Analysing energy upgrading projects of single-family houses towards a Norwegian nZEB level

Abstract As the existing building stock is responsible for high energy use and greenhouse gas emissions, energy upgrading projects have been acknowledged as crucial for the energy performance improvement of existing buildings, as well as for environment preservation and rational use of resources. The aim of this article is to investigate the definition of a nearly zero-energy building (nZEB) level for the energy upgrading of single-family houses. In particular, the findings from a research project, i.e., “energy upgrading of wooden dwellings to nearly zero energy level” (OPPTRE), are presented and discussed. A core task of OPPTRE was to carry out an architectural competition, where six interdisciplinary teams proposed innovative solutions for upgrading to a nZEB level representative Norwegian wooden single-family houses, from the period 1950-1990. The upgrading measures proposed in the OPPTRE competition focused on several aspects, such as architectural quality, indoor thermal environment, energy use/generation, carbon footprint, and cost effectiveness. General principles for a nZEB level achievement in upgrading projects are discussed in this article, as deducted from the evaluation of the results of the OPPTRE architectural competition. In particular, the focus is on examining the solutions proposed for upgrading building envelope and technical building systems. Energy use, energy generation, investment costs, and CO2 emissions are examined across the various OPPTRE projects, striving to define a trade-off among different parameters for the achievement of a nZEB level. The findings of this paper support the creation of knowledge in nearly zero-energy upgrading of wooden single-family houses, aiming to a more systematic definition of a nZEB level in such projects. This can be relevant for several stakeholders, such as governmental institutions, homeowners, builders, and private or public decision makers, towards the market uptake of nZEB upgrading by 2030.

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Architectural Elements with Respect to the Energy Performance of Buildings

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1020.561 ◽

2014 ◽

Vol 1020 ◽

pp. 561-565 ◽

Cited By ~ 1

Author(s):

Rastislav Ingeli ◽

Katarína Minarovičová ◽

Miroslav Čekon

Keyword(s):

Energy Demand ◽

Energy Use ◽

Energy Performance ◽

High Energy ◽

Primary Energy ◽

Zero Energy ◽

Architectural Elements ◽

Zero Energy Building ◽

Very High Energy ◽

Building Operation

Buildings account for 40% of the primary energy use and 24%of the generation of green house gases worldwide. Therefore, a reduction of the specific energy demand of buildings and increased use of renewable energy are important measures of climate change mitigation. On the 18th of May 2010 a recast of the EPBD was approved which further clarifies the intention that buildings shall have a low energy demand. The recast of the EPBD specifies that by the end of 2020 all new buildings shall be “nearly zero-energy buildings”. A nearly zero-energy building is defined as a building with a very high energy performance and very simple shape. The current focusing on the energy efficiency of the building operation may lead to uniform cuboid architecture with heavy insulated building envelopes. The paper deals with the influence of energy concept on architectural elements (and their properties as shape, material, colour, texture etc.)

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Energy Performance, Indoor Air Quality and Comfort in New Nearly Zero Energy Day-care Centres in Northern Climatic Conditions

Journal of Sustainable Architecture and Civil Engineering ◽

10.5755/j01.sace.24.1.23228 ◽

2019 ◽

Vol 24 (1) ◽

pp. 7-16 ◽

Cited By ~ 3

Author(s):

Kalle Kuusk ◽

Ahmed Kaiser ◽

Nicola Lolli ◽

Jan Johansson ◽

Tero Hasu ◽

...

Keyword(s):

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Day Care ◽

Energy Use ◽

Thermal Environment ◽

Energy Performance ◽

Indoor Climate ◽

Zero Energy ◽

Day Care Centres

The European energy policy pushes the member states to transform building stock into nearly Zero-Energy Buildings (nZEB). This paper is focused on data collected from existing nZEB day-care centres,in order to be able to assess possible differences between predicted and actual energy and indoorenvironmental performance. Building structures, service systems and the indoor climate and energyperformance of five day-care centres were investigated in Estonia, Finland and Norway.Indoor climate condition measurements showed that in general, the thermal environment and indoor airquality corresponded to the highest indoor climate categories I and II (EN 15251). Building heating andventilation systems in studied buildings are working without major problems. Good indoor climate conditions were also reflected in the occupant satisfaction questionnaires. For most of the studied buildings, over 80%of the people marked all indoor environment condition parameters (thermal comfort, indoor air quality,acoustics, odour and illuminance) acceptable. The thermal environment in the cooling season was reportedproblematic because it was lower than the minimum temperature for indoor climate category II.Energy consumption analysis showed that measured real energy use was higher, or even significantlyhigher, than the energy use calculated during the design phase. Potential causes of the higher actualenergy consumption are caused by differences of measured and designed solutions, methodology of theenergy calculations, and the differences in user behaviour.Lessons learnt from previously constructed day-care centres can be utilised in the planning and designof new nZEBs.

