Analyzing power and energy flexibilities by demand response in district heated buildings in Finland and Germany

Figures & data

Fig. 1. General description of simulation study.

Fig. 2. Flow chart of simulation process.

Fig. 3. Finnish and German synthetic DH prices.

Table 1. Description of the Finnish synthetic DH price.

Month	Average (€/MWh)	Maximum (€/MWh)	Minimum (€/MWh)	Standard deviation (€/MWh)
January	67.6	138.0	32.3	26.5
February	72.1	145.4	22.4	34.5
March	65.9	133.2	36.1	27.5
April	44.7	54.6	28.2	5.8
October	41.3	50.0	24.1	5.3
November	57.2	136.7	33.8	22.7
December	65.5	136.4	27.0	30.7
Heating season	59.1	145.4	22.4	26.7

Table 2. Description of the German synthetic DH price.

Month	Average (€/MWh)	Maximum (€/MWh)	Minimum (€/MWh)	Standard deviation (€/MWh)
January	72.1	84.1	48.5	5.7
February	74.0	83.6	64.1	3.2
March	71.3	80.6	56.9	4.2
April	68.7	84.6	53.9	5.1
October	62.9	84.6	35.5	6.3
November	70.6	82.3	47.4	5.7
December	75.5	90.6	61.9	4.6
Heating season	70.7	90.6	35.5	6.4

Table 3. Description of Helsinki and Hamburg outdoor temperatures of test reference years.

Month	Average (ºC)		Maximum (ºC)		Minimum (ºC)		Standard deviation (ºC)
	Finland	Germany	Finland	Germany	Finland	Germany	Finland	Germany
January	−4.0	1.8	2.8	9.5	−20.4	−9.4	5.7	3.6
February	−4.5	2.6	8	10.2	−20.6	−5	7.2	2.7
March	−2.6	5.1	6.2	19.5	−19.9	−5.2	4.6	4.0
April	4.5	9.0	18.3	19.6	−3.7	−1.5	4.6	4.2
October	6.2	9.9	13.9	17.5	−2.1	−0.4	3.6	3.8
November	0.5	5.7	8.9	15.1	−17.8	−4.6	6.3	4.7
December	−2.2	2.0	4.9	8.4	−15	−6	4.5	3.2
Heating season	−0.3	5.2	18.3	19.6	−20.6	−9.4	6.6	4.9

Table 4. Building model parameters.

Parameters	Apartment building	Cultural center	Office building
Heated net floor area (m^2)	4885	3937	2383
Floor number	4	3	4
Envelope area (m^2)	4780	6921	3855
Window/envelope area	7.6%	8.8%	9.5%

Table 5. U values and airtightness of buildings.

Parameters		Finland			Germany
		Apartment building	Cultural center	Office building	Apartment building	Cultural center	Office building
U value (W/m^2·K)	External walls	0.28	0.28	0.28	1.70	0.20	0.20
	Roof	0.22	0.22	0.22	1.40	0.19	0.19
	Ground slab	0.36	0.36	0.36	1.00	0.28	0.28
	Windows	1.00	1.00	1.00	3.00	3.00	3.00
Air leakage rate, n50 (1/h)		1.00	2.00	1.60	7.00	3.00	4.50

Fig. 4. Inlet water temperature adjustment in relation to outdoor temperature.

Table 6. Design powers of space heating systems.

Space heating system	Apartment building		Cultural center		Office building
	Finland	Germany	Finland	Germany	Finland	Germany
Design power at design temperature (kW)	169	225	229	175	129	101
Specific design power at design temperature (W/m^2)	35	46	58	44	54	42

Table 7. Ventilation systems for simulated buildings.

Country	Building type	Ventilation system	Air change rate	Operation time
Finland	Apartment building	Mechanical supply and exhaust ventilation (CAV) without heat recovery	0.5 L/h	Always on
	Cultural center	Mechanical supply and exhaust ventilation (VAV with CO2 control) with heat recovery (65%) except toilets, basement, and technical spaces	0.35–5.4 L/s, m^2	8 am–10 pm
		Mechanical supply and exhaust ventilation (CAV) for basement, toilets, and technical spaces	0.35–4.5 L/s, m^2
	Office building	Mechanical supply and exhaust ventilation (VAV with CO2 control) with heat recovery (65%) for meeting rooms	0.35–3 L/s, m^2	6 am–6 pm for workdays
		Mechanical supply and exhaust ventilation (CAV) for office rooms and hallway	0.35–1.5 L/s, m^2
Germany	Apartment building	Natural ventilation	0.24 L/h	Always on
	Cultural center	Mechanical supply and exhaust ventilation (CAV) without heat recovery for kitchen, restaurant, basement, and hall	1.7–2.36 L/s, m^2	8 am–10 pm 7 am–10 pm (Basement)
		Mechanical exhaust ventilation (CAV) for toilets	2.5–4.5 L/s, m^2	Always on
		Natural ventilation for other spaces	0.2–0.43 L/s, m^2	Always on
	Office building	Mechanical supply and exhaust ventilation (CAV) without heat recovery	2.1 L/s, m^2	6 am–6 pm for workdays

Table 8. Usage time and annual internal heat gains.

