Search

The mismatching between the predicted and the operational performance of buildings designed to be nearly zero-energy underlines the importance to study the post-occupancy behavior, to understand if the building-HVAC system is capable to meet the variable conditions even due to the progressive climate change. The paper proposes a discussion about the operational performance of an existing nearly zero-energy building in the Mediterranean climate, during the heating and cooling seasons. The monitoring shows that the required electrical power is always lower than the nominal one, also because the external conditions are not extreme as the design ones. In the colder days, the difference in the required power is −21%. In summer, there is a delay of two hours between the external maximum temperature and the maximum required power. However, the monitored power is usually higher than the nominal one, with a maximum value of +11%. Considering all proposed combinations for the design calculation, it is demonstrated that the real performance cannot be predicted during the design, because indoor and external conditions influence the dynamic behavior of the building-HVAC system. [ABSTRACT FROM AUTHOR]

In this paper, 16 cities representing four major architectural climate zones of China were selected, and the heating and cooling loads of office building during the period of 1961–2017 were simulated by using TRNSYS software. Daily extreme heating and cooling loads were determined by percentile methods, and the climate change impact on extreme loads was analyzed. The results showed that the days of extreme heating load of office building significantly decreased in almost all the selected cities, whereas there were no significant changes in the days of extreme cooling load. The daily extreme heating load was dominantly affected by the temperature (R2 = 0.43–0.79), but the daily extreme cooling load was related to multiple climate factors, including temperature, relative humidity, and solar radiation. Single temperature can only explain 3–37% of the changes of daily extreme cooling load, and the combination of multiple climate factors can explain 58–85%. Importantly, the effect of temperature on extreme cooling load showed decrease from the cold to hot climate zones, but the impacts of relative humidity and solar radiation gradually increased. These results suggest that the maximum design capacity of heating systems can properly decrease, and the design capacity of cooling systems may not largely increase with the climate warming. In addition, the combined effect of multiple climate factors rather than the single temperature, as well as the different responses of extreme cooling energy consumption to climate change in different climate zones, should be considered when making measures for improving operating efficiency of air-conditioning system. [ABSTRACT FROM AUTHOR]

The energy consumption necessary to maintain thermal comfort in buildings remains a significant and partially unjustified part, accounting for about 30–40% of the total energy consumption. Despite the increasingly pressing regulations in the energy sector (EPBD recast), the quality of the internal environment remains one of the critical parameters on which to pay more attention in view of a consistent evaluation of the Nzeb building. The windowed components are often designed with thermal insulation performances higher than the minimum requirements but still they lack in design of the incident solar radiation control, which is a particularly delicate topic for indoor comfort and more generally for a higher energy efficiency in buildings. If we think of the numerous variables of influence (typology, orientation, geographical location, etc.), the possibilities to associate energy saving, lighting control and users' comfort are inevitably entrusted to dynamic systems integrated into the glass. In this paper authors present the results related to the experimental characterization of two identical test rooms with different typologies of windows. One room is furnished with a traditional high thermal performance glass and the other, with an electrochromic glass suitably controlled by remote. The operative temperature measured in both test rooms have been utilized to verify the simulation model developed to assess the energy saving achievable in a Mediterranean climate, taking properly into account the hourly variations of the climate and the actions on the shading regulation systems. [ABSTRACT FROM AUTHOR]

This paper investigates the climate change impact on cooling energy consumption of office buildings in four major architectural climate zones in China. The results show that there are apparent differences in the responses of monthly or yearly cooling loads to climatic change in different climates. Dominant factors affecting monthly cooling loads change from dry bulb temperature (DBT) to wet bulb temperature (WBT) with the climate zones changing from severe cold to hot. The yearly cooling load was mainly afftectd by DBT in severe cold climate, whereas the WBT had the dominant effect in the other climates. With the continuous warming climate, the yearly cooling load did not rise significantly for any climate zone except for severe cold climate zone where cooling load had a significant increase ( p  < 0.01). More importantly, the cooling load showed a weak decrease in Guangzhou. These results suggest that different measurements for buildings cooling energy conservation should be made in different climate zones. The humidity effect should be fully considered to improve buildings energy efficiency, especially in the hot climate zones. The continuous increase of temperature in the future does not necessarily increase cooling loads of buildings in the cold, hot summer & cold winter and hot summer & warm winter climate zones, and change trendency of humidity in the future need to be considered to predict cooling energy consumption. [ABSTRACT FROM AUTHOR]