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Evaluation of in-situ cooling performance at renovation 2050: comparing zone vs. central based cooling systems for single family dwellings

10.32920/ryerson.14649075 ◽

2021 ◽

Author(s):

Anthony Guadagnoli

Keyword(s):

Relative Humidity ◽

Energy Use ◽

Energy Performance ◽

Building Envelope ◽

Single Family ◽

Energy Usage ◽

Central System ◽

Cooling Performance ◽

Central Air Conditioning ◽

Air Conditioning Systems

The objective of this Major Research Project has been to compare the benefits of cooling performance of zoned and central air conditioning systems using summer 2013 as an evaluation period. Three adjacent houses in Toronto have been studied as part of the Renovation2050 research program. Total cooling energy usage was measured directly from all cooling equipment, along with temperature and cooling energy usage was measured directly from all cooling equipment, along with temperature and relative humidity readings via remote sensors. The goal of this 1-year study was to compare the cooling energy performance of each house, temperature, and relative humidity. The study has used energy simulation, to compare zoned and central systems while accounting for weather, human occupancy, and construction types. Results have shown that there is potential for energy benefits on a zoned system compared to a central system by approximately 95% in total cooling energy use for the study period,and these results are dependent on the building envelope and user types and these results are dependent on the building envelope and user types.

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Benchmarks for Embodied and Operational Energy Assessment of Hellenic Single-Family Houses

Energies ◽

10.3390/en13174384 ◽

2020 ◽

Vol 13 (17) ◽

pp. 4384

Author(s):

Elena G. Dascalaki ◽

Poulia A. Argiropoulou ◽

Constantinos A. Balaras ◽

Kalliopi G. Droutsa ◽

Simon Kontoyiannidis

Keyword(s):

Energy Use ◽

Energy Intensity ◽

Construction Materials ◽

Energy Performance ◽

Embodied Energy ◽

Single Family ◽

Zero Energy ◽

Relative Significance ◽

Climate Conditions ◽

Operational Energy

Building energy performance benchmarking increases awareness and enables stakeholders to make better informed decisions for designing, operating, and renovating sustainable buildings. In the era of nearly zero energy buildings, the embodied energy along with operational energy use are essential for evaluating the environmental impacts and building performance throughout their lifecycle. Key metrics and baselines for the embodied energy intensity in representative Hellenic houses are presented in this paper. The method is set up to progressively cover all types of buildings. The lifecycle analysis was performed using the well-established SimaPro software package and the EcoInvent lifecycle inventory database, complemented with national data from short energy audits carried out in Greece. The operational energy intensity was estimated using the national calculation engine for assessing the building’s energy performance and the predictions were adapted to obtain more realistic estimates. The sensitivity analysis for different type of buildings considered 16 case studies, accounting for representative construction practices, locations (climate conditions), system efficiencies, renovation practices, and lifetime of buildings. The results were used to quantify the relative significance of operational and embodied energy, and to estimate the energy recovery time for popular energy conservation and energy efficiency measures. The derived indicators reaffirm the importance of embodied energy in construction materials and systems for new high performing buildings and for renovating existing buildings to nearly zero energy.

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Efficient energy use and storage practices within residential facilities for compliance with the nZEB criteria

E3S Web of Conferences ◽

10.1051/e3sconf/20198508002 ◽

2019 ◽

Vol 85 ◽

pp. 08002

Author(s):

Ion Murgescu ◽

Lucia-Andreea El-Leathey ◽

Rareş-Andrei Chihaia ◽

Gabriela Cîrciumaru

Keyword(s):