Parameters	Apartment building	Cultural center	Office building
Usage time	Continuous	8 am–9 pm (everyday)	8 am–4 pm (workdays)
Annual internal heat gains of lighting (kWh/m^2·a)	15.9	29.1	18.3
Annual internal heat gains of equipment (kWh/m^2·a)	11.3	14.7	3.7

Fig. 5. Control algorithms 1 and 2 for space heating.

Fig. 6. Smoothed set-points for a day of cases with nighttime set-back.

Fig. 7. Charging and discharging energies during increasing and decreasing price trends.

Table 9. Simulation cases for different building types.

Country	Building type	Cases	Marginal value with DR (€/MWh)	Nighttime set-back mode
Finland	Apartment building	FAB (Reference)	No DR	–
		FAB-DR-15-NS	15	–
		FAB-DR-15	15	–
		FAB-DR-75	75	–
	Cultural center	FCC(Reference)	No DR	–
		FCC-DR-15-NT	15	√
		FCC-DR-75-NT	75	√
	Office building	FOB (Reference)	No DR	–
		FOB-DR-15	15	–
		FOB-DR-15-NT	15	√
		FOB-DR-75-NT	75	√
Germany	Apartment building	GAB (Reference)	No DR	–
		GAB-DR-15	15	–
		GAB-DR-75	75	–
	Cultural center	GCC (Reference)	No DR	–
		GCC-DR-15-NT	15	√
		GCC-DR-75-NT	75	√
	Office building	GOB (Reference)	No DR	–
		GOB-DR-15-NT	15	√
		GOB-DR-75-NT	75	√

Fig. 8. The effect of DR and set-point smoothing on hourly DH power demand.

Fig. 9. Set-point variation hours in Finnish cases for each month with marginal value 15 €/MWh.

Table 10. Number of total set-point variation hours in Finnish and German cases for each month during the heating season.

Country	Condition	Set-point temperature (°C)	January	February	March	April	October	November	December	Total hours
Finland	DR-15	23	201	215	119	0	0	78	175	788
		20	354	247	366	419	458	401	369	2614
	DR-15-NT	23	112	123	74	0	0	34	90	433
		18/20	511	438	543	566	586	556	547	3747
	DR-75	23	0	0	0	0	0	0	5	5
		20	455	358	413	419	458	442	415	2960
	DR-75-NT	23	0	0	0	0	0	0	3	3
		18/20	583	502	574	566	586	575	563	3949
Germany	DR-15	23	1	0	0	0	0	0	5	6
		20	436	415	510	470	533	472	441	3277
	DR-15-NT	23	1	0	0	0	0	0	3	4
		18/20	478	450	556	528	569	517	489	3587
	DR-75	23	0	0	0	0	0	0	5	5
		20	436	415	510	470	533	472	441	3277
	DR-75-NT	23	0	0	0	0	0	0	3	3
		18/20	478	450	556	528	569	517	489	3587

Table 11. Number of total set-point variation periods per month in Finnish and German cases during the heating season.

Country	Condition	Set-point temperature (°C)	January	February	March	April	October	November	December
Finland	DR-15	23	15	13	13	0	0	8	14
		20	24	16	27	22	24	20	24
	DR-15-NT	23	17	15	13	0	0	7	14
		18/20	32	26	31	24	24	25	29
	DR-75	23	0	0	0	0	0	0	1
		20	21	16	23	22	24	18	24
	DR-75-NT	23	0	0	0	0	0	0	1
		18/20	26	21	27	24	24	23	27
Germany	DR-15	23	1	0	0	0	0	0	1
		20	29	35	44	45	48	25	33
	DR-15-NT	23	1	0	0	0	0	0	1
		18/20	29	34	40	44	44	28	31
	DR-75	23	0	0	0	0	0	0	1
		20	29	35	44	45	48	25	33
	DR-75-NT	23	0	0	0	0	0	0	1
		18/20	29	34	40	44	44	28	31

Fig. 10. Variations of charging/discharging energies during a single charging/discharging period in the Finnish apartment building (FAB), cultural center (FCC), and office building (FOB) with marginal values of 15 €/MWh and 75 €/MWh.

Table 12. Total specific charging and discharging energies of the Finnish cases per heated net floor area.

