scholarly journals Dynamic Energy Modelling as an Alternative Approach for Reducing Performance Gaps in Retrofitted Schools in Denmark

2020 ◽  
Vol 10 (21) ◽  
pp. 7862
Author(s):  
Muhyiddine Jradi

When considering that over 80% of buildings in Denmark were built before the 1980′s, a holistic energy retrofitting of the existing building stock is a major milestone to attain the energy and environmental targets of the country. In this work, a case study of three public schools is considered for post-retrofit process evaluation. The three schools were heavily retrofitted by September 2018 with energy conservation and improvement measures that were implemented targeting both the building envelope and various energy systems. A technical evaluation of the energy retrofit process in the schools was carried out, when considering one year of operation after the completion of the retrofitting work. Actual data from the heating and electricity meters in the schools were collected and compared with the pre-retrofit design numbers which rely majorly on static tabulated numbers for savings evaluation. It was shown that the retrofit design numbers largely overestimate the attained savings, where the average performance gap between the expected and real numbers for the three schools is around 61% and 136% for annual heating and electricity savings, respectively. On the other hand, an alternative approach was proposed where calibrated dynamic energy performance models, which were developed for the three schools in EnergyPlus, were used to simulate the impact of implementing the retrofit measures. It was shown that implementing this approach could predict much better the impacts of the retrofit process with an average gap of around 17% for heating savings and 21% for electricity savings. Based on the post-retrofit process evaluation in the three schools, it was concluded that using dynamic model simulations has the potential of lowering the performance gap between the promised and real savings when compared to static tabulated approaches, although the savings are still generally over-estimated in both approaches.

2016 ◽  
Vol 2016 ◽  
pp. 1-180
Author(s):  
Katerina Petrushevska

AIM: This research examines the important issue of energy efficient improvements to the existing building stock through building envelope upgrade. To facilitate this, the energy performance characteristics of the existing building stock were identified with a view to establishing an existing building stock type, where building envelope upgrades can contribute to a higher level of energy efficiency improvements. The literature review along with the selected building precedents was used to establish the best current practice for building envelope upgrades.MATERIAL AND METHODS: Established building precedents and identified best practice for building envelope upgrade, a high rise block of flats was identified and used as a case study, with the current and predicted, following building envelope upgrade, energy performance of the building calculated. This has allowed us to identify the possible energy efficiency improvements for this type of building following the building envelope upgrade. RESULTS: In the projected case, the building with energy class - "D" become class "B". In addition, increased quality of the living room in the attic was enabled. It was possible to obtain a decrease of the heating energy from 130.76 kWh/m²a to 37.73 kWh/m²a or to jump in the class "B" of energetic passport.CONCLUSION: This research contributes to the local implementation of the global agenda for sustainable development, design and construction, and it demonstrates the possible way and level of energy efficiency improvements to the least efficient building stock through existing building envelope upgrade.


2020 ◽  
Vol 12 (18) ◽  
pp. 7557 ◽  
Author(s):  
Lingjun Hao ◽  
Daniel Herrera-Avellanosa ◽  
Claudio Del Pero ◽  
Alexandra Troi

Historic buildings account for more than one-quarter of Europe’s existing building stock and are going to be crucial in the achievement of future energy targets. Although a drastic reduction in carbon emissions would slow climate change, an alteration in the climate is already certain. Therefore, the impact of climate change on retrofitted historic buildings should be considered in terms of occupants’ comfort, heritage conservation, and energy performance. Inappropriate interventions might weaken the potential of traditional climate adaptive solutions, such as thermal mass and night cooling, leading to higher risks of overheating in a warming climate. Similarly, retrofit solutions will change the moisture dynamics of historic envelopes, which might lead to moisture damages when combined with more extreme precipitation events. This paper reviews recent literature that provides evidence of climate change’s impact on retrofitted buildings, reveals potential future risks, and thereby sheds light on new factors influencing the decision-making process in the retrofit of historic buildings.


2020 ◽  
pp. 50-64
Author(s):  
Kuladeep Kumar Sadevi ◽  
Avlokita Agrawal

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.


2021 ◽  
Vol 11 (4) ◽  
pp. 1423
Author(s):  
José Manuel Salmerón Lissen ◽  
Cristina Isabel Jareño Escudero ◽  
Francisco José Sánchez de la Flor ◽  
Miriam Navarro Escudero ◽  
Theoni Karlessi ◽  
...  

The 2030 climate and energy framework includes EU-wide targets and policy objectives for the period 2021–2030 of (1) at least 55% cuts in greenhouse gas emissions (from 1990 levels); (2) at least 32% share for renewable energy; and (3) at least 32.5% improvement in energy efficiency. In this context, the methodology of the cost-optimal level from the life-cycle cost approach has been applied to calculate the cost of renovating the existing building stock in Europe. The aim of this research is to analyze a pilot building using the cost-optimal methodology to determine the renovation measures that lead to the lowest life-cycle cost during the estimated economic life of the building. The case under study is an apartment building located in a mild Mediterranean climate (Castellon, SP). A package of 12 optimal solutions has been obtained to show the importance of the choice of the elements and systems for renovating building envelopes and how energy and economic aspects influence this choice. Simulations have shown that these packages of optimal solutions (different configurations for the building envelope, thermal bridges, airtightness and ventilation, and domestic hot water production systems) can provide savings in the primary energy consumption of up to 60%.


2021 ◽  
Vol 13 (11) ◽  
pp. 6018
Author(s):  
Theo Lynn ◽  
Pierangelo Rosati ◽  
Antonia Egli ◽  
Stelios Krinidis ◽  
Komninos Angelakoglou ◽  
...  

