The Core Work Package solutions implemented by FairHeat identified transformative results. The flow and return temperatures were optimised from 82/59°C to a more efficient 59/46°C. This optimisation, coupled with other measures, identified substantial financial savings for residents, as the expected heat tariff dropped around 53%. The measures translated to a 48% reduction in yearly gas consumption, a 40% decrease in electricity usage, and a commendable 47% cut in total carbon emissions, reducing the carbon footprint from 243,424 kgCO2/year to 128,053 kgCO2/year. Additionally, the network’s heat losses were curtailed by an impressive 87%, and flow temperature stability saw marked enhancement, maintaining consistent temperatures over 85% of the time.
The project identified a significant improvement in carbon reduction which was prominently highlighted through a 47% reduction in its total carbon consumption. By reducing carbon emissions from 243,424 kgCO2/year to 128,053 kgCO2/year, the development can minimise its carbon footprint, as well as contribute to UK’s Net Zero Carbon goals.
Heat losses are a primary concern in any heating system, as they directly impact efficiency, cost, and environmental sustainability. The substantial 87% reduction in heat losses from the network is a testament to the effectiveness of the solutions identified. By dramatically reducing these losses, the system would operate at a much higher efficiency, ensuring that the majority of the generated heat is utilised for its intended purpose rather than being wasted. This not only translates to better performance and reliability but also means that less energy is required to achieve the desired heating outcomes, leading to further reductions in costs and emissions.
One of the most tangible benefits of the interventions was the significant reduction in the heat tariff for residents identified. By optimising the system’s efficiency and reducing operational costs, the savings were passed on to the residents in the form of reduced tariffs. The heat tariff reduction identified was around 53%. This not only lightens the financial burden on residents but also enhances their overall satisfaction and trust in the system. A reliable and cost-effective heating system can significantly improve the quality of life for residents, ensuring comfort without the concern of escalating costs.
