Page 76 - Build 152

Technology
concept. Initially an air conditioning (AC) unit, without night ventilation, was used in both huts to charge the PCM during low peak periods, showing very little savings in electricity.
However, when night ventilation was used to charge the PCM instead, weekly electricity savings of 73% were achieved (see Table 1).
Need to use the right scenario
Computer-based simulations of a typical New Zealand home construction were performed using the simulation software Design Builder and Energy Plus to show the bene ts of using PCM in real homes. Both energy savings and comfort were assessed.
By varying the heating set point and the phase change temperature of the PCM, signi cant bene t could be observed.
Some poor scenarios show that the integration of PCM can increase both the
discomfort by up to 6% and the energy requirements of up to 25%. On the other hand, appropriate scenarios bring signi cant energy savings of up to 33% and comfort enhancement of up to 31%.
Good design is necessary
This highlights the need for clever design when integrating PCM into buildings. The goal is to nd a trade-o between energy savings and comfort enhancement. The PCM
with a phase change temperature range of 21–26°C shows the best results.
Our analysis also showed that the pay-o period could be as long as 15 years if PCM is not used wisely. However, this could be reduced to less than 5 years if the PCM quantity and the location where it is used are optimised.
For more Visit www.engineering.auckland.ac. nz/en/about/our-research/energy-research/ phase-change.html.
Table 1
Energy and electricity cost saving achieved using night ventilation system
DAY 2
DAY 3
DAY 4
DAY 5
DAY 6
DAY 7
DAY 8
TOTAL
Energy saving
57%
64%
55%
48%
83%
92%
76%
73%
Electricity cost saving
67%
34%
58%
52%
85%
93%
73%
67%
Here’s
a top deck
solution
Deck Joist Fixing
AlternAtive solution
to clAuse 7.4.1.3 nZs 3604:2011 Provides the required xing between the deck joist and boundary joist to suit a cantilever baluster system
Trade Pack of 50 stainless steel cleats and 250 corresponding screws
74 — February/March 2016 — Build 152
FEATURE SECTION