This paper aims at investigating the effect of combining thermal insulation with high thermal inertia on building’s thermal performance in a hot semi-arid climate. The impacts of these passive techniques on the cooling/heating loads and the indoor comfort are analyzed by means of dynamic simulation as well as on-site monitoring of a two floor detached house located in the Green City of Benguerir in Marrakech region (Morocco). This house, mostly built using local materials, integrates many other passive and hybrid systems. The present study focuses on the hemp-gypsum, the double slab technique for thermal insulation, the double glazing and the high thermal inertia of the walls. Thermal performance of these techniques are assessed by comparison to a hypothetical reference case of the house lacking the considered techniques and built with regular classic construction materials. The results show that the investigated passive systems have a remarkable effect on the indoor air temperature, the thermal comfort and the cooling/heating loads of the building. When the three systems are integrated into the studied house, better comfort conditions are achieved compared to the reference case as its indoor air temperature minimum is up to 5 °C higher in winter while the indoor air temperature maximum is reduced by up to 9 °C in summer. In addition, the daily air temperature amplitude (peak-to-peak difference) is drastically reduced compared to the reference case. Moreover, the discomfort hours based on an acceptable thermal comfort zone of 16 °C–28 °C are reduced by 62% compared to the reference case. Furthermore, the house performs up to 81% of reduction in the annual cooling and heating load compared to the reference case. [ABSTRACT FROM AUTHOR]

Climate change, driven by greenhouse gas emissions, is a growing global concern, threatening world-wide environment, health and economy. Energy needs for buildings are a large source of greenhouse gas emissions. As the energy needs of buildings strongly depends on weather patterns, this paper investigates how climate change may impact building heating and cooling loads, cost-optimal efficiency measures, and renewable energy production. Eight locations (Stockholm, Milan, Vienna, Madrid, Paris, Munich, Lisbon, and Rome) highlight differences among European climates. Weather datasets, commonly used in building energy simulations, are evaluated to see how climatic parameters have changed over recent decades. A future climate change scenario (with uncertainties) is analyzed for the year 2060. Weather files are used to drive building energy simulations for a standard baseline and a (Nearly Zero Energy Building) NZEB residential building whose design is improved using a cost-optimization approach. The analysis indicates most currently available weather datasets cannot assure reliable results with building simulations. We find the energy balance in European buildings will significantly change under future conditions: heating will decrease by 38%–57%, while cooling will increase by +99%–380% depending on location. In future NZEBs, efficiency measures to reduce cooling needs and overheating will be favored (e.g. roof insulation, window type, solar shading, envelope finishes), illustrating how improving energy efficiency will be more crucial within climate change scenarios. Compared to the baseline, more efficient NZEBs will enable renewable energy to much better cover building needs. There will also be advantages from reducing winter and summer peak demand, particularly when coupled to short-term electrical storage. When solar resource is limited in winter, more airtight, better-insulated NZEBs improve PV self-consumption. • Climate change impact is studied in baseline and NZEBs in different climates. • Different weather datasets and a climate change scenario are simulated. • Future heating loads decrease by 38%–57%, cooling increase by +99%–380%. • Energy efficiency measures to reduce cooling and overheating are favored. • NZEBs enable renewable energy to much better cover building needs. [ABSTRACT FROM AUTHOR]

Free convection is the most often used method in order to reduce solar load gains on a building with double glazed façades (DGFs). However, depending on the climate factors, the thermal performance of a DGF may not be satisfactory and extra energy costs are required to obtain suitable comfort conditions inside the building. Forced ventilation systems are a feasible alternative to improve the thermal performance of a DGF in Mediterranean climates where large solar gains are a permanent condition throughout the year. In this paper the feasibility of using diverse forced ventilation methods in DGF is evaluated. In addition, an economical comparison between different mechanical ventilation systems was performed in order to demonstrate the viability of DGF forced ventilation. Moreover, an environmental study was carried out to prove the positive energetic balance on cooling loads between free and forced convection in DGF for Mediterranean climates. For this investigation, a CFD model was used to simulate the thermal conditions in a DGF for the different ventilation systems. Results obtained for heat flux, temperature and reductions in solar load gains were analyzed and applied for the economic and environmental research. [ABSTRACT FROM AUTHOR]

Abstract: The impact of natural ventilation of a roof cavity on improvement of the thermal environment and reduction of cooling load of a factory building is discussed. A computer program was developed with the logic in a companion paper to observe the effect of cavity ventilation on the operative temperature of the occupied zone in the factory. Comparisons were made between factories with a cavity roof and a single roof in the Japanese climate. Results showed that the cavity roof was superior to the single roof in lowering the operative temperature by about 4.4°C. When the factory was air conditioned, the cooling load reduction reached approximately 50% during the summer to maintain an operative temperature of 26°C. Results showed that a naturally ventilated cavity roof has excellent potential for improving the indoor thermal environment and energy savings of factory buildings without complicated cooling installations and life time power consumption. [ABSTRACT FROM AUTHOR]

• Climate change and building load variations may impact optimised building designs. • A method using climate models and optimisation is used to optimise future buildings. • A case study is conducted on two cities in Australia: Canberra and Brisbane. • Results show that optimising for future climates can save energy for Canberra. • For Brisbane, savings are small and the present-optimised design seems acceptable. Building energy optimisation is generally performed under present climate conditions with fixed simulation parameters (e.g. internal loads). However, climate change and variations in simulation parameters over the building's life span may impact the optimised design. A key question is whether a particular energy-optimised design under present climate conditions would remain energy-optimised in the future. Accordingly, in this paper, a new simulation-based optimisation method is developed, which uses climate models and Ant Colony Optimisation to compare the energy-optimised designs under present and future climates. To demonstrate its potential, this method is applied to a typical office building in two Australian cities, Brisbane and Canberra. The results show that optimising under future climate conditions can lead to different optimal building designs. For Brisbane, the energy difference between optimising under present and future climate conditions is small, but in Canberra the cooling load is increased by up to 6%. This suggests that optimising the studied office building under present climate conditions is acceptable for Brisbane, while considering future climate may yield some savings in Canberra. Results also show that the energy-optimised building configuration for both future and present climates in Brisbane is less sensitive to changes in the load scenario than in Canberra. [ABSTRACT FROM AUTHOR]

• Building Bio-Climatic Charts are proposed for different climate change scenarios. • Time-varying significance of nine design parameters in this century are provided. • Effectiveness of airtightness will increase up to 329% by the end of this century. • Cooling potentials of natural ventilation will significantly decrease up to 69%. • A holistic passive design can reduce the building annual cooling load by 56.7%. The application of passive design strategies is crucial at the early architectural design stage for building energy use minimization. However, the time-varying effectiveness of passive design strategies in responding to future climate change in hot and humid climates are rather limited in the literature. This paper aims to examine the dynamic effectiveness of passive design strategies for residential buildings in Hong Kong under the context of future climate change. Using the newly developed hourly weather data and adaptive comfort standard model, the dynamic effectiveness of viable passive design strategies for residential buildings are evaluated over time in the 21st century by plotting Givoni building bio-climatic charts (BBCC) and simulation-based sensitivity analyses in a validated EnergyPlus model. Results show that solar protection strategies are still the highly sensitive strategies for building energy performance and the effectiveness of external windows' airtightness is expected to increase up to 329% by the end of this century, whereas the cooling potential of ventilation utilization will significantly decrease over time. When the different combination of sensitive passive design parameters is implemented onto the baseline residential building model for different climate scenarios, the annual and peak cooling load can be reduced up to 56.7% and 64.5%, respectively. [ABSTRACT FROM AUTHOR]

• The climate change is identified by the ground measurement of HK over the 37 years. • The building energy needs can be influenced by the climate change. • The TMY is suggested to be updated every 10 years or less for the climate change. • 10 to 12 years of the latest data can be proper for TMY in the changing climate. The weather data is essential to simulation-based building energy studies. The weather data should render the features of the changing climate. The typical meteorological year (TMY) developments using the long-term climate data, however, may weaken the impact of the recent climate change and the corresponding building energy responses. This paper studies the changes of the climate data (by ground measurements) and their impacts on the simulation results of the subtropical Hong Kong over 37 years. The climate changes for solar radiation, temperature and wind speed were summarised, and their daily total, average, extreme, and/or deviation values were presented. The typical weather data developed by the ground measurements of different times and period lengths (within the 37 years) determined the cooling load of a representative building in the Hong Kong, and the outcomes were compared to that of the yearly data. The period (length) of the raw measurements and the update frequency of TMY were optimized for the building energy simulations in the changing climate. [ABSTRACT FROM AUTHOR]