Zero Emission Buildings Research Articles

Living Labs and Partnerships for Progress: How Universities can Drive the Process towards the Sustainable City

Universities can play an active role in facilitating the deployment at a wide scale of the sustainability concept, strictly cooperating with public-private institutions and civil society. Following this path, the University of Genoa, Italy, decided to transform its Savona Campus into a Living Lab aimed at creating a model of a sustainable urban district, to be replicated at the city level with specific implementation projects. Different actions on sustainable energy, smart environment and social health & wellbeing have been deployed: energy efficiency interventions, smart grid connected to a zero-emission building, electrical mobility and outdoor sport activities. All the projects have been developed with the active involvement and the empowerment of the Campus community (students and faculty) and thanks to important collaborations with local public institutions and industrial companies.

Simulation of design and operation of hydrogen energy utilization system for a zero emission building

Nearly 40% of the total greenhouse gases (GHGs) are emitted from the energy consumption in buildings in Japan, which should be reduced to address global warming. A hydrogen energy utilization system with renewable energy (RE) was designed by MATLAB/Simulink simulations for realizing a zero emission building (ZEB), comprising a hydrogen-producing electrolyzer, a hydrogen storage tank, fuel cell, and battery for short-term power storage with estimated specifications of 3.0 Nm3/h, 36 Nm3, 4.2 kW, and 10 kW/17 kWh, respectively. We identified a small low-rise building (total floor area: ∼1000 m2, demand: ∼5 kW) as the planned ZEB to construct and operate a bench-scale system. A 20-kW photovoltaic (PV) system was selected as the RE source. Two hydrogen production processes (constant power of 10 kW or with excess PV power) were evaluated by simulating 48-h operations on fine and cloudy days, where the former showed higher efficiency. The results with excess power on a fine day agreed well with that of actual operation, validating our simulation models. Further, the constant case was suitable for practical application.

Exploring the pathway from zero-energy to zero-emission building solutions: A case study of a Norwegian office building

This paper explores the most influential aspects regarding the environmental and economic performance of zero-energy and zero-emission buildings and proposes a pathway for transition in building solutions. A representative zero-energy office building in Norway is investigated with alternative design solutions to achieve zero-emission status i.e., the extensive use of locally generated energy through photovoltaic (PV) panels and the use of materials with low embodied emissions, such as low-carbon concrete and wood. A life cycle environmental and economic assessment is performed to evaluate specific indicators during the building life cycle: cumulative energy (CED), global warming potential (GWP), and equivalent annual cost (EAC).The extensive use of PV panels was most effective in lowering the operational energy because it reduced the CED by about 30% compared to the building as-built. However, the extensive use of wood in the construction contributed the most to GWP reduction, with around 30% decrease compared to the building as-built. Finally, the differences in EAC were interestingly insignificant among the alternatives, with the investment costs dominating the EAC for all designs examined.The findings of this paper emphasise that a full compensation of the life cycle GHG emissions from materials is difficult to achieve through renewable energy, even with extensive use of PV panels, especially in a low-carbon grid situation as in Norway. A pathway strategy from zero-energy towards zero-emission buildings must therefore strongly focus on the materials’ embodied energy and emissions because low operational energy demand is already a regulatory priority in most countries.

Analysis of energy signatures and planning of heating and domestic hot water energy use in buildings in Norway

Widespread introduction of low energy buildings (LEBs), passive houses, and zero emission buildings (ZEBs) are national target in Norway. In order to achieve better energy performance in these types of buildings and successfully integrate them in energy system, reliable planning and prediction techniques for heat energy use are required. However, the issue of energy planning in LEBs currently remains challenging for district heating companies. This article proposed an improved methodology for planning and analysis of domestic hot water and heating energy use in LEBs based on energy signature method. The methodology was tested on a passive school in Oslo, Norway. In order to divide energy signature curve on temperature dependent and independent parts, it was proposed to use piecewise regression. Each of these parts were analyzed separately. The problem of dealing with outliers and selection of the factors that had impact of energy was considered. For temperature dependent part, the different methods of modelling were compared by statistical criteria. The investigation showed that linear multiple regression model resulted in better accuracy in the prediction than SVM, PLS, and LASSO models. In order to explain temperature independent part of energy signature the hourly profiles of energy use were developed.