The building stock accounts for a significant portion of worldwide energy consumption and greenhouse gas emissions. While the majority of the existing building stock has poor energy performance, deep renovation efforts are stymied by a wide range of human, technological, organisational and external environment factors across the value chain. A key challenge is integrating appropriate human resources, materials, fabrication, information and automation systems and knowledge management in a proper manner to achieve the required outcomes and meet the relevant regulatory standards, while satisfying a wide range of stakeholders with differing, often conflicting, motivations. RINNO is a Horizon 2020 project that aims to deliver a set of processes that, when working together, provide a system, repository, marketplace and enabling workflow process for managing deep renovation projects from inception to implementation. This paper presents a roadmap for an open renovation platform for managing and delivering deep renovation projects for residential buildings based on seven design principles. We illustrate a preliminary stepwise framework for applying the platform across the full-lifecycle of a deep renovation project. Based on this work, RINNO will develop a new open renovation software platform that will be implemented and evaluated at four pilot sites with varying construction, regulatory, market and climate contexts.


2021 ◽  
Vol 13 (20) ◽  
pp. 11554
Author(s):  
Fahad Haneef ◽  
Giovanni Pernigotto ◽  
Andrea Gasparella ◽  
Jérôme Henri Kämpf

Nearly-zero energy buildings are now a standard for new constructions. However, the real challenge for a decarbonized society relies in the renovation of the existing building stock, selecting energy efficiency measures considering not only the energy performance but also the economic and sustainability ones. Even if the literature is full of examples coupling building energy simulation with multi-objective optimization for the identification of the best measures, the adoption of such approaches is still limited for district and urban scale simulation, often because of lack of complete data inputs and high computational requirements. In this research, a new methodology is proposed, combining the detailed geometric characterization of urban simulation tools with the simplification provided by “building archetype” modeling, in order to ensure the development of robust models for the multi-objective optimization of retrofit interventions at district scale. Using CitySim as an urban scale energy modeling tool, a residential district built in the 1990s in Bolzano, Italy, was studied. Different sets of renovation measures for the building envelope and three objectives —i.e., energy, economic and sustainability performances, were compared. Despite energy savings from 29 to 46%, energy efficiency measures applied just to the building envelope were found insufficient to meet the carbon neutrality goals without interventions to the system, in particular considering mechanical ventilation with heat recovery. Furthermore, public subsidization has been revealed to be necessary, since none of the proposed measures is able to pay back the initial investment for this case study.


Author(s):  
Darija Gajić ◽  
Erdin Salihović ◽  
Nermina Zagora

Yielding from an overall quantitative study of the residential sector of Bosnia and Herzegovina (B&H), this chapter concentrates on the ratio between single-family and collective housing, as well as on the urban-rural ratio of the single-family housing. Based on the data from the existing building stock (buildings built by 2014) and the statistical estimates, 23% of the buildings belong to the urban areas and 77% belong to the rural areas. The main goal was to study the correlation between the characteristics of the building envelope, the shape factor (A/V ratio) and the energy savings potential for the application of conventional measures of refurbishment of the building envelope of the single-family houses (type of buildings, which dominate in rural and urban areas). The chapter wraps up with recommendations for the adequate level of the energy performance indicator (energy need for heating) for the approved energy class for single-family houses located in the climate zone of the northern B&H.


Proceedings ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
Michele Vavallo ◽  
Marco Arnesano ◽  
Gian Marco Revel ◽  
Asier Mediavilla ◽  
Ane Ferreiro Sistiaga ◽  
...  

Buildings are the key factor to transform cities and to contribute to recent European energy efficiency objectives for 2030 and long-term 2050. New buildings account to only 1–2% annually. Yet, ninety percent of the existing building stock in Europe was built before 1990, it is therefore necessary to promote their energy renovation to achieve the set objectives. Renovation solutions are available on the market, yet a wrong implementation and integration due to a lack of knowledge neither maximizes the energy performance of the post-retrofitting nor the financial optimisation and viability of the projects. This paper presents research on a plug & play, modular, easy installable façade and ICT decision making technologies to provide affordable solutions in order to overcome those deep renovation barriers. The paper sets out by defining a value framework that can be applied by real estate investors for making better retrofitting decisions for residential buildings, through mapping targeted building typologies and investigating new building revalorisation strategies, new renovation concepts and KPIs for evaluation. Thereafter the paper presents the modular and easy-to-install façade system that is replicable and scalable at European level.


2019 ◽  
Vol 111 ◽  
pp. 06073 ◽  
Author(s):  
Ioan Silviu Dobosi ◽  
Cristina Tanasa ◽  
Nicoleta-Elena Kaba ◽  
Adrian Retezan ◽  
Dragos Mihaila

The building sector has been identified as having the greatest energy reduction potential and therefore represents a key factor for the European Union climate change combat objectives of achieving an 80-95% greenhouse gas emissions reduction by 2050. Hospitals buildings represent 7% of the nonresidential building stock in the European Union and are responsible for approximately 10% of the total energy consumption in this sector. The design and construction of hospital buildings is a complex and challenging activity for all the involved specialists, especially when energy performance is one of the objectives. This paper discusses the energy performance simulation on an hourly basis of a new hospital building that was constructed in the city of Mioveni, Romania. At this stage of the study, the building energy model solely investigates the performance of the building envelope, without modelling the HVAC system. The complexity of the building model derives from the multitude of thermal zones depending on interior temperature and ventilation air changes conditions. Several simulations are performed investigating the heating and cooling energy need depending on the building location.


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