Ben's Garage

[bennelson]

Hi folks!

After thinking about it for years, I finally have the money and other requirements to rebuild my garage. If you've seen my various videos of working on electric vehicles, etc., you've probably already seen my garage, the fact that it is uninsulated, roof leaks, and there are giant cracks everywhere in the concrete.

So, it's time to build a new garage. The new garage will be fairly traditional construction BUT will have a Pex heated slab, plenty of insulation, and a metal roof with solar panels.

The first step was emptying the garage. Not an easy step, as my house has no basement, and one bedroom doesn't even have a closet. I'm at a bare minimum for storage space. The new garage will be larger than the current one, and give me some warm winter workshop room and storage space.

Now on to the fun step. Destroying the old garage. We just did this yesterday. We got a construction dumpster, and my brother stopped over. In one day we tore down and completely removed the existing garage.

Please enjoy this silent film style video of us tearing down the garage. Future updates to come as the project advances.

https://www.youtube.com/watch?v=jZBrN8pV1mw

PS: To charge my electric car, I rewired my garage breaker panel to the back porch. The EVSE (car charger) cord reaches from the porch to the driveway.

[pinballlooking]

Nicely done.
I like the video.

[Daox]

Wooo, very cool Ben. I know you've been wanting to do this for years now. Glad to see progress!

[bennelson]

Here's some more info on what I'm planning.

The garage will be 27' x 29'. Unfortunately, the county won't let me build more than 18' high, so that limits my roof angle and upstairs storage space.

I'm planning on hydronic heat in the concrete slab. I haven't decided for sure the exact details of what to heat with. I'm leaning towards an electric micro-boiler. That could be set on a timer to use "off-peak" electricity for heating.
I would cast 1/2 PEX in the concrete during the pour. 2" of foam insulation around and under the slab.

The roof will have solar panels over a standing seam metal roof. I should be able to fit 21 panels (3 rows of 7 panels each) in the 250-280 watt size on the due-south facing half of the roof, and make a roughly 5KW PV system. I'm planning on using Enphase micro inverters for simplicity and nice monitoring.

The garage will also have power for electric car charging.

Walls will be traditional "stick-building" as it's affordable and easy to do myself. Fiberglass insulation with a little foam on the outside of the sheathing.

Here's a still image of the plans as they are right now. Solar in the image is NOT to scale, only there to give a rough idea. Details of concrete slab is still to be determined. I need a slab design that holds up to my weird ground-water movement, but can also be insulated so it can be heated.

I'm located near Milwaukee, WI. The point of heating is to have a workspace that's comfortable to work in in the winter. That means it does NOT have to be heated to 70 degrees. I mostly want to work without wearing long underwear and a bulky coat. 50 degrees in a garage is pretty luxurious when it's 10 degrees out otherwise.

[bennelson]

Another thing.

I'm also planning on adding a glazed door to one of the two garage doors so that on a sunny winter day I can open the garage door and use the entire doorway for passive solar gain.

It's this idea: Solar Workshop or Studio

I would do one of the two doors so that I could still actually get a car in and out of the garage. We have two cars. I could park one in the driveway, or, I think that with the extra space in the garage that I could pull in through the one door and still maneuver to the next space over. We would just park the more fuel-efficient car in the handy space, so that car was always the first one used.

[dh1]

Originally Posted by bennelson

Here's some more info on what I'm planning.

The garage will be 27' x 29'. Unfortunately, the county won't let me build more than 18' high, so that limits my roof angle and upstairs storage space.

I'm planning on hydronic heat in the concrete slab. I haven't decided for sure the exact details of what to heat with. I'm leaning towards an electric micro-boiler. That could be set on a timer to use "off-peak" electricity for heating.
I would cast 1/2 PEX in the concrete during the pour. 2" of foam insulation around and under the slab.

The roof will have solar panels over a standing seam metal roof. I should be able to fit 21 panels (3 rows of 7 panels each) in the 250-280 watt size on the due-south facing half of the roof, and make a roughly 5KW PV system. I'm planning on using Enphase micro inverters for simplicity and nice monitoring.

The garage will also have power for electric car charging.

Walls will be traditional "stick-building" as it's affordable and easy to do myself. Fiberglass insulation with a little foam on the outside of the sheathing.

Here's a still image of the plans as they are right now. Solar in the image is NOT to scale, only there to give a rough idea. Details of concrete slab is still to be determined. I need a slab design that holds up to my weird ground-water movement, but can also be insulated so it can be heated.

I'm located near Milwaukee, WI. The point of heating is to have a workspace that's comfortable to work in in the winter. That means it does NOT have to be heated to 70 degrees. I mostly want to work without wearing long underwear and a bulky coat. 50 degrees in a garage is pretty luxurious when it's 10 degrees out otherwise.

