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The work provided herein involves a comparison of natural gas and hydrogen fuels for the purpose of energy conservation for buildings via alternative energy generation methodologies. A case study simulation was developed for an average type of commercial building, a nine storey hotel located in Toronto. The two alternative energy source case studies involved the generation of hydrogen via the wind turbine for the fuel cell, and the use of natural gas directly in the steam reforming fuel cell. The simulations for both scenarios were run and the recorded results were compared to the original case study, as well as between the scenarios. To supply for the base load of the building the fuel cells were given the same kW rating for both scenarios. The identification of all existing technologies for hydrogen gas and natural gas has been carried out, and the similar technologies between the two gases were found. For the purpose of realism, only existing purchasable technologies were considered in this paper. Due to the lack of commercially available technologies for hydrogen gas, only a comparison of fuel cell systems could be accomplished. Over the course of the investigative work it was found that when there is no direct supply of hydrogen to the site of utilization, the natural gas fuel cell is beneficial to the building due to its greater efficiency and lower cost. The major drawback for the hydrogen gas fuel cell, when the on-site generation is involved, is that no thermal power extraction systems currently exist for purchase and utilization in the buildings. 2014 Elsevier Ltd. All rights reserved. This paper was made possible by NPRP Grant # [ NPRP 5-209-2-071 ] from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. Scopus 2-s2.0-84921768244

The rapid development of the building industry has become an important driving force for the fast growing energy use in China. The building industry contributed 26.4% of China’s GDP, and the building energy use accounted for 33% of the total energy use in China. Building energy conservation plays an important role in reaching the peak of carbon emissions before 2030, which was committed by the Chinese government in the Paris Agreement. Building energy conservation is a complex system. The guidance and support of government policies are one of the important issues. This research analyzed the institutional framework for building energy conservation in China. The roles and functions of each institution were critically reviewed. The policy system for building energy conservation was also analyzed, which included National Laws; Regulations of the State Council; Provisions of Ministries under the State Council; and National Standards, Plans and Programs. The suggestions for further improvements were drawn from the critical analysis such as defining clear and specific responsibility of management institutions, improving regulations and standard system, establishing the market leading mechanism, etc. This research draws an overall picture of the building energy conservation in China from the policy and institutional perspective. Findings provide a useful reference for increasing environmental performance in the building industry.

With energy use growing rapidly around the world, building energy conservation is becoming a great concern especially for large commercial buildings. Therefore, it is of great significance to develop appropriate methods for energy use assessment of commercial buildings. In recent years, energy monitoring system (EMS) has been applied in some large-scale commercial buildings, which has laid the foundation for exhaustive and authentic evaluation. However, most of the current studies are only focused on annual or monthly aggregated energy consumption. Though end-use data are monitored in some buildings, only major categories or equipment are included. Little has been done to analyze the energy performance of numerous buildings with detailed hourly end-use data. With the access to hourly sub-metered data of detailed end uses, this study aims to introduce a comparing method to evaluate building energy performance through a case study. Information on selected buildings in the case was introduced. The research intends to compare energy use intensity (EUI) of the 19 malls based on a uniform energy data model, from total energy to detailed end-uses. It was shown that there is a significant discrepancy on the total energy use among these buildings, mainly due to HVAC (Heating, Ventilation and Air Conditioning) and public lighting. Then an in-depth comparative study was conducted on the energy consumption of public lighting and HVAC respectively. An unexpectedly remarkable discrepancy was illustrated on the EUI of public lighting. Thus the daily and hourly energy of public lighting were compared to identify the discrepancy in management mode. The study on HVAC was focused on the comparison of daily and hourly EUI in terms of four subordinate end uses (chillers, chilled water pumps, fans and cooling systems). The result showed that chillers accounts for larger proportions of total energy use, and the daily and hourly data were compared between buildings with similar climate. At last, the methods were summarized and challenges were discussed.

