The University of Sheffield

Sheffield, South Yorkshire, United Kingdom

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Department of Mechanical Engineering
526
Total Impact Points
229
Members
Department of Materials Science and Engineering
2,052
Total Impact Points
200
Members

Publication History View all

  • [Show abstract] [Hide abstract]
    ABSTRACT: Reducing carbon emissions from buildings is vital to achieve goals for avoiding dangerous climate change, and supplying them with low-carbon heat is essential. In the UK, the development of heat networks for supplying low-carbon heat is being encouraged for urban areas where there is high heat demand density. This paper investigates heat demand variability, the role of heat networks and combined heat and power (CHP) in satisfying this demand, and finally the advantages of using heat storage in the system. Building heat demands from 50 buildings were analysed at a half-hour resolution with modelling to determine CHP operation patterns with and without heat storage. Daily total heat demand was found to vary from 25% of the full-year average in summer months up to 235% of the average on the coldest days in winter. The heat demand was shown to correlate to outdoor temperatures measured with the degree-day parameter, except for approximately 100 days during the warmest part of the year falling outside the heating season. Sharp spikes in heat demand were seen at the half-hourly time scale coinciding with the switching on of heating systems in some buildings with consequences for building energy supply options. It was shown that for an annual heat demand of 40,000 MW h, the use of thermal storage can significantly increase the running time of a CHP energy centre with 4 MW capacity designed to supply this demand. The cost savings resulting from increased on-site heat and electricity production resulted in a payback period for heat storage investment of under four years with further benefits if it can assist other heat sources on the heat network. Environmental advantages of using heat storage included further carbon dioxide emission reductions of 1000–1500 tonnes per year depending upon the CHP configuration.
    Energy Conversion and Management 11/2014; 87:164–174.
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    ABSTRACT: One of the main goals of building acoustics is the prediction of airborne sound insulation between rooms to determine the quality of sound protection. In many practical cases, however, the objective measures of the airborne sound insulation using procedures in standards are not in agreement with the subjective assessment. This paper, therefore, after reviewing the conventional model to calculate airborne sound insulation, introduces a calculation scheme based on loudness level linked with specific fluctuation strength, yielding a weighted normalised loudness level difference, Lnor,w . By analysing the difference between standard airborne sound insulation values and the introduced weighted normalised loudness level difference, it is revealed that the sound pressure level that is transmitted through a partition decreases with increasing frequency, and this is independent of the type of signal and of the airborne sound insulation values (Rw′-values), whereas if the transmitted signal is converted into a loudness level, it tends to rise with increasing frequency. Moreover, it is found that, whereas a simple level difference does not exhibit the effect of a given signal to the frequency-dependent airborne sound insulation curve, using Lnor,w, a significant change can be observed, in terms of both computed and measured results. Furthermore, the frequency-dependent results allow more details to be investigated for a certain sound insulation. A comparison between the measured and predicted airborne sound insulation with no obvious malfunction suggests that at some frequency ranges, a hypothetical subjective related failure might occur. Overall, the proposed Lnor,w could reveal detailed insights into the in situ measured airborne sound insulation compared with standard airborne sound insulation values. The frequency-dependent values discussed in this paper form a basis for developing a single-number index.
    Applied Acoustics 11/2014; 85:34–45.
  • [Show abstract] [Hide abstract]
    ABSTRACT: As yet, no standard equipment exists for the measurement of heat transfer through porous materials, such as metal foams (metals with a high volume fraction of porosity). Most research in this area has been carried out using bespoke test rigs. Here the creation of a test rig specifically developed for the measurement of the heat transfer of metal foams is reported. This method has been applied to laboratory made samples processed by replication and examples of commercially available aluminium foams (Duocel and Corevo), and should be suitable for the testing of all materials with comparable permeability. As this equipment is new and unique, the design will be discussed in detail, along with the various tests that were performed to ensure reliability and consistency with other methods and published data.
    Measurement 10/2014; 56:37–49.

Information

  • Address
    Western Bank, S10 2TN, Sheffield, South Yorkshire, United Kingdom
  • Head of Institution
    Sir Peter Middleton
  • Website
    http://www.shef.ac.uk/
  • Phone
    0114 222 2000
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01/2002;
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Management Decision 12/2005; 44(1):9-30.
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