This work aimed to quantitatively study the carbon emissions and carbon reduction potential of a nearly Zero Energy Building in a severe cold zone of China from the perspective of its life cycle. The methods were based on China’s “Standard for building carbon emission calculation” (GB/T51366-2019), which include the production, transportation, operation, and demolition stages. For the nearly Zero Energy Building, the total carbon emissions over its whole life were 789.43 kg CO₂/m², an 86.20% reduction compared to the 5719.68 kg CO₂/m² for a 65% energy-saving building. The carbon emission percentages of the production stage and operation stage for the building materials are 75.62% and 20.40%, respectively. To enhance the carbon reduction potential, a sensitivity analysis was conducted to explore the impact of the use of a wood structural system, recycled concrete replacement, and photovoltaic power generation. The use of a wood structure system can achieve zero or negative carbon emissions in the production stage. The sensitivity of the carbon emissions of the nearly zero energy building (nZEB) to the increment of photovoltaic power generation is much higher than that of the recycled concrete replacement rate, providing a basis for further exploration of the development of nZEBs into zero carbon buildings.

A nearly zero-energy building is characterised by its low energy demand and enhanced thermal insulation, with great potential to integrate renewable energy systems to satisfy various demands and improve energy efficiency. Solar energy is a primary renewable energy resource that can be harnessed in different ways to provide electricity, heating, and cooling in building applications. In this study, a solar–ground-source heat pump system was designed and established in a nearly zero-energy building. The system’s performance was presented, and its control strategy was optimised. To evaluate and assess the operation of the solar energy system, an experimental setup was built, and the experiment was divided into two periods, taking into account the weather conditions. In the first experimental period, different parameters of the heating system were tested and evaluated. In this regard, the variation trends of the heat pump unit’s coefficient of performance, the system coefficient of performance, the collector start-up temperature difference, and the heat pump setting temperature were analysed under different parameter combinations. On this basis, the optimal operating parameters were identified for different heating periods. In the second period, the optimal operating parameters identified were used to carry out heating experiments. The results highlighted that the adoption of the preferred operating parameters increases the percentage of direct solar energy supply by 2.0%. Additionally, the system coefficient of performance increases by 8.9%, the unit coefficient of performance increases by 6.7%, the carbon emissions are reduced by 4.18 tonnes, the SO₂ emissions are reduced by 0.143 tonnes, and the dust emissions are reduced by 0.1 tonnes. The findings of this study can provide useful data and a guiding reference for optimising and promoting the implementation of renewable-energy-driven heating systems for nearly zero-energy buildings in severe cold regions.