Boyd Solar’s new Shop

Updated on February 16th 2010        All moved in

Our new shop has been getting a fair amount of attention lately and probably for good reason. What sets this building apart is the fact that there is no back up heat source or secondary heat source that burns any fuel what so ever. This building has a Gross Zero footprint, or put another way, a zero emission building. Using only energy from the sun to support our working power and keep us warm, the idea from the beginning was to construct a building to showcase what can be done through energy efficiency and renewable energy. This shop will continue to demonstrate like the rest of our facility that, even in our climate, a building can be totally powered and heated by solar energy.

We do have to say that the goal of this is a comfortable assembly and office space, not just a stay above freezing situation. To prove that a commercial building or home in the same situation, so long as the building design is suitable can be solar heated this far north.

So How does it work?

The pressures to do customer commitments rather than our own pushed our project back deep into the winter. It was not until the second week of December we could call the building “Tight”. Through the end of November and early December we worked feverishly to complete the sealing and insulating the attic was just about the last thing to get done.

When we finished this stage the interior had dropped to a mere 1c, not bad considering outside temperatures were -16c to -25 and you could look out the gaps in the large door since no seals were installed yet. No insulation in the attic also gave us the energy efficiency of a Victorian cottage, and the heat loss showed.

A revised insulation design in the attic has proven to be incredible, with higher R value than the original design.  Attention to detail on sealing and secondary areas completed the cocoon. Still we do not have a TES which should be working by fall (it would do no good now since it would not be heated)

So the big question is, does it work? It certainly does. We expected the design to do well and it does but it actually seems to be performing better than we had estimated in our design study.

Considering that: With no stored heat the interior was 1c on Dec 10th, by Dec 28th we had risen to 9c and with ups and downs with cloudy times has continued to rise slowly since.

Also:

• Other than 5 sets of vacuum tube collectors there is no other heat source
• The early December weather was colder than usual and there was no stored heat in the TES to buffer it. There has been little clear sky this winter compared to most through this Nov- Dec period, and we were loosing heat through this time.
• Most importantly we are now gaining temperature and heating the thermal mass of the building in the shortest days of the year

We are starting to compile data and will use that towards the next generation of our customers buildings.

More Details

The shop is totally heated by 5 evacuated tube solar collectors and powered by 16 – 130 watt solar modules.

The construction is Logix brand ICF (insulated concrete form) with an additional 3” of EPS Type 3 (Expanded Polystyrene) on the outside.

There is 3” of EPS Type 3 under the slab . One section under the slab will has a “double bubble” reflective foil type of insulation instead of the EPS to test the effectiveness of each.

There is 3” of EPS Type 3 under the trusses, this styrofoam insulation will minimize convection losses, and one section of it also has “double bubble”under the EPS for test purposes. other combinations of insulation above complete the R-100 plus barrier.

To minimize winter heat losses into the ground, a dump loop from the solar collector heats the ground around the perimeter of the shop in the summer and anytime there is excess heat available. A second loop is placed low on the inside of the frost wall to heat the ground under the slab for the same purpose.

Thermostatic probes will be able to monitor the temperatures in the following places

• Inside the building on the wall
• Between the ICF insulation on the inside and the concrete
• Between the concrete and the outside ICF insulation
• Between the ICF insulation and the extra 3” of EPS on the outside
• Outside air
• Close to the footings on the outside of the building
• Close to the footings on the inside
• Under the EPS that is under the slab
• Under the “double bubble” under the slab
• Between the “double bubble” and the slab
• In the slab above the EPS
• In the slab above the “double bubble”
• Just under the ceiling
• Between the “double bubble” and the EPS under the trusses
• Between the EPS and the blown in insulation
• In the Attic space above the insulation

The thermal output of the double wall evacuated tube collectors is being logged to provide accurate data for this location.

All design, controls and equipment are specified and installed by (of course) Boyd Solar corp.

Although a new construct, the building does use used materials where possible, for instance the steel siding was recovered from a renovation of another building, which would otherwise have likely gone to the land fill.

Is it worth the extra cost and effort?

Especially with renewables, this effort is easily rewarded. Looking at the charts at the bottom shows us that we would need a heating system more than 3 and a half times the size to heat an identically sized building built by conventional construction.

We will use 5, 30 tube collectors (double wall evacuated tube collectors), a conventionally constructed building would need 16. That difference would add more than $60,000 to the heat collection system, increase the complexity of the system and create the problem of where to put all those collectors. The extra cost of upgrading the whole building, was approximately 1/4 the cost of adding the additional collection.

This picture shows the extra 3 inches of insulation over the ICF blocks. The south face of the roof is angled so the collectors and PV panels mount directly.

This heat loss pie chart shows the calculated heat losses as per our MC4 heat loss calculation software for our location. (based on .3 air changes per hour) 8437 BTU heat loss

Now compare this to a conventional building exactly the same size with the same door and window sizes