Nottingham aims to become the UK's first carbon-neutral city by 2028.As part of this drive, low temperature district heating has been trialled in the city via the EU-funded project REMOURBAN.
Low temperature district heating (LTDH) technology is an approach long explored to deliver the energy systems of the future. It provides a low temperature transport medium with the capacity and flexibility to incorporate multiple innovative renewable energy generation and storage technologies. It does this through minimising system losses from source to user, these normally inherent in modern high-temperature district heat systems.
Nottingham City Homes (NCH), which manages the city's social housing, is pushing the boundaries with two LTDH pilot projects in Nottingham city centre, one of which is the REMOURBAN-Courts.
The REMOURBAN-Courts pilot project includes the retrofit of four two/three-storey maisonette blocks originally built in the 1960s. The buildings range in size, the smallest comprising fourteen homes, and the largest having thirty-one. All of them feature a combination of either two-floor or single-floor apartments. There are ninety-four homes in the full development, the majority having NCH tenants with a small number of private leaseholders (~10%).
Prior to the works, heat to most REMOURBAN-Courts properties was supplied via gas central heating, although some used electric storage heaters. The retrofit included energy-efficient upgrade of all building fabric, windows, doors, improvements to infiltration-ventilation, and home dimension remodelling to provide tenants with more space. The final action was a complete upgrade of each building’s energy system. This included the installation of a LTDH system, and a private-wire electric supply powered by roof–mounted PV panels with battery storage installed in basement energy centres.
The LHDH innovation focuses on acquisition of heat from the city district-heat return of the Bentick-Manvers-Kingston high-rise development (in the same area). The return mentioned runs through a heat exchanger that feeds new heat interface units (HIUs) installed in each REMOURBAN-Courts property. All the heat and electricity used in the homes are monitored, providing bills and information on a monthly, quarterly, and annual basis. Data drawn from this process enable in time assessment of how the properties / buildings perform in terms of energy efficiency and carbon reduction against predictions. Going forward NCH aim to use lessons learnt from the project to refine and improve on future district heating-electricity developments similar to that completed. Additionally NCH aim to gain more buy-in from tenants using its example to show what is possible for their quality of life improvement.
At this stage NCH have identified some key areas of improvement following the REMOURBAN project works. Firstly, many variations exist on the system designed against that which is installed. This led to a high extra contractor consultation time and time wasted. The lesson learnt is to complete a full design first. Furthermore, a sequencing approach should be used for integrating the system into the buildings as this would avoid some of the installation issues that arose during the project. Finally, all legal procedures should be clarified before works commence.
These lessons will serve in other initiatives as Nottingham seeks to deliver better energy systems ready for the future and the national 2050 targets.
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 646511