Energy-Saving Trio: Positive Energy House / ZHU Architecture

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Inspired by the adaptability and self-renewal capabilities of nature, the "Positive Energy House" seeks to minimize negative impacts on the natural environment and strives to create a more resilient future.
▲Overall bird's-eye view @Zhang Chao
  Introduction
"How to face future low-carbon life, obviously we need a newer lifestyle, not only to make us convenient and comfortable, we also have a responsibility, how to make people develop healthier, we cannot waste." An entrepreneur said so at the first ESG Global Leaders Summit in 2021. Symbiosis with the environment, advocating low-carbon behavior, meeting the needs of comfortable living in a zero-energy house (not just obtaining zero-energy labeling certification and technology stacking), this is the main goal of this project transformation, indicating that this transformation is not only the design of a single project, but also an exploration of a future energy-saving transformation model.
▲Overall bird's-eye view @Zhang Chao ▲East side bird's-eye view @ZHU Architecture
The Positive Energy House is a renovation of a hillside residential building in Shenzhen's coastal area, facing the sea on the south side and backed by mountains on the north side. The coastal environment not only makes the interior humid, but the high-salt sea breeze also damages equipment and power systems. The lush trees cannot block the summer sun, and the south side of the interior has excessive sunlight, while the north side rooms, due to their excessive depth, lack sufficient lighting and ventilation. Coupled with the low energy-saving standards of the building during its initial construction, the existing building has high overall energy consumption.
Facing a series of problems with the building itself, and the goal of exploring energy-saving renovation models, ZHU Architecture proposes a replicable modular renovation method: a three-layer skin system. ▲Modular renovation analysis diagram @ZHU Architecture ▲Overall bird's-eye view @ZHU Architecture
  Three-Layer Skin System
The three-layer skin system is a simple, sustainable, and cost-effective way to upgrade a residence into a highly energy-efficient building. Addressing each skin separately avoids the complexity of integrating different functions into a single building envelope; flexible gap spaces are also formed between each layer of skin. ▲Single-unit renovation strategy analysis diagram @ZHU Architecture ▲East side bird's-eye view @ZHU Architecture ▲South side bird's-eye view @Zhang Chao ▲Overall bird's-eye view @ZHU Architecture
The innermost layer is the original building facade, without major modifications. Appropriately increasing the window openings to increase natural ventilation, natural lighting, and spatial openness. The middle layer is an airtight heat insulation layer, serving as thermal insulation for the north-south glass curtain walls and the east wall; this layer ensures energy savings when using air conditioning. The outermost skin is an external solar panel shading system; optimal shading also provides the maximum usable area for solar photovoltaic panels. The external shading system is staggered to ensure comfortable indoor views and allow for air circulation. ▲Three-layer skin renovation analysis diagram @ZHU Architecture ▲South side elevation @ZHU Architecture ▲Southeast view @Zhang Chao
The solar panel shading system of the outermost skin is a hanging structure. Utilizing the existing roof structure, newly added outward extending struts are used to hang downward a horizontal triangular truss structure supporting the solar panels, a total of four layers, staggered downward to avoid mutual obstruction. ▲External hanging structure analysis diagram @ZHU Architecture ▲Solar panel shading system elevation @Zhang Chao ▲Solar panel shading system elevation @Zhang Chao ▲Solar panel shading system elevation (partial) @Zhang Chao ▲Solar panel shading system elevation (partial) @Zhang Chao
The inclined surface of the triangular truss is equipped with keel and perforated steel plates to fix 200*200mm cadmium telluride photovoltaic panels. The small-sized photovoltaic panels are staggered in a scale-like manner to form shading layers of different scales, as well as personalized appearances such as arc corners, to further realize the integrated design of architecture and photovoltaics.
▲Overhead view of solar panel shading system @ZHU Architecture ▲Overhead view of solar panel shading system @ZHU Architecture ▲Overhead view of solar panel shading system @ZHU Architecture ▲Sectional perspective @ZHU Architecture
  Hybrid Environmental System
The gap spaces between the three layers of skin form a hybrid environmental system, with flexible usage in different weather conditions.