You might want to rethink the shape of your garage, especially the south wall.
Something like this might work better for you. House heating Solar Shed -- homemade collectors

[bennelson]

Originally Posted by dh1

You might want to rethink the shape of your garage, especially the south wall.
Something like this might work better for you. House heating Solar Shed -- homemade collectors

There are a number of limitations imposed on me by the size and shape of my property, as well as by the county in which I live.

The garage doors need to be on the south side, as that's where the driveway is. The corner of the garage was already on the property line, and I needed special permission (and permits, and stupid meetings, and $$$$) just to be able to rebuild the garage where it was. I was also limited by the county board on how tall I could build the garage.

So, yes, I certainly have considered different shapes. I also considered a gambrel roof and some other options, all of which had negatives as well.

Moving the man door to around the corner would have been a possibility, but I do like the look of where it is. Also, the main electric breaker panel will go right in that south-west corner. My parent's garage has the layout of a man door around the left corner, and it's NOT a great design, it ends up making the corner less usable. I don't think that door on their property has been opened in 20 years. Also, my property is on a bit of a slope. If the door was on the west side, it would be a BIG step down out of that door. At a bare minimum it would need a concrete stoop, and I'm already building to the west as far as the county will let me.

The big upsides of what I am able to do are:

1) Rotating the roof 90 degrees. The old roof faced east-west. The new one will face north-south. The south-face really does face nearly due south - perfect for solar.

2) The garage will have an upstairs. We will be using "storage trusses" which leave a space down the middle. It will be a little over 6'6" tall (which is good because I'm 6') and about 4' wide on the flat of the ceiling, with lower storage space on either side of that.

3) It's bigger. The new garage is 5 feet wider and 7 feet deeper than the old one. This gives me storage space, so that I can for example store my riding lawn mower indoors, instead of in my yard, and have space for workbenches and tools.

4) Heat and insulation
The old garage was completely uninsulated. I could literally see daylight through the siding. Simply insulating that structure wouldn't have made sense. It was falling down. I experimented with heating. What worked best was using some old TV Studio lights - 1,000 watts each, as radiant heaters. As long as they were pointed right at me, they worked pretty well. They really didn't heat the garage, but as long as they were pointed at me, I stayed somewhat warm. Still not ideal, especially depending on the outdoor winter temperatures.

Lastly, as far as solar-thermal goes, because the garage doors DO face south, I'm planning on building some glazing for one of the two doors, so that on a sunny winter day, I can open the garage door and use it as a giant picture window, letting the light in.

[dh1]

I was just thinking that if you could change the angle of the roof so whatever collectors you put up there would be more efficient.
Rotating the roof to catch the sun from the south would do it.

[Daox]

Does anyone have any good info on using an air source heat pump to heat hydronics? I was talking with Ben the other day about this and he hasn't been able to find any good info. I know we have a bunch of people doing heat pump water heaters, but this is a bit different.

[jeff5may]

Originally Posted by Daox

Does anyone have any good info on using an air source heat pump to heat hydronics? I was talking with Ben the other day about this and he hasn't been able to find any good info. I know we have a bunch of people doing heat pump water heaters, but this is a bit different.

Building your own out of what have you is not impossible. AC Hacker, Randen, and Aquario all have discussion threads detailing their custom builds. The general principles used in the smaller units remain the same, but instead of using a portable or window unit, you would be using a larger outdoor ASHP unit with defrost control. For the condenser, you could run a buffer tank with a submerged heating coil in it, or a refrigerant-to-water heat exchanger with or without a buffer tank.

The major manufacturers all offer air-to-water heat pump systems now. The main two types of systems are monobloc (packaged, single unit with water pipe/hose connections) and split (separate indoor and outdoor units). Some of the bigger name brands are listed here:

Daikin Altherma

Maritime Geothermal Nordic ATW

Fujitsu Waterstage

Panasonic Aquarea

A new technology being used in some of these systems is generically known as enhanced vapor injection (EVI). The term describes a new compressor design that has 3 ports instead of 2: suction, injection, and discharge. The injection port is used to add cool vapor (at intermediate pressure) at a certain point inside the compressor. This has the effect of increasing the capacity of the compressor at high compression ratios without wasting energy or overheating the compressor. This is especially useful when heating during frigid outdoor conditions, where the low suction pressure needed to run the evaporator effectively limits raw BTU output.

EVI heat pump technology


EVI technology is kind of like the polar opposite of VSI (variable speed inverter) technology. A VSI compressor changes the speed of the compressor to match the heat load, saving energy by lowering the compression ratio and power draw (when it is running slower). An EVI compressor boosts the output of the compressor by feeding itself higher suction pressure. The newest compressor designs include both technologies, and the manufacturers are really talking up the performance of these new systems.