Research on low-carbon energy-saving technical solutions for office buildings in Chengdu, China

A multi-factor optimization method based on thermal comfort for building energy performance with natural ventilation

This article focuses on adopting effective and affordable bioclimatic building design strategies in Ouagadougou, in the Sudano-Sahelian zone of Burkina Faso. A model representing a standard office building and relevant parameters were input in EnergyPlus, and scenarios were analyzed to evaluate the effect of natural ventilation, window shading, dehumidification with night ventilation, and evaporative cooling with night ventilation on thermal comfort and energy consumption. First, the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 55 adaptive comfort model was used to compare discomfort hours and interior temperatures between a conventional office design and improved models using passive approaches. The simulations further tested the reduction in energy cooling demand and energy consumption. The results demonstrated that natural ventilation was the most effective passive cooling technique, helping to reduce the annual discomfort hours by 40% and the annual energy consumption by 30%. Combining passive strategies is the best scenario, with a year of office occupancy resulting in just 617 h of discomfort, a 42% reduction in the annual energy cooling demand, and a 43% reduction in the annual energy consumption. The simulations demonstrated the effectiveness of affordable passive design solutions applicable even in existing office buildings and their significance for the sustainable development of fast-urbanizing Sub-Saharan countries.

Nowadays, building energy consumption is responsible for 30% to 40% of total energy usage in many countries. The energy performance of each building is related to many factors. Most of them are determined in design stage. Meanwhile, natural ventilation is one of the most potential passive energy conservation, especially in hot summer and cold winter climate zone. This study aims to figure out how to make the most of natural ventilation in building energy conservation in hot summer and cold winter climate zone. By comparing different building design plans, this study try to provide a method to help find the best-optimized building parameters design solutions. Six main factors are selected, including: building orientation, exterior wall masonry, window wall ratio, shading overhang depth, binds slat angel(include the situation when there is no blinds at all), exterior window structure. A seven-layer office building in hot summer and cold winter zone is modelled and simulated in Energyplus. Two building running plans are compared: (a) the air conditioning system is always on during office occupancy time; (b) the air conditioning system is off when natural ventilation can guarantee thermal comfort inside the building. The results shows, plan (b) saves more than 40% energy on different building parameters designs comparing to plan (a).

In 2008, the European Energy Performance of Buildings Directive (EPBD) facilitated the introduction of two mandatory energy assessment methods in the UK. Energy Performance Certificates (EPCs) reveal the modelled energy performance of buildings when they are constructed, sold or let based on their intrinsic energy attributes, whereas Display Energy Certificates (DECs) reveal operational energy performance in a subset of buildings that is operated by the public sector, based on annual energy consumption data.EPCs were conceived as a marketing mechanism for property market participants and they have been used in studies that have sought to investigate the links between energy performance and financial performance of buildings. Yet they are based on modelled energy performance and the ratings that they express are hypothetical, whereas DECs are based on actual energy consumption figures. Furthermore, EPCs are valid for 10 years, whereas DECs need to be renewed annually.This study will investigate energy performance patterns as recorded in DEC certificates in existing office buildings over time. The study uses detailed DEC data for commercial office buildings from the Department for Communities and Local Government. This dataset is matched to data on building attributes from CoStar UK to investigate the relationship between energy performance and building features such as age and building quality. This study models the magnitude of observed changes in operational energy performance in existing buildings, to investigate how operational energy performance assessment can be used to track energy performance improvements over time, and reveal how different control variables may impact on recorded changes. These findings will provide further insights into the effects and impacts of the introduction of energy certification for buildings. The further aim of this study is to develop a building typology based on commonly shared building and energy performance attributes.

Purpose Office buildings confront with the issue of high energy demand during the day time mainly due to heavy use of energy for HVAC and lighting systems. Demand-side energy retrofits (DSER) are identified as effective in controlling electricity demand of existing buildings. The purpose of this paper is to analyse the potential of incorporating DSER in to existing office buildings. The paper reports the cost benefits of using DSER in existing office buildings. Furthermore, it reveals several enablers that can be used to promote retrofits in office buildings of Sri Lanka. Design/methodology/approach An industry survey was conducted by selecting a sample of 35 office buildings to study the usage of DSER in office buildings of Sri Lanka. Furthermore, three case studies were conducted to analyse the costs benefits of widely used DSER techniques in office buildings. Findings Research revealed that the use of DSER techniques in existing office buildings of Sri Lanka is at a lower level. However, it found that the financial viability of those DSER was at a promising level. Furthermore, 11 enablers in two levels as organisational level and national level were identified to enhance the use of DSER. Originality/value The study justifies the potential of DSER in reducing energy demand of existing office buildings through in-depth cost benefit analysis, which is useful for a country like Sri Lanka which faces massive energy crisis. This encourages Facility Managers towards using DSER to reduce building energy demand. Furthermore, study provides enablers at organisational and national levels to enhance the use of DSER.

