The global share from buildings towards energy usage in residential and commercial buildings have been increasing constantly reaching between 20% to 40% in developed countries and has overtook the other major sectors: industrial and transportation. Energy demand reduction in the building sector is important for Sweden to achieve national energy aims for reduced energy use in the future.  For this reason, energy efficiency measures in buildings today is one of the main objective for energy policy towards 2020 goals.   This project moves on the same path to find energy efficiency potential in Fridhemsskolan buildings in Gävle, Sweden by performing energy audit using IDA-ICE software to simulate energy performance for the buildings under study. In addition, measurements have been made on three of the school buildings named Hus 1, Hus 2 and Hus 3.   The results include different energy efficiency retrofits on each building and economic analysis of these retrofits for each building individually and for the whole buildings together. The presented measures are reducing working hours of the ventilation system in Hus 2, change of CAV system with VAV system in (Hus 1 and Hus 2) and lights changing to LED, s efficient lights and building envelope improvement which includes walls and roof extra insulation and windows replacement.   Replacement of the CAV system in Hus 1 and Hus 2 were not economically beneficial when considering their high cost compared to energy reduction that can be achieved by applying them. On the other hand, energy retrofits analysis showed that combination of the following energy efficiency measures is the most effective and profitable: extra insulation (walls and roof), windows replacement and lights change to LED in the three buildings. In addition to these measure is reducing running hours of the ventilation system in Hus 2.   Implementation of the recommended energy efficiency measures will save 120, 737 kWh/ year of the district heating and 21, 962 kWh/year electricity consumption with capital investment of 417, 396 SEK and 98, 957 SEK/ year cost saving with payback period of 4.2 years. These figures represent 40.3% and 18.1% reduction in district heating and electricity energy use respectively.   Since reducing working hours of ventilation system measure has no capital investment and have the highest figure of energy reduction it reduces payback period significantly. In case the amount of money saved by this measure doesn’t consider; payback period for the other measures which require capital investment will be 13.5 years and the energy saving in terms of cost will be 30, 874 SEK/ year.

Master of Architecture / Department of Architecture / Gary J. Coates / Buildings account for a large part of total U.S. energy consumption and generate far more greenhouse gas emissions than any other sector of the economy. The purpose of this thesis is to demonstrate how buildings can be designed in a way that helps to mitigate global environmental problems, while resolving local urban design, architecture and social issues. This purpose was achieved by designing a zero-energy garage apartment for a site located along an alley in Manhattan, Kansas. The methodology for the design was to: identify a client; define project goals and design criteria; determine solar and geothermal renewable energy system requirements; design the garage apartment by employing energy efficient strategies relating to bioregional design and passive solar design; identify eco-friendly materials obtainable within a 500-mile radius of the site; and identify energy-efficient construction methods. The energy performance of the garage apartment was constantly monitored using eQUEST and Energy-10 simulation softwares. Operational definitions: Garage apartment- a building behind the main building[superscript]1, which is part of the same plot as the main building. It is also called a 'backhouse', 'granny flat' or a 'rear house'. Zero-energy house- for this thesis, a grid connected self-standing zero-energy house, which results in zero utility bills throughout the year.

