Title: Use of Phase Change Materials for Thermal Comfort and Electrical Energy Peak Load Shifting
1Use of Phase Change Materials for Thermal Comfort
and Electrical Energy Peak Load Shifting
U21 International Conference on Energy
Technologies and Policy 8th to 10th September
2008, Birmingham, UK
- Mohammed Farid and Nahidh Mecaial
- Department of Chemical Materials
EngineeringThe University of Auckland, New
Zealand
2Why Thermal Storage?
- How heat is lost from buildings?
- What is thermal energy storage (TES)?
- Why do we want to increase thermal mass of
buildings? - How can thermal energy be stored?
- Why do we use phase change materials (PCMs)?
- How do we use PCMs (micro and macro
encapsulation)? - Demonstrating the benefits of using PCM.
3Percentages of heat losses from ordinary homes
(EECA, 2004)
4Thermal Mass of Buildings
- Do we improve buildings insulation only or do we
need to increase their thermal mass ? - How can we increase thermal mass of buildings
without going back to the heavy construction used
in the old days ?
5Heavy thermal mass construction Egyptian
mud-brick rooms, 3200 years old
6Phase Change Materials
- What are the phase change materials (PCMs)?
- How do they work?
- How can they be encapsulated in building
materials?
7Phase Change (melting and solidification at
almost constant temperature)
8Energy density of thermal storage materials
(Rubitherm, 2003)
9THERMAL MASS OF PCM-GYPSUM WALLBOARDS (PCMGW)
10FULL-SCALE SIZE TESTING FACILITY
Schematic plan view of outdoor full-scale
test-rooms
11North-facing test rooms
CONSTRUCTION
12THEORETICAL ANALYSIS AND SIMULATION
Table 1 Thermo-physical properties of the mass
types
Siding
Insulation
External Side
Internal Side
Table 2 Thermo-physical properties of the PCM
Gypsum Boards
Wood
13USE OF THERMAL ENERGY STORAGE IN SUMMER FOR
THERMAL COMFORT
14Solar radiation and wind speed measurements
(1st to 8th of January 2007)
15Ambient and indoor rooms temperatures (1st to
8th of Jan., 2007)
16Simulated inside rooms temperature (1st to 8th
of January 2007)
17USE OF THERMAL ENERGY STORAGE IN WINTER FOR
CAPTURING SOLAR RADIATION AND SHIFTING HEATING
LOAD
18Measurements of Solar radiation and wind speed
(18th to 21th of July, 2006)
19Measured Indoor rooms temperatures (18th to 21th
of July, 2006)
20Simulated indoor rooms temperatures (18th to
21th of July, 2006)
21Solar radiation and wind speed measurements (17th
to 22th July, 2008) Heating systems (1am to 7
am), (850W)
22Measurement s of rooms indoor temperatures
(17th to 22rd July, 2008) Heating systems (1 am
to 7 am), (850W)
23Measurements of solar radiation and wind speed
(29th July to 3th August, 2008) Heating systems
(5 pm to 11 pm), (850W)
24Measurements of indoor rooms temperatures (29th
July to 3th August, 2008) Heating systems (5pm
to 11 pm), (850W)
25Effect of PCM quantity used Simulation of indoor
air temperatures
26Effect of PCM melting point Simulation of indoor
air temperatures
27NUMBER OF SUMMER DAYS BENIFITING FROM THE USE OF
PCM
39 full utilization 55.5 partial utilization
5.5 no utilization
28CONCLUSIONS
- Building materials impregnated with PCM
efficiently smooth- out daily temperature
fluctuations. It leads to a healthier interior
spaces with more pleasant temperatures. - Use of PCM-building materials can reduce heating
or cooling cost by using strategies of peak load
shifting. - PCM-building materials could be installed with
the same technique and equipments used for
conventional building materials. - Micro or macro encapsulation of the PCM is
necessary to prevent PCM leakage