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The UK government has announced its ten-point plan to annually install 600,000 low-carbon heat pumps by 2028. However, there is a lack of evidence showing potential overheating risk in dwellings retrofitted with heat pumps. This paper examines the prevalence and magnitude of summertime overheating across 24 naturally ventilated social housing dwellings retrofitted with ground source heat pumps (GSHPs). The dwellings are located in a socially deprived area in Oxford (UK). The empirical study included longitudinal monitoring of indoor temperatures in the living rooms and bedrooms during the non-heating seasons of 2021 and 2022 (May–September), which included a record-breaking heatwave in July 2022. Indoor temperature and CO2 levels in bedrooms were monitored across a subset of six dwellings alongside the monitoring of window opening state in three bedrooms to understand the effect of natural ventilation in removing excess heat. About 136 thermal comfort surveys were conducted to ascertain the subjective responses of residents. Overheating risk assessment was carried out using CIBSE static and adaptive methods, which revealed that summertime overheating was prevalent across half of the dwellings in the non-heating season of 2022, as compared to 17% overheated dwellings in 2021. Bungalows with upgraded cavity wall insulation and top floor flats facing south and south-west had a propensity to overheat. The variation in indoor temperature and CO2 levels across a small sample also indicated the relationship between overheating and residents' behaviour. Given that the majority of the dwellings were occupied by retired elderly people with low incomes who are vulnerable to heat and cannot afford active forms of cooling, it is vital to deploy passive design measures, such as appropriate shading devices that are suitable for a heating-dominated climate and enhanced ventilation, as part of home energy retrofits. Implementing reversible heat pumps coupled with solar PVs can provide cooling during heatwaves while delivering low-carbon heat in the winter. [ABSTRACT FROM AUTHOR]

• GB domestic heat pump electricity demand in 2050 is modelled. • Modelling is based on monitored data from heat pumps and gas boilers in homes. • Uptake of heat pumps in all homes more than doubles peak GB electricity demand. • Moderate improvements in HP performance and dwelling fabric reduce peak GB demand. • Flexibility in DHW and space heating provision also reduce peak GB demand. To meet net zero carbon targets by 2050s, countries with cold winters, such as Great Britain (GB), will turn to low carbon domestic heating systems such as electric heat pumps. In this paper, a statistical model is developed using measured performance data from over 550 heat pumps installed in GB homes in 2012. The model is used to predict the additional load on the GB electricity generation and distribution infrastructure for various current and future (2050) climates, dwelling energy efficiencies and heat pump deployment scenarios. For a cold year in the 2020s, a 100% uptake of heat pumps in the existing GB dwelling stock gave a peak electricity demand for the heat pumps of 78 GW and an annual electricity demand of 189 TWh. When added to the other, existing electricity demand, this represents an increase in the GB peak electricity demand in excess of 100% and an annual electricity demand increase of around 60%. Making reasonable assumptions about heat pumps' future efficiency and use, and the future climate and dwelling stock fabric efficiency, and assuming 80% heat pump uptake and no load shifting, the peak heat pump electricity demand for a cold year in the 2050s halved to 37 GW. By shifting demand for water and space heating the 2020s cold year peak demand reduced by 15%. The work provides a more robust estimate of future GB heat pump electricity demands than any previously available. The predicted future ramp rates, peak and annual total electricity demands, are lower than predicted by previous analysts. [ABSTRACT FROM AUTHOR]

Energy load forecasting is essential to effectively optimise the use of energy for the purpose of smart grid operation. In this work, a focus is placed on Short-Term Load Forecasts (STLF) using measured heat pump data from the UK utilising the Long Short-Term Memory (LSTM) method. A load forecasting program is developed to forecast the electricity consumption of heat pumps based on historical data. LSTM is compared to Backpropagation Neural Network (BPNN), Seasonal Autoregressive Integrated Moving Average (SARIMA), Random Forest (RF) and Holt-Winters Exponential Smoothing (ES). The best average Mean Absolute Percent Error (MAPE) of 1.59% is achieved for the test data set by LSTM, which outperforms other models compared and a number of models presented in papers in the literature. By conducting the Wilcoxon signed-rank test, it is proven that the prediction accuracy improvement of LSTM compared to other models is statistically significant with the exception when comparing with RF with the training data. The impact of data aggregation resolution to forecast accuracy is investigated. The proposed LSTM model performs best on 1-h resolution data compared with other resolution time periods. The results of the LSTM model are integrated with Home Energy Management Systems (HEMS). The electricity costs of the HEMS are compared when using forecasted and measured heat pump data respectively. The results indicate an average percentage difference of 2.06% between the predicted and the actual electricity cost of HEMS for the test data. Furthermore, this paper presents a combined neural network and Particle Swarm Optimisation (PSO) model to develop an optimised energy management system while proving the effectiveness of the LSTM algorithm. • A LSTM algorithm is used to forecast the electricity consumption of heat pumps. • The proposed forecast model outperforms models found in the literature. • The Wilcoxon signed-rank test is used to prove the effectiveness of LSTM model. • The impact of data aggregation resolution to forecast accuracy is investigated. • The load forecast model is integrated with a Home Energy Management System model. [ABSTRACT FROM AUTHOR]