Evaluating the efficiency of Building Heat Networks in Social Housing

Centralised heating systems and building heat networks are seen as a cost-effective and efficient method of heating supply and are encouraged by the UK’s government schemes to reduce carbon emissions and assure residents can... [ view full abstract ]

Centralised heating systems and building heat networks are seen as a cost-effective and efficient method of heating supply and are encouraged by the UK’s government schemes to reduce carbon emissions and assure residents can afford heating their homes. Hence, the UK’s, specifically England’s domestic building stock is being retrofitted to upgrade heating systems, with particular focus in social housing. Social housing represents 17% of buildings in England and hosts low-income residents, who could greatly benefit from affordable heating. Thus, it is important to understand the characteristics of the demand and the factors that affect the performacnce of heat networks, to assure an efficiency heat supply and occupants’ comfort. This papers presents research conducted on five identical high-rise social housing tower blocks located in the city of Southampton, United Kingdom and recently refurbished to meet BREEAM Excellent standards. Heating in each tower block is supplied through a high temperature wet network from gas boilers to heat exchangers in each flat. Monthly gas consumption at building level and heating demand for space heating and hot water at flat level were monitored from 2013 to 2017. Results showed that: (a) the efficiency of the heat network was lower than 70% at all times, reaching minimum values during summer months (b) the heat demand in the flats was lower than expected for the building characteristics – 34 kWh/m²year for hot water and 21 kWh/m²year for space heating, (c) heat demand variability was higher during the period from November to January. The analysis identifies building thermal performance, layout of the heat network,  and resedents’ comfort requirements and financial limitations as the main determinants of heat demand.