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This paper presents the application of multi-objective genetic algorithms for holistic building design that considers multiple criteria; building energy use, capital cost, daylight distribution and thermal indoor environment. The optimization focus is related to building envelope parameters. To obtain relevant feedback from multi-objective optimizations in early design stages, evaluation speed is a key concern. The paper presents a fast evaluation method fit for the early design stages. It uses a combination of two different quasi-steady-state methods for energy and indoor environment evaluations, a Radiance implementation for daylight simulations and a scripted algorithm for capital cost evaluations. The application of the method is developed around an integrated dynamic model which allows visual design feedback from all evaluations to be an integrated part of the design tool experience. It is concluded, that quasi-steady-state methods implemented as part of integrated dynamic models are fast and flexible enough to support building energy-, indoor environment- and cost-optimization the early design stages. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a strategy for a simple demand controlled ventilation system for single family houses where all sensors and controls are located in the air handling unit. The strategy is based on sensing CO2-concentration and moisture content in the outdoor air and exhaust air. The CO2-concentration is used to ensure adequate ventilation during occupancy and the moisture content is used to ensure adequate removal of moisture produced in the house. The ventilation rate can be switched between two flow rates: a high rate and a low rate. The high flow rate is based on existing requirements in the Danish building regulations and the low flow rate is based on minimum requirements in indoor air quality standards. Measurements were performed on an existing single family house where the controls were installed on the existing mechanical ventilation system. The results showed that the ventilation can be reduced to the low rate 37% of the time without significant changes in the CO2-concentration and moisture level in the house. In theory this gives a 35% saving on electric energy for fans. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a simple building simulation tool for integrated daylight and thermal analysis. The tool is capable of importing the thermal and visual properties for different glazings and shading positions from the Window Information System (WIS) program. A coupled ray-tracing and radiosity methodology is used to derive the daylight levels for different sky conditions. Both detailed daylight distribution for a particular day and time and hourly discrete values on a yearly basis may be obtained. For an integrated simulation the hourly daylight levels are fed into an existing simple thermal simulation program capable of calculating energy demand and the indoor environment. Straightforward control systems for general and task lighting systems have been implemented together with a shading control strategy that adjusts the shading according to the indoor operative temperature, the risk of glare and the profile angle of the sun. The implemented daylight calculation method allows for shades from the window recess and overhang, and for distant shades blocking the sky vault. Comparisons with the ray-tracing program Radiance show that the accuracy of this approach is adequate for predicting the energy implications of photoresponsive lighting control. The amount of input is small, which makes the tool useful for integrated daylight optimisation in the early design process. [Copyright &y& Elsevier]

Abstract: Using mechanical ventilation with highly efficient heat-recovery in northern European or arctic climates is a very efficient way of reducing the energy use for heating in buildings. However, it also presents a series of problems concerning condensation and frost formation in the heat-exchanger. Developing highly efficient heat-exchangers and strategies to avoid/remove frost formation implies the use of detailed models to predict and evaluate different heat-exchanger designs and strategies. This paper presents a quasi-steady-state model of a counter-flow air-to-air heat-exchanger that takes into account the effects of condensation and frost formation. The model is developed as an Excel spreadsheet, and specific results are compared with laboratory measurements. As an example, the model is used to determine the most energy-efficient control strategy for a specific heat-exchanger under northern European and arctic climate conditions. [Copyright &y& Elsevier]

Abstract: A simplified building simulation tool to evaluate energy demand and thermal indoor environment in the early stages of building design is presented. Simulation is performed based on few input data describing the building design, HVAC systems and control strategies. Hourly values for energy demand and indoor temperature are calculated based on hourly weather data. Calculation of the solar energy transmitted through windows takes into account the dependency of the total solar energy transmittances on the incidence angle, shades from far objects and shades from the window recess and overhangs. Several systems including heating, cooling, solar shading, venting, ventilation with heat recovery and variable insulation can be activated to control the indoor temperature and energy demand. Predicted percentages of dissatisfied occupants are calculated for a given time period to support decisions concerning the thermal indoor environment. The simplified building simulation tool gives reliable results compared to detailed tools and needs only few input data to perform a simulation. The tool is therefore useful for preliminary design tasks in the early design stages where rough estimates of the building design are given and rough estimates of energy use and thermal indoor environment are needed for decision support. [Copyright &y& Elsevier]

Abstract: The International Building Physics Toolbox (IBPT) is a software library developed originally for heat, air and moisture system analysis in building physics. The toolbox is constructed as a modular structure of standard building elements, using the graphical programming language Simulink. To enable development of the toolbox, a common modelling platform is defined: a set of unique communication signals, material database and documentation protocol. The IBPT is an open source and available on the Internet. Any user can utilize, expand and develop the contents of the toolbox. This paper presents structure and essence of the library. Potential applications of the toolbox are illustrated through examples. [Copyright &y& Elsevier]

• An extensive overview of the current EPBD regarding the RLM is presented. • Several barriers are linked to the RLM, preventing the implementation of energy measures. • More detailed legislation is needed to avoid loose implementations. • The RLM are rarely perceived as useful for the building owners. • A strong method to develop renovation measures is needed to strengthen the certification system. The Energy Performance Certificate (EPC) has an especial feature for existing buildings, a Recommendation List of Measures (RLM) designed to improve the energy performance of these buildings. This feature has not been properly studied by researchers or policymakers, in spite of being one of the main tools that can encourage building owners to perform renovation activities. Considering the scarce research focusing on the recommendations list of measures, more information is needed in order to identify weaknesses, barriers and improvements of this tool. This is especially important since the European commitment to reduce their emissions in 2020 are far from reaching the proposed goals, mainly becouse of the low renovation rate. This critical review is based on the current literature mainly from reports delivered by the Commission and academic research. The study focuses on the requirement set by the directive, its current performance, barriers and improvements that can be made to take this tool to a level that can be effectively used by policymakers, certifiers and owners. The upgrade of the recommendation list of measure should strengthen their calculation methods and procedure from both local authorities and the Commission. This should be in line with the certifiers' needs in order to do relevant work, including proper training, mandatory field inspections and tools. Lastly, financial policies and information should be implemented to accompany the certificate, ensuring that building owners interested in renovation have assistance and financial facilities or easy access to relevant information on this matter. The main conclusion of this study reveals that the regulatory framework could use some strictness in order to avoid 'just enough' implementations. Ambiguous definitions and too flexible obligations should be revised, especially cost-effectiveness and training for the certifiers. Attention on how to deliver the information to building owners should be increased, allowing them to understand the results, its implications and how to concretize renovation work through financial mechanisms, thus increasing the reliability of the EPC and the RLM. [ABSTRACT FROM AUTHOR]