Division 4 Specific conditions for the seasonal space heating energy efficiency of solid fuel boilers

Seasonal space heating energy efficiency η_s is defined as:

η_s = η_son – F(1) – F(2) + F(3)

where:

1. (1)

   η_son is the seasonal space heating energy efficiency in active mode, expressed as a percentage, calculated as set out in point 4(b);

2. (2)

   F(1) accounts for a loss of seasonal space heating energy efficiency due to adjusted contributions of temperature controls; F(1) = 3 %;

3. (3)

   F(2) accounts for a negative contribution to the seasonal space heating energy efficiency by auxiliary electricity consumption, expressed as a percentage, and is calculated as set out in point 4(c);

4. (4)

   F(3) accounts for a positive contribution to the seasonal space heating energy efficiency by the electrical efficiency of solid fuel cogeneration boilers, expressed as a percentage, and is calculated as follows:

   F(3) = 2,5 × η_el,n

the seasonal space heating energy efficiency in active mode, η_son , is calculated as follows:

1. (1)

   for manually stoked solid fuel boilers that can be operated at 50 % of the rated heat output in continuous mode, and for automatically stoked solid fuel boilers:

   η_son = 0,85 × η_p + 0,15 × η_n

2. (2)

   for manually stoked solid fuel boilers that cannot be operated at 50 % or less of the rated heat output in continuous mode, and for solid fuel cogeneration boilers:

   η_son = η_n

F(2) is calculated as follows:

1. (1)

   for manually stoked solid fuel boilers that can be operated at 50 % of the rated heat output in continuous mode, and for automatically stoked solid fuel boilers:

   F(2) = 2,5 × (0,15 × el_max + 0,85 × el_min + 1,3 × P_SB )/(0,15 × P_n + 0,85 × P_p )

2. (2)

   for manually stoked solid fuel boilers that cannot be operated at 50 % or less of the rated heat output in continuous mode, and for solid fuel cogeneration boilers:

   F(2) = 2,5 × (el_max + 1,3 × P_SB )/P_n