Colloquia

Summary

The Netherlands’ residential built community has an enormous challenge to reduce natural gas burning and bring down emissions in the existing buildings. The Netherlands’ government has made various heat transition regulations to switch from natural gas to a renewable heating source. Hybrid heat pumps (HHP) are one such alternative source of heating systems that have the potential to reduce current natural gas consumption and lower overall emissions. The current study aims to develop a prediction model of HHP and analyse the gas demand profiles when replaced with the conventional standalone boiler. Specifically, the prediction model investigates the annual and peak gas savings from HHP compared to a standalone boiler.

The annual gas savings were observed between 50.62 to 67.28 % when operated with a 2.5 kW heat pump capacity and 72.79 to 81.72 % when operated with a 5.5 kW heat pump capacity. The  difference in the annual gas savings were observed due to changes with ‘insulation level of building’, ‘HHP control strategy’, ‘heat pump capacity’ and ‘building type/period’. Peak gas savings were not observed when the building's insulation was very poor. But, with increased insulation for middle age and new buildings, there was a peak gas saving in the range of 33.3 % to 43.12 % when observed in the morning. When observed in the evening, peak gas savings were in the range of 73.08 % to 86.34 %, which depends on HHP settings. For a low-demand hot summer day, when there’s no requirement for space heating load, there are no gas savings with HHP. When there was, HHP gas savings were nearly 75.7 %.

Furthermore, the impact of several model parameters on the HHP’s gas demand profile has been analyzed. The ‘building type’ and ‘building period’ were observed to have a huge impact on the HHP gas demand profile, and it can vary annual gas consumption between 55 % to 70 %.  The ‘control strategy’ was observed to have less impact, with a 7.6 % variation in annual gas consumption profiles. All the results from the HHP prediction model were validated with real-time HHP integrations in the Netherlands and were observed to have comparable results in HHP gas consumption profiles.