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Modelling results on New Generation Solar Cooling systems
Chiara Dipasquale
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
4 examples of new generation solar cooling systems:
• Building description and solar cooling plant layout;
• Working modes and characteristics of system components;
• Operational modes and system size variants, and results.
INTRODUCTION
2
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Building description
CASE 1
Reference Single Family House - SFH Reference Small Multi Family House - sMFH
Number of floors 2
Living area per floor 50 m²
Yearly heating demand 45 kWh/(m²y)
Number of floors 5
Living area per dwelling 50 m²
Number dwelling per floor 2
Yearly heating demand 45 kWh/(m²y)
3
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Solar cooling plant layout
CASE 1
GENERATION DEVICE
HJ_HYDRAULIC JUNCTION
DHW
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
T5.2
T1.3
T5.4
T5.5
T5.6
T6.1
PV_PHOTOVOLTAIC
DISTRIBUTION DEVICES
1. Solar thermal collectors2. PV panels3. Air-to-water heat pump4. Storage tank5. Buffer6. DHW distribution circuit7. H&C Distribution circuit
1
2
3
4
5
7
6
• Use of solar thermal energy for DHW production and space heating
• Use of PV energy for the HVAC system electricity consumption
4
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
A/W HEAT PUMP
HJ_HYDRAULIC JUNCTION
DHW
VM2_3
VM1_6
C5
C6
C1
C2
TES_SNS5
C1
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
C6
C5
0
1
PM1_5C2
C1
0
1
1
0
VM1_7
C6
C5
0
1
PM1_6C2
C1
VM1_5PM2_4
C6
C5
C2
C1
HX_2
PM1_1
PM2_2
VM1_4VM_2
1
0
TES_SNS3
TES_SNS2
200 l
C3
C5
T5.2
0
1
PM2_3
C2
C1
T1.3
C2
C4 C6
C5
C6
C4C3out
BUF_SNS1
BUF_SNS5
HX_1
T5.3
T5.4
T5.5
T5.6
T6.1
PV_PHOTOVOLTAIC
VD_1
VM2_2
VM
CASE 1
5
Working conditions
TES charging by solar energy
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
A/W HEAT PUMP
HJ_HYDRAULIC JUNCTION
DHW
VM2_3
VM1_6
C5
C6
C1
C2
TES_SNS5
C1
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
C6
C5
0
1
PM1_5C2
C1
0
1
1
0
VM1_7
C6
C5
0
1
PM1_6C2
C1
VM1_5PM2_4
C6
C5
C2
C1
HX_2
PM1_1
PM2_2
VM1_4VM_2
1
0
TES_SNS3
TES_SNS2
200 l
C3
C5
T5.2
0
1
PM2_3
C2
C1
T1.3
C2
C4 C6
C5
C6
C4C3out
BUF_SNS1
BUF_SNS5
HX_1
T5.3
T5.4
T5.5
T5.6
T6.1
PV_PHOTOVOLTAIC
VD_1
VM2_2
VM
CASE 1
6
Working conditions
TES charging by heat pump
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
A/W HEAT PUMP
HJ_HYDRAULIC JUNCTION
DHW
VM2_3
VM1_6
C5
C6
C1
C2
TES_SNS5
VD_1
VM2_2
C1
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
C6
C5
0
1
PM1_5C2
C1
0
1
1
0
VM1_7
C6
C5
0
1
PM1_6C2
C1
EH6
VM1_5PM2_4
C6
C5
C2
C1
HX_2
PM1_1
PM2_2
VM1_4VM_2
1
0
TES_SNS3
TES_SNS2
200 l
C3
C5
T5.2
0
1
PM2_3
C2
C1
T1.3
C2
C4 C6
C5
C6
C4C3out
BUF_SNS1
BUF_SNS5
HX_1
T5.3
T5.4
T5.5
T5.6
VM
T6.1
PV_PHOTOVOLTAIC
CASE 1
7
Working conditions
Buffer charging by heat pump
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
A/W HEAT PUMP
HJ_HYDRAULIC JUNCTION
DHW
VM2_3
VM1_6
C5
C6
C1
C2
TES_SNS5
C1
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
C6
C5
0
1
PM1_5C2
C1
0
1
1
0
VM1_7
C6
C5
0
1
PM1_6C2
C1
VM1_5PM2_4
C6
C5
C2
C1
HX_2
PM1_1
PM2_2
VM1_4
PV_PHOTOVOLTAIC
VM_2
1
0
TES_SNS3
TES_SNS2
200 l
C3
C5
T5.2
0
1
PM2_3
C2
C1
T1.3
C2
C4 C6
C5
C6
C4C3out
BUF_SNS1
BUF_SNS5
HX_1
T5.3
T5.4
T5.5
T5.6
T6.1
VD_1
VM2_2
VM
CASE 1
8
Working conditions
Buffer charging by solar energy
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
A/W HEAT PUMP
HJ_HYDRAULIC JUNCTION