From the view of life cycle, the energy consumption and CO 2 emission of office buildings are found to mainly occur during the operation and maintenance stages and can be up to 80%. Furthermore, building design factors such as orientation, window glass types, window to wall ratio, building envelope insulation, sunshade device, air conditioner temperature, and illumination control all have significant impacts on the energy consumption of the office buildings. Therefore, the objective of this study is to investigate the efficacy of energy conservation strategies for office buildings in Taiwan. An existing office building in Taichung is used as a case study and energy conservation strategies are simulated and evaluated by Energy Plus model. It is found that the building investigated in this study can save up to 20% annual energy consumption by implementing suitable energy conservation strategies into the existing system.

A three-stage decision-making process for cost-effective passive solutions in office buildings in the hot summer and cold winter zone in China

Impact of outdoor particulate matter 2.5 pollution on natural ventilation energy saving potential in office buildings in China

The intense solar radiation absorbed through the window glassing and transmitted into the indoor environment constitute thermal discomfort and increased cooling energy demand for buildings in the tropical climatic zone. This is because tropical climates are generally characterised by hot thermal distress almost all the year round. The need for improvement on window glassing of office buildings arise as a result of the global consensus on reducing energy demand of building sector. In office buildings, higher level of thermal and visual comfort is required for productive work performance within the indoor environment. This place office buildings in a position to enhance the realisation of a sustainable environment in the tropical climatic zone. This paper focus on effect of two types of window glassing on indoor air temperature and achieving improvement on single pane ordinary clear glassing window through the use of low-solar gain low-emissivity windows of two existing office buildings in the warm-humid zone of the tropical climate of Nigeria. An experimental investigation was scheduled during rainy and dry seasons of the year to collect outdoor and indoor microclimatic data of air temperatures in the west-facing natural ventilated office spaces within the existing office buildings through the use of Tiny Tag Ultra 2 Dual Channel Temperature/Relative Humidity (TGU-4500) Data loggers. Data collected were sorted and analysed through descriptive statistics. Improvement on single glassing window of existing office building was obtained through calculation of heat gain characteristics and comparison with that of low-solar gain low-emissivity glass window heat gain characteristics. Results showed that single pane ordinary clear glassing window exhibits higher indoor temperatures in the monitored office space. 89.54% improvement was recorded by using low-solar gain low-emissivity glass window over single pane clear glass window in the investigated office buildings. The study therefore recommends the use of low-solar gain glass low-emissivity window in office buildings within the warm-humid zone of tropical climate of Nigeria.

Ventilation, cooling and air-conditioning contribute significantly to the energy consumption of many existing office buildings, particularly when primary energy factors are taken into account. “Lean” building concepts however can diminish this energy consumption by natural ventilation and passive cooling strategies. Compared to fully air-conditioned buildings the resulting indoor temperatures float in a broader band during summer and might exceed the boundaries for thermal comfort for short periods. This paper presents the monitoring results of a naturally ventilated and passively cooled bank building in Germany and shows that, even during the very hot summer of 2003, the indoor climate could be held in an acceptable range by only passive means if the rooms were operated properly. The air quality was shown to be high with natural ventilation. Investigations on the night ventilation strategy revealed an incorrect implementation of design parameters in the building management system. Further optimization potential for nocturnal airflow was found by simulations based on recorded data. The low total primary energy consumption for heating, cooling, ventilation and lighting of 115 kWh m-2a-1 confirmed an excellent performance of the building. Monitoring proved to be a necessary and efficient way to optimize the building’s operation.

Performance and feasibility of utilizing solar powered ice storage system for space cooling applications

The potential effects of window configuration and interior layout on natural ventilation buildings: A comprehensive review

Challenges to energy retrofitting of existing office buildings in high-rise high-density cities: The case of Hong Kong

Assessment of operational carbon emissions for residential buildings comparing different machine learning approaches: A study of 34 cities in China

Background: The green building industry has significantly impacted the construction market, providing various sustainable solutions for the community. However, conventional green building standards have yet to adequately address occupant health and well-being, leading to challenges with performance. This has caused many businesses to take note of the latest report from the Bureau of Labour Statistics, which indicated that productivity in the US has dropped by the sharpest level since the 1940s [1]. Addressing these issues, organisations like International WELL Building Institute (IWBI) developed WELL Building Rating System (WELL), prioritising occupant health and well-being as critical components for improving performance and avoiding potential vulnerabilities brought about by sickness or pandemics. For this reason, this study will explore how to improve employee productivity within office buildings by bettering their overall health and well-being. Methods: The methodology is designed to collect data from traditional office design, new trended successful office designs, and the WELL Building Rating System to understand healthy building design. Additionally, using DesignBuilder computer software simulates natural daylight, ventilation, and thermal heat gain in the case study to compare implementation results to the base case result. Results: Showing thermal comfort, ventilation, and natural daylight significantly influence employees’ productivity. Implementing conducted design features from WELL achieved an average of 20.2%-35.6% decrease in thermal gain throughout the year, a 20% increase in airflow, an average 2.4%-6.5% decrease in Air temperature, enhanced temperature distribution by 7%, and direct sunlight minimum reduction by 9% in Winter and maximum 21.9% in Spring. Conclusion: Our research analysed that new design features in famous office buildings positively impact employee productivity. We particularly examined the features outlined by WELL Building Rating System to identify the most influential factors affecting occupant productivity. The results of this study informed recommendations for enhancing productivity in existing office buildings in Alexandria, Egypt.