Earthship/Solar gain greenhouse

What I've noticed is that alot of earthships have the green houses and they have another glass wall or partition from the green house to the living quarters. Any info??

Mark
If you watch the videos put out by the esrthship corp, on the design of the earthships, i believe you will find the answers you are looking for.

Thank you

Also any body have opinions on the issue?

Not exactly sure what youre asking about Mark. There are several things in the Earthship passive solar design book that go against mainstream passive solar thinking. The non-vertical glass is the biggest but I think they are getting away from that detail (finally). I personally dont agree with the separate partitions either. I think Homes should be separate from greenhouses altogether.

earthbag houses have double pane walls, the same reason why regular house have double pane windows. Insulation.

I'm looking for opinions from peoples knowledge or experiences concerning greenhouses connected to a house such as an earthship. With or with out the window partitions separating the greenhouse and living quarters

I would like to hear the reasons to mingle green houses for plants and green houses for humans because all I can think of is why it may not be a good idea. I think the best reasons are that plants tend to clean the air and generally make people feel better. The biggest drawback has to be humidity. Generally, plants need higher humidity and create higher humidity in big numbers which isnt really a good thing for our dwellings in most cases.

You cant really grow enough food to be meaningful in something the size of an earthship sunroom. That leaves us with houseplants. It could be argued that homes could handle or even benefit from the extra humidity on the West coast but not here on the East.

As to air quality, having houseplants should come far behind building airtight and providing mechanical ventilation; fresh air introduction with outdoor air.

There could be an entire discussion on the types of houseplants that would do well in an earthship style sunroom. I have been in some really cool homes that have built in planters throughout the home instead of loaded up on the South elevation. I think that planters like that tend to be plagued with problems from leaks, cleaning to excess humidity. Most of them end up being abandoned.

I feel separate partitions create more problems than they solve. The whole idea of passive solar design is to heat your home. Partitions are not necessary in a proper passive solar design. They are added to sunspaces to try to solve issues created by bad design. Maybe in that respect they can be helpful but if youre designing properly from scratch why would you need them?

Thank you for the reply. I am taking all informations into consideration.

The interior glass wall in an Earthship should not reduce the solar gain; any reflected or absorbed energy will still be contained within the structure. The addition of this wall is simply a compromise to maintain the comfort of the living spaces while having an attached greenhouse.

Is an attached greenhouse ideal? Probably not. The main reason it is there is for the "feeling" that you are living along with your plants. The fact that the greenhouse is far, far, far too small to actually PRODUCE the food you would need to live there usually falls on deaf ears, as well as the fact that you have to make compromises between people comfort and plant comfort....

I think ideally the greenhouse should be seperate, and probably 10-20 times as big as in the Global Earthship model. (If you really want to laugh look up the specs for the "survival" model. Can you survive on 90 square feet of planting space?)

To be fair, though, Earthship design history has all been trial-and-error. Michael Reynolds is an architect, not a systems engineer. So, chances are good that there are improvements still to be made!

Thank for the reply. Ok here's what I have concluded so far. Green house attached to the house such as the earthships great got solar gain. It would be especially useful in the northeast climat that I am in. Any less heating fuel(oil/wood/electric) I would have to use is a plus. Next the green house as a food source. What my idea was just to have little herb garden maybe a few ornamental plants. It wasn't something I wanted to have to depend on for a main food source. I love the outdoors. but I I did want to find out what it is capable of. I could still start my seedlings in there but I realize what I was originally looking to do with it(herbs and ornamental) is about at it's capabilities. Major problems I came across are- leaky windows that were slanted or set at an angle, high moisture in the house, work and or material value versus actual output and fictionality of the greenhouse attached to the house similar to earthships.Benefits- huge supply of solar gain yr round, grey water recycle to water plants, fresh herbs yr round, entertainment esthetics.

To be fair, Earthship designs that you can buy need to be as generic as possible. They are there to help streamline getting a permit. IMHO for a structure to work right it needs to be customized not only for your climate but also your topography and terrain! (Maybe even availability of local materials)

Slanted windows are a bad idea in wet climates. Michael Reynolds admits this in Comfort in any Climate, but you can't expect custom plans to be available for every possibility! You can, however, look at different things that have been created around the world. The Earthship built in Haiti, for example, looks nothing like a Global model.

If you have the coin to drop, Earthship Biotecture (tm) will build you a completely custom Earthship. Or, you can do the design yourself, and pick and choose what options you like from Earthship construction versus other methods of sustainable construction.

I am actually still in the "finding-the-right-bit-of-land" stage, and I am leaning toward a plot of land with a south-facing hillside. This would allow me to build a house (using Earthship design principles combined with permaculture principles) with a living space and one or more large greenhouses on stepped terraces. This way I could still have grey and blackwater recycling (and more roof space for rainwater collection), with a much larger greenhouse area that is semi-attached to the house. (Semiattached in that thermal mass is shared, but not air)

I love living with my plants. The slanted windows even in a dry climate (arizona) are a bad idea. Nor am i really fond of the opening skylights. Also there is a reason the house should be facing south...not south west, it is too hot in the summer. The only problem in the winter in a cold climate would be too much solar loss. It can get to -10 or lower here. As long as we have sun it is ok. But when the sun goes down at night, for comfort, we still need extra heat.

I can grow sweet potatoes inside that shade the windows in the summer. But like with green houses the pests get in aphids, snakes, roly poly bugs and lizards. Now the green house idea is my next one. I think I want to do aquaponics also. We shall see. I have no idea why micheal did the double window thing...not the double pane but the double walls. I would imagine that it would still get hot or humid depending. I keep trying to convince my husband to redo the front wall so we have vertical windows and could either expand the greenhouse area out or get rid of the fogged windows. But it falls on deaf ears. So maybe I will have to build a separate green house.

Thank you for the reply amber m.

i was always under the impression that the wall between the greenhouse and the peoplehouse is a newer idea as originally all of the earthships had grow spaces within the home (ie no partition).

i believe this new style allows the "greenhouse" to heat up as usual. but the glass partition, which has windows into the home, can be used to heat the house. in the event that the house is hot enough, there are vents on top of the greenhouse that can be opened to vent hot air away.

in short, it allows more precise temperature control to help with overheating in hotter cimlates

i have also read reports of condensation/humidity issues in more humid climates, so this may be to help with that.
It may also be done for privacy as well since most earthships are of the open hallway design.

here is a picture of what Mark is referring to:

Thanks Kelly....Sigh....I wish that was how our earthship is but ours is one of the original ones with all the quirks. In the high desert I like the humidity. Our bedrooms we added walls and doors to as teenagers and adults need privacy, but the main area is open. Will have to look into venting with something other than having the doors and windows open 6 months of the year, lol.

is the problem just moving air through your rooms?
Would some sort of solar operated fan that either:
1: pulls air through vents into your room, and out the back of your room through ceiling or
2: pushes air from the now walled off area into your room. (assuming you have a skylight/vent in your room to vent air)


can you post a picture of what youre trying to do?

Sorry, the problems are that we didnt face the earthship south...but southwest so in the summer we get lots of sun even with shades on the windows. We didn't like the view of the monster power lines. Also only one of the skylights works, the one in the main area, the kitchen. The rest either stick or leak. Dont get me wrong i dont mind having the windows and door open for 6 months. But in the summer when there is no wind it is like a oven in the main area. The rooms that are partitioned off stay cooler. We use fans and wet tee shirts when it is horribly hot, or just dont stay in the house. I am trying to come up with a plan to get the air coming in the front and back doors to be cooler. Maybe with shade of some kind and a mister.

I just watched a video of the new earthships. It looks like they have changed a lot since we build ours. Maybe if we made some of those new vents in the walkway it would be better. But with our 70 mph winds something sticking up like that could cause problems.

Thanks for trying to help. The heat is worth baring compared to heating bills in the winter.

is it possible to plant some deciduous trees that shade the windows during the summer, but allow light through during the winter?

you may also try to add some vents (that open into the house) in the higher portions of the greenhouse area to help vent some of the hot air before it gets into the main area.
or maybe some sort of solar attic fan that can pull air out of the front portion of the house.

may also try to bring some air into the house from the north/east where it should be shaded, and hopefully cooler.

Amber,

I would recommend looking into a solar chimney, I think this could solve a lot of your problems. The solar chimney heats up in the sun, the air inside heats up and rises. The rising air draws air into the bottom of the chimney as a natural form of ventilation. Then you could build a shade porch off the north of the house and have some windows or ventilation you can open to draw this cool air into the house. Alternatively you could install some earthtubes to cool the incoming air with the earth temperature. This is a natural form of air conditioning. If you really want to get crazy you could build a solar chimney and a down draft tower and have some pretty serious A/C for the price of running a small water pump.

I had the great fortune today to tour an Earthship under construction and meet Michael Reynolds. He has a Q+A and touched on some of the topics people have brought up here.

One thing he said is that they have standardized the window angle to 70 degrees. He said it got too expensive to customize the angle for each latitude. They also definitely had a glass wall in between the greenhouse and the house. This served a number of purposes.

First off it served as a buffer for the earth-burmed part of the structure. When it gets really cold in the greenhouse it won't be as cold in the house, and likewise for heat. The other thing it does is provides a strong solar siphon for the ventilation system. Like in one of Bill Mollison's books this is using the rising heat from the greenhouse/solar collector/front of earthship to draw cool air in from the north. In the case of this earthship there were two vents up high at the top of the greenhouse. These let the solar heated air escape drawing air from the house into the greenhouse. This action draws air in through the earthtubes to the north. You basically get a solar heat pump to pull air from the north, through the ground, into the house. This provides vital coolling, especially in the fall.

In the fall the temperature is still warm even though the sun starts to be lower in the sky. It's like two sine waves out of phase with one another. It can be in the 80's outside, yet the 70 degree solar collector is still catching a ton of heat from the sun. This was the main gripe I heard from someone who has lived in one of the earthships without the glass wall in-between.

It was a very cool experience, Michael Reynolds is a rebel architect for sure!

I just read an ebook on ZED (zero energy design) which can be found on the web. Very interesting information about using a double envelope for a home. An attached greenhouse is great for this. I will warn you that the book content is at least 80% political rambling. Still, worth the read for the information within it. I've adjusted a lot of my thinking on many, but not all things since reading it.

I am imagining that the solution to all the problems would be as follows:

A) Controlling humidity. Having the greenhouse completely partitioned from the living space. You could still grow some plants in the living space, just not as many and with less water. For example, you could control the seasonal variations of light that so many plants respond to when completing an annual cyle of fruiting by using those growing pods--think oranges, apples, maybe even bananas, all of which I think come in midget varieties. No 420 jokes, please. Just use LED lights and timers. Hook everything up to a computer to eliminate the hassle of manually adjusting everything every two weeks. To partition the greenhouse, just build another set of true vertical floor-to-celing windows. Use the largest panes of glass possible, as the framing will add to the shading already created by the framing of the outer windows. This way, your house is still getting most of the sunshine that makes it past the plants in the greenhouse. Remember, not all sunlight makes it past the glass, and having two panes of glass between the sunshine and atmosphere and the inner living area will cause the brightness to drop quite a bit. Consider a black or near-black color motif for the inner area to take maximum advantage of what sunlight does make it through in the wintertime. I've read ZED also, and although this idea doesn't conform with the total idea of ZED, it might be useful in an Earthship.

B) Controlling heat loss in the wintertime. Regular single or double-paned glass isn't your only option. There is a space-age material available to consumers called "Aerogel". This is a translucent, nearly-transparent insulation with an R-Value of 14. R-Value is a measure of how well a substance prevents heat from passing across it from a warmer zone to a colder zone. Fiberglass insulation has an R-Value of, I think, 4. The