DHW
VM2_3
VM1_6
C5
C6
C1
C2
TES_SNS5
C1
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
C6
C5
0
1
PM1_5C2
C1
0
1
1
0
VM1_7
C6
C5
0
1
PM1_6C2
C1
VM1_5PM2_4
C6
C5
C2
C1
HX_2
PM1_1
PM2_2
VM1_4VM_2
1
0
TES_SNS3
TES_SNS2
200 l
C3C5
T5.2
0
1
PM2_3
C2
C1
T1.3
C2
C4 C6
C5
C6
C4C3out
BUF_SNS1
HX_1
T5.4
T5.5
T5.6
T6.1
PV_PHOTOVOLTAIC
VD_1
VM2_2
Working conditions
CASE 1
9
DHW distribution
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
ST and PV performance with varying field size and tilt angle
RESULTS – CASE 1
GENERATION DEVICE
HJ_HYDRAULIC JUNCTION
DHW
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
T5.2
T1.3
T5.4
T5.5
T5.6
T6.1
PV_PHOTOVOLTAIC
DISTRIBUTION DEVICES
Solar Fraction and stagnation hours referred
to the total heating production (space heating
+ DHW)10
0
100
200
300
400
500
600
700
0%5%
10%15%20%25%30%35%40%
30° 90° 30° 90°
STC_1 STC_1 STC_3 STC_3 Stag
nat
ion
nu
mb
er h
ou
rs [h
]
Sola
r Fr
acti
on
[%]
Solar Thermal Collectors - s-MFH
SF_ROM SF_STO Hour_ROM Hour_STOROM – Rome
STO - Stockholm
Solar ThermalUnit s-MFH
STC_1 m² 18.4STC_2 m² 27.6STC_3 m² 36.8
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
RESULTS – CASE 1
GENERATION DEVICE
HJ_HYDRAULIC JUNCTION
DHW
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
T5.2
T1.3
T5.4
T5.5
T5.6
T6.1
PV_PHOTOVOLTAIC
DISTRIBUTION DEVICES
Solar ThermalUnit s-MFH
STC_1 m² 18.4STC_2 m² 27.6STC_3 m² 36.8
Solar Fraction and stagnation hours referred
to the total heating production (space heating
+ DHW)11
PV production and self-consumption for two
different fields size and panel slope
0
2000
4000
6000
8000
10000
30° 90° 30° 90° 30° 90° 30° 90°
ROM_3 kW ROM_5 kW STO_3 kW STO_5 kW
Ener
gy [k
Wh
]
PV production - s-MFH
PV self HVAC PV self other PV to the grid
0
100
200
300
400
500
600
700
0%5%
10%15%20%25%30%35%40%
30° 90° 30° 90°
STC_1 STC_1 STC_3 STC_3 Stag
nat
ion
nu
mb
er h
ou
rs [h
]
Sola
r Fr
acti
on
[%]
Solar Thermal Collectors - s-MFH
SF_ROM SF_STO Hour_ROM Hour_STO
PhotovoltaicUnit s-MFH
PV_1 kWp 3PV_2 kWp 4PV_3 kWp 5
ROM – Rome
STO - Stockholm
ST and PV performance with varying field size and tilt angle
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
RESULTS – CASE 1
GENERATION DEVICE
HJ_HYDRAULIC JUNCTION
DHW
BUF_BUFFER
TES_THERMAL ENERGY STORAGE
STC_SOLAR THERMAL COLLECTORS
T5.2
T1.3
T5.4
T5.5
T5.6
T6.1
PV_PHOTOVOLTAIC
DISTRIBUTION DEVICES
Comparison of similar field areas of STC (27 m²) or
PV (24 m²) in terms of electric energy savings for
DHW, heating and cooling uses
12
0
5
10
15
20
25
30
35
40
NO_ST_PV STC_2 PV_1 NO_ST_PV STC_2 PV_1
ROME STOCKHOLM
Fin
al E
ner
gy [
kWh
/(m
²y)]
Electricity consumption - s-MFH
14%20
%
23%
14%
ST and PV performance for different sizes and slopes
• Slightly higher energy savings in Southern climates due to higher cooling loads
• Same energy savings for a solar thermal (STC) or photovoltaic (PV) field in Northern climates
ROM – Rome STO – Stockholm
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Building description
CASE 2
Wooden Residential Building (WRB)
Number of floors 2
Living area per floor 130 m²
13
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Solar cooling plant layout
CASE 2
1. Compound Parabolic Collectors (CPC)2. Storage tank – 1000 l3. Electric Heater4. Adsorption chiller – 10 kW5. Dry cooler6. Fan coil
• Adsorption chiller for space cooling;• Solar collectors (CPC) for heating
and DHW demands• Heat rejection through dry-cooler.