From Zero Emission Buildings (ZEB) to Zero Emission Neighbourhoods (ZEN): A Mapping Review of Algorithm-Based LCA

The building industry is responsible for approximately 40% of energy consumption and 36% of greenhouse gas emissions in the European Union (EU). The most efficient way of reducing a building’s environmental impact is addressing it in the design stage. Here, design freedom is the greatest, but uncertainty is high and there is a nearly limitless number of design options. Based on experiences with zero emission buildings (ZEB) and zero emission neighbourhoods (ZEN), a mapping review has been conducted to analyse how parametric life cycle assessment (LCA) and algorithms have been used to address neighbourhoods, buildings, and construction materials. Results have identified a general gap of knowledge regarding the use of parametric LCA models for decision-support purposes, demonstrated by the substantial focus on analytical methods compared to procedural methods. Implications for the evolution from ZEB to ZEN are twofold: (i) an integrated approach with multiple tools and methods is required, and (ii) further development of algorithms in the tool are needed to address complexity, sensitivity, and uncertainty. This study is expected to foster the development of algorithmic approaches to improve the ZEB tool as a decision-support tool. Further research should address the key questions of when and how.

Housing stock in cold-climate countries: Conversion challenges for net zero emission buildings

The residential sector is responsible for 11.7% of global greenhouse gas (GHG) emissions. Space and domestic hot water (DHW) heating accounts for about 80% of the energy consumption of households in cold-climate regions. This study investigates the status of the housing stock in a set of cold-climate countries (i.e., Northern Europe and Canada) with the goal of identifying the barriers to achieving net zero emission (NZEm) status in the residential sector. Several parameters are analyzed, including vintage, energy mixture for onsite heating and offsite electricity generation, energy use, and GHG emissions intensities. Potential scenarios of energy supply and their impact on energy consumption and GHG emissions of the residential sector are discussed. Results show that the existing houses are not energy efficient, and it will be a challenge to reduce the GHG emissions of the residential sector. The energy outlooks indicate that the carbon intensity of grid electricity would not be zero due to reliance on fossil fuels. Therefore, an existing household could not achieve NZEm status by solely using grid electricity. Deep energy retrofits, renewable energy technologies, and reducing the carbon intensity of energy sources are measures to be implemented to achieve NZEm status for the residential sector.

Lessons learnt from embodied GHG emission calculations in zero emission buildings (ZEBs) from the Norwegian ZEB research centre

The objective of this work is to present, evaluate and discuss the calculation methodology and embodied greenhouse gas (GHG) emission results from zero emission building (ZEB) case studies from the Norwegian ZEB research centre, to extract design drivers and lessons learnt. In all, two virtual models, and five ZEB pilot buildings are assessed; consisting of three residential, two office and two school buildings. The embodied GHG emission results show that the building envelope (ca. 65%) and production and replacement of materials (ca. 55–87%) are the main contributors to total emissions across the Norwegian ZEB case studies. Although difficult to draw definitive conclusions, this work builds upon the current body of knowledge on embodied GHG emissions in Norwegian ZEBs, and provides some practical indications for embodied GHG emission calculations and reduction strategies in future Norwegian ZEB and zero emission neighbourhood (ZEN) projects.

Between craft and regulations: experiences with the construction of two “super insulated” buildings in Norway

Building regulations set standards that aim to reduce energy use and CO2 emissions, and thereby to support the development of a more sustainable building stock. The Norwegian government uses building regulations to influence the construction industry, and they directly affect how craftspeople from the industry apply their skills. Regulations are converging with understandings about sustainability, energy use, building materials, and comfort requirements that are circulating in society. In this paper, we investigate the negotiations between the meaning and value associated with the requirements for the material structure and the craftsperson’s role. Two houses in Central Norway are the starting point, where qualitative methods, primarily semi-structured interviews and observation, are used to gain insight into the craftsperson’s view of the Norwegian building regulations. The two houses represent two different building standards. A Passive House in Åfjord Municipality, completed in 2014, and ZEB Living Lab in Trondheim, a zero emission building (ZEB), completed in 2015. In Norway, the building regulations are reviewed every five years. In 2011, craftspeople were constructing buildings to the low-energy standard. This led to an increased focus on “super insulating” building techniques during period 2013-16 when the case studies took place. Starting with a craftsperson’s (in this case most often a carpenter’s) view of current and future building standards, this paper asks what implications the increasing demands for energy efficient and environmentally friendly buildings have on the role of the craftsperson and their application of skill. The paper shows that the construction industry bases much of its activity on Norwegian construction traditions and skill; and that this guides the development of new generations of buildings. The use of established skills and knowledge is both a strength and a challenge when dealing with a new set of building regulations. Skill is a resource to build upon, but it is also influenced by a conservativism that has difficulties getting beyond the extra time and costs associated with new regulations. It can therefore function as a barrier to the use of construction crafts to establish more sustainable building forms within the Norwegian market.

