Challenge / Goal
The Nottingham City Council aims to create a citywide heat network that will further enable Nottingham to cope with climate change and build resilience to external energy price pressures. To speed up the process toward 20 % energy efficiency improvement required by the EU by 2020, the huge energy-saving potential in the building sector and the expansion of existing district heating network with more energy efficient ones should be exploited.
From the 375 GWh heat generated by the Combined Heat and Power (CHP) plant, 144 GWh are used for heat distribution and 60 GWh for electricity production. This means that 171 GWh of valuable heat energy resource is unused and can be potentially recovered by various schemes like the present Low Temperature District Heating (LTDH) scheme for annual heat sales to improve the efficiency and profitability.
The technological innovation (specifically regarding the thermal insulation) of the last decades, enabled to reduce the temperature level of the transfer fluid used in the DH system between 50°C and 60°C (and become a LTDH system) which would be enough to heat low energy buildings. This decrease offers many advantages and improves consistently the energy efficiency of the DH system.
In Nottingham, the LTDH flow will be drawn from the return pipe of the main district heating with the medium-temperature water travelling back to the CHP for reuse. In this case, planned routes of high to low temperatures infrastructure were built to connect the four maisonette blocks with a total of 94 properties in the demo site to meet the demand of space heating and DHW. The LTDH will provide a primary flow temperature at approximately 50 ºC to 60 ºC and return temperature approximately at 30 ºC, which are much lower than usual and result in lower transmission losses.
Due to the lower flow temperature, the network heat loss will be reduced by 75% compared to the present district heating systems. This makes the LTDH systems economically more sustainable and competitive for modern well-insulated, low energy buildings or significantly improved, retrofitted properties.
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Improving Energy Supply Efficiency,
Reducing Operation Costs,