Zero Emission Buildings Research Articles

IAQ and ventilation measurements at the “ZEB Laboratory” office building in Norway

This study aims to assess indoor environmental quality (IEQ) within a Zero Emission Building (ZEB) office in Norway, focusing on occupant impact (CO2, temperature, humidity) and materials/substances influence (formaldehyde, particulate matter (PM2.5), total volatile organic compounds (TVOC)). It presents a detailed data collection spanning 14 months from March 30th, 2022, to June 1st, 2023.Occupancy varied significantly, affecting measured indoor air quality (IAQ) parameters, with the lowest temperatures recorded on the second floor and specific areas like the canteen experiencing temperature drops during low usage times. Relative humidity levels remained over 20% in winter despite the building's low occupancy, a notable aspect given Norway's dry winters. PM2.5 levels stayed below World Health Organization (WHO) guidelines, indicating effective pollution management.The study also evaluates the impact of reducing the ventilation rates on IAQ, noting no significant IAQ compromise. An analysis correlating IAQ measurements with building occupants' satisfaction post-intervention revealed that temperature is the most significant factor affecting satisfaction levels, excluding acoustic satisfaction. Occupants generally reported satisfaction with the indoor environmental quality (IEQ), with specific dissatisfaction tied to thermal environment and IAQ, suggesting the importance of temperature control in occupant perception.This research not only provides valuable insights into IEQ management in Zero Energy and Zero Emission office buildings but also emphasizes the critical role of indoor temperature and the potential of wooden structures to stabilize humidity levels, contributing to occupant comfort and satisfaction.

Impact of space utilization and work time flexibility on energy performance of office buildings

This study investigates the impact of different space utilization on energy use intensity, heating load, cooling load, and thermal comfort of occupants using a combination of empirical data gathering and simulation-based studies. The increasing worldwide preoccupation with energy consumption and environmental sustainability has led to increased attention on optimizing interior spaces to mitigate total energy demand. The considered case study for conducting this research was the Norwegian living lab namely Zero Emission Building (ZEB) Flexible Lab in Trondheim, Norway. In this study, 10 different scenarios of occupancy schedules based on flexible arrangements from standard workweeks to extensive remote work configurations were designed and analyzed using IDA ICE 5.0. The findings demonstrate significant reductions in energy use across scenarios with increased teleworking and compressed work weeks. The remote scenario achieved the most significant decrease in Energy Use Intensity (EUI), with a reduction of 46 % compared to the base case. Similarly, the implementation of flexible hours and remote working in scenarios resulted in a reduction of electric heating demand by up to 23 %, underscoring the potential of occupancy-based strategies in enhancing building energy efficiency. However, uncomfortable hours increased by 59 % in the 2-day remote working scenario compared to the base case, demonstrating the need to consider climate conditions when implementing remote work. The research offers valuable insights into the complex connections between flexible arrangements and energy efficiency, considering many elements such as occupancy schedule and use dynamics. This article offers a comprehensive analysis that may give architects, building managers, and policymakers valuable insights. This study contributes to the developing sustainable architecture by emphasizing the impact of dynamic occupancy on the energy performance of office buildings.

The environmental performance of zero-emission buildings in a fossil-free energy system

Buildings can play an important role in reducing GHG emissions through increased energy efficiency. The European Commission mandates that all new buildings should be “zero emission buildings” (ZEB), aiming at a zero GHG emission building stock by 2050. The extent to which ZEB can contribute to reduced GHG emissions, however, varies between countries, due to different energy systems. It is also important to consider other environmental effects to avoid that climate benefits come with unintended consequences. Here, we explore the life-cycle environmental performance for a ZEB in a case where electricity and heating are largely fossil-free. The assessment concentrates on i) environmental impact of the use stage in relation to the product stage, ii) the interrelation between different energy sources, with focus on household electricity, and iii) the performance for more impact categories than primary energy use and climate change. While our results generally support the use of ZEBs from an environmental perspective, they also show that the climate benefit in this setting is marginal. However, given that energy systems are connected and energy savings in one place can reduce the demand for fossil energy elsewhere, the climate benefit of ZEBs is likely underestimated. Besides methodological implications for future studies, this indicates that current EU policy is promising, as incentives for implementation of ZEBs are unaffected by domestic effects.