Boundary Objects As Facilitators in Sustainable Building Research

In recent years, the claim has become mainstream that to reach ambitious environmental goals, building research can greatly profit from a transdisciplinary collaboration that crosses academic disciplines and includes non-academic partners. We summarize experiences accrued in 7 years of intensive transdisciplinary work performed in the Norwegian Research Centre on Zero Emission Buildings. Our analysis, which employs conceptual tools from symbolic interactionism (social worlds and boundary objects), is based on two surveys among the Centre’s researchers and industrial partners and eighteen qualitative interviews exploring the Centre’s members’ views and experiences. In the analysis of the material, the research centre’s eight pilot buildings emerge as boundary objects that facilitated collaboration among the non-academic partners, while ‘robust solutions’ was the main boundary object which enabled interdisciplinary academic work. Practical recommendations for transdisciplinary (building) research derived from these observations conclude the article.

Domestication, acceptance and zero emission ambitions: Insights from a mixed method, experimental research design in a Norwegian Living Lab

The Trondheim Living Lab is a detached single-family zero emission building (ZEB) that is planned to reach a zero-emission balance over the course of its estimated 60-year lifetime. This is achieved by a broad variety of technical strategies such as passive and active energy design and efficient installations, as well as calculations of embodied emissions. In qualitative experiments conducted between September 2015 and April 2016 six different groups lived in the house for 25 days each. Based on direct observation (mainly through sensors registering temperature, humidity, CO2 levels and energy use), participant observation and interviews before, during and after the stay, the paper analyses the unfolding domestication of the building along three dimensions; practical, symbolic and cognitive. The paper provides an account of which expected or unexpected occupant actions matter in which way for the zero emission ambitions of the building. Moreover, by studying the way in which the six groups within the three different categories student, family and elderly experienced living in this demonstration building this paper contributes a more detailed understanding of the overall acceptance of a ZEB in Norway.

Energy Toolbox—Framework for the Development of a Tool for the Primary Design of Zero Emission Buildings in European and Asian Cities

This paper discusses the framework for the development of an Energy Toolbox (ETB). The aim of the ETB is to support the design of domestic Zero Emission Buildings (ZEBs), according to the concept of net zero-energy buildings during the early architectural design and planning phases. The ETB concept is based on the calculation of the energy demand for heating, cooling, lighting, and appliances. Based on a building’s energy demand, technologies for the onsite conversion and production of the specific forms and quantities of final and primary energy by means of renewable energy carriers can be identified. The calculations of the ETB are based on the building envelope properties of a primary building design, as well as the physical and climate parameters required for the calculation of heat transfer coefficients, heat gains, and heat losses. The ETB enables the selection and rough dimensioning of technologies and systems to meet, and, wherever possible, reduce the thermal and electric energy demand of a building. The technologies included comprise green facades, adaptable dynamic lighting, shading devices, heat pumps, photovoltaic generators, solar thermal collectors, adiabatic cooling, and thermal storage. The ETB facilitates the balancing of the energy consumption and the production of renewable energies of a primary building design.

The techno-economic analysis of a hybrid zero-emission building system integrated with a commercial-scale zero-emission hydrogen vehicle

This study conducts a techno-economic analysis to seek the feasibility to integrate a zero-emission building (ZEB) with a commercial-scale hydrogen vehicle (HV). The parametric analysis is conducted in 16 simulation groups with respect to the equipment options of the solar thermal collectors, the ground source heat pump (GSHP) and the HV refueling methods, while each group contains a series of cases with a range of on-site renewable electricity (REe) generation capacities between 0 and 16 kW. The assessment criteria include the annual operational equivalent CO2 emission and the relative net present value (NPVrel). By the parametric analysis, the sets of the non-dominated cases within the cloud of the analysed solutions have been comprehensively investigated regarding the aims to reduce the emission and the cost. With respect to the criteria of the equivalent emission and NPVrel under the normal market scenario of the electrolyzer (5000 EUR/kW), none of the cases with the on-site H2 system can be identified as superior to those without the on-site H2 system. The non-dominated cases will mainly happen to those with a 0–9.61 NOCT kW photovoltaic (PV) panel and a 5 kW GSHP but without any solar thermal collector, which have a range of NPVrel between −4115 and 12,556 EUR along with a range of emission between 19.72 and 6.65 kg CO2,eq/m2 a. However, by reducing the electrolyzer cost to the lowest market scenario of 2000 EUR/kW, parts of the cases with the on-site H2 system start to challenge those without the on-site H2 system. Moreover, the change of the emission factor of the H2 fuel from 0.267 to 0.141 kg CO2,eq/kWhLHV will not alter the set of the overall non-dominated cases, but will uniformly reduce the annual emission of these cases by a magnitude of 3.83 kg CO2,eq/m2 a.

