du.sePublications
Change search
Refine search result
1 - 4 of 4
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Zhang, Xingxing
    et al.
    University of Nottingham.
    Shen, Jingchun
    Adkins, Deborah
    Yang, Tong
    Tang, Llewellyn
    Zhao, Xudong
    He, Wei
    Xu, Peng
    Liu, Chenchen
    Luo, Huizhong
    The early design stage for building renovation with a novel loop-heat-pipe based solar thermal facade (LHP-STF) heat pump water heating system: Techno-economic analysis in three European climates2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 106, 964-986 p.Article in journal (Refereed)
    Abstract [en]

    Most of the building renovation plans are usually decided in the early design stage. This delicate phase contains the greatest opportunity to achieve the high energy performance buildings after refurbishment. It is therefore important to provide the pertinent energy performance information for the designers or decision-makers from multidisciplinary and comparative points of view. This paper investigates the renovation concept of a novel loop-heat-pipe based solar thermal facade (LHP-STF) installed on a reference residential building by technical evaluation and economic analysis in three typical European climates, including North Europe (represented by Stockholm), West Europe (represented by London) and South Europe (represented by Madrid). The aim of this paper is firstly to explore the LHP-STF’s sensitivity with regards to the overall building socio-energy performance and secondly to study the LHP-STF’s economic feasibility by developing a dedicated business model. The reference building model was derived from the U.S. Department of Energy (DOE) commercial buildings research, in which the energy data for the building models were from the ASHRAE codes and other standard practices. The financial data were collected from the European statistic institute and the cost of system was based on the manufactured prototype. Several critical financial indexes were applied to evaluate the investment feasibility of the LHP-STF system in building renovation, such as Payback Period (PP), Net Present Value (NPV), and the modified internal rate of return method (IRR). Four common investment options were considered in this business model, including buying outright (BO), buying by instalment (BI), energy efficiency funding (EEF) and power purchase agreement (PPA). The research results indicate that the LHP-STF could contribute to the hot water load throughout the year with substantially reduced heating load in winter, and yet a slight increased cooling load in summer. Among four investment options, the BO was considered as the best investment method with the highest NPV, IRR and the shortest payback period. With regards to relatively limited solar resources, London was found to be the best place for investment with the highest economical revenues and an attractive payback period of less than four years for all purchase options. Although Madrid has the richest solar resource, this system has the lowest economic profit and the longest payback period. This outcome confirms that the renewable energy incentives have a higher impact than solar resources on current solar thermal facade technologies under such pricing fundamentals. This multidisciplinary research is expected to be helpful for the strategic decisions at the early design stage for building renovation with the proposed system and further promote development of solar driven service system, leading to the savings in fossil fuel consumption and reduction in carbon emission.

  • 2.
    Zhang, Xingxing
    et al.
    University of Hull; University of Nottingham.
    Shen, Jingchun
    He, Wei
    Xu, Peng
    Zhao, Xudong
    Tan, Junyi
    Comparative study of a novel liquid-vapour separator incorporated gravitational loop heat pipe against the conventional gravitational straight and loop heat pipes - Part I: Conceptual development and theoretical analyses2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 90, 409-426 p.Article in journal (Refereed)
    Abstract [en]

    Aim of the paper is to investigate the thermal performance of a novel liquid–vapour separator incorporated gravity-assisted loop heat pipe (GALHP) (T1), against a conventional GALHP (T2) and a gravitational straight heat pipe (T3), from the conceptual and theoretical aspects. This involved a dedicated conceptual formation, thermo-fluid analyses, and computer modelling and results discussion. The innovative feature of the new GALHP lies in the integration of a dedicated liquid–vapour separator on top of its evaporator section, which removes the potential entrainment between the heat pipe liquid and vapour flows and meanwhile, resolves the inherent ‘dry-out’ problem exhibited in the conventional GALHP. Based on this recognised novelty, a dedicated steady-state thermal model covering the mass continuity, energy conservation and Darcy equations was established. The model was operated at different sets of conditions, thus generating the temperature/pressure contours of the vapour and liquid flows at the evaporator section, the overall thermal resistance, the effective thermal conductivity, and the flow resistances across entire loop. Comparison among these results led to determination of the optimum operational settings of the new GALHP and assessment of the heat-transfer enhancement rate of the new GALHP against the conventional heat pipes. It was suggested that the overall thermal resistance of the three heat pipes (T1, T2, and T3) were 0.10 °C/W, 0.49 °C/W and 0.22 °C/W, while their effective thermal conductivities were 31,365 W/°C m, 9,648 W/°C m and 5,042 W/°C m, respectively. This indicated that the novel heat pipe (T1) could achieve a significantly enhanced heat transport effect, relative to T2 and T3. Compared to a typical cooper rod, T1 has around 78 times higher effective thermal conductivity, indicating that T1 has the tremendous competence compared to other heat transfer components. It should be noted that this paper only reported the theoretical outcomes of the research and the second paper would report the follow-on experimental study and model validation. The research results could be directly used for design, optimisation and analyses of the new GALHP, thus promoting its wide applications in various situations to enable the enhanced thermal performance to be achieved.

