The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform

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

Doosam Song - One of the best experts on this subject based on the ideXlab platform.

  • possibility of coupling outdoor air cooling and radiant floor cooling under hot and humid climate conditions
    Energy and Buildings, 2014
    Co-Authors: Doosam Song
    Abstract:

    Abstract Existing radiant floor cooling systems introduce minimum outdoor air to provide ventilation and to Prevent Condensation on the floor surface. Conventional radiant floor cooling systems save energy relative to conventional air conditioning systems; these savings arise from the use of higher set-point temperatures and the minimization of outdoor air. In this work, the possibility was analyzed of coupling outdoor air cooling with radiant floor cooling in a hot and humid climate. A radiant floor cooling system using a dehumidified ventilation system with an outdoor air cooling mode was analyzed by a simulation method. Moreover, the behavior of the indoor thermal environment, the system's operation and its energy consumption were reviewed. Simulation modeling to analyze the possibility of using the coupled system was validated against experimental results. Simulations showed that the proposed system can provide cooling energy savings of more than 20% compared to the existing radiant floor cooling system in the hot and humid climate of Seoul, Korea; these savings arise primarily from a reduced operation rate of the radiant floor cooling loop and from reduced energy consumption by the chiller realized through proper operation of the outdoor air cooling strategy. The outdoor air cooling reduced the chiller's electricity use by about 24%. Two outdoor air cooling modes were tested: a temperature-based outdoor air cooling mode was more energy-efficient than an enthalpy-based mode even during the hot and humid season in Korea.

Lukas Graber - One of the best experts on this subject based on the ideXlab platform.

  • the critical electric field of gas mixtures over the extended range of cryogenic operating conditions
    Journal of Applied Physics, 2017
    Co-Authors: Chanyeop Park, Sastry Pamidi, Lukas Graber
    Abstract:

    In this study, we provide the critical electric field and dielectric strength of cryogenic gas mixtures over an extended cryogenic temperature and pressure range that covers most of the operating conditions of superconducting applications. For gas-cooled cryogenic systems, Condensation must not occur during operation. To Prevent Condensation, we determine the maximum allowed mole fractions of gas species consisting cryogenic gas mixtures by accounting for the operating conditions of cryogenic applications. Subsequently, we estimate the dielectric strength of the gas mixtures in terms of the density-reduced critical electric field ( ( E / N ) c r), obtained by solving the Boltzmann equation with the two-term approximation method. Using the values of ( E / N ) c r, we calculate the critical electric field (Ecr) over the extended cryogenic operation range of 10–100 K at pressures between 1.0 and 2.0 MPa. The results show that the dielectric strength of cryogenic gas mixtures varies as a function of temperatu...

A. J. Runia - One of the best experts on this subject based on the ideXlab platform.

Matthias Wessling - One of the best experts on this subject based on the ideXlab platform.

  • flue gas dehydration using polymer membranes
    Journal of Membrane Science, 2008
    Co-Authors: Hylke Pieter Sijbesma, Kitty Nymeijer, Rob Van Marwijk, Rob Heijboer, Jens Potreck, Matthias Wessling
    Abstract:

    Coal-fired power plants produce electricity and in addition to that large volume flows of flue gas. To Prevent Condensation of the water vapor present in this flue gas stream, water has to be removed before emission to the atmosphere. The application of membrane technology for this separation is attractive due to the additional energy savings and the possible re-use of water. In the present work, we present such a membrane system with extremely high separation factors and fluxes for the removal of water vapor from flue gasses. Process simulations indicate the importance of a membrane material with very high water vapor permeabilities combined with very low inert gas fluxes. Two potential membrane materials for flue gas dehydration (PEBAX® 1074, a block copolymer, and sulfonated poly(ether ether ketone) (SPEEK)) are compared and the results clearly show the superior performance of SPEEK. Composite hollow fiber membranes with a top layer of SPEEK were developed and built into fiber bundles. Twenty of such fiber bundles were placed in large gas flows of artificial and real flue gas. Short- and long-term testing of the membrane bundles revealed good mass transport properties and resistance against the flue gas conditions. This study not only demonstrates the technical viability of flue gas dehydration, but also suggests that polymer membranes may be a viable option in direct removal of CO2 from flue gas