Influence of occupant behavior and operation on performance of a residential Zero Emission Building in Norway

It has been proven that occupant behavior may significantly change building energy performance. The effect of the occupant behavior is becoming even bigger when it comes to highly energy efficient buildings. Specifically Zero Emission Buildings (ZEB) may become an issue for the electric grid, because they are supposed to be actively connected to the electricity grid for electricity import and export. Therefore, the aim of this study was to evaluate the change in the energy performance of a ZEB located in Norway. Occupant behavior was modelled by using the following methods standard schedules, well-defined profiles based on thorough statistical analysis, and stochastic methods To analyze the grid stress, 31 scenarios for different occupant behaviors were analyzed. The overall estimation of investigated parameters showed that the change in occupant behavior resulted in grid stress variance from −5% to +13% compared to the reference case based on the standard values. The results showed that the occupant behavior might change the annual energy balance reliability by 20%. However, the results showed that the influence of the occupant behavior related to the window opening and domestic hot tap water would not significantly change the ZEB energy performance. Window opening would even decrease the cooling load. A very important conclusion of this study is that consideration of occupant behavior through challenging the standard values are highly necessary for reliable energy analysis of the ZEB solutions.

Energy performance assessment of a semi-integrated PV system in a zero emission building through periodic linear regression method

The ZEB Living Laboratory is a pilot building and experimental facility realized within the Research Centre on Zero Emission Buildings. The building is a single-family house designed to reach the ZEB-OM target – Zero emission Buildings when emissions for operation and building materials are accounted.The building has a semi-integrated photovoltaic (PV) plant installed over two slopes of the building’s roofs. The total installed power (DC) is approximately 12.5 kWP. Each PV roof is connected to a power inverter with a nominal AC rated power output of 4.6 kW, based on a layout that optimize energy conversion, given the fact that shading over the two roof slopes is different.In this paper, the performance analysis of the PV system is carried out considering the six months in the first year of operation of the system. A graphical analysis based on the linear regression method is presented and the array yield is compared against the reference yield (Performance Ratio). The analysis gives a general overview of the performance of the system, and a focus is then placed on the understanding of the system’s output in relation to the undersizing of the PV inverters.

Analysis of reduction of energy demands for Zero Emission Renovated Office Building by using thermal mass and ventilative cooling

Zero emission buildings (ZEB) are characterized by high levels of insulation and air tightness. Powerhouse Kjørbo is the first Zero Emission Renovated Office Building in Norway. In 2013-2014 the building from 1985 underwent a major renovation to passive house standard (class A), keeping only the concrete framework to reduce emissions. The building has been monitored for one year. The data has been used to build and validate an IDA ICE simulation model in order to study possible improvements in energy consumption by changing the thermal mass and the ventilation strategies.The thermal mass effect is strongly dependent on the volumetric heat capacity and the thermal admittance. Thermal mass placement within the structure would modify the energy use for heating and cooling. For instance, placing the thermal mass in the internal walls will not have the same effect as placing it between the floors. The interaction with the ventilation system also affects the energy use. Using nighttime setback with heavy walls, (large thermal inertia) proves to reduce cooling demands during summer time. Other strategies of window control with heavy mass during daytime are studied focusing on reduced energy demands.The conclusion for the studied case is that given that the concrete structure was already built, the use of thermal mass is smart. However, when designing to achieve ZEB, increase of thermal mass in the form of concrete must be thoroughly thought as it would decrease cooling demand and shift temperature peaks, but will not be so beneficial for heating. At the same time increased thermal mass will increase the greenhouse gas emissions.

Zero emission office building in Bergen: Experiences from first year of operation

The Visund office building is a pilot project within the Research Centre on Zero Emission Buildings (ZEB) in Norway. The building has been in operation since January 2016. The design aimed at meeting the ZEB-criterion of net zero energy balance, excluding energy for appliances. The energy performance has been closely monitored and the energy measurements during the first year corresponds well with the predicted and required performance. A high focus on shared goals, contract based economic incentives, building design and technology choices, energy monitoring and follow-up measures have been key-factors to achieve the goals.

Synthesis of Silica-Based Nano Insulation Materials for Potential Application in Low-Energy or Zero Emission Buildings

Sacrificial polystyrene (PS) templates have been used for synthesis of silica-based nano insulation materials (NIM). The PS was synthesized by a simple procedure where parameters as polyvinylpyrrolidone/styrene ratio and potassium persulfate amount were adjusted. Thereafter the PS templates were coated with silica by using tetraethyl orthosilicate (TEOS). The time used for adding TEOS was varied to investigate the effect on how the silica particles attached to the PS surface and the resulting silica spheres. By modifying the process, different PS templates were obtained. The thermal conductivity was measured for hollow silica spheres originating from the coating process of 198 nm PS templates, and the results showed thermal conductivities around 38 mW/(mK) for long-time measurements (160-640 s). Controlled synthesis of this silica-based NIM might be a stepping-stone on the path to a new generation of high-performance thermal insulation materials with low thermal conductivity, which can be used in the building envelope of low-energy or zero emission buildings in the future.

Towards Zero Energy and Zero Emission Buildings—Definitions, Concepts, and Strategies

This paper focuses on the definition and application of Zero Energy and Zero Emission Buildings (ZEBs). Based on a review of mainly European and Norwegian definitions, case studies, and pilot buildings, the paper summarizes some main challenges with respect to the implementation of ZEBs; What kind of strategies are used in current pilot projects of ZEBs? How to apply definitions and targets for ZEBs that take into account different available resources and boundary conditions? Previous studies have shown that most definitions of ZEBs include only the energy use for operation of buildings, while recent developments also include the embodied energy or emissions in materials. Published analyses of pilot building projects and case studies also show that most ZEBs apply a strategy of first reducing the energy need by applying efficiency measures, and then applying on-site or off-site renewable energy technologies. The findings indicate that prescribing a hierarchy of different ambition levels for the definition of ZEBs would be beneficial to allow for flexibility with respect to available resources and different boundary conditions.

Rethinking investment planning and optimizing net zero emission buildings

Increased awareness of climate change has precipitated more stringent mitigation targets. Public sector institutions in Canada are committed to becoming carbon neutral to attain a leadership position in climate change mitigation-related initiatives. Recent statistics reveal that buildings account for the majority of the corporate carbon footprint of public sector institutions. Hence, there is an increasing interest towards developing net zero energy and net zero emission buildings to comply with climate action targets. With limited financial resources, public sector institutions must optimize investments into building energy retrofits by considering lifecycle cost (LCC), overall energy performance, and related greenhouse gas (GHG) emission. The aim of this paper is to develop an investment planning approach for net zero emission buildings (NZEB). First, an investment planning approach for NZEB is proposed. A typical recreational centre building in British Columbia, Canada, was used as the archetype to demonstrate the concept. Second, innovative and proven building energy retrofits were analysed using energy simulation software to assess the impact on energy consumption reduction, GHG emissions, and LCC. Third, impacts of geographical location, tariff regimes, and grid emission factors on energy retrofits were studied by locating the same building in other provinces of Canada. This study revealed that net zero energy investment has a strong correlation to the grid emission factor. The proposed approach in this paper will assist building managers and owners in retrofitting and budget planning.

Comparative emission analysis of low-energy and zero-emission buildings

ABSTRACTDifferent designs and concepts of low-energy and zero-emission buildings (ZEBs) are being introduced into the Norwegian market. This study analyses and compares the life cycle emissions of CO2 equivalents (CO2e) from eight different single-family houses in the Oslo climate. Included are four ZEBs: one active house, two passive houses, and a reference house (Norwegian building code of 2010). Monthly differences in CO2e emissions are calculated for the seasonally sensitive Norwegian context for electricity generation and consumption. This is used to supplant the previous applied symmetric weighting approach for CO2e/kWh factors for import and export of electricity for the ZEB cases. All the ZEBs have lower use-stage emissions compared with the other buildings or the reference case. Embodied impacts are found to be 60–75% for the analysed ZEB cases, confirming the importance of embodied impacts in Norwegian ZEBs. The lowest total emissions were from the smallest ZEB, emphasizing area efficiency. The highest emissions were from the reference case. By abandoning the symmetric approach, a new perspective was developed for assessing the performance of ZEBs within the Norwegian context. One of four ZEB cases managed to balance out its annual energy-related emissions.