Renewable Energy ◽

Energy Use ◽

Electricity Consumption ◽

Energy Performance ◽

High Energy ◽

Photovoltaic System ◽

Zero Energy ◽

Starting Point ◽

Very High Energy ◽

Zero Energy Buildings

Solar energy, today, is the leader in renewable energy and the world's increasing new energy source. In 2016, for the first time, newly installed photovoltaic capacity has increased by more than 50%, exceeding the new coal-fired power stations capacity established worldwide. At the beginning of the year, the European Parliament agreed the target that 35% renewable sources by 2030. Studies show that by 2050 approximately 45% of all the households in the EU could produce their own renewable energy and more than a third of them could be part of a renewable energy cooperative, despite the worries of the distribution companies. Furthermore, the EPBD directive (EU) - Energy Performance of Buildings pushes towards new and more performing buildings - nearly zero energy buildings (nZEB) - where energy efficiency and energy flexibility are essential to achieve the required performance targets. Nearly zero-energy buildings (NZEBs) have very high energy performance and could be achieved through the integration of renewable and decentralized energy sources, continuous grid optimization and the inclusion of increasing numbers of consumers becoming producers, so called prosumers. So far, the photovoltaic system is the single technology that can combine data from utility networks with household consumption and therefore should be considered a starting point for streamlining the electricity consumption and production which will be imposed by strict regulations.

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Evaluation of in-situ cooling performance at renovation 2050: comparing zone vs. central based cooling systems for single family dwellings

10.32920/ryerson.14649075.v1 ◽

2021 ◽

Author(s):

Anthony Guadagnoli

Keyword(s):

Relative Humidity ◽

Energy Use ◽

Energy Performance ◽

Building Envelope ◽

Single Family ◽

Energy Usage ◽

Central System ◽

Cooling Performance ◽

Central Air Conditioning ◽

Air Conditioning Systems

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PROPOSAL OF A NORWEGIAN ZEB DEFINITION: ASSESSING THE IMPLICATIONS FOR DESIGN

Journal of Green Building ◽

10.3992/jgb.6.3.133 ◽

2011 ◽

Vol 6 (3) ◽

pp. 133-150 ◽

Cited By ~ 5

Author(s):

I. Sartori ◽

T. H. Dokka ◽

Inger Andresen

Keyword(s):

Energy Demand ◽

Building Design ◽

Energy Performance ◽

High Energy ◽

Single Family ◽

Energy Supply System ◽

Paradoxical Situation ◽

Energy Efficient Buildings ◽

Zero Emission ◽

Definition Of

Conceptually a Zero Emission Building (ZEB) is a building with greatly reduced energy demand and able to generate electricity (or other carriers) from renewable sources in order to achieve a carbon neutral balance. However, a clear and agreed definition of Zero Emission Building (ZEB) is yet to be achieved, both internationally and in Norway. However, it is understood that both the definition and the surrounding energy supply system will affect significantly the way buildings are designed to achieve the ZEB goal. A formal definition of ZEB is characterized by a set of criteria that are: the system boundary, feeding-in possibilities, balance object, balancing period, credits, crediting method, energy performance and mismatch factors. For each criterion different options are available, and the choice of which options are more appropriate to define ZEBs may depend on the political targets laying behind the promotion of ZEBs, hence may vary from country to country. This paper focuses on two of these criteria: energy performance and credits used to measure the ZEB balance. For each criterion different options are considered and the implications they have on the building design are assessed. The case study is on a typical Norwegian single family house. It is shown that for certain choices on the two criteria options, a paradoxical situation could arise. When using off-site generation based on biomass/biofuels, achieving the ZEB balance may be easier for high energy consuming buildings than for efficient ones. This is the exact opposite of what ZEBs are meant to promote: design of energy efficient buildings with on-site generation options. Recommendations on how to avoid such a paradox are suggested.

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Cost and Energy Reduction of a New nZEB Wooden Building

Energies ◽

10.3390/en13143570 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3570

Author(s):

Endrik Arumägi ◽

Targo Kalamees

Keyword(s):

