Cost optimality and net-zero energy in the renovation of Portuguese residential building stock – Rainha Dona Leonor neighbourhood case study

Modern cities emerged as the main accumulator for primary and waste materials. Recovery of both types from buildings after demolition/disassembly creates a secondary material stream that could relieve pressure from primary resources. Urban mining represents this circular approach, and its application depends on redefining current construction practice. Through the life cycle assessment (LCA) methodology and assuming primary resources as step zero of urban mining, this study estimates the impacts and benefits of conventional versus a circular construction practice applied to various buildings with different parameters and the country-level environmental potential savings that could be achieved through this switch in construction practice—using the increase of the residential building stock in Switzerland between 2012 and 2016 as a case study and key values from the experimental unit “Urban Mining and Recycling”, designed by Werner Sobek with Dirk E. Hebel and Felix Heisel and installed inside the NEST (Next Evolution in Sustainable Building Technologies) research building on the Empa campus in Switzerland. The results exhibit lower total impacts (at least 16% in each examined impact category) at building level and resulting benefits (i.e., 68–117 kt CO2-Eq) at country level over five years, which can be further reduced/increased respectively by using existing or recycled components, instead of virgin materials.

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Net zero energy buildings: Application in Lebanon on a typical residential building

2012 International Conference on Renewable Energies for Developing Countries (REDEC) ◽

10.1109/redec.2012.6416707 ◽

2012 ◽

Cited By ~ 2

Author(s):

Tarek Samarji ◽

Adnan Jouni ◽

Ali Karaki

Keyword(s):

Residential Building ◽

Zero Energy ◽

Net Zero Energy ◽

Net Zero ◽

Net Zero Energy Buildings ◽

Zero Energy Buildings

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Net Zero Energy Retrofit Shading Strategies of Buildings in Gaza, Case Study: Multi-Storey Residential Buildings

2019 IEEE 7th Palestinian International Conference on Electrical and Computer Engineering (PICECE) ◽

10.1109/picece.2019.8747198 ◽

2019 ◽

Author(s):

Rania Mohammad Ashour ◽

Ahmed S. Muhaisen ◽

Suheir Ammar

Keyword(s):

Residential Buildings ◽

Zero Energy ◽

Energy Retrofit ◽

Net Zero Energy ◽

Net Zero

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An exploration of the feasibility of converting the New Zealand commercial building stock to be Net Zero Energy

10.26686/wgtn.17082833 ◽

2021 ◽

Author(s):

◽

Shaan Cory

Keyword(s):

Renewable Energy ◽

Energy Consumption ◽

New Zealand ◽

Commercial Buildings ◽

Commercial Building ◽

Zero Energy ◽

Building Stock ◽

Energy Models ◽

Net Zero Energy ◽

Net Zero

This thesis explores the feasibility of converting the current New Zealand commercial building stock to Net Zero Energy (NZE). The analysis presented is grounded in real building performance and construction information. The goal was to establish results that are as realistic as possible to actual building performance. The Net Zero Energy Building (Net ZEB) concept is one of many low energy building movements that respond to the issues of climate change and energy security. The Net ZEB concept strives to reduce demand for energy and then to offset any residual energy consumption with non-CO2 emitting renewable energy technologies. The (re-)design focus for Net ZEBs is to reduce annual energy consumption to be equal to or less than any generated renewable energy. This is an important concept since approximately 40 percent of all energy and emissions worldwide are building related. If all buildings were designed and operated to be NZE, the existing energy can be used by other sectors which will increase energy security. Conversely, reducing the fossil fuel CO2 producing component of the energy consumed by buildings has the benefit of negating building’s contribution to climate change. The Net ZEB concept assumes each building is grid-connected, and balances the energy taken from the grid against the energy put back into the grid over a year. This study exploits the available synergies of the grid connection to achieve NZE for the whole building stock. Thus each individual building does not need to be NZE at the site, but they act as a community to reach NZE collectively. Furthermore, any grid-tied renewable energy does not need to be offset, only the non-renewable portion. A NZE target was calculated to determine the percentage reduction in current energy consumption needed before the current commercial building stock could be considered NZE. It was found that a 45 percent reduction in primary energy would offset all non-renewable CO2 emitting energy supply currently consumed by the New Zealand commercial building stock. Previous studies assessing whether converting an entire stock of commercial buildings to NZE is possible used prototypical building energy models. Prototypical models represent a hypothetical average building and have many assumptions about the way a building is operated. This thesis develops a method that takes a representative sample of real commercial buildings and makes calibrated energy models that can be aggregated to represent energy consumption for all commercial buildings in New Zealand. The developed calibration method makes use of as-built building information and a standardised procedure for identifying the inaccurate model inputs which need to be corrected for a building energy model to be calibrated. To further base the process in reality, a set of Energy Conservation Measures (ECM) that had been implemented in real Net ZEBs worldwide was adopted for the proposed retrofits. These ECMs were combined into Net ZEB solution sets for retrofitting the aggregated commercial building models. Optimisation of the Net ZEB solution sets was performed on hundreds of models to maximise energy savings. It took over six months for all of the optimisations to be completed. This thesis demonstrates the estimated New Zealand commercial building stock’s energy consumption based upon the calibrated energy models was robust by comparing it to an external estimate. It shows that NZE can be achieved by applying well understood Net ZEB solution sets to the New Zealand commercial building stock. 96 percent of the NZE goal is attainable just through demand reduction without the use of onsite renewable energy generation. The additional four percent of reduction required to meet NZE is easily attainable with onsite renewable generation. Another benefit is that the retrofitted commercial buildings will provide improved thermal comfort for the occupants. Having established NZE was possible, this thesis concludes with an analysis of the broader implications of achieving the NZE goal. It identifies the next step would be to design a NZE commercial building stock that reduces the stresses on the existing energy infrastructure. The Solution Set adopted was not developed with the interaction of the building and electrical grid in mind. To have a practical implementation of NZE will require costing and community prioritisation. This would be the next phase of work assessing nationwide NZE retrofit.

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Towards net zero energy modular housing: a case study

Modular and Offsite Construction (MOC) Summit Proceedings ◽

10.29173/mocs43 ◽

2018 ◽

Cited By ~ 2

Author(s):

Caroline Hachem-vermette ◽

Chinyere Dara ◽

Rhys Kane

Keyword(s):

Hot Water ◽

Housing System ◽

Positive Energy ◽

Energy Status ◽

Zero Energy ◽

The South ◽

Net Zero Energy ◽

Net Zero ◽

Modular Housing

The paper summarizes an investigation of the performance of container based housing units developed by Ladacor Ltd, and compares this performance to traditional housing constructed according to existing standards and codes. The results indicate that the case study housing system can reduce thermal loads (heating and cooling) by about 57% as compared to the same house designed according to the code. Implementing additional efficiency measures and solar design strategies such as increased south window size, suitable shading devices, thermal mass, and more airtight construction, leads to improved performance. This enhanced scenario can reduce the thermal load by 72% as compared to the code scenario and by about 35% as compared to the original case study system. Achieving a net-zero energy status can be reached by integrating photovoltaics on the south roof of the single-family housing designed with Ladacor roof, assuming energy efficient appliances, lighting and domestic hot water. The optimal case can reach a net positive energy status, with a PV system integrated on the south facing roof surface. Results from this investigation can serve in developing innovative design concepts and guidelines for the design of low cost, self-sufficient modular housing.

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