The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

V Belessiotis - One of the best experts on this subject based on the ideXlab platform.

  • investigation of the performance of a combined solar thermal heat pump Hot Water System
    Solar Energy, 2013
    Co-Authors: G Panaras, E Mathioulakis, V Belessiotis
    Abstract:

    Abstract The use of a heat pump as an auxiliary energy source for solar domestic Hot Water Systems can achieve significant energy savings, due to the remarkable potential of heat pumps on the efficient provision of thermal energy. In this work, the performance of a combined solar thermal heat pump Hot Water System is investigated. A component based simulation model for the whole System was experimentally validated. Emphasis was paid on the formulation of a simple and efficient approach for the modeling of the heat-pump. The performance of the System on an annual basis is investigated, with regard to the methodology used in solar domestic Hot Water Systems testing. According to the results of the analysis, the System achieves significant auxiliary energy savings, which can present a value in the order of 70% for the climatic data of Athens. The temperature set-point for the activation of the heat pump proves to be an important parameter for the performance of the System, noting that the higher the value of the set-point, the lower the efficiency of the heat pump.

  • analytical approach of thermosyphon solar domestic Hot Water System performance
    Solar Energy, 2002
    Co-Authors: V Belessiotis, E Mathioulakis
    Abstract:

    Abstract An efficient and simple simulation approach for thermosyphon solar Water heaters has been developed and compared with experimental data. This approach, valid for solar-only Systems, gives the ability to link the System main design and constructional parameters with the expected energy output through an analytical determination of the coefficients of the characteristic input–output equation of the System. The proposed methodology can be used not only for energy optimization of the System in the design phase but also for evaluation of test results of an existing System in order to improve it further.

  • a new heat pipe type solar domestic Hot Water System
    Solar Energy, 2002
    Co-Authors: E Mathioulakis, V Belessiotis
    Abstract:

    Abstract The performance of a new solar Hot Water System with an integrated heat-pipe is investigated theoretically and experimentally. The new System uses a wickless gravity assisted loop heat-pipe for the heat transfer from the collector–evaporator to the tank through a heat exchanger–condenser. A detailed heat transfer experimental study is performed, focused on the thermal behaviour of the different parts of the System. The results show that the System can reach satisfactory efficiencies which, in combination with manufacturing simplicity, absence of moving parts and good behaviour under freeze conditions, make it an interesting technological solution. Furthermore, a theoretical model for the collector is proposed and comparison with experimental results is performed. This model can be used for the optimisation of the System design.

E Mathioulakis - One of the best experts on this subject based on the ideXlab platform.

  • investigation of the performance of a combined solar thermal heat pump Hot Water System
    Solar Energy, 2013
    Co-Authors: G Panaras, E Mathioulakis, V Belessiotis
    Abstract:

    Abstract The use of a heat pump as an auxiliary energy source for solar domestic Hot Water Systems can achieve significant energy savings, due to the remarkable potential of heat pumps on the efficient provision of thermal energy. In this work, the performance of a combined solar thermal heat pump Hot Water System is investigated. A component based simulation model for the whole System was experimentally validated. Emphasis was paid on the formulation of a simple and efficient approach for the modeling of the heat-pump. The performance of the System on an annual basis is investigated, with regard to the methodology used in solar domestic Hot Water Systems testing. According to the results of the analysis, the System achieves significant auxiliary energy savings, which can present a value in the order of 70% for the climatic data of Athens. The temperature set-point for the activation of the heat pump proves to be an important parameter for the performance of the System, noting that the higher the value of the set-point, the lower the efficiency of the heat pump.

  • analytical approach of thermosyphon solar domestic Hot Water System performance
    Solar Energy, 2002
    Co-Authors: V Belessiotis, E Mathioulakis
    Abstract:

    Abstract An efficient and simple simulation approach for thermosyphon solar Water heaters has been developed and compared with experimental data. This approach, valid for solar-only Systems, gives the ability to link the System main design and constructional parameters with the expected energy output through an analytical determination of the coefficients of the characteristic input–output equation of the System. The proposed methodology can be used not only for energy optimization of the System in the design phase but also for evaluation of test results of an existing System in order to improve it further.