Cases	Total specific charging energy (kWh/m^2)
	January	February	March	April	October	November	December	Heating season
FAB-DR-15	1.2	1.1	0.9	0.3	0.3	0.7	1.2	5.6
FAB-DR-75	0.4	0.4	0.5	0.3	0.3	0.4	0.5	2.9
FCC-DR-15-NT	1.5	1.5	1.2	0.4	0.5	1.0	1.4	7.5
FCC-DR-75-NT	0.8	0.8	0.8	0.4	0.5	0.8	0.9	5.1
FOB-DR-15-NT	3.6	3.4	2.9	1.2	1.5	2.4	3.3	18.3
FOB-DR-75-NT	2.5	2.3	2.2	1.2	1.4	2.1	2.6	14.4
Total specific discharging energy (kWh/m^2)
FAB-DR-15	−1.1	−0.9	−1.0	−0.5	−0.5	−0.8	−1.0	−5.9
FAB-DR-75	−0.7	−0.6	−0.7	−0.5	−0.5	−0.6	−0.6	−4.2
FCC-DR-15-NT	−1.9	−1.8	−1.6	−0.8	−1.1	−1.5	−1.7	−10.3
FCC-DR-75-NT	−1.5	−1.3	−1.4	−0.8	−1.1	−1.3	−1.5	−8.8
FOB-DR-15-NT	−4.0	−3.8	−3.4	−1.6	−2.2	−3.0	−3.6	−21.7
FOB-DR-75-NT	−3.2	−2.9	−3.0	−1.6	−2.2	−2.8	−3.2	−19.0

Fig. 11. Variations of charging/discharging energies during a single charging/discharging period in the German apartment building (GAB), cultural center (GCC), and office building (GOB) with marginal values of 15 €/MWh and 75 €/MWh.

Table 13. Total specific charging and discharging energies of the German cases per heated net floor area.

Cases	Total specific charging energy (kWh/m^2)
	January	February	March	April	October	November	December	Heating season
GAB-DR-15	0.5	0.4	0.4	0.2	0.2	0.4	0.5	2.7
GAB-DR-75	0.5	0.4	0.4	0.2	0.2	0.4	0.5	2.7
GCC-DR-15-NT	1.5	1.2	1.0	0.6	0.6	1.0	1.5	7.3
GCC-DR-75-NT	1.5	1.2	1.0	0.6	0.6	1.0	1.5	7.3
GOB-DR-15-NT	2.2	1.7	1.3	0.6	0.6	1.3	2.0	9.7
GOB-DR-75-NT	2.2	1.7	1.3	0.6	0.6	1.3	2.0	9.7
Total specific discharging energy (kWh/m^2)
GAB-DR-15	−0.9	−0.8	−0.8	−0.4	−0.6	−0.8	−0.8	−5.1
GAB-DR-75	−0.9	−0.8	−0.8	−0.4	−0.6	−0.8	−0.8	−5.1
GCC-DR-15-NT	−2.6	−2.3	−2.2	−1.5	−1.7	−2.1	−2.6	−15.0
GCC-DR-75-NT	−2.6	−2.3	−2.2	−1.5	−1.7	−2.1	−2.6	−15.0
GOB-DR-15-NT	−4.1	−3.5	−3.4	−1.8	−2.5	−3.3	−3.9	−22.5
GOB-DR-75-NT	−4.1	−3.5	−3.4	−1.8	−2.5	−3.3	−3.9	−22.5

Fig. 12. Power flexibility factors P⁺ and P⁻ of the Finnish office building without and with nighttime set-back.

Fig. 13. Hourly heating power demand with (red line) and without (blue line) nighttime set-back in the Finnish office building.

Table 14. Flexibility factors and average indoor temperature of Finnish and German cases.

Country	Case	FF^+ (%)	FF^− (%)	Average temperature, Tave (°C)	Average temperature during occupied hours, Tave, occ (°C)
Finland	FAB-DR-15	7.7	−8.1	21.3	21.3
	FAB-DR-75	4.0	−5.8	21.1	21.1
	FCC-DR-15-NT	8.5	−11.6	21.1	21.6
	FCC-DR-75-NT	5.7	−10.0	20.9	21.4
	FOB-DR-15	18.0	−18.9	21.4	21.5
	FOB-DR-15-NT	25.9	−30.7	20.5	21.2
	FOB-DR-75-NT	20.4	−26.9	20.3	20.9
Germany	GAB-DR-15	3.1	−6.0	21.2	21.2
	GAB-DR-75	3.1	−6.0	21.2	21.2
	GCC-DR-15-NT	6.5	−13.4	20.8	21.5
	GCC-DR-75-NT	6.5	−13.4	20.8	21.5
	GOB-DR-15-NT	8.4	−19.6	20.5	20.9
	GOB-DR-75-NT	8.4	−19.6	20.5	21.0