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The construction industry is responsible for 36% of the European Union's greenhouse gas emissions. The main goal of the EU in the last decade has been to boost energy efficiency and expand the use ...

Implementation of energy efficiency and renewable energy in the construction industry has become a main strategy towards a sustainable built environment. One of the pillars of sustainable development, besides the environmental and social aspects, is the economic efficiency. Therefore, economic efficiency throughout the life cycle should be addressed as well when designing highly energy efficient buildings. Buildings are long term investments, which assume that the initial decision on the quality of the investment has long term consequences. The purpose of this chapter is to present the method of life cycle cost (LCC) analysis from the various perspectives existing in the literature and standards. LCC of evaluation is extremely important towards the promotion of energy efficiency measures in front of investors, building owners and authorities. Therefore, it is necessary for architects and engineers to have the basics for applying the LCC analysis and to include it in the design phase of a building.

Following the 21st Conference of the Parties (COP 21), the 2015 Paris Agreement on Climae Change strengthens the attempts of the European Union to decarbonize the building sector and to facilitate the transition from fossil fuels towards cleaner energy. The last version of the Energy Performance of Buildings Directive 2018/844/EU is human centric and requires the integration of indoor environmental quality assessment, simultaneously with energy performance and cost-optimal requirements. In other words, efforts to improve the energy efficiency of buildings must actively contribute on reducing the building stock's climate impact while ensuring healthy indoor climate conditions, wellbeing and productivity. This paper introduces the cost-optimal analysis and indoor environmental quality assessment for nearly zero-energy buildings in temperate climate. The study presents several nearly zero-energy buildings (NZEB) scenarios for residential buildings, which include measures that are either upgrades that can be implemented in the as-built case study building or different other configurations of thermal envelope, technical systems and on-site renewable energy production. The cost-optimal analysis results show that among the investigated scenarios, the lowest global cost is achieved by the as-built house, which is an all electric building that has passive house envelope, mechanical ventilation with heat recovery, heat pump and solar collector. Furthermore, the study reveals that with the implementation of PV panels, the primary energy demand can be reduced with 55% at a global cost increase of only 3%. The results and data can be used to compare energy efficincy measures and the related costs between EU Member States.

Environmental issues have received ascending attention in recent years due to the increase of their negative effects. Greenhouse gas emission levels have experienced an exponential increase in the last decades mainly on account of the development of the building sector. Life cycle assessment (LCA) of buildings is a proper tool to analyse the full environmental impact during their designed lifespan. Inventory databases have a shortage of local parameters in some countries and need to be developed constantly. Life cycle cost (LCC) analysis evaluates the global costs of an investment. Besides the initial cost of implementing a project, usage, maintenance, repair, replacement and demolition costs are also taken into account. The goal of the research presented in this paper is to evaluate the environmental impact of a highly energy efficient residential house, built in western Romania. Life cycle assessments of buildings show that in most cases the impact of operating phase is much higher than construction phase, but in case of highly energy efficient buildings, the results are slightly different. However, energy related processes play a major role in determining the impact of buildings. A cradle-to-grave life cycle analysis, using SimaPro software, offers a complete image of the studied building s environmental impact. The main objective is to determine the fraction of each component of the building with relevant contribution to the human health and ecosystems categories.

In a temperate climate such as that of Romania, due to the high differences between comfort parameters and temperate environmental conditions, energy is needed in order to achieve a comfortable indoor environment in both winter and summer. Yet, due to the higher initial investment cost, in Romania, the new solutions for highly energy efficient buildings are rarely used. In order to increase the awareness of the investors on the long-term advantages of these solutions, pilot projects are necessary that provide real-time monitoring on the energy performance and behaviour of energy efficient buildings. At the Politehnica University of Timisoara, an experimental programme was developed to demonstrate that applying passive house design principles could be an alternative solution for energy-efficient buildings, reflecting the Romanian local climate conditions, materials, and construction techniques. An energy-efficient house was built following the passive house design principles and was subjected to extensive monitoring. In the design phase, the discussed house is compared to a reference house designed following the energy efficiency requirements in Romania, in order to emphasise the differences in terms of energy demand and life-cycle cost. The life-cycle cost analysis results are dependent on the future growth of energy prices. The study contains the results from the monitoring campaign of the energy efficient house, including the monitoring of the energy consumption as well as of the indoor parameters. The monitoring results indicate that the studied house is meeting the passive house design target of total primary energy requirement of less than 120 kWh/m 2 year.

Building energy modelling and simulations play an important role in the design of energy efficient buildings but also in post-construction phases for commissioning, operation and optimization. With the use of data from monitoring systems related to the operation conditions of a building, calibrated simulations can be performed that accurately follow the real energy performance of a building. This paper present a procedure to achieve a calibrated building energy model simulation using monitoring data. The aim of the study is to verify/validate the results of the building energy model simulation against measured data. The study is based on an existing highly energy efficient building, which is continuously monitored in terms of energy consumptions and environmental parameters for several years now. The performance of the building energy model was assessed using statistical indices. The monthly total energy consumption comparison between simulated and measured shows that the building energy model managed to predict very closely the measured values. The accuracy of the building energy model in predicting air temperature was assessed as well.

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.

The significant share of energy consumption of the building sector in the total energy consumption makes it responsible for 36% of CO2 emission in the European Union. In the last decade a key objective of the EU is to improve the energy efficiency and increase the use of renewables in buildings. Ground-to-air heat exchangers can be a solution for reducing primary energy consumption from nonrenewable sources in buildings and contribute to the share of energy from renewable sources. The research in this paper deals with investigations on a ground to air heat exchanger of a pilot energy efficient building, constructed in west side of Romania. The study presents the assessment of the heating and cooling energy potential of the ground-to-air heat exchanger serving the energy efficient building. Three full years of measurements of the air temperature entering the ground-air heat exchanger and the outlet air temperature are available and were used in the study. A comparison is made between the energy potential determined based on temperature measurements and the energy potential based on calculated outlet temperatures using a computational model and conventional climate data for the building location.

This paper presents the design and monitoring scheme of an energy efficient high school building with emphasis on the analysis of constructive and geometric thermal bridges that can affect the overall energy consumption and thermal comfort. The ANTHERM software is used to accurately assess the specific details and determine isotherms, heat flux distribution and the Psi-values (Ψ value) of the sections where different types of materials connect. A monitoring system with temperature sensors installed in the layers of the building envelope elements has been designed in order to compare the obtained values with the real time thermal performances of the envelope elements. The study highlights the influence of the type and thickness of the insulation materials used in the specific constructive details on the overall thermal performance of buildings.

Improving the Power Quality and the Energy Efficiency are the strategic goals of the Electricity Distribution and Supply Company — ELECTRICA. In Romania, there are eight subsidiaries as a regional part of the mother company — ELECTRICA. Each of the subsidiaries has about one-milion electricity customers. Generally speaking, Power Quality has an important influence on the market shares of the company (in deregulated market) and Energy Efficiency has an influence on the profitability of the company. There is an important relationship between Power Quality and Energy Efficiency, and both have an important influence on the Performance of the ELECTRICA Company. All of these concepts are important in perspective of total liberalisation of the electricity market in 2007 and in the privatisation process — in progress in Romanian Electricity sector.