• Energy Research

Abstract Both a well-designed on-board monitoring campaign and an adequate data-driven statistical modeling method are required to accurately characterize the building’s overall heat transfer coefficient (HTC). In this paper, we reflect on the latter by means of a theoretical deduction of the heat balance equation and case studies on simulation data. We demonstrate the impact of using air temperatures as a proxy for equivalent temperatures and neglecting the intercept when characterizing the HTC using a linear regression method on measurement data.

Recently, there has been an increasing interest in the development of an approach to characterize the as-built heat loss coefficient (HLC) of buildings based on a combination of on-board monitoring (OBM) and data-driven modeling. OBM is hereby defined as the monitoring of the energy consumption and interior climate of in-use buildings via non-intrusive sensors. The main challenge faced by researchers is the identification of the required input data and the appropriate data analysis techniques to assess the HLC of specific building types, with a certain degree of accuracy and/or within a budget constraint. A wide range of characterization techniques can be imagined, going from simplified steady-state models applied to smart energy meter data, to advanced dynamic analysis models identified on full OBM data sets that are further enriched with geometric info, survey results, or on-site inspections. This paper evaluates the extent to which these techniques result in different HLC estimates. To this end, it performs a sensitivity analysis of the characterization outcome for a case study dwelling. Thirty-five unique input data packages are defined using a tree structure. Subsequently, four different data analysis methods are applied on these sets: the steady-state average, Linear Regression and Energy Signature method, and the dynamic AutoRegressive with eXogenous input model (ARX). In addition to the sensitivity analysis, the paper compares the HLC values determined via OBM characterization to the theoretically calculated value, and explores the factors contributing to the observed discrepancies. The results demonstrate that deviations up to 26.9% can occur on the characterized as-built HLC, depending on the amount of monitoring data and prior information used to establish the interior temperature of the dwelling. The approach used to represent the internal and solar heat gains also proves to have a significant influence on the HLC estimate. The impact of the selected input data is higher than that of the applied data analysis method.

Buildings and the mobility sectors are the two sectors that currently utilize large amount of fossil-based energy. The aim of the paper is to, critically analyse the integration of electric vehicles (EV) energy load with the building’s energy load. The qualitative and quantitative methods are used to analyse the nearly/net zero energy buildings and the mobility plans of the Europe along with the challenges of the plans. It is proposed to either include or exclude the EV load within the building’s energy load and follow the emissions calculation path, rather than energy calculation path for buildings to identify the benefits. Two real case studies in a central European climate are used to analysis the energy performance of the building with and without EV load integration and the emissions produced due to their interaction. It is shown that by replacing fossil-fuel cars with EVs within the building boundary, overall emissions can be reduced by 11–35% depending on the case study. However, the energy demand increased by 27–95% when the EV load was added with the building load. Hence, the goal to reach the nearly/net zero energy building target becomes more challenging. Therefore, the emission path can present the benefits of EV and building load integration.

Abstract A building with a great amount of thermal mass is able to time-shift and flatten out heat flow fluctuations; this is referred to as the thermal inertia of a building. This paper presents a literature review focussing on the reported impacts of building thermal inertia on thermal comfort and energy use for space heating and cooling. A wide range in research methods, building types and climatic conditions considered by the respective authors, contributes to a large spread in research outcomes. As a general tendency it can be concluded that for most buildings and climates, higher amounts of thermal mass at the inner side of the thermal insulation appear to be beneficial with regard to improving thermal comfort and reducing the energy demand. The impact on energy demand is however relatively small. With an order of magnitude of a few percent for most cases, other design parameters such as thermal insulation of the building envelope and solar heat gains will be more significant. The paper reviews some practical applications exploiting the effect of thermal inertia in design and operation of HVAC systems, and concludes with a discussion on the apparent discrepancy in simulation outcomes and suggestions for further research.

The residential sector is one of the EU's priority sectors where carbon mitigation needs to be realised. In this paper, we carry out a review of the effectiveness of individual policies or policy packages in terms of the uptake of these carbon mitigation measures and/or energy savings realised as a result. The focus lies on the existing residential building stock. The literature reviewed in this paper covers panel data studies, applied behavioural research, and situated approaches. Most of the reviewed quantitative studies find that financial incentives and subsidies have a positive impact on the probability of energy efficiency improvements being undertaken. However, when evaluating the energy efficiency improvements or CO2 reductions induced by the incentives and therefore their effectiveness, the presence of free riding turns out to be a problem. Energy and CO2 taxation should play a larger role in encouraging people to save energy and reduce CO2 emissions, since the reviewed studies indicate that people are responsive to savings in energy costs and expected price increases in the future. The evidence on the relative impact of regulation vs. financial incentives is inconclusive. For information policies the quantitative evidence is still limited. The reviewed panel data studies find no or a negative impact. This finding however does not necessarily imply that information policies are useless, as panel data do not allow for a detailed analysis of different types of informational approaches. Situated accounts provide further necessary qualitative findings on best practices for energy savings by households.

Abstract Promoting energy efficiency improvements of residential buildings is considered to play an important role in achieving the Kyoto targets. That is because it allows us to reduce energy consumption without curtailing social welfare. It is worth noting that there is an increasing amount of literature on this topic that has been published in recent years. This paper therefore provides an updated review of the literature on improving the energy performance of residential buildings. The set of materials obtained has been examined according to the following topics: area of application and design variables, objectives and performance measures, type of analysis, solution methodology, software tools, case study location and type of building. Apart from trends related to the different topics, opportunities for future research are also presented.

Indoor climatic conditions are strongly influenced by outdoor meteorological conditions. It is thus expected that the combined effect of climate change and the urban heat island effect negatively influences working conditions in urban office buildings. Since office buildings are particularly vulnerable to overheating because of the profound internal heat gains, this is all the more relevant. The overheating in office buildings leads to elevated cooling costs or, because additional work breaks are required by legislation in some countries, productivity losses. We have developed a methodology incorporating urban climate modelling and building energy simulations to assess cooling costs and lost working hours in office buildings, both for current-day and future climate, extending towards the end of the twenty-first century. The methodology is tailored to additionally assess the impact and benefits of adaptation measures, and it is designed to be transferable from one city to another. Results for a prototype building located in three different European cities (Antwerp, Bilbao and London) illustrate the challenge in keeping Western-European office buildings comfortable until the end of the twenty-first century without adaptation measures, and the beneficial effect of adequate adjustments. The results further illustrate the large decreases in cooling costs (up to 30%) caused by the introduction of (external) shading and increased night-time ventilation in actively cooled buildings, and the improvements in working conditions in free-running buildings caused by moving workers to cooler locations and splitting workdays in morning and evening shifts.