14
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 2
Running the solar system
Working conditions
15
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
<
CASE 2Working conditions
Space cooling mode
16
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 2Working conditions
Running the back-up heater
17
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 2Working conditions
Domestic Hot Water and space heating
18
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Absorption chiller in different climates
RESULTS – CASE 2
19
# solar collectors
SPF heating[-]
SPF cooling[-]
SF total [%]
PER total[-]
Freiburg 6 6.7 5.2 51% 1.2
Stuttgart 6 9.5 7.9 56% 1.3
Marseille 6 11.6 9.6 92% 1.9
Messina 8 14.8 12.3 67% 2
Luca 8 14.3 13.0 66% 2
Athens 8 10.4 10.9 69% 2.4
Barcelona 8 12.9 11.7 73% 2.4
Almeria 8 10.7 11.8 66% 1.9
Larnaca 10 11.9 12.7 63% 2.1
• The highest SF is in Marseille where heating and cooling demands are similar;
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Absorption chiller in different climates
RESULTS – CASE 2
20
# solar collectors
SPF heating[-]
SPF cooling[-]
SF total [%]
PER total[-]
Freiburg 6 6.7 5.2 51% 1.2
Stuttgart 6 9.5 7.9 56% 1.3
Marseille 6 11.6 9.6 92% 1.9
Messina 8 14.8 12.3 67% 2
Luca 8 14.3 13.0 66% 2
Athens 8 10.4 10.9 69% 2.4
Barcelona 8 12.9 11.7 73% 2.4
Almeria 8 10.7 11.8 66% 1.9
Larnaca 10 11.9 12.7 63% 2.1
• The highest SF is in Marseille where heating and cooling demands are similar;
• Northern climates have low SF due to small collector size and high heating demand;
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Absorption chiller in different climates
RESULTS – CASE 2
21
# solar collectors
SPF heating[-]
SPF cooling[-]
SF total [%]
PER total[-]
Freiburg 6 6.7 5.2 51% 1.2
Stuttgart 6 9.5 7.9 56% 1.3
Marseille 6 11.6 9.6 92% 1.9
Messina 8 14.8 12.3 67% 2
Luca 8 14.3 13.0 66% 2
Athens 8 10.4 10.9 69% 2.4
Barcelona 8 12.9 11.7 73% 2.4
Almeria 8 10.7 11.8 66% 1.9
Larnaca 10 11.9 12.7 63% 2.1
• The highest SF is in Marseille where heating and cooling demands are similar;
• Northern climates have low SF due to small collector size and high heating demand;
• Although Northern climates are not the best application for adsorption chillers, all the cases have PER (Primary Energy Ratio) > 1 and Solar Fraction > 60%
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Building description
CASE 3
TheBat Building (Task 44)
Number of floors 2
Living area per floor 70 m²
Yearly heating demand 45 kWh/(m²y)
Location: Innsbruck (Austria)
22
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Solar cooling plant layout
CASE 3
1. PV PV panels – 20 m² - 40 m²2. HP Heat pump – 10 kW3. DHW Domestic Hot Water4. SH Space heating5. TES Thermal Energy Storage6. TABS Thermal Activated Building
Structure
Use of PV for covering the heat pump consumption:
