English

Minimum levels of attic ventilation have been required by residential building codes in the United States for years, but the precise attic temperature reductions of “poking holes in the roof” and corresponding energy impacts have rarely been robustly quantified. This study investigates electric energy and demand impacts from passive attic ventilation using field study measurements and building energy simulations for homes in the American Southwest.

The benefits and limitations of time-dependent and steady state computational fluid dynamics simulations when evaluating natural ventilation were explored in a naturally ventilated case study apartment in the Mediterranean. For wind driven flows, indoor air properties responded quickly (i.e. within 1-min) to changing outdoor conditions, except indoor air temperatures (up to 30-min). The outdoor air temperature variations could reverse the flow direction during buoyancy-driven ventilation.

In the frame of a multi-year EU project, the set of European Standards from 2006/7 to support the European Energy Performance of Buildings Directive (EPBD) is undergoing a revision. The majority of the standards describe calculation methods. Based on the experience with the first generation of the standards and on a EU research project investigating the application of the standards in the Member States, a rigorous set of requirements has been set up. This includes issues like unambiguity and software proofness.

Domestic Hot Water (DHW) production can account for a quarter of the energy consumed in UK dwellings and this proportion is likely to increase as the energy required for space heating reduces in order to achieve demand reduction targets. As the margins for improving the performance of heating system technologies diminish, the need for improving modelling accuracy and precision increases. Although studies have considered DHW use, there is a lack of reflection on the consumption and performance of systems in contemporary UK dwellings.

This paper aims at assessing the energy savings potential of cold climate Air Source Integrated Heat Pumps (AS-IHP)s for Canadian households. The AS-IHP studied in this paper consists of a highly efficient Air Source Heat Pump (ASHP) which can supply both space heating and cooling in extreme weather conditions and of a heat pump water heater (HPWH) providing domestic hot water (DHW) that is integrated with the ASHP. The system features zoned air distribution to improve thermal comfort and energy performance.

In order to address the lack of reliable methods that can analyze the overall effects of PDEC tower with a spray system, analytical models that predict supply air conditions of the system were implemented into a whole building energy simulation program EnergyPlus. This paper describes the simulation algorithm of the new module to predict the performance of the system. Case studies were performed to verify the capability of the module.

Energy models are used in the residential sector to determine the baseline energy consumption and to predict the future energy demand. They represent a useful tool for evaluating energy saving measures and the effects of different CO2 emission reduction strategies. However, the results of the modeling are subject to multiple sources of uncertainty which are mainly related to the input parameters. In this work, the uncertainty of seven residential energy models is analyzed.

Buildings are the main consumers of electricity across the world. In the electricity system, it is critical to have a realistic forecast of buildings’ demand for adequate power planning and management. However, in the research and studies related to building performance assessment, the focus has been on evaluating energy efficiency of buildings whereas the instantaneous power consumption of systems has been overlooked.

This paper presents a new methodology of machine aided HVAC system optimization with currently available building simulation and optimization frameworks. The method consists of a two part approach using Modelica for accurate but simple system simulation as well as Matlab for automated model configuration, result evaluation and parameter variation.

The paper focuses on control optimization of nonlinear system models where the differential-algebraic equations are formulated in Modelica. Two optimiziation approaches utilizing (i) direct search methods and (ii) derivative-based methods are compared. The approaches are applied to a thermohydraulic low-exergy heating and cooling system model in form of a borehole heat exchanger, a heat pump, a hydraulic distribution system, thermally activated building systems (TABS) and a simplified building model.