Feasibility study on applicable net-zero energy buildings solution considering embodied energy and environmental issue

The building sector contributes 39% of process-related greenhouse gas (GHG) emissions and approximately 36% of final energy. A comprehensive net-zero energy design would greatly help the global climate crisis and accelerate the rate of meeting carbon neutrality.

The effectiveness of many new net-zero energy building projects was being questioned, as the projects typically facilitate flat building design that occupied a large green area. The devastation of natural habitats paid for more solar energy production and satisfied the annual energy consumption of the building. At the same time, most of the net-zero energy projects were found in a remote areas. The energy of building material transportation and the resident's commute was generated and has not been considered.

The passive retrofit design and the optimal photovoltaic solar system are significant for enhancing energy efficiency and supplying sufficient operational and embodied energy for the building. It eliminates the concerns of green area development and embodied energy. Two existing social housing projects located in cities were studied, and the retrofit and photovoltaic design simulation results showed the feasibility of a retrofit net-zero energy building design. Two housing projects are Rosewood Village and Sunnyside Manor. There are three building types in the Rosewood Village; apartment, townhouse, and office; they all belong to low-rise buildings. The improved annual energy consumption of the whole community was estimated 382MWh after passive design consideration, and 604MWh was expected to generate by the rooftop and canopy photovoltaic solar system. After deducting embodied energy, the annual energy production was 233MWh, and Rosewood Village would be regarded as a net-zero energy community.

Another social housing project, Sunnyside Manor, is more complicated as it is a high-rise building. The limited rooftop area was insufficient to supply enough energy for the building operation consumption. The improved annual energy consumption of the building was estimated 500MWh after passive design consideration, and 122MWh was expected to generate by the rooftop and canopy photovoltaic solar system. The annual operational and embodied energy consumption was 511MWh; Sunnyside Manor alone would not be a net-zero energy building. A co-operative net-zero energy community was introduced in this scenario, which refers to all individual buildings connected with the load match system. The effective district energy eco-systems allow access to renewable energy from different buildings within a small community. There are ten townhouses, three municipal facilities, and corresponding open areas nearby Sunnyside Manor, which can produce 552MWh net annual energy (with embodied energy consideration). The co-operative community system generated net 1.1MWh yearly energy production and proved the effectiveness of a net-zero community.

The following study outlined retrofit net-zero energy building and net-zero energy community applications. The retrofit net-zero energy building design considering embodied energy and natural habits protection can eliminate the related concerns and challenges.

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