IBCs for Espalier?

I am planning a new home orchard on the border of USDA hardiness zones 5a and 4b (one block into the 5a side). I've got a brilliant southern exposure but I'm looking for additional ideas to keep zone 5 fruit safer. I'm also keen to keep these trees on the smaller side for easy hand-picking and will be building things solo. I will definitely be emphasizing hardier varieties, but... peaches, I NEED them.

So my idea is to use IBCs for an insulated wall on the north side of these trees, two on two for an 8 x 8' garden wall behind each tree. I can place the IBCs by myself and fill them in place. I can use the aluminum cages as the trellis for training espalier. Espaliered trees can be kept smaller/denser. And the water inside the tanks can collect thermal energy from the sun to keep the trees warmer overnight. I can paint the liners black to increase thermal collection. I can use antifreeze in the tanks or a pump/heater for winter. Or, if I keep the water pure, I could use these as rain barrels to irrigate the trees/guilds around them. I don't hate the industrial look of IBCs already, but I also think that they'd be pretty covered up by the trees in 4-5 years, so the appearance isn't an issue for me.

I'll be clearing trees from this land for the orchard and I'd like to keep them/use them right there. I will also be digging a pond. I could use the cleared trees and the dislocated pond soil to build (tall!) hugel berms around the IBC walls for insulation (also maybe decomposition heat for a few years?) and for growing surface for the other guild plants. The wall would also be a convenient thing to hang a tree cover from if the weather looked especially bad. I could build the walls "flat" for full-on southern sun or I could angle them to create a sort of V-shape for more protection from the winds (NW prevailing in winter).

My hypothesis is that having a solar/thermal wall behind my trees with warmer needs will help them through the harsher winters. Am I on the right track? Any ideas or advice? Alternatives?

The first thing that comes into mind for me is the weathering on the totes. What is the expected lifespan you are hoping to achieve with these?

I have heard of well protected totes lasting a while, I've heard of them springing leaks at around five years in the worst of weather. Water would be less of a hazard compared to something like antifreeze so there is that.

I think that has lots of promise.  Pending how long the totes last with freezing/thawing stresses.  Maybe if the trees could be detached from them the totes could be replaced if they leak?

Additionally, you could turn them into a crude "Chinese Greenhouse" for the coldest month of the year if you wanted (duckduckgo that term).  

If wind is a problem, Ving them could be worthwhile. But you'd end up with a gap at the corner of the V which might let more cold in.  Actually, even if they're butted tight to each other, there will be a gap for wind to come through.  Maybe filling any gaps with leaves would help...  And actually, to get any real wind protection from a V, I suspect it would have to be a relatively tight V (90 degrees?) and then the totes would block some sun early and late in the day.  

For anyone who doesn't know what IBS totes are, they're these big square tanks:

I'm concerned about the longevity of the IBC totes, both the cages (galvanized steel) and the tanks (HDPE ?). Rust and freeze-thaw cycles of the tank might breakdown the cage; and sunlight, freeze-thaw, animal/rodent chewing, or accidental physical damage might cause the tank capacity to diminish or fail altogether. Paint might help both parts, or a known UV stable covering might help the tank.

I also wonder about using water as the thermal mass, in an outdoor situation. I've only seen it used indoors in a greenhouse or a solarium attached to a house, where the tanks presumably are not subject to freezing. Aside from the physical stress that it will cause, once it is frozen to ice, it will have the reverse thermal effect being an enduring source of cold that, due to the phase-change occurring, will also take more energy to thaw than something like stone, earth, concrete, or brick.

On the other hand... that cold could be beneficial? in a recent year (last year?) here in Massachusetts, the peach crop statewide was lost due to an unseasonably late frost which damaged the peach buds. Maybe the case of breaking dormancy too soon is something to consider... I'm not sure that was what happened here, but with climate changing and becoming more unpredictable, maybe a buffering effect could help?

In France they did this sort of thing just with brick or rock walls. What about removing and recycling the plastic, attaching some wire to the remaining "cage", and filling it with rocks or soil like a gabion?

I think totes are liable to outlast your trees.
The steel is galvanized and the plastic is thick enough to hold a large man's weight.

I echo the concern about early blooming.
Sean, from Edible Acres just posted a video where he speaks about using pines to sheild peach trees from the low winter sun thus preventing early budding.
He also mentions a  siberian peach tree variety.
He is also in zone 5:

Court said, I can place the IBCs by myself and fill them in place.

I see some pros and cons.

During the summer the IBC would be a good source of water.

Would a frozen block of ice (IBC) do you are wanting the IBC to do?

What about a wall of straw? Similar to Jay`s suggestion of brick or rocks.

In summer the straw could be used as mulch.

The aluminum is highly conductive of temperatures. I would use wood to train the espalier trees as whatever you use will make physical contact with the tree.

Another thought is to consider the lay of your land. Valleys collect colder air and take longer to warm up in the daytime. On my property I’m fortunate to have the western border adjacent to a logged tract of land, so I get a good amount of afternoon sun. The eastern side adjoining property is wooded and also a valley, so that stays cooler. I’m doing my gardening on the western side.

In my professional horticulture studies I’ve come to understand the power of afternoon sun can double the milder power of morning sun. In the morning the sun’s rays run parallel to the earth’s surface. In the afternoon the suns rays are perpendicular. We all feel the difference between morning sun and afternoon sun.


Edit: Meant to also suggest to buy from local stock or a similar climate. The study of epigenetics suggests that plants (and animals as well) carry a genetic history that is unlocked at seed germination and improves local environmental adaptations.