  • 3.
    Zhang, Xingxing
    et al.
    University of Nottingham; University of Hull.
    Shen, Jingchun
    He, Wei
    Xu, Peng
    Zhao, Xudong
    Tan, Junyi
    Comparative study of a novel liquid-vapour separator incorporated gravitational loop heat pipe against the conventional gravitational straight and loop heat pipes - Part II: Experimental testing and simulation model validation2015In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 93, 228-238 p.Article in journal (Refereed)
    Abstract [en]

    Aim of the paper is to report the experimental study of a novel liquid–vapour separator incorporated gravity-assisted loop heat pipe (GALHP) (T1), against the conventional GALHP (T2) and a gravitational straight heat pipe (T3). Based on the results derived from the theoretical analyses and computer modelling, three prototype heat pipes, one for each type, were designed, constructed and tested to characterise their thermal performance under a series of operational conditions. By using the experimental data, the computer simulation model reported in the authors’ previous paper was examined and analysed, indicating that the model could achieve a reasonable accuracy in predicting the thermal performance of the three heat pipes. Under the specifically defined testing condition, T1 has more evenly distributed axial temperature profile than the other two heat pipes (T2 and T3). The start-up timings for T1, T2 and T3 were 410 s, 1400 s and 390 s respectively, indicating that the heat transfer within T2 was affected by the larger evaporator dry-out surface area and restricted evaporation area. The overall thermal resistance of T1 was 0.11 °C/W, which was around 20% and 50% that of T2 and T3. The tested effective thermal conductivity in T1 was 29,968 W/°C m, which was 296% and 648% that of T2 and T3, and 7492% that of a standard copper rod. It is therefore concluded that the novel heat pipe (T1) could achieve a significantly enhanced heat transport effect, relative to T2, T3 and standard cooper rod. The experimental results derived from this research enabled characterisation of the thermal performance of T1, relative to other heat pipes, and validation of the developed computer simulation model derived from the authors’ previous research. These two parts researches in combination will enable design, optimisation and analyse of such a new GALHP, thus promoting its wide application and achieving efficient thermal management.

  • 4. Zhao, Xudong
    et al.
    Zhang, Xingxing
    De Montfort University.
    Riffat, Saffa B.
    Su, Yaxin
    Theoretical study of the performance of a novel PV/e roof module for heat pump operation2011In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 52, no 1, 603-614 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, a novel PV/e roof module was designed to act as the roof element, electricity generator and the evaporator of a heat pump system. The modules, in conjunction with a heat pump, are able to provide heat and power supply to buildings with an enhanced efficiency. Energy profiles of the PV/e modules and modules-based heat pump system were analysed and temperature distribution across the module layers was studied. It was found that the PV/e roof modules-based heat pump system can achieve significant improvement in thermal and electrical efficiencies. Variation of the system efficiencies (thermal, electrical and total) with a number of factors, i.e., top cover, PV cells, evaporation and condensation temperature of the heat pump was investigated, which led to suggestion of the optimised system configuration and operating conditions. The study indicated that the combined system should operate at 10 °C of evaporation and 60 °C of condensation temperature. Borosilicate as a top cover has better thermal performance than polycarbonate and glass; whilst the mono-crystalline photovoltaic cells are of higher electrical efficiency over the poly-crystalline and thin-films. Under a typical Nottingham (UK) operating condition, the modules would achieve 55% of thermal efficiency and 19% of electrical efficiency, while the module-based heat pump system would have an overall efficiency of above 70%. It was also addressed that the integration of the PV cells and evaporation coil into a prefabricated roof would lead to large saving in both capital and running costs over separate arrangements of PV, heat pump and roof structure.

1 - 4 of 4
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • chicago-author-date
  • chicago-note-bibliography
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf