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.

[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.

[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

[Daox]

If you move your man door to the west wall, you could open up some solar space. Maybe even just for a passive solar hot air collector.

[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.

[randen]

Bennelson

Congrats on your decision for the construction on your man cave. It looks like a beautiful project. Forgive me but which EV are you currently driving???

If you would like I would strongly suggest HEATED FLOORS. I've installed and live with 2 systems. The first is at my shop in the office, lunch room area. If you have been following my posts its heated with my DIY Geo-thermal HP. Its working extremely well.

The second is in my home heated with SOLAR HOT WATER and backed up by Geo-thermal. Some seasons 1/2 my space heating is FREE from the sun. And you can't beat, free.

Heated floors are the holy grail. They are sooooo comfortable.

Now you have a few options. It looks like PV is your 1st choice EXCELLENT. With the prices and equipment that is now available, awesome. TESLA power wall comes to mind. OH did you see the unveiling of the PV shingles.

Another option is Solar Hot water heating your floor. for your application this maybe a great fit. It may keep your space comfortable all the time at no cost!!! 50-60 deg. The floor will stay warm for about 4 days without sun. (6" of concrete and well insulated)

To go hand in hand add a small mini split if you need a little boost of heat AND in the summer air conditioning. This can be powered by your solar PV.

The option to build your own air to water heat pump is entirely do-able but its a lot of work and to get all the parts to play nice is daunting at times. The thought to try a direct exchange to concrete had crossed my mind.

IMHO it would be best to stay away from a utility bill. The technology is here that will prevent that bill from arriving. Your already ahead of the curve with your EV. I'm thinking you really enjoy driving by the gas-station.

Randen