Poblaciones de Archaea

The country is divided into eight regions to take into account the varying climate conditions of Norway. These regions, which are the same regions as used by Statistics Norway in their surveys, are:

1. Akershus County 2. Oslo

3. Østlandet, inland counties (Hedmark, Oppland)

4. Østlandet, coastal counties (Østfold, Buskerud, Vestfold, Telemark) 5. Agder and Rogaland (Vest-Agder, Aust-Agder, Rogaland)

6. Vestlandet (Hordaland, Møre og Romsdal, Sogn og Fjordane) 7. Trøndelag (Sør-Trøndelag, Nord-Trøndelag)

8. Nord-Norge (Nordland, Troms, Finnmark)

The calculation of average monthly mean outdoor temperatures for the entire dwelling stock is based on four steps:

• First, average monthly mean outdoor temperatures are calculated for each of the eight regions by weighting monthly mean temperatures from each municipality in the different regions by the number of dwellings in these municipalities.

• Second, average degree-day numbers are estimated for the different regions on the basis of the calculated average monthly mean outdoor temperatures.

• Third, a weight factor is calculated for each region, based on the calculated average degree-day number and the number of dwellings in the different regions, divided by the average energy consumption per dwelling in the regions.

• Finally, weighted monthly mean outdoor temperatures for the entire dwelling stock are calculated by weighting the average monthly mean temperatures for the different regions by the weight factors calculated for the regions.

Average monthly mean outdoor temperatures for the different regions of the country Average monthly mean outdoor temperatures for the eight regions of the country are calculated by weighting monthly mean temperatures from each municipality in the

different regions by the number of dwellings in these municipalities. Table 3.2 shows the average monthly and yearly mean temperatures calculated for the different regions. The monthly mean temperatures for the different municipalities are taken from

meteorological stations which are assumed to be representative for the municipalities. Appendix D shows the meteorological stations used in the calculations together with the corresponding degree-day number calculated for each meteorological station. The

appendix also shows the number of households in each municipality in 1990.

Table 3.2. Average monthly mean outdoor temperatures for the different regions of the country, based on average mean temperatures of each municipality in the regions, and weighted by the number of dwellings in each municipality. Based on NS 3031 (1987) and FoB90 (1992).

Region Average monthly mean outdoor temperatures (oC) Avg.

Jan. Feb. Mar Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Oslo -4.7 -4.0 -0.5 4.8 10.7 14.7 17.3 15.9 11.3 5.9 1.1 -2.0 5.9 Akershus -5.6 -5.0 -1.3 4.1 10.1 14.2 16.7 15.4 10.7 5.4 0.5 -2.7 5.3 Østlandet, Inland -8.7 -7.6 -3.1 2.9 9.0 13.4 15.9 14.3 9.4 3.9 -1.3 -5.3 3.6 Østlandet, Coast -5.0 -4.4 -0.9 4.4 10.2 14.2 16.8 15.5 11.0 5.9 1.2 -2.0 5.6 Agder/Rogaland -0.1 -0.2 1.8 5.3 10.1 13.1 15.5 15.1 12.1 8.0 4.6 2.1 7.3 Vestlandet 0.8 0.6 2.5 5.3 9.6 12.2 14.7 14.4 11.5 7.7 4.9 2.6 7.3 Trøndelag -3.5 -3.1 -0.8 3.3 7.8 11.3 14.4 13.4 9.6 5.1 1.5 -1.1 4.9 Nord-Norge -3.9 -4.2 -2.4 1.2 5.4 9.7 13.4 12.2 8.3 3.7 0.2 -2.0 3.5

Average degree-day numbers for the different regions

A degree-day number is calculated for each region based on the estimated average monthly mean temperatures and an assumed indoor temperature of 17o_{C. The estimated}

degree-day numbers for the different regions are shown in Table 3.3. It should be noted that since the degree-day numbers are based on monthly mean temperatures, they differ slightly from degree-day numbers calculated using daily mean temperatures. As an example, the degree-day number is estimated to be 3733 oC×days for Blindern (Oslo) based on the monthly mean temperatures, while it is given as 3770 oC×days in NBI A552.103 (1990) based on daily mean temperatures (see Table 3.1).