Energy and cost performance optimization for commercial building system design is growing in popularity, but it is often criticized for its time consuming process. Moreover, the current process lacks integration, which not only affects time performance, but also investors’ confidence in the predicted performance of the generated design. Such barriers keep building owners and design teams from embracing life cycle cost consideration. This thesis proposes a computationally efficient design optimization platform to improve the time performance and to streamline the workflow in an integrated multi-objective building system design optimization process. First, building system cost estimation is typically completed through a building information model based quantity take-off process, which does not provide sufficient design decision support features in the design process. To remedy this issue, an automatic cost estimation framework that integrates EnergyPlus with an external database to perform building systems’ capital and operation costs is proposed. Optimization, typically used for building system design selection, requires a large amount of computational time. The optimization process evaluates building envelope, electrical and HVAC systems in an integrated system not only to explore the cost-saving potential from a single high performance system, but also the interrelated effects among different systems. An innovative optimization strategy that integrates machine learning techniques with a conventional evolutionary algorithm is proposed. This strategy can reduce run time and improve the quality of the solutions. Lastly, developing baseline energy models typically takes days or weeks depending on the scale of the design. An automated system for generating baseline energy model according to ANSI/ASHRAE/IESNA Standard 90.1 performance rating method is thus proposed to provide a quick appraisal of optimal designs in comparison with the baseline energy requirements. The main contribution of this thesis is the development of a new design optimization platform to expedite the conventional decision making process. The platform integrates three systems: (1) cost estimation, (2) optimization and (3) benchmark comparison for minimizing the first cost and energy operation costs. This allows designers to confidently select an optimal design with high performance building systems by making a comparison with the minimum energy baseline set by standards in the building industry. Two commercial buildings are selected as case studies to demonstrate the effectiveness of this platform. One building is the Center for Sustainable Landscapes in Pittsburgh, PA. This case study is used as a new construction project. With 54 million possible design solutions, the platform is able to identify optimal designs in four hours. Some of the design solutions not only save the operation costs by up to 23% compared to the ASHRAE baseline design, but also reduce the capital cost ranging from 5% to 23%. Also, compared with the ASHRAE baseline design, one design solution demonstrates that the high investment of a product, building integrative photovoltaic (BiPV) system, can be justified through the integrative design optimization approach by the lower operation costs (20%) as well as the lower capital cost (12%). The second building is the One Montgomery Plaza, a large office building in Norristown, PA. This case study focuses on using the platform for a retrofit project. The calibrated energy model requires one hour to complete the simulation. There are 4000 possible design solutions proposed and the platform is able to find the optimal design solution in around 50 hours. Similarly, the results indicate that up to 25% capital cost can be saved with $1.7 million less operation costs in 25 years, compare to the ASHRAE baseline design.

Urban energy system planning can play a pivotal role in the transition of urban areas towards energy efficiency and carbon neutrality. With the building sector being one of the main components of the urban energy system, there is a great opportunity for improving energy efficiency in cities if the spatio-temporal patterns of energy use in the building sector are accurately identified. A bottom-up engineering energy model of buildings, known as urban building energy model (UBEM), is an analytical tool for modeling buildings on city-levels and evaluating scenarios for an energy-efficient built environment, not only on the building-level but also on the district and city-level. Methods for developing an UBEM vary, yet, the majority of existing models use the same approach to incorporating already established building energy simulation software into the main core of the model. Due to difficulties in accessing building-specific information on the one hand, and the computational cost of UBEMs on the other hand, simplified building modeling is the most common method to make the modeling procedure more efficient. This thesis contributes to the state-of-the-art and advancement of the field of urban building energy modeling by analyzing the capabilities of conventional building simulation tools to handle an UBEM and suggesting modeling guidelines on the zoning configuration and levels of detail of the building models. According to the results from this thesis, it is concluded that with 16% relative difference from the annual measurements, EnergyPlus is the most suitable software that can handle large-scale building energy models efficiently. The results also show that on the individual building-level, a simplified single-zone model results in 6% mean absolute percentage deviation (MAPD) from a detailed multi-zone model. This thesis proposes that on the aggregated levels, simplified building models could contribute to the development of a fast but still accurate UBEM.

There is a large potential in making the residential and service sector more energy efficient and the first step towards achieving a more efficient use of energy is to implement an energy audit. In this study a property with an approximate area of 8 000 m2, consisting of a main building and three building extensions from different eras has been examined. The main building and its extensions were built in different stages and the first one in the early 20th century and some parts of the last building extension were modified at the time that the examination was carried out. This indicates that there is a vast energy savings potential in the property and an energy audit was performed. The main aim of the study was to examine where the energy was being used and where energy could be saved. Energy saving measures has been suggested together with a calculated approximate energy decrease and payback period. The total energy savings potential for the measures is approximately 146 MWh. The energy audit showed that a large amount of electricity was being used during non-work hours and that energy was lost through the building envelope. The electricity use during non-work hours was examined during the night walk, however, it is suggested to carry out further examinations regarding the property’s vast electricity use during non-work hours. To add loose wool in the roof of B2 has an energy savings potential of 33 000 kWh/year. Another measure is to clean the heat exchangers, this measure has an energy savings potential of 26 000 kWh/year. Also it is suggested to optimize the operational hours for the lighting by implementing presence control and to decrease the energy use for ventilation by cleaning the heat exchangers. Further examinations that would improve the study would be to do measurements of the electricity and temperatures to get a better understanding of the buildings energy use. Also to model the building in a simulation tool would give a calculated energy loss that is more like the actual energy loss of the building and make the results more reliable.