In suitable weather, the inner and middle layers are fully opened to form good natural ventilation; in hotter weather, the inner layer is opened, the middle layer is closed, and mechanical ventilation is used to promote indoor air circulation and control humidity to some extent; in extremely hot weather, both the inner and middle layers are closed, and the air conditioning and fresh air systems are turned on to control humidity. This different combination of skin openings effectively reduces the use of air conditioning throughout the year while ensuring comfort. ▲Three-layer skin ventilation mode analysis @ZHU Architecture
The gap layer between the middle and outer layers of skin is a semi-outdoor space, with high-rise large terraces, small balconies, and ground courtyard spaces, with good shading and ventilation.
▲South side terrace @Zhang Chao ▲South side balcony @Zhang Chao ▲South side courtyard @Zhang Chao
The gap layer between the middle and inner skin layers is a full-height indoor space used for buffering, with neat glass curtain walls on one side and uneven changes in the original residential facade on the other. Combined with staggered platforms and a four-story climbing wall, a transitional space connecting indoors and outdoors is formed.
▲South side gap layer @Zhang Chao ▲South side gap layer @Zhang Chao ▲Sectional perspective @ZHU Architecture
  Positive Energy System
After adding the outermost shading system to the positive energy house, while improving the lighting environment, it can generate enough electricity through solar photovoltaic panels. The power generation efficiency of solar panels in different parts is different, with a total power generation of about 18,000 degrees, exceeding the estimated maximum power consumption of 12,000 degrees, to achieve "positive" energy. Excess electricity can be stored or fed into the municipal power grid. ▲ Shading analysis diagram before and after renovation @Z+ Architects
This is a way to conduct energy micro-renovation on buildings to achieve self-sufficiency in energy for individual buildings, or even a positive surplus of energy. On the one hand, it fully utilizes renewable energy; on the other hand, it reduces building energy consumption through active energy-saving technologies such as mechanical ventilation and intelligent fresh air systems, as well as passive energy-saving designs such as ventilation design in high-rise gaps, high-efficiency shading, and high-performance maintenance systems. The superposition of these two aspects forms the positive energy of the final renovation of existing buildings.
▲Solar panel shading system elevation @Zhang Chao ▲ East view of the solar panel shading system @Zhang Chao ▲ South view of the solar panel shading system @Zhang Chao ▲ Partial south view of the solar panel shading system @Zhang Chao
  Prospect
The positive energy house attempts to find a building renovation method and a renewable energy usage method that reduce carbon emissions throughout its life cycle. Ultimately, we hope to achieve an example of a positive energy house where energy production exceeds consumption through a three-layer skin renovation strategy and a prefabricated system that integrates photovoltaic panels and shading systems. This will ultimately become a widely promoted energy-saving micro-renovation model for existing buildings.
▲ Bird's-eye view from the east @Zhang Chao
▲ Site plan ▲ First-floor plan ▲ Second-floor plan ▲ Basement plan (-1F) ▲ Basement plan (-2F) ▲ North elevation ▲ East elevation ▲ South elevation ▲ Section A-A ▲ Section B-B ▲ Section C-C ▲ East wall detail ▲ South wall detail
Project: Positive Energy House Project Location: Longgang District, Shenzhen Design Company: Z+ Architects Design Principals: He Zhe, Shen Hai'en (James Shen), Zang Feng Design Team: Xu Jiaqi, Wang Chengchen, Yuan Yingzi, He Jingyun (Anouchka van Driel), Lin Mingkai, Zhang Meng, Yang Quanyue, Hou Yingqi, Huang Jia, Xie Ruoying Structural Design: Liu Su / Beijing Shou'ang Architectural Structure Studio, Beijing Research Institute of Building Design, Guangzhou Ruihua Architectural Design Institute Equipment Design: Beijing Research Institute of Building Design, Guangzhou Ruihua Architectural Design Institute Photovoltaic Design: Shenzhen SEG Longyan Energy Technology Co., Ltd. General Civil Engineering/Construction: Shenzhen Bosheng Real Estate Co., Ltd. Design Period: January-September 2022 Completion Time: May 2023 Building Area: 505 square meters Photography: Zhang Chao, Z+ Architects (Wang Chengchen) Drawing: Zhi Liu, Zhang Meng