From PROBE to net zero: A study of soft landings’ contribution

This study reviews Soft Landings (SL) implementations, focusing on its role in achieving Low and Net Zero Emission (LZE) buildings and reducing the energy performance gap. With buildings contributing significantly to global carbon emissions, it is crucial to understand the effect of integrating approaches like SL for meeting Net Zero goals. Notably, this research identified that the extended 3-year aftercare phase of SL does not always lead to reduced operational carbon emissions. While SL promotes collaboration and structured delivery, its overall impact on consistently achieving LZE buildings remains unclear, largely due to insufficient in-use performance data. The paper advocates for integrating SL with other performance-based methods, emphasising the need for enhanced industry collaboration and data sharing to augment the understanding and effectiveness of SL in delivering LZE buildings. Practical Application This paper offers a thorough analysis of the Soft Landings (SL) framework in achieving Low and Net Zero Emission (LZE) buildings. It examines barriers at each project lifecycle stage and evaluates SL’s effectiveness through case studies, revealing inconsistencies in reducing operational emissions. The findings emphasise integrating SL with performance-based initiatives and enhancing industry collaboration and data sharing. Built environment professionals can leverage these insights to improve project delivery, optimise building performance, and achieve LZE goals more effectively.

District Heating Deployment and Energy-Saving Measures to Decarbonise the Building Stock in 100% Renewable Energy Systems

Achieving a zero-emission building heating sector requires numerous strategies and detailed energy planning, in order to identify the optimal decarbonisation pathway. This work aims to assess the impact of district heating expansion and the implementation of energy-saving measures on the decarbonisation of the Italian building stock by 2050, analysing their combined impact, reciprocal effects, and technical–economic implications on the entire national energy system. The scenarios have been implemented and simulated with the H2RES software, a long-term energy planning optimisation model, built for the Italian national energy system. Results indicate that it is possible to decarbonise the heating system in an efficient and cost-effective manner by the year 2040. Heat pumps represent the optimal technology at both centralised and decentralised levels. District heating expansion is a priority for the decarbonisation of the building stock, allowing us to reduce costs, exploit thermal storage systems and provide system flexibility. In the best scenario, 40% of the Italian heat demand can be supplied by fourth-generation district heating. Energy-saving measures can reduce heat demand and primary energy but at higher annual costs and with a significant increase in investment. The combined simulation of the strategies within an optimisation model of the entire energy system enables the accurate assessment of the real impact of the various measures, considering their reciprocal effects and technical–economic implications.

A New Tailored Approach to Calculate the Optimal Number of Outdoor Air Changes in School Building HVAC Systems in the Post-COVID-19 Era

Air conditioning systems can play a positive or negative role in the spread of COVID-19 infection. The importance of sufficient outdoor air changes in buildings was highlighted by the World Health Organization, therefore these should be guaranteed by mechanical ventilation systems or adequate air conditioning systems. The proposed case study concerns the optimal number of outdoor air changes to limit COVID-19 contagion for a school building in Central Italy. The Wells–Riley model is used to assess the risk of airborne infection, while energy consumption is calculated by a dynamic energy simulation software. The scope of the paper offers an innovative method to define the optimal ventilation strategy for the building’s HVAC system design to reduce the risk of infection with limited increases in energy consumption and greenhouse gas emissions. Results show that the desirable approach is the one in which the same low value of contagion risk is set in all rooms. This new approach results in significant energy savings, compared to the most common ones (setting the same high outdoor air rates for all rooms) to counteract the risk of infection. Finally, the zero-emission building target is verified by introducing a suitable photovoltaic system to offset pollutant emissions.

Optimizing designs for net zero emission buildings – technical and conceptual feasibility in a Norwegian context

Optimizing designs for net zero emission buildings – technical and conceptual feasibility in a Norwegian context

Experiences from teaching graduate students how to design net Zero Emission Buildings in Norway

Experiences from teaching graduate students how to design net Zero Emission Buildings in Norway

Building Integrated Photovoltaics (BIPV): Analysis of the Technological Transfer Process and Innovation Dynamics in the Swiss Building Sector