International audience; The coupled heat, air and moisture transfer between building envelopes and indoor air is complicated, and has a significant influence on the indoor environment and the energy performance of buildings. In the paper, a model for predicting coupled multi-zone hygrothermal-airflow transfer is presented. Both heat and moisture transfer in the building envelope and multi-zone indoor airflow are simultaneously considered; their interactions are modeled. The coupled system model is implemented into Matlab–Simulink, and is validated by using a series of testing tools and experiments. The new program is applied to investigate the moisture transfer effect on indoor air humidity and building energy consumption in different climates (hot-humid, temperate and hot-dry climates). The results show that not accounting for hygrothermal effects in modeling will result in overestimation of energy costs for hot and humid climate situations and possible over sizing of plant leading to inefficient operation.

Thesis (Master)--Izmir Institute of Technology, Energy Engineering, Izmir, 2009, Includes bibliographical references (leaves: 79-83), Text in English; Abstract: Turkish and English, xiii, 83 leaves, Energy performance of the buildings can be evaluated by measuring energy consumptions or performing simple or detailed simulation methods. In this study, IZTECH Administrative Building which is a university building, is selected as case study and energy audit is performed to evaluate energy performance of the building. Indoor conditions are recorded with dataloggers and outdoor climatic data is taken from IZTECH Meteorological Station. Fuel consumption is tracked by two flowmeters and electricity consumption is measured with three power analyzer connected to heating, cooling and lighting and general use electricity meters. Energy consumption of the building is simulated by three different methods which are TS 825 (static), CIBSE Admittance (simple dynamic) and ASHRAE Heat Balance (full dynamic) methods. Sensitivity of these methods is tested by comparing energy consumption measurements and simulations and performance improving measures are proposed. Also a hypothetical no-HVAC case is simulated. ASHRAE Heat Balance Method is determined as the most accurate model compared to measurement results and performance improving measures are simulated with this method, reduction in energy consumption and greenhouse gas emissions are observed.

The airtightness of building envelopes is one of the factors which most affects the hygrothermal conditions and the air quality of the indoor environment, as well as the energy consumption of the building. In multi-dwelling units this contributes significantly to the overall load for heating or air conditioning, making it possible to calculate the repercussion of infiltrations on the energy demand of a dwelling as between 20 to 50% of the total amount, depending on the climate zone and construction characteristics of the envelope. Hence the importance of knowing the parameters that characterise it. Pressurisation/depressurisation tests are the best method for characterisig these, but must be carried out in accordance with specific measurement procedures. The main objective of this paper is the proposal of five specific protocols for carrying out these tests in MDU, and their specific use in buildings in Southern European regions. In order to develop and validate this proposal we have carried out a series of multi test in ten dwelling units in a block recently built in the south of Spain. The results of these tests are presented and analysed here. These confirm the need for some protocols to distinguish between wet and dry spaces within the dwelling, given the difference in airtightness between them, and to expand the study indicators proposed by international regulations for a more accurate rendering of the behaviour of the envelope and the elements within it.

In developing countries with a large population and fast urbanization, High-rise Residential Buildings (HRBs) have unavoidably become a very common, if not the most, accommodation solution. The paradigm of HRB energy consumption is characterized by high-density energy consumption, severe peak effects and a limited site area for integrating renewable energy, which constitute a hindrance to the low-carbon transition. This review paper investigates low-carbon transition efforts in the HRB sector from the perspective of urban energy systems to get a holistic view of their approaches. The HRB sector plays a significant role in reducing carbon emission and improving the resilience of urban energy systems. Different approaches to an HRB low-carbon transition are investigated and a brief overview of potential solutions is offered from the perspectives of improving energy efficiency, self-sufficiency and system resilience. The trends of decarbonization, decentralization and digitalization in the HRB sector allow a better alignment with transitioning urban energy systems and create crosssectoral integration opportunities for low-carbon transition. It is also found that policy tools are powerful driving forces in China for incentivizing transition behaviors among utilities, end users and developers. Based on a comprehensive policy review, the policy implications are given. The research is geared for the situation in China but could also be used as an example for other developing countries that have similar urbanization patterns. Future research should focus on quantitative analysis, life-cycle analysis and transdisciplinary planning approaches.