Mapping the low enthalpy geothermal potential of shallow Quaternary aquifers in Finland

Geothermal Energy

Science – Society – Technology

Table 3 The results of design power simulations

Climatic zone I					Climatic zone II
(minimum outside temperature = -26C)					(minimum outside temperature = -29C)
Class	Detached house		Apartment building		Detached house		Apartment building
	Design power (W/m ² )		Design power (W/m ² )		Design power (W/m ² )		Design power (W/m ² )
	Heating	Re-heating of air supply unit	Heating	Re-heating of air supply unit	Heating	Re-heating of air supply unit	Heating	Re-heating of air supply unit
A	97	-	65	-	103	-	69	-
B	34	9	16	12	36	10	17	13
C	25	7	12	10	26	8	13	11
Climatic zone III					Climatic zone IV
(minimum outside temperature = -32C)					(minimum outside temperature = -38C)
Class	Detached house		Apartment building		Detached house		Apartment building
	Design power (W/m ² )		Design power (W/m ² )		Design power (W/m ² )		Design power (W/m ² )
	Heating	Re-heating of air supply unit	Heating	Re-heating of air supply unit	Heating	Re-heating of air supply unit	Heating	Re-heating of air supply unit
A	109	-	74	-	121	-	82	-
B	38	11	18	15	42	14	20	17
C	28	10	14	12	31	12	15	15

The results are divided according to the four climate zone categories in Finland, and the design power is calculated separately for detached houses and apartment buildings. The outside temperature limit for the design is according to the National Building Code of Finland (2012). Class definition: A = House or apartment building built before 1960. Ventilation: natural ventilation, air exchange rate 0.4 l/h. Heat distribution system: water radiators 70/40°C. B = Thermal insulation according the minimum requirement of the National building code of Finland (2010). Ventilation: mechanical supply and exhaust with heat recovery, air exchange rate 0.5 l/h. Temperature ratio of supplied air is 0.6. Air tightness rate (n50) in detached house 2.0 l/h and apartment building 0.7 l/h. Heat distribution system in detached house by hydronic floor heating (design temperatures 40°C/30°C), in apartment building hydronic radiators (design temperatures 70°C/40°C). C = Ultra-low energy building. Ventilation: mechanical supply and exhaust with heat recovery, air exchange rate 0.5 l/h. Temperature ratio of supplied air is 0.85. Air tightness rate (n50) in detached house 0.6 l/h and apartment building 0.6 l/h. Heat distribution system in detached house by hydronic floor heating (design temperatures 40°C/30°C), in apartment building hydronic radiators (design temperatures 70°C/40°C).