Question

An office building is space heated between October and April (inclusive). The degree days and the corresponding fuel consumptions in units of 1000 litres for two consecutive years are shown in the following Table. In between the two seasons the heating plant was modernized and insulation work was carried out which cost $27 000. The cost of fuel was 22 c/litre when the costing was done. Plot the fuel consumption/ degree-day characteristics for the two seasons and calculate: (i) the average fuel consumptions for the two seasons in litres per degree day; (ii) the saving to be expected per annum based on the average degree-day figures for the district tabulated, for the same months, over a 20-year period; (iii) the period of repayment for the cost of the modifications. Oct Nov Dec Jan Feb Mar Apr Total 175 14.5 290 24.0 320 280 275 23.3 300 25.0 23.0 200 16.5 26.5 1840 152.8 First year Degree days Fuel/(10 litre) Second year Degree days Fuel/(10 litre) 20-year average Degree days 240 12.0 1775 240 12.0 220 11.0 255 12.8 290 14.5 315 15.8 215 10.8 88.9 133 243 301 338 306 273 203 1797

Answer 1

(I) the average fuel consumption is 1350

(Ii) the saving to expected is 95

(Iii) the period for repayment for cost of modifications is 10 years