Towards measurement and verification of energy performance under the framework of the European directive for energy performance of buildings

Directive 2002/91/EC of the European Parliament and Council on the Energy Performance of Buildings has led to major developments in energy policies followed by the EU Member States. The national energy performance targets for the built environment are mostly rooted in the Building Regulations that are shaped by this Directive. Article 3 of this Directive requires a methodology to calculate energy performance of buildings under standardised operating conditions. Overwhelming evidence suggests that actual energy performance is often significantly higher than this standardised and theoretical performance. The risk is national energy saving targets may not be achieved in practice. The UK evidence for the education and office sectors is presented in this paper. A measurement and verification plan is proposed to compare actual energy performance of a building with its theoretical performance using calibrated thermal modelling. Consequently, the intended vs. actual energy performance can be established under identical operating conditions. This can help identify the shortcomings of construction process and building procurement. Once energy performance gap is determined with reasonable accuracy and root causes identified, effective measures could be adopted to remedy or offset this gap

Energy performance evaluation of a photovoltaic window

A photovoltaic window specially built by a manufacturer has been studied. An amorphous silicon photovoltaic module encapsulated between two transparent glass sheets, an air chamber and a second double glass sheet with an air chamber forms the photovoltaic window. Everything is framed in a PVC structure. The effective dimensions of the a-Si photovoltaic module are 0.57x1.17 m2, equivalent to a standard measurement of 0.60x1.20 m2. To know the electrical characteristics of PV window in standard test conditions, a test in accordance with IEC standard 61646 it has carried out. A peak power of 50.74 Wp was obtained. Measurements of energy production in real sunlight were carried out. The window was placed vertically facing south on a test bench. Measurements of the energy produced by the photovoltaic window were made in several sunny days of August and September 2016 from sunrise to sunset. On average, the irradiance received on the plane of the photovoltaic window was 4114 Wh/m2 and the energy produced 71.2 Wh each day. These results match those obtained using the Malaga radiation databases. For one square meter of the window studied, 79.868 kWh/m2/year are obtained, when an overall efficiency of 0.8 is considered. Integrating this PV window in a building in Malaga (Spain), an annual electric production of 345030 kWh is obtained when a glazing surface of 4320 m2 is considered. This energy is enough to meet the annual electricity needs of the 68 household of the building.Universidad de Málaga. Campus de Excelencia Internacional Andalucia Tech. This work is partially derived from the contract nº 8.06/5.31.4644 Libre Evolución de Energía S.L

Energy Transparency in the Multifamily Housing Sector

Mirroring recent trends in other real estate sectors, the multifamily housing sector is subject to an increasing number of rules and regulations related to energy-performance benchmarking and performance disclosure. State and local governments are moving rapidly to institutionalize benchmarking and make energy performance information available in the real estate marketplace, while major lending institutions are taking initial steps to factor building energy performance into financial products. The goal of these new rules is to enable transparent building energy-performance information to drive energy efficiency improvements in multifamily housing that lower energy bills for residents; contribute to greater local housing affordability; and new jobs and services related to energy efficiency. Many multifamily owners and operators have never benchmarked the energy performance of their buildings, while other parties -- including state, local, and federal policymakers, tenants, utilities, and lenders -- have little or no access to building energy-performance information that can help shape real estate decisions or inform the development of policies, incentives, and financial vehicles to advance energy efficiency. This critical shortage of information about building energy performance has prevented property markets from valuing energy efficiency and severely undermined both public and private efforts to increase the energy efficiency of multifamily housing.While energy benchmarking and disclosure policies are an innovative approach to overcome energy-performance information gaps in the multifamily sector, several challenges must be addressed. The multifamily sector is fragmented and resists a one-size-fits-all approach, ranging from low-income public housing to luxury properties, all with varied sources of public and private financing. Policies must reflect and accommodate the diversity of both the building stock and its stakeholders. In many cases, underlying barriers continue to limit the ability of many multifamily owners to conduct benchmarking and other energy-performance assessment measures. This report is intended to serve as a guide for policymakers and multifamily stakeholders on benchmarking and disclosure rules and regulations. It provides an introduction to the multifamily housing sector, followed by a thorough review of existing benchmarking and disclosure policies and an assessment of continuing policy challenges and opportunities

