8/6/2019 Cold Storage Poster

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THE STORAGE OF COLD - LASTING COOL BREEZE THAT DOES NOT COST THE PLANETPeter Hou, ANU CECS Solar Thermal Group, peter.hou@anu.edu.au. Supervisor: Mike Dennis

Most of the building cooling systems use grid-supplied

electricity, and are designed to meet peak demand. With more

buildings built every year, this has put enormous pressure on

the electricity supply network.

Solar cooling technologies are promising in terms of reducing

pressure on the electricity supply network, and cuttinggreenhouse gas emission. However, current systems have little

capability to handle cooling demand when solar energy is not

available (e.g. night time).

Storage is Natures way of Balancing

Supply and Demand.It is intuitive to think that the above issues could be addressed

by devising a storage of cold as a reservoir of coolingcapacity, just like using battery for electricity. In fact, such

systems have been commercialized decades ago. However, the

technology is still evolving and there are unsolved problems, and

fundamental questions to be answered.

Figure 1: Ice storage system at a university campus in the U.S.

Water and ice are the most commonly used storage media,

they are cheap, non-toxic, and compatible with most existing

systems which require minimal retrofitting. But liquid water has

inherently low energy storage density, which require larger

storage to achieve required storage capacity. Ice melts and

freezes at 0, meaning the chiller have to work under lower

Coefficient of Performance (CoP) when charge the storage.

Other studied storage media such as paraffin wax and salt

hydrates also have properties limiting their application.

Clathrate hydrates is a promising candidate that tick more

boxes than other materials as storage media, but has not yet

been sufficiently studied.

Figure 2: Left: R141-b clathrate hydrate produced at ANU

Right: TBAB hydrate slurry produced by JFE Engineering

Research Questions:

1. When and where do we need cold storage?

2. What is most suitable selection/design?

3. How assess the value of a cold storage?

4. What is the best cold storage for solar cooling?5. What are the fundamental properties of gas hydratecomplexes, and how could they help in developing coldstorage technology?

To Answer the Questions - an

Engineering Approach

Computer Simulation: TRNSYS models could developed andused in evaluating the performance of various thermal storage

configurations, to help answer question 1 to 3.

There are a number of potential integration points

for the cold storage, under a given external

condition, which one works the best?

Experimental Study: Prototyped cold storage will bestudied in details regarding:

charging/discharging rate;

heat/mass transfer properties;

thermal cycling stabilities;

chemical stability/corrosivity

If things go well, an experimentally tested cold

storage module could be integrated with a solar

cooling system soon!

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