Sensitivity analysis plays an important role in building energy analysis. It can be used to identify the key variables affecting building thermal performance from both energy simulation models and observational study. This paper is focused on the application of sensitivity analysis in the field of building performance analysis. First, the typical steps of implementation of sensitivity analysis in building analysis are described. A number of practical issues in applying sensitivity analysis are also discussed, such as the determination of input variations, the choice of building energy programs, how to reduce computational time for energy models. Second, the sensitivity analysis methods used in building performance analysis are reviewed. These methods can be categorized into local and global sensitivity analysis. The global methods can be further divided into four approaches: regression, screening-based, variance-based, and meta-model sensitivity analysis. Recent research has been concentrated on global methods because they can explore the whole input space and most of them allow the self-verification, i.e., how much variance of the model output (building energy consumption) has been explained by the method used in the analysis. Third, we discuss several important topics, which are often overlooked in the domain of building performance analysis. These topics include the application of sensitivity analysis in observational study, how to deal with correlated inputs, the computation of the variations of sensitivity index, and the software issues. Lastly, the practical guidance is given based on the advantages and disadvantaged of different sensitivity analysis methods in assessing building thermal performance. The recommendations for further research in the future are made to provide more robust analysis in assessing building energy performance.

A review of sensitivity analysis methods in building energy analysis

A review of human thermal comfort in the built environment

Shading effect on long-term outdoor thermal comfort

Estimating the effect of using cool coatings on energy loads and thermal comfort in residential buildings in various climatic conditions

Battery energy storage systems have gained increasing interest for serving grid support in various application tasks. In particular, systems based on lithium-ion batteries have evolved rapidly with a wide range of cell technologies and system architectures available on the market. On the application side, different tasks for storage deployment demand distinct properties of the storage system. This review aims to serve as a guideline for best choice of battery technology, system design and operation for lithium-ion based storage systems to match a specific system application. Starting with an overview to lithium-ion battery technologies and their characteristics with respect to performance and aging, the storage system design is analyzed in detail based on an evaluation of real-world projects. Typical storage system applications are grouped and classified with respect to the challenges posed to the battery system. Publicly available modeling tools for technical and economic analysis are presented. A brief analysis of optimization approaches aims to point out challenges and potential solution techniques for system sizing, positioning and dispatch operation. For all areas reviewed herein, expected improvements and possible future developments are highlighted. In order to extract the full potential of stationary battery storage systems and to enable increased profitability of systems, future research should aim to a holistic system level approach combining not only performance tuning on a battery cell level and careful analysis of the application requirements, but also consider a proper selection of storage sub-components as well as an optimized system operation strategy.

https://www.mdpi.com/1996-1073/10/12/2107/pdf

Lithium-Ion Battery Storage for the Grid—A Review of Stationary Battery Storage System Design Tailored for Applications in Modern Power Grids

This paper presents the findings of an outdoor thermal comfort study conducted in Hong Kong using longitudinal experiments—an alternative approach to conventional transverse surveys. In a longitudinal experiment, the thermal sensations of a relatively small number of subjects over different environmental conditions are followed and evaluated. This allows an exploration of the effects of changing climatic conditions on thermal sensation, and thus can provide information that is not possible to acquire through the conventional transverse survey. The paper addresses the effects of changing wind and solar radiation conditions on thermal sensation. It examines the use of predicted mean vote (PMV) in the outdoor context and illustrates the use of an alternative thermal index—physiological equivalent temperature (PET). The paper supports the conventional assumption that thermal neutrality corresponds to thermal comfort. Finally, predictive formulas for estimating outdoor thermal sensation are presented as functions of air temperature, wind speed, solar radiation intensity and absolute humidity. According to the formulas, for a person in light clothing sitting under shade on a typical summer day in Hong Kong where the air temperature is about 28°C and relative humidity about 80%, a wind speed of about 1.6 m/s is needed to achieve neutral thermal sensation.

https://link.springer.com/content/pdf/10.1007%2Fs00484-010-0396-z.pdf

Outdoor thermal comfort study in a sub-tropical climate: a longitudinal study based in Hong Kong.

Urban human thermal comfort in hot and humid Hong Kong

Effect of envelope colour and thermal mass on indoor temperatures in hot humid climate

This paper presents the development, evaluation and application of the Domestic Energy and Carbon Model (DECM) for predicting the energy consumptions and carbon dioxide emissions of the existing English housing stock. A novel feature of DECM is the adoption of an occupancy pattern model which is derived from the household employment status data. We believe this modification has significantly improved the accuracy of the estimation in space heating energy use. At national level, the model estimation of carbon emissions and gas and electricity consumptions are respectively 4.5%, 3.4% and 1.0% higher than the national statistics. At the sub-national level (Local Authority), two methods are used to produce estimations: one based on dwelling type and the other based on socio-economic class. For both methods, the correlations between the model estimations and the government records are statistically significant and substantial (all r"s > 0.9 and ps<0.01). According to the results, it can be inferred that over 85% of the variance in dwelling energy consumptions and carbon emissions can be accounted for by dwelling type and the socio-economic class of households. The paper presents a local sensitivity analysis which examines the effects of various building fabric and service system parameters on the modelled average carbon emissions per dwelling. Based on the findings, a set of predictive charts are developed which can provide rapid estimations of the effect of various energy efficiency measures on dwelling energy consumptions and carbon emissions taking into account the potential rebound effect. In summary, this paper shows that the DECM model can be a useful tool to assist the formation of energy efficiency policies at both national and local levels.

Modelling domestic energy consumption at district scale: A tool to support national and local energy policies

Rapid urbanization in recent years has exerted tremendous pressure on urban development. In the face of the largely unexamined fashion for densification, it is vital that the environmental impact of compaction be researched. This study comprises solar simulation of eighteen generic models; each represents a particular combination of built form and density. This paper examines the relationships between built forms, density and solar potential, with reference to three design criteria i.e. openness at ground level, daylight factor on building facade and PV potential on building envelope. The result shows the different effects of horizontal and vertical randomness on urban solar potential and it also reveals the interrelation between randomness, plot ratio and site coverage, which can provide helpful insights for planning solar cities.

Vicky Cheng

Papers

Outdoor thermal comfort study in a sub-tropical climate: a longitudinal study based in Hong Kong.

Urban human thermal comfort in hot and humid Hong Kong

Effect of envelope colour and thermal mass on indoor temperatures in hot humid climate

Modelling domestic energy consumption at district scale: A tool to support national and local energy policies

Urban Form, Density and Solar Potential