THERMOELECTRIC PLANTS WASTE HEAT UTILIZATION FOR PROTECTED ORNAMENTAL CULTIVATIONS

F. Parrini, D. Casarotti, S. Pulvirenti
The use of thermoelectric power plants waste water heat can be viewed as an energy saving application in the heating of those systems needing low temperature, as greenhouses (G) for example.

The supply of low enthalpy water becomes costless for the users as far as its thermal content is concerned but not with regard to the distribution. The pumping costs have to be considered seriously as there are considerable delivery capacities involved because of the low energy content (in Italy during winter, the temperature of the cooling water of a closed cycle wet tower thermoelectric power plant reaches values averaged between 20 and 23°C).

Furthermore, taking always into consideration the low thermal level of these waters, there is a considerable increase of the exchange surface necessary to maintain a prefixed thermal level in the G's.

In order to reduce the exchange surface and the relating costs of investment the greenhouse should be adequately insulated, providing that degree of insulation obtained and relating investment make a ratio higher than the unit, at least within the depreciation time of the installation.

The experiment which is being carried on at Conphoebus test field in Catania makes a comparison between the performance of a double layer air inflated polyethylene G-tunnel fed by low temperature water (whose level simulates that one of the mentioned thermoelectric power plant) and that of two test greenhouses, same type of the first, one of which is provided with back-up heating and the other with traditional heating.

Ornamental plants have been cultivated in the three G's and have been used as agronomic validation of the same.

The first results, either technical (energy consumption, air and ground thermal level in the three G's) or agronomic (product quality and productivity) have indicated the advantages of the use of low temperature water for the conditioning of G's during winter in a Mediterranean climate.

Parrini, F., Casarotti, D. and Pulvirenti, S. (1990). THERMOELECTRIC PLANTS WASTE HEAT UTILIZATION FOR PROTECTED ORNAMENTAL CULTIVATIONS. Acta Hortic. 263, 239-252
DOI: 10.17660/ActaHortic.1990.263.23
https://doi.org/10.17660/ActaHortic.1990.263.23

Acta Horticulturae