An Integrated Approach to Optimal Energy Operations in Buildings
1. Oviedo, 27 February 2014
Paolo Michele Sonvilla
Minerva Consulting & Communication
Ahorros energéticos obtenidos con el
EnRima DSS
2. An Integrated Approach to Optimal Energy
Operations in Buildings
P. Rocha1
M. Groissböck2
A. Siddiqui1,3
M. Stadler2
1
University College London
2
Center for Energy and Innovative Technologies
3
Stockholm University
e-nova 2013 Conference,
15 November 2013
3. Background
EU policy objectives for year 2020 include:
• ↓ greenhouse gas emissions by ≥ 20% below 1990 levels
• ↑ contribution of renewable resources to EU energy consumption
to 20%
• ↓ primary energy use by 20% relative to projections
=⇒ energy efficiency of
existing buildings
must be improved
6. Lower-Level Operational Module1
• Determines operation of heating, ventilation & cooling systems given:
• thermodynamics of conventional heating & HVAC systems
• building’s physics
• external temperatures & solar gains
• internal loads
• Range for zone temperature =⇒ endogenous space heat & cooling
demand
1Groissböck et al. (2013), Liang et al. (2012)
7. Upper-Level Operational Module
• Determines sourcing of energy & operation of installed equipment
• Upper-level constraints:
• Energy balance equation:
EnergyPurchased − EnergySold + EnergyOutput − EnergyInput +
EnergyFromStorage − EnergyToStorage = Demand
• Technology capacity limits
• Energy trading limits
• Energy storage constraints
• King and Morgan (2007), Marnay et al. (2008), Stadler et al. (2012),
Pruitt et al. (2013)
8. Integrated Operational Optimisation
Model
minimise Energy trading costs + technology operation costs
subject to Upper-level constraints:
Energy balance
Technology capacity limits
Energy trading limits
Storage constraints
Lower-level constraints:
Zone temperature update & bounds
Energy flows & operational constraints for radiators
Energy flows & operational constraints for HVAC systems
9. Numerical Examples
• Two test sites:
• Centro de Adultos La Arboleya (Siero, Spain), from Fundación
Asturiana de Atención y Protección a Personas con
Discapacidades y/o Dependencias (FASAD)
• Fachhochschule Burgenland’s Pinkafeld campus (Pinkafeld,
Austria)
• Typical winter day, hourly decision intervals
• Cases:
• FMT: Fixed mean temperature
• OPT: Optimisation
10. Operating Scenarios for FASAD
• Scenario 1 (Baseline):
• Conventional heating and natural ventilation
• 1293.3 kW and 232.6 kW natural gas-fired boilers, 5.5 kWe CHP
unit
• Exogenous daily end-use electricity demand of 691 kWhe and
domestic hot water demand of 1592 kWh
• Flat energy tariff rates: 0.14 e/kWhe for electricity purchases, 0.05
e/kWh for natural gas purchases
• Electricity feed-in tariff (FiT) of 0.18 e/kWhe
• Scenario 2: Revocation of FiT
• Scenario 3: Regulation imposes that zone temperature ≤ 21◦
C
• Scenario 4: Installation of a 7.58 kW solar thermal system
11. FASAD’s Results
Scenarios 1, 2 and 4
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
−4
−2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
FMT
Time (h)
Temperature(o
C)
Estimated Zone Temperature
= Required Zone Temperature
External Temperature
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
−4
−2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
OPT
Time (h)
Temperature(
o
C)
Lower Limit Temperature
Optimal Zone Temperature
Upper Limit Temperature
External Temperature
15. Operating Scenarios for Pinkafeld
• Scenario 1 (Baseline):
• Heating and HVAC systems
• 1.28 kWp PV system
• Exogenous daily end-use electricity demand of 543 kWhe
• Flat energy tariff rates: 0.15 e/kWhe for electricity purchases, 0.08
e/kWhe for electricity sales, 0.08 e/kWh for district heat purchases
• Scenario 2: Installation of a 100 kWp PV system & availability of an
electricity FiT (0.18 e/kWhe)
• Scenario 3: Change to a time-of-use (TOU) electricity purchasing tariff
(0.16 e/kWhe at 7:00-14:00 and 17:00-20:00, 0.15 e/kWhe at
14:00-17:00, 0.14 e/kWhe otherwise)
• Scenario 4: Installation of a 75 kW solar thermal system
16. Pinkafeld’s Results
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
−4
−2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
FMT
Time (h)
Temperature(o
C)
Estimated Zone Temperature
= Required Zone Temperature
External Temperature
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
−4
−2
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
OPT
Time (h)
Temperature(
o
C)
Lower Limit Temperature
Optimal Zone Temperature, Scenarios 1−3
Optimal Zone Temperature, Scenario 4
Upper Limit Temperature
19. Summary
• Short-term building energy management model consisting of
upper- and lower-level operational modules
• Evaluated using data from two EU test sites and plausible future
operating scenarios
• 10-30% ↓ space heat demand and associated CO2 emissions
• 5-7% ↓ overall primary energy consumption
• Reflects load-shifting behaviour
• Future work:
• Multi-criteria objective function
• Further policy insights