Modelling of shaded and unshaded shallow-ground heat pump system for a residential building block in a Mediterranean climate

Heat pumps may be coupled to shallow-ground geothermal fields and used for the purpose of space heating and cooling of buildings. However, quite often it is not possible to locate the geothermal field in cleared grounds, especially in cities where building density is high and land has a high premium. This leads to the possibility of burying the geothermal field under the basement of new building blocks, before construction of the building. In the present work, the shaded-unshaded arrangement is numerically studied by coupling the software DesignBuilder-EnergyPlus to assess the building's energy requirement with the software FEFLOW to solve the heat transfer equation in porous media. Assuming a standard residential building block, the coupling between the two software is performed by assigning the thermal energy requirement for air conditioning, as calculated by EnergyPlus, to a flat-panel typology of ground heat exchanger simplified in a 2D FEFLOW's domain. The results show that it is necessary to opt for a dual-source heat pump (air/geothermal) system to ensure that the ground is not frozen or over-heated at peak times and to improve the overall performance of the system.peer-reviewe

Three-dimensional Navier-Stokes heat transfer predictions for turbine blade rows

Results are shown for a three-dimensional Navier-Stokes analysis of both the flow and the surface heat transfer for turbine applications. Heat transfer comparisons are made with the experimental shock-tunnel data of Dunn and Kim, and with the data of Blair for the rotor of the large scale rotating turbine. The analysis was done using the steady-state, three-dimensional, thin-layer Navier-Stokes code developed by Chima, which uses a multistage Runge-Kutta scheme with implicit residual smoothing. An algebraic mixing length turbulence model is used to calculate turbulent eddy viscosity. The variation in heat transfer due to variations in grid parameters is examined. The effects of rotation, tip clearance, and inlet boundary layer thickness variation on the predicted blade and endwall heat transfer are examined

Simulation and experimentation of heat transfer in a solar distillation still

This paper deals with a simple and inexpensive solar desalination configuration. The performance of a simple solar still operating under Maltese climatic conditions is analysed both theoretically and experimentally. The internal and external heat transfer modes of the distillation unit are examined. This paper concludes that the distillation rate in a simple solar distiller increases with ambient temperature and solar radiation, even though the condensation capacity of the glass is reduced. A higher wind speed decreases the evaporation and condensation processes. The energy fractions within the solar still have also been analysed. The simulations and the experiments conclude that the glass components handle the bulk of the heat transferred in a solar still namely radiation, evaporation and condensation and thus the distillation efficiency is enhanced by improving the thermal and optical properties of the glass.peer-reviewe

The application of MCP techniques and CFD modelling for wind resource assessment in a Mediterranean Island context

This paper presents salient results from an ongoing investigation into wind behaviour and resources characterisation on the central Mediterranean Maltese archipelago. The ultimate aim is to enable a more accurate determination of the potential for electrical wind power generation in the onshore and inshore marine environments. One area of this research is seeking to generate longer-term wind characteristics at selected locations. The strategy used involves a combination of field measurements at a number of onshore points and the use of Measure-Correlate-Predict (MCP) techniques in conjunction with Computational Fluid Dynamics (CFD) software. This current study will present selected results from the validation process underway to establish the performance of MCP and CFD in a sub-tropical island context.peer-reviewe

Challenges in developing a solar powered stirling engine for domestic electricity generation

This paper investigates the challenges in developing a solar powered Stirling engine for domestic electricity generation. All the system components, the parabolic troughs, heat transfer fluid and the Stirling engine are individually analysed. The analysis includes a market survey and performance assessments of such components. A mathematical analysis for the Stirling engine is carried out in order to understand the affect of varies parameters with the work output per cycle and the engine efficiency. Such parameters are the phase angle between pistons, the diameter ratio of the power and displacer piston, and change in temperature.peer-reviewe

The incremental contour method using asymmetric stiffness cuts

An incremental Contour Method (iCM) of residual stress measurement is proposed where residual stresses in the body of interest are sequentially reduced by successive contour cuts and the risk of stress re-distribution plastic- ity is mitigated or eliminated. The cutting-induced plasticity is known to cause significant inaccuracies when try- ing to measure the near-yield residual stresses using a conventional single cut contour method. The iCM procedure implements a new displacement data processing approach for the general case of sectioning at an ar- bitrary plane where the cut parts do not possess mirror-symmetric elastic stiffness. The basis for the new asymmetric stiffness data analysis approach is presented and the accuracy of the new method demonstrated using both numerical and experimental case studies

Transient Response of a Hollow Cylindrical-Cross-Section Solid Sensible Heat: Storage Unit- Single Fluid

plosion which have been interpreted in terms of the kinetic theory of nucleation can likewise be viewed in terms of film boiling destabilization with attendant fine scale fragmentation of the hot material. Vol. 77, No. 23, 1973, pp. 2730-2736 26 Cronenberg, A. W., Benz, R., to be published, Advances in Nuclear Science and Technology, 1978. 27 Anderson, R. P., Armstrong, D. R., ASME Meeting on Nuclear Reactor Safety Heat Transfer, Atlanta, Ga., Nov. 1977. 28 Henry, R. E., Fauske, H. K., McUmber, L. M., Proceedings of ANS Conference on Fast Reactor Safety, Chicago, 111. (Oct. 1976). Conclusions 29 Fauske, H. K., Nuclear Science and Engineering, Vol. 51, 1973, pp. 95-101. 30 Fauske, H. K., Reactor Technology, Vol. 15, No. 4, 1972-1973 3