Energy efficiency of social housing existing buildings – a portuguese case study

The European energy performance building regulations, Directive 2002/91/EC - Energy Performance of Buildings Directive (EPBD) of the European Parliament and Council, require that new buildings present minimum standards of energy efficiency. Accordingly the Portuguese regulations require that new buildings comply with minimum requirements on the energy performance and must have an energy performance certification through witch an energy efficiency label is attributed to the housing. It also require that existing buildings must have an efficiency energy label when submitted to a commercial transaction or to a deep rehabilitation. To achieve this goal the study of energy performance of existing buildings must be done. As many essentials elements to determine the U-factor and other thermal parameters are unknown, Portugal developed a simplified methodology to achieve the thermal performance of existing buildings. The aim of this paper is to present the study of the energy performance of a set of social dwellings that were constructed during the decade of 80, constructed before the former building thermal comfort specifications came into force. During the study the referred methodology was applied and conclusions of the energy efficiency label obtained were put out as the encountered difficulties. The study also compares the results obtained by the simplified methodology and by the detailed methodology that is required by Portuguese building thermal comfort specifications

Actual energy performance of a zero-carbon neighbourhood

The evolution towards zero-energy buildings and districts brings along uncertainties about the operational performance, strengths and weaknesses of these technologies, that are often new and unfamiliar to both the designers, owners and users. In Kortrijk, an exemplary zero-carbon neighbourhood is designed, built and evaluated in the framework of a European demonstration project ECO-Life ‘Sustainable zero-carbon ECO-town developments improving quality of life across EU’. The neighbourhood counts about 200 dwellings in highly energy-efficient buildings with different ventilation technologies and collective RES based on solar, biomass or aero-thermal energy. During the building process and the first years of operation, the energy performance of the neighbourhood is evaluated after intensive monitoring and testing by Ghent University’s research group of building physics, construction and services. This paper presents two focal points of the research: the energy demand of the buildings and the interaction with the occupants, and the energy performance of the neighbourhoods' low-temperature district heating system

Modelling of double ventilated facades according to CEN Standard 13790 method and detailed simulation

The European Energy Performance of Buildings Directive (EPBD) encourages the use of technologies in buildings that can potentially improve their energy performance. Double ventilated façades can often have a positive contribution to this objective and their effect has to be quantified during the calculation of the overall energy performance of the buildings. The updated EN ISO 13790 Standard is part of the new set of CEN Standards that have to be delivered to support the EPBD requirement for a general framework for the methodology of calculation of the total energy performance of buildings. It contains a method to calculate the contribution of the double ventilated façades to the annual heating and cooling requirements of buildings. At the same time (validated) detailed simulation tools, which are also allowed in this Standard, offer an alternative way to quantify the effect of the double ventilated façades on the buildings' energy performance. This paper examines a case study where the ESP-r simulation program and the method described in the Standard were used for a common building specification to investigate the impacts from a double ventilated façade on the energy performance of the building. It discusses the potential differences that might appear when a detailed simulation tool (ESP-r) is used with constrained (according to the Standard) inputs and also unconstrained inputs, compared to the outputs obtained from the method described in the Standard. Some parametric studies are included to show whether the same trends are obtained using both the method in the Standard and the detailed simulation approach

Benchmark-based, Whole-Building Energy Performance Targets for UC Buildings

Benchmark-based, whole building energy performance targets are becoming the best practice method for designing energy efficient and zero net energy buildings. There are several advantages to energy performance targets, including a static baseline (to allow for comparison of buildings over time), the ability to capture energy use and efficiency for all building energy loads (not just the loads regulated by code), and the ability to carry design targets through to operations. UC Merced has been using whole-building energy performance targets since its founding and has had great success in delivering buildings with very energy efficient designs that perform to those design targets in their ongoing operations. In addition, benchmarks available for UC campuses provide targets that address peak demand. For these reasons, the UC campuses are encouraged to adopt whole-building energy performance targets in their building design process, to help maintain UC’s leadership in energy efficiency