1. SELF consumption;2. Overheating the TES;3. Overheating the TABS;4. Overheating TES and TABS.
23
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Working conditions
CASE 3
TES charging for DHW uses
24
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 3
TES charging for space heating use
25
Working conditions
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 3
Direct space heating from the heat pump
26
Working conditions
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
SPF and HP performance at different working conditions
RESULTS – CASE 3
27
• The strategy of overheating the TES reduces the HP performance (SPFel,HP) because of the higher working temperatures;
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
RESULTS – CASE 3
28
• The strategy of overheating the TES reduces the HP performance (SPFel,HP) because of the higher working temperatures;
• Overheating the BUI and the TES+BUI increases the thermal losses;
SPF and HP performance at different working conditions
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
RESULTS – CASE 3
29
• The strategy of overheating the TES reduces the HP performance (SPFel,HP) because of the higher working temperatures;
• Overheating the BUI and the TES+BUI increases the thermal losses;
• Bigger PV field area and storage capacity reduce the used energy from the grid, but increase energy losses;
• Bigger storages do not significantly improve the system performance.
SPF and HP performance at different working conditions
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Building description
CASE 4
Multi-family house HVACviaFaçade
Location: Graz (Austria)
Number of floors 3
Living area per dwelling 50.3 m² (average)
Dwellings per floor 4
Yearly heating demand 15 kWh/(m²y) – BUI 15
Yearly heating demand 30 kWh/(m²y) – BUI 30
30
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
Layout description
CASE 4
Central outdoor air heat pump Decentralized outdoor air heat pump Direct electric heating
31
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 4 - 1
Central outdoor air heat pump
1. PV panels 189 m² - 15.75 m²/dwelling2. Heat pump 10 kW (BUI 15) – 20 kW (BUI 30)3. Buffer Tank – 1500 l (BUI 15) – 2000 l (BUI 30)4. DHW tank – 150 l/dwelling5. Mechanical Ventilation with Heat Recovery
• Maximize PV production for the centralized heat pump electric consumption;
• Use of decentralized storages for DHW uses;• Use of two set temperatures for the tanks.
1
23
4
5
32
Layout description and working conditions
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 4 - 2
Decentralized outdoor air heat pump
1. PV panels 176 m² - 14.5 m²/dwelling2. Heat pump 2 kW/dwelling3. Direct space heating from the heat pump4. DHW tank – 150 l/dwelling5. Mechanical Ventilation with Heat Recovery
• Maximize PV production for the decentralized heat pumps consumption;
• Use of decentralized storages for DHW uses;• Use of two set temperatures for the tanks.
1
2
3
4
5
33
Layout description and working conditions
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CASE 4 - 3
Direct electric heating
1 2
3 4
1. PV panels 1 176 m² - 14.5 m²/dwelling2. PV panels 2 419 m² - 34.9 m²/dwelling3. Electric heater 2.5 kW and 150 l4. Mechanical Ventilation with Heat Recovery
• Maximize PV production for self-use;• Use of two set temperatures for the tank;• Use of the roof surface for additional PV
panels.
34
Layout description and working conditions
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
SPF and SCOP
RESULTS – CASE 4
#1: Central heat pump #2: Heat Pump in each apartment #3: Direct electrical heating
35
• SCOP is slightly lower in cases with a PV field due to the higher working temperatures
• The highest SPFs are encountered in the decentralized configuration;
• However, a low energy demanding building with a big PV field has a high SPF.
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
SPF and SCOP
RESULTS – CASE 4
#1: Central heat pump #2: Heat Pump in each apartment #3: Direct electrical heating
36
• SCOP is slightly lower in cases with a PV field due to the higher working temperatures
• The highest SPFs are encountered in the decentralized configuration;
• However, a low energy demanding building with a big PV field has a high SPF.
• Self-consumption accounts for one third to a half of the total production.
• The excess of electricity fed into the grid is high in all cases, with exception of the direct heating with small PV field
Chiara Dipasquale – Modelling results on New Generation Solar Cooling systems
CONCLUSIONS• Solar driven systems can assume different configurations, from the PV coupled to a heat
pump for heating production to the integration of solar thermal collectors for decreasing thermal loads to the use of sorption chillers for the cooling loads;
• When designing a solar energy system, the solar field size is key, in fact bigger solar thermal fields can cause stagnation problems and in PV systems the self-consumption can be only a small fraction of the produced energy (20% to 30%);
• Solar technologies have good results in terms of solar fraction and SPF also in northern climates thanks to the longer winter season and the inclination of solar radiation in this period.
• The use of thermal storages can help to maximize the use of solar energy also in combination with PV systems.
37