Energy Efficiency ◽

Energy Use ◽

Net Present Value ◽

Performance Indicator ◽

Energy Levels ◽

Energy Performance ◽

Building Envelope ◽

Zero Energy ◽

Construction Costs ◽

The Cost

The current study demonstrates the possibilities of reducing energy use and construction costs and provides evidence that wooden nearly-zero-energy buildings (nZEB) are technically possible at affordable construction costs by using novel design processes and procurement models that enable scalable and modular production. The energy efficiency solutions were derived by increasing/decreasing the insulation value of the building envelope in successive steps. Financial calculations were based on the investment needed to achieve the nearly-zero-energy levels. Overall, many opportunities exist to decrease the cost and energy use compared to the current (pre-nZEB) practice because the net present value can change up to 150 €/m² on the same energy performance indicator (EPI) level. The EPI in the cost-even range was reached by combining a ground-source heat pump (between 115 and 128 kWh/(m2·a)) and efficient district heating (between 106 and 124 kWh/(m2·a)). As energy efficiency decreases, improving energy efficiency becomes more expensive by insulation measures. Throughout the EPI range the most cost efficient was investment in the improvement of the thermal transmittance of windows (3–13 €/(kWh/(m2·a))) while investments in other building envelope parts were less effective (4–80 €/(kWh/(m2·a))). If these were possible to install, photovoltaic (PV) panels installed to the roof would be the cheapest solution to improve the energy performance. Integrated project delivery procurement (design and construction together) and the use of prefabricated wooden structures reduced the constructing cost by half (from ~2700 €/net m2 to 1390 €/net m2) and helped to keep the budget within limits.

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Comfort within Budget: Assessing the Cost-Effectiveness of Envelope Improvements in Single-Family Affordable Housing

Sustainability ◽

10.3390/su13063054 ◽

2021 ◽

Vol 13 (6) ◽

pp. 3054

Author(s):

Renata Tubelo ◽

Lucelia Rodrigues ◽

Mark Gillott ◽

May Zune

Keyword(s):

Cost Effectiveness ◽

Affordable Housing ◽

Energy Use ◽

Thermal Conditions ◽

Building Envelope ◽

Single Family ◽

Design Strategies ◽

Housing Type ◽

The Cost ◽

The Impact

In Brazil, the delivery of homes for low-inc ome households is dictated by costs rather than performance. Issues such as the impact of climate change, affordability of operational energy use, and lack of energy security are not taken into account, even though they can severely impact the occupants. In this work, the authors evaluated the thermal performance of two affordable houses as-built and after the integration of envelope improvements. A new replicable method to evaluate the cost-effectiveness of these improvements was proposed. The case study houses comprise the most common affordable housing type delivered widely across Brazil and a proposition of a better affordable housing solution, built in Porto Alegre, southern Brazil, integrating passive design strategies to increase thermal comfort. The findings reveal a potential for improving indoor thermal conditions by up to 76% and 73%, respectively, if costs are not a concern, and 40% and 45% with a cost increase of 12% and 9% if a comfort criterion of 20–25 °C was considered. Equations to estimate costs of improvements in affordable housing were developed. The authors concluded that there is a great scope for building envelope optimisation, and that this is still possible without significant impact on budget.

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Redefining cost-optimal nZEB levels for new residential buildings

E3S Web of Conferences ◽

10.1051/e3sconf/201911103035 ◽

2019 ◽

Vol 111 ◽

pp. 03035 ◽

Cited By ~ 2

Author(s):

Raimo Simson ◽

Endrik Arumägi ◽

Kalle Kuusk ◽

Jarek Kurnitski

Keyword(s):

Energy Use ◽

Net Present Value ◽

Residential Buildings ◽

Energy Performance ◽

Optimal Level ◽

Building Envelope ◽

Simulation Software ◽

The European Union ◽

Apartment Building ◽

Detached House

In the member states of the European Union (EU), nearly-Zero Energy Buildings (nZEB) are becoming mandatory building practice in 2021. It is stated, that nZEB should be cost-optimal and the energy performance levels should be re-defined after every five years. We conducted cost-optimality analyses for two detached houses, one terraced house and one apartment building in Estonia. The analysis consisted on actual construction cost data collection based on bids of variable solutions for building envelope, air tightness, windows, heat supply systems and local renewable energy production options. For energy performance analysis we used dynamic simulation software IDA-ICE. To assess cost-effectiveness, we used Net Present Value (NPV) calculations with the assessment period of 30 years. The results for cost-optimal energy performance level for detached house with heated space of ~100 m2 was 79 kWh/(m2 a), for the larger house (~200 m2) 87 kWh/(m2 a), for terraced house with heated space of ~600 m2 71 kWh/(m2 a) and for the apartment building 103 kWh/(m2 a) of primary energy including all energy use with domestic appliances. Thus, the decrease in cost-optimal level in a five-year period was ~60% for the detached house and ~40% for the apartment building, corresponding to a shift in two EPC classes.

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