Weight factors for the different regions

A weight factor is calculated for each region, based on the calculated average degree-day number for the region, multiplied with the number of dwellings in the region, and divided by the average yearly energy consumption per dwelling in the same region. The

calculation procedure of these weight factors (wf_j) is shown in Equation 3.1.

wf_j = Gj·nj Qj

∑

wf_j is the weight factor for region j,

G_j is the calculated average degree-day number for region j,

n_j is the number of dwellings in region j,

Q_j is the average yearly energy consumption per dwelling in region j,

k is the total number of regions.

Data on the average yearly energy consumption per dwelling in the different regions are taken from the Residential Energy Use Survey 1990 (Ljones et al., 1992). These data are based on the heating season 1989/1990. The fact that the heating season 1989/1990 was unusually mild, is assumed not to influence the relative importance of the various regions in the calculations.

Table 3.3 shows the number of dwellings, the yearly energy consumption per dwelling, and the calculated average degree-day number for the different regions. The relative importance of Oslo and Nord-Norge is reduced through the weighting procedure. For Oslo this is particularly important, as the weight is reduced from 14% (based on number of dwellings) to less than 10%. Similarly, the importance of the mild coastal regions of Agder/Rogaland and Vestlandet is increased. This indicates that dwellings in the mild regions are relatively more energy consuming when corrections are made for the milder climate conditions.

Weighted monthly mean temperatures for the dwelling stock

The average monthly mean temperatures calculated for each region (Table 3.2), are finally weighted by the weight factors calculated for each region. The weighted monthly mean temperatures shown in Table 3.4 can then be used to calculate the energy

consumption of the stereotypes of houses defined in the estimation model.

Weighted degree-day numbers for the entire dwelling stock

Based on the monthly temperatures shown in Table 3.4, a weighted degree-day number of 3678 oC·days may be calculated for the entire dwelling stock. The corresponding length of this "average" heating season is 242 days.

The degree-day number calculated to be average for the entire country, will be slightly exaggerated if it is not taken into account that dwellings in the mild regions of Norway have poorer thermal performance compared to dwellings in the colder regions. As an

Table 3.3. Regional data on the number of dwellings, estimated average degree-day number, average yearly energy consumption per dwelling, and calculated weight factors for the regions. Based on FoB90 (1992) and Ljones et al. (1992).

Region Number of dwellings 3 Nov. 1990 % of total number of dwellings Yearly energy consumption Q_i Degree-day number, G_i Weight factor wf_i

Units kWh/dwelling o_C⋅days

Oslo 244 434 14.0% 15 400 3 733 9.9% Akershus 166 544 9.5% 22 500 3 952 9.3% Østlandet, Inland 149 190 8.5% 26 700 4 529 8.6% Østlandet, Coast 340 610 19.4% 21 900 3 811 19.2% Agder/Rogaland 224 251 12.8% 22 000 3 064 15.8% Vestlandet 292 086 16.7% 20 500 3 032 19.4% Trøndelag 151 083 8.6% 23 100 4 005 8.5% Nord-Norge 183 163 10.5% 23 500 4 564 9.3% Whole country 1 751 361 100% 21 500 100%

Table 3.4. Weighted monthly mean outdoor temperatures for the entire dwelling stock. The temperatures are based on average monthly mean temperatures for the different regions, weighted by the number of dwellings, the average degree-day number, and the average yearly energy consumption per dwelling in the regions. Based on FoB90 (1992), NS 3031 (1987) and Ljones et al. (1992).

Weighted monthly mean outdoor temperatures for the entire dwelling stock (oC) Avg. Jan. Feb. Mar Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec.

example, if monthly temperatures for the different regions are weighted only by the number of dwellings in the regions, ignoring the thermal performance of the dwellings, the calculated degree-day number will be 3725 oC·days. This value is 1.2% higher than the weighted degree-day number of 3678 oC·days.