Energy usage deriving from human activities is increasing day by day acting against the quality of the environment and the sustainable use of natural resources. The major impact of these actions is reflected on the quality of daily life. In order to face the challenge of preserving an acceptable balance between human needs and environmental status, the combination of proper design and energy simulation of buildings is the key towards smarter and more sustainable solutions. Solutions that covers a respectable percentage of the current domestic energy needs without further environmental foot printing. In the scope of this project, an existing single-family house in Southern Greece (Heraklion, Crete) is modeled using Revit ® Architecture software and then is simulated with IES® VE (plug-in) in order to give the level of energy intensity. The energy model used is fully harmonized with the new rules set by the "National Regulation for Energy Performance of Buildings - (K.En.A.K)" as it was put in force from October 2010 and onwards, and fully complies with the European Standards (EN ISO) published for the various tasks of building`s thermal performance. The structure and contents presented in this report are in full compliance with the technical directives [31, 32, 33] published by the Technical Chamber of Greece, in favour of the complex task of "Energy Certification of Buildings". The most significant capabilities of sophisticated software tools, like Revit® Architecture, IES® VE, Polysun® and PVsyst®, in favour of sustainable building design and simulation are shown throughout the whole report. Moreover, their valuable contribution is highly acknowledged by the engineers encountered with the task of studying the energy performance of existing or newly constructed buildings in Greece and issuing, the mandatory by law, "Energy Performance Certificates".

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Buildings account for over 35% of the energy demand in OECD countries, making them a prime target for improvement. (EIA 2011) To help building owners reduce energy usage, ratings systems such as LEED have been developed. A prerequisite for certification is the demonstration of energy efficiency through computer modeling; however, the complex nature of building energy simulations too often leads to errors of up to 30% (Turner and Frankel 2008). One source of significant error can be the assumptions made of environmental conditions, which are often simplified to speed up simulations. To demonstrate the significance of active microclimate modeling, a building energy model combined with a microclimate model has been created in RadTherm, a commercial CAE thermal solver. Simulations are run using Passive House construction in three types of environments, and demonstrate an increase in energy demand over an annual time scale when microclimatic components are included. The increase in demand is less than 1%, however the decrease in radiant heat losses are up to 30%. Using the same methodology with revisions to the building construction and urban geometry, a larger increase in energy demand is expected.

The pursuit of reducing energy consumption and enhancing thermal efficiency across various sectors to foster sustainable practices has gained significant prominence in recent years, driven by the global environmental crisis. Sweco consultancy has undertaken a study focusing on underfloor heating systems for bathrooms in low-energy buildings located in Sweden. The objective is to analyse the energy usage and thermal loss to the ground based on the thickness of insulation employed. Literature findings indicate that the thermal loss to the ground should comprise approximately 15 % of the total energy, and there exists a logarithmic relationship between the thermal conductivity and density of the insulation material. In the present study, multiple simulation models were developed using IDA-ICE to assess the supplied energy and the percentage of heating loss through the ground for two typical bathrooms situated on adjacent floors of a residential building in Stockholm. The analysis encompasses scenarios where the construction is directly built on the soil or on a concrete slab, as well as the potential thermal loss from the upper level bathroom to the lower level. The results demonstrate that without an insulation layer the heating loss through the ground is remarkably high, approximately 60 %. When employing an insulation thickness of 200 mm or greater, the distinction between constructing on a concrete slab or on the soil becomes negligible. Furthermore, with a 300 mm insulation thickness, the heating loss percentage decreases to over 15 %. The simulations also reveal that the lower level bathroom can benefit from the energy loss occurring in the upper level bathroom. In instances where there is no insulation, the upper level experiences a 56 % energy loss, resulting in energy savings of over 70 % for the lower level bathroom. By incorporating a 45 mm insulation thickness on the upper level floor, this percentage is reduced to 13 %, leading to energy savings of over 25 % for the lower level bathroom.