FARM-ECONOMIC ASPECTS OF LOW TEMPERATURE ENERGY FOR HEATING IN THE DUTCH GLASSHOUSE-INDUSTRY
The calculations have been made for average watertemperatures from about 80° down to 30°C and for different heating systems or other circumstances in actual practice. Factors which have a great influence are the heating capacity (W/m2), the type of condensor, the heating intensity (m3 gas per m2) and the coverage of the heating demand (i.e. the share of low temperature energy in the annual heat consumption).
In case of no condensor, a low heating capacity (180 W/m2), a heat intensity of 50 m3 natural gas equivalents (n.g.e.), a heating installation of 51 mm steel and a gasprice of 20 cents per m3 the break-even points will range from 18.1 cents per n.g.e. at a watertemperature of 55°C to 13.2 cents at 28°C. Polyethene heating systems or heating systems with thinner steel pipes or winged aluminium pipes which release the heat more easily, provide different break even points. The same is true of variations in heating intensity, condensor type, heating capacity and coverage of the heating demand.