CO2 from gas-fired heating boilers - its distribution and exchange rate.

Abstract

Glasshouse levels of CO2 were recorded on 2 tomato and 2 chrysanthemum holdings in which CO2 enrichment was provided via gas-fired heating boilers. The daily levels could range widely, from 300 to 6000 p.p.m. More consistent levels of distribution were provided by using a main duct with lay-flat perforated plastic tubing than by using a main duct with holes through which the CO2 was fed directly into the greenhouse. The latter system produced a more pronounced CO2 gradient with tomatoes than with chrysanthemums. Levels within and outside the beds did not differ except in the case of chrysanthemums supplied with CO2 from a main duct with lay-flat tubing, where levels at a height of 10 cm were markedly greater than elsewhere. A close relationship was found between the internal air exchange rates (with the ventilators closed) and the wind speed. The exchange rates varied from 0.2 to 1.4 times/h. (Abstract retrieved from CAB Abstracts by CABI’s permission)