Exergy

Thermal Storage Build Log Overview

The first Thermal Pig.
The first Thermal Pig.

We’re not quite sure how it got its name, but the thermal pig is the device that stores the heat generated during computation. Acting much like a hot water heater, this unit gives us the ability to test Henry in an environment representative of a typical house.

The Beginning

We started with two, five gallon buckets and 20’ of copper tubing to make the heart of the thermal storage system. The copper tubing wass wound in concentric, equidistant circles and zip tied in place. The buckets were then fitted atop a modified furniture dolly to make the system portable.

The equipment in its aluminum enclosure.
The equipment in its aluminum enclosure.

A layer of Mylar was laid on the base of the dolly along with 2½” thick slabs of insulating foam. The tops of the buckets were then insulated with ½” foam and sealed with duct tape. The buckets are then wrapped in several layers of fiberglass insulation. The entire assembly was then covered with heat reflective Mylar.

A CPVC plumbing system was configured with check valves and high temp silicon hose to control coolant flow. An aluminum cover was designed and sent off to Chris Paulsen for fabrication.

The aluminum cover and a power supply were mounted to the furniture dolly and access ports were drilled to allow connection of the electrical and hydraulic systems. Finally, we added a logging watt meter to measure energy consumption.

Our new tanks and fittings.
Our new tanks and fittings.

The Test

After several months of testing at temperatures up to 180°F we decided to inspect the unit, and unfortunately, the high temperatures had compromised the tanks.

The heat was so high that it softened the CPVC piping we had used to construct the loop. To fix this, we swapped in sealed steel tanks with copper fittings and high temperature silicon hoses.

The new tanks regularly see temperatures of up to 200°F during testing and can withstand up to 15 psi at those temperatures.


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