ISHS Acta Horticulturae 70: Technical and Physical Aspects of Energy Saving in Greenhouses
APPLICATION OF CONDENSING HEAT EXCHANGERS IN THE STACK OF NATUREL GAS FIRED BOILERS FOR SOIL HEATING IN GREENHOUSES |
| Author: | B.J. Heijna |
| Abstract:
The small degree of contamination of the fluegases of natural gas fired boilers make it possible to use these gases for CO2-enrichment but also to obtain extra latent heat by cooling off below the condensation temperature. This is done in heat exchangers with as cooling medium the water of a soil heating system on account of its low temperature. The dewpoint of the gases depends on the CO2-concentration and varies between 55° and 58°C. To get a reasonable recovery of the latent heat the dewpoint of the gases leaving the exchanger should be considerably lower than 55–58°C. The dewpoint is mainly determined by the surface temperature of the heatex-changing parts and not by the dry bulb gas temperature. The outletgases can, therefore, have a relative humidity of 70–80%. | |
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