The present study highlights the exergetic performance characteristics of an underground air tunnel for greenhouse cooling with a 47m horizontal, 56cm nominal diameter U-bend buried galvanized ground heat exchanger. This system was designed and installed in the Solar Energy Institute, Ege...

Japan has few indigenous energy supplies, and imports the bulk of its energy, so it is hardly surprising that, following the oil crises of the mid 1970's, it has taken renewable energy seriously. Moreover, increasing constrains on energy and the environment, especially the global environmental...

Different renewable energy sources can be used for greenhouse heating, but several problems have to be solved before renewable energies can substitute fossil fuels. Possibilities and criteria are discussed.

The paper deals with the in situ experimental determination of the thermal properties of the underground soil for use in the design of borehole heat exchangers (BHE). The approach is based on recording the unsteady thermal response of a BHE that has been installed for the first time in Saudi...

Geothermal and solar heat can be directly converted into electricity by using thermoelectric generators. Perovskite-type metal oxides are potential materials to improve the efficiency of these devices. Cobaltates with p-type conductivity and n-type manganates are considered for the development...

Market penetration of renewable energy sources, such as geothermal energy, could be promoted even by small cost reductions, achieved through improved development design. This paper deals with optimization of the exploitation system of a low enthalpy geothermal aquifer, by means of the method of...

At the beginning of the 1980s the installed geothermal electric capacity in the world was 1960 MW, rising to 3698.5 MW in 1985, and 5835.5 MW in 1990. At the beginning of 1993 the installed capacity had reached 5915 MW, an increase of 202% with respect to 1980. The percentage increase in...

In the absence of any likely international law in the near future to impose comprehensive obligations on nations to take action to promote renewable energy or energy conservation, such action will be required at national level. This paper proposes a generic legislative framework for the control...

In the paper renewable energy resources in Poland were analysed and estimated. The following sources were taken into consideration: solar radiation, biomass including biogas, liquid and solid biofuels, geothermal, hydro and wind energy. Some technologies suitable for application in Polish...

Afyon geothermal district heating system (AFJET) provides heating to 4519 residences, covering an area of 513,683m2. Due to limitations in reinjection capacity, geothermal waters are released to the Akarcay Stream, detrimentally affecting the environment. Optimum heating load of the system was...