  • a new heat pipe type solar domestic Hot Water System
    Solar Energy, 2002
    Co-Authors: E Mathioulakis, V Belessiotis
    Abstract:

    Abstract The performance of a new solar Hot Water System with an integrated heat-pipe is investigated theoretically and experimentally. The new System uses a wickless gravity assisted loop heat-pipe for the heat transfer from the collector–evaporator to the tank through a heat exchanger–condenser. A detailed heat transfer experimental study is performed, focused on the thermal behaviour of the different parts of the System. The results show that the System can reach satisfactory efficiencies which, in combination with manufacturing simplicity, absence of moving parts and good behaviour under freeze conditions, make it an interesting technological solution. Furthermore, a theoretical model for the collector is proposed and comparison with experimental results is performed. This model can be used for the optimisation of the System design.

Baolong Wang - One of the best experts on this subject based on the ideXlab platform.

  • simulation of a combined heating cooling and domestic Hot Water System based on ground source absorption heat pump
    Applied Energy, 2014
    Co-Authors: Wei Wu, Baolong Wang, Xianting Li
    Abstract:

    The amount of energy used for heating and domestic Hot Water (DHW) is very high and will keep increasing. The conventional ground source electrical heat pump used in heating-dominated buildings has the problems of thermal imbalance, decrease of soil temperature, and deterioration of heating performance. Ground source absorption heat pump (GSAHP) is advantageous in both imbalance reduction and primary energy efficiency (PEE) improvement; however, the imbalance is still unacceptable in the warmer parts of cold regions. A combined heating/cooling/DHW (HCD) System based on GSAHP is proposed to overcome this problem. The GSAHPs using generator absorber heat exchange (GAX) and single-effect (SE) cycles are simulated to obtain the performance under various working conditions. Different HCD Systems in Beijing and Shenyang are simulated comparatively in TRNSYS, based on which the thermal imbalance, soil temperature, heat recovery, and energy efficiency are analyzed. Results show that GSAHP–GAX–HCD is suitable for Beijing and GSAHP–SE–HCD is suitable for Shenyang. The imbalance ratio can be reduced to −14.8% in Beijing and to 6.0% in Shenyang with an annual soil temperature variation of only 0.5°C and 0.1°C. Furthermore, about 20% and 15% of the total condensation/absorption heat is recovered to produce DHW, and the PEE can reach 1.516 in Beijing and 1.163 in Shenyang. The combined HCD Systems can achieve a PEE improvement of 23.6% and 44.4% compared with the normal heating/cooling Systems.

  • Simulation of a combined heating, cooling and domestic Hot Water System based on ground source absorption heat pump
    Applied Energy, 2014
    Co-Authors: Wei Wu, Wenxing Shi, Tian You, Baolong Wang, Xianting Li
    Abstract:

    The amount of energy used for heating and domestic Hot Water (DHW) is very high and will keep increasing. The conventional ground source electrical heat pump used in heating-dominated buildings has the problems of thermal imbalance, decrease of soil temperature, and deterioration of heating performance. Ground source absorption heat pump (GSAHP) is advantageous in both imbalance reduction and primary energy efficiency (PEE) improvement; however, the imbalance is still unacceptable in the warmer parts of cold regions. A combined heating/cooling/DHW (HCD) System based on GSAHP is proposed to overcome this problem. The GSAHPs using generator absorber heat exchange (GAX) and single-effect (SE) cycles are simulated to obtain the performance under various working conditions. Different HCD Systems in Beijing and Shenyang are simulated comparatively in TRNSYS, based on which the thermal imbalance, soil temperature, heat recovery, and energy efficiency are analyzed. Results show that GSAHP-GAX-HCD is suitable for Beijing and GSAHP-SE-HCD is suitable for Shenyang. The imbalance ratio can be reduced to -14.8% in Beijing and to 6.0% in Shenyang with an annual soil temperature variation of only 0.5. ??C and 0.1. ??C. Furthermore, about 20% and 15% of the total condensation/absorption heat is recovered to produce DHW, and the PEE can reach 1.516 in Beijing and 1.163 in Shenyang. The combined HCD Systems can achieve a PEE improvement of 23.6% and 44.4% compared with the normal heating/cooling Systems. ?? 2014 Elsevier Ltd.

  • energy saving potential of low temperature Hot Water System based on air source absorption heat pump
    Applied Thermal Engineering, 2012
    Co-Authors: Xianting Li, Xiaoling Zhang, Wei Wu, Baolong Wang
    Abstract:

    Abstract Boilers are widely used to generate low temperature Hot Water for heating and domestic Hot Water. In order to improve the efficiency and decrease the emission of pollution in the process of producing low temperature Hot Water, a heating System based on air source absorption heat pump (ASAHP) is proposed. A simplified model of the proposed System is built based on the heat and mass balance. The model is verified by comparing the predicted results with those from a previous reference. The performances of ASAHP using H 2 O/LiBr and NH 3 /LiNO 3 as working fluids are simulated at different air temperatures. Based on the simulated performance, energy saving potential of the proposed System applied in four typical Chinese cities is analyzed. The results show that the proposed System can provide energy saving rates of 18%, 28.5%, 37% and 42% in Shenyang, Beijing, Shanghai and Guangzhou respectively, showing great potentials in future applications of low temperature Hot Water.

  • Energy saving potential of low temperature Hot Water System based on air source absorption heat pump
    Applied Thermal Engineering, 2012
    Co-Authors: Xianting Li, Wenxing Shi, Xiaoling Zhang, Wei Wu, Baolong Wang
    Abstract:

    Boilers are widely used to generate low temperature Hot Water for heating and domestic Hot Water. In order to improve the efficiency and decrease the emission of pollution in the process of producing low temperature Hot Water, a heating System based on air source absorption heat pump (ASAHP) is proposed. A simplified model of the proposed System is built based on the heat and mass balance. The model is verified by comparing the predicted results with those from a previous reference. The performances of ASAHP using H 2O/LiBr and NH 3/LiNO 3 as working fluids are simulated at different air temperatures. Based on the simulated performance, energy saving potential of the proposed System applied in four typical Chinese cities is analyzed. The results show that the proposed System can provide energy saving rates of 18%, 28.5%, 37% and 42% in Shenyang, Beijing, Shanghai and Guangzhou respectively, showing great potentials in future applications of low temperature Hot Water. ?? 2011 Elsevier Ltd. All rights reserved.

H Okla - One of the best experts on this subject based on the ideXlab platform.

  • Assessment of real-time PCR for quantification of Legionella spp. in spa Water
    Journal of Applied Microbiology, 2016
    Co-Authors: Eva Theres Gensberger, Marlies Polt, Marianne Konrad-köszler, Paul Kinner, B Rozwadowska, M Albertynska, G Hudzik, Tanja Kostić, Tatjana Kostic, Angela Sessitsch, H Okla
    Abstract:

    We evaluated a ready-to-use real-time quantitative Legionella pneumophila PCR assay System by testing 136 Hot-Water-System samples collected from 55 sites as well as 49 cooling tower samples collected from 20 different sites, in parallel with the standard culture method. The PCR assay was reproducible and suitable for routine quantification of L. pneumophila. An acceptable correlation between PCR and culture results was obtained for sanitary Hot-Water samples but not for cooling tower samples. We also monitored the same L. pneumophila-contaminated cooling tower for 13 months by analyzing 104 serial samples. The culture and PCR results were extremely variable over time, but the curves were similar. The differences between the PCR and culture results did not change over time and were not affected by regular biocide treatment. This ready-to-use PCR assay for L. pneumophila quantification could permit more timely disinfection of cooling towers.

Francois Vandenesch - One of the best experts on this subject based on the ideXlab platform.

  • Integrated real-time PCR for detection and monitoring of Legionella pneumophila in Water Systems
    Applied and Environmental Microbiology, 2007
    Co-Authors: Diaraf Farba Yaradou, Yves Hillion, Janine André, Gabriel Festoc, Monique Reyrolle, Karine Delabre, Florence Poty, Sylvie Hallier-soulier, Sophie Moreau, Francois Vandenesch
    Abstract:

    We evaluated a ready-to-use real-time quantitative Legionella pneumophila PCR assay System by testing 136 Hot-Water-System samples collected from 55 sites as well as 49 cooling tower samples collected from 20 different sites, in parallel with the standard culture method. The PCR assay was reproducible and suitable for routine quantification of L. pneumophila. An acceptable correlation between PCR and culture results was obtained for sanitary Hot-Water samples but not for cooling tower samples. We also monitored the same L. pneumophila-contaminated cooling tower for 13 months by analyzing 104 serial samples. The culture and PCR results were extremely variable over time, but the curves were similar. The differences between the PCR and culture results did not change over time and were not affected by regular biocide treatment. This ready-to-use PCR assay for L. pneumophila quantification could permit more timely disinfection of cooling towers.