Solar has confirmed its dominance among all power generation technologies, and along with the demand for zero-emission buildings, Photovoltaics (PV) is contributing to transforming the building skin. More than 200 products for Building Integrated Photovoltaics (BIPV) are commercialized nowadays in the EU market. However, only 1–3% of all PV installations are BIPV due to the weak penetration in the construction sector. At the state of the art, the sector lacks a specific analysis from a construction technology perspective, describing the dynamics and the traits that BIPV innovation articulates on construction and architectural processes. The authors, elaborating a new model from the building technology sector to explore the relationship between PV technology and architectural innovation, aim to identify the main principles, forms, and approaches that describe the structural organization of the “integrability” concept of PV in buildings. This study applies the method to a database of 233 real buildings located in Switzerland, a unique country leading with a 10% BIPV rate on PV installations documented between the years 1997 and 2023. The novel findings of the research suggest the definition of the levels of innovation and the reference traits of the innovative process of BIPV in the Swiss construction sector, which can also be used in other practical applications and contexts. The results of the paper are expected to impact both the scientific academy and the key players from the construction sector, encouraging the adoption of an integrated research and design approach to revolutionize the energy role of building skins with PV.

Transformation of existing inefficient buildings into nearly zero-emission buildings – A case study of a residential building from the Czech Republic

This article presents a case study focusing on the conversion of an existing typical residential building in the Czech Republic into a near-zero emission building. Five parameters were compared in the study: average heat transfer, coefficient of the building envelope, non-renewable primary energy, energy requirements for heating, total energy supplied, and carbon dioxide emissions. A total of five energy-saving options were developed for the building, covering the building envelope and building services. The study was conducted considering two separate heat sources for heating and domestic hot water. The evaluation was carried out for a scenario involving a heat pump, and a district heating system.

Energy demand parametric analysis and geothermal heat exchanger design applied to a nearly zero energy PV building in northern Italy

Nearly-Zero-Energy and Zero-Emission Buildings are one fundamental part of the world strategies addressed at mitigating the global warming trend and coping with the goal of setting 1.5 °C the planet temperature increase with respect to the pre-industrial conditions. The present paper refers to a specific case study, the Smart Energy Building (SEB) located in the Savona Campus of the University of Genoa. The SEB is a very innovative building for both the envelope (ventilated highly insulated facades) and the energy systems (including a ground coupled heat pump and an exhaust air-to-air heat pump for building ventilation); the building is equipped also with a PV module field on the rooftop for electricity production. The present paper first evaluates the heating and cooling loads of the building by means of an EnergyPlus model and analyses the impact of different control strategies related to the temperature setpoints. In particular, case #1 refers to a minimum temperature to be assured by heating only in winter and to a maximum one to be avoided by cooling only during summer; on the other hand, in case #2 the temperature inside the building is controlled within a defined range (both heating and cooling modes) all year long. From EnergyPlus simulations, the hourly heat loads have been averaged as monthly values and employed for the calculation of the required overall length of the ground heat exchangers of the geothermal heat pump of the SEB building. The ground-side analysis is performed by applying the Authors’ ASHRAE-Tp8 method, in its recently released web version. For the BHE (borehole heat exchanger) calculations, a parametric analysis has been performed in terms of ground thermal conductivities. Finally, the PV electrical production has been estimated by EnergyPlus simulations and compared with the corresponding measured one, thus showing the net energy zero behaviour of the present building.

Optimization of Electrical and Thermal Storage in a High School Building in Central Greece

Nearly zero-emission buildings (nZEBs) are increasingly being constructed in Europe. There are also incentives to refurbish older buildings and transform them into nZEBs. However, permission is not always granted for their connection to the grid to infuse surplus photovoltaic electricity due to the grid being overloaded with a large number of renewables. In this study, the case of a refurbished school building in Central Greece is examined. After refurbishing it, a significant amount of photovoltaic electricity surplus is observed during the summer and neutral months, which cannot be exported to the grid. The absence of an adequate battery storage capacity resulted in the rejection of an application for exporting the school’s surplus to the network and the photovoltaic installation staying idle. An alternative approach is proposed in this work, involving a shift in the export of the photovoltaic electricity surplus to the evening hours, in order for the school to be granted permission to export it to the network. To this end, an optimal battery storage size is sought by employing a building energy system simulation. The mode of operation of the battery designed for this application is set to discharge daily, in order to export the electricity surplus in the afternoon hours to the evening hours, when it is favorable for the network. Additionally, the optimal size of the thermal energy storage of the heating system is studied to further improve its energy efficiency. Our battery and storage tank size optimization study shows that a significant battery capacity is required, with 12 kWh/kWp photovoltaic panels being recommended for installation. The ever-decreasing cost of battery installations results in the net present value (NPV) of the additional investment for the battery installation becoming positive. The solution proposed forms an alternative path to further increase the penetration of renewables in saturated networks in Greece by optimizing battery storage capacity.

Demonstration and data analysis of a Zero Emission Building (ZEB) in Beijing, China

Building mounted photovoltaic (BMPV) technology is a promised way to achieve carbon peak in building sector. Focused on the influence of heat from PV modules on building envelope’s heat transfer and energy saving performance, and the power generation, the coupling mechanism of power generation and heat transfer of integrated photovoltaic technology on building façades has been investigated. The synergy of solar energy generation and building energy consumption have been studied in this paper. The installation method of building PV system was proposed, with which can achieve the maximum energy saving. Furthermore, the achievements have been applied in Zero Emission Building (ZEB) of China Academy of Building Research (CABR), demonstrating way to realize zero carbon building by integration of photovoltaic technology. Total of 236.1 kWp PV systems were installed in ZEB. Monitoring data shows that the annual power generation of ZEB could reach 212,382 kWh, and the power generation per building area is 73.79 kWh/m2, which could meet all the energy demands. In addition, it can supply extra power to surrounding buildings. The ZEB can provide experience and practice data supporting carbon peak in building sector.

Influence of air changes per hour on hydrogen leaks in mechanically ventilated enclosures

The integration of hydrogen energy systems into nearly zero-emission buildings (nZEB) is emerging as a viable strategy to curtail greenhouse gas emissions associated with energy use in these buildings. However, the indoor or outdoor placement of certain hydrogen system components or equipment necessitates stringent safety measures, particularly in confined environments. This study aims to investigate the dynamics of hydrogen dispersion within an enclosure featuring forced ventilation, analyzing the interplay between leakage flow rates and ventilation efficiency both experimentally and numerically. To simulate hydrogen's behavior, helium gas, which shares similar physical characteristics with hydrogen, was utilized in experiments conducted at leakage flows of 4, 8, and 10 L/min, alongside a ventilation rate of 30 air changes per hour (ACH). The experiments revealed that, irrespective of the leakage rate, the oxygen concentration returned to its initial level approximately 11 min post-leakage at a ventilation rate of 30 ACH. This study also encompasses a numerical analysis to validate the experimental findings and assess the congruence between helium and hydrogen behaviors. Additionally, the impact of varying ACH rates (30, 45, 60, 75) on the concentrations of oxygen and hydrogen was quantified through numerical analysis for different hydrogen leakage rates (4, 8, 10, 20 L/min). The insights derived from this research offer valuable guidance for building facility engineers on designing ventilation systems that ensure hydrogen and oxygen concentrations remain within safe limits in hydrogen-utilizing indoor environments.

Readiness of Zero-Emission Buildings (ZEBs) implementation in the European Union

The building sector plays a central role in the reduction of greenhouse gas (GHG) emissions in the European Union (EU). The revision of the Energy Performance of Buildings Directive (EPBD) sets out ambitious requirements to make the EU building stock decarbonised by 2050. The proposal for a recast EPBD introduces Zero-Emission Building (ZEB) as the building target for all new buildings as of 2030. This paper offers insights into the concept of ZEB, analysing its key methodological aspects, with a focus on ambition, the role of energy efficiency, and the role of renewable energy. Additionally, the paper evaluates the performance levels of new buildings in EU Member States, highlighting the gaps between current Nearly Zero-Energy Buildings’ performance levels and potential ZEB performance levels, specifically in terms of primary energy demand and renewable energy contribution. The findings emphasise the necessity to enhance initiatives aimed at improving energy efficiency and harnessing renewable energy sources to adopt the ambitious ZEB concept as of 2030. Additionally, the paper highlights the importance of addressing GHG emissions comprehensively, extending beyond the operational phase of a building to include embodied impacts, in order to achieve a life-cycle zero-emission building stock.

CO2 emission reduction, loads analysis, and strategies for new healthcare facilities design – Application on a case study

To understand the “Zero Emission Building” goal introduced by the Energy Performance of Buildings Directive (EPBD) revision, it is certainly important to define its scope, since different considerations must be made for buildings with different uses, characteristics and locations. In this paper, the case study of a new construction hospital building is analysed, bringing attention to two main aspects: the correct identification of energy needs of the Heating, Ventilation and Air Conditioning (HVAC) systems; Mechanical, Electrical and Plumbing (MEP) design strategies aimed at minimizing CO2 emissions. To pursue these objectives, the hourly trends of energy consumption are examined, focusing on the interpretation of their distribution, the main influencing variables and on the distribution of such energy consumption among the different utilities of the analysed system. It is opinion of the authors that this in-depth study is preparatory to the proper MEP design of the systems: in fact, by knowing the most energyconsuming users and the distribution of heating and cooling loads during the year, it is possible to identify the optimal design strategies and generation technologies to reduce the consumption of Primary Non-Renewable Energy. In this regard, the choice of an ap-propriate calculation model is highlighted as crucial. Possible design strategies related to the case study under consideration are analysed in this paper, ultimately exposing the general considerations regarding the ZEB issue in the hospital setting.

Comprehensive Design and Transient Analysis of Novel Off‐Grid Zero Energy and Nearly Zero Emission Building with Hydrogen‐Integrated Storage System

The present study investigates the provision of heating, cooling, electricity, and domestic hot water consumption for a 100 m2 off‐grid zero‐energy residential building housing four occupants. Notably, the building is equipped with a hydrogen stove for cooking, and its electricity consumption is sustained throughout the year using renewable energies, independently of the electrical grid, with hydrogen energy storage. Using a Trombe wall for heating, surplus power is converted and stored in a dedicated hydrogen tank. TRNSYS software models analyze the system, demonstrating thermal comfort for 98.3% of the year. With 83 m2 of photovoltaic panels, the house operates off‐grid, slashing CO2 emissions by 8154.7 kg annually by reducing boiler energy consumption through waste heat utilization. The hydrogen tank minimizes the required battery size while the Trombe wall significantly contributes to heating, especially in colder climates. Remarkably, the building's renewable energy usage curtails emissions up to 8.5 times more than a Toyota Prius, showcasing its environmental impact in reducing greenhouse gas emissions.

Smart Integrated Housing Complex (SIMPLEX) Based On Carbon Capture and Engineering Wood Products to Achieve Net Zero Emission Building

In an effort to support the achievement of SGD, especially pillar No.13 (Climate Change), the existence of a technological model that enables to reduce negative impact of carbon emissions is one of the prerequisites for supporting the sustainability of life on Earth. To answer these challenges, this paper aims to introduce the idea of carbon capture technology in residential called SIMPLEX (Smart Integrated Housing Complex). This idea aims to introduce the use of engineering wood products as one of the innovative solutions to combat the adverse effects of carbon emissions. SIMPLEX is arranged in a housing complex inside there are Transparent Wood, Transparent Nano paper, Wind Turbines, Structural Applications, Water Treatment, and Energy Storage Devices. In the end, consideration of the negative impacts of SIMPLEX and the need for regulations supporting the implementation of SIMPLEX at the public level is conveyed. The SIMPLEX idea will also initiate the achievement of zero carbon emission building in Indonesia. In contrast to efforts to reduce carbon emissions by using alternative energy approaches and mobilizing the use of electric cars, efforts to reduce carbon emissions through a residential management approach based on carbon capture technology is a breakthrough that overlooked by Indonesian policymakers.

Technical-economic and financial feasibility of new technologies in the energy refurbishment of residential buildings

The revision of the Energy Performance of Building Directive (EPBD) provides for the construction of zero-emission buildings. The present work investigates possible solutions aimed at phasing out fossil fuel systems in buildings, in accordance with the EPBD requirements. An insulated residential building located in Rome is presented. The proposed refurbishment approach is based on the heating system replacement (heat pump, hydrogen fuel cell, hydrogen-ready boiler), and the use of renewable energy produced by a photovoltaic system. The results show that, although the energy optimal solution consists of the replacement of the heat plant with a heat pump coupled to both a PV and a fuel cell system, from the economicfinancial point of view the proven solution of heat pump coupled with PV is still the only feasible one.

Towards Zero-Emission Building Machinery: Insights From the Dutch Innovation System

Towards Zero-Emission Building Machinery: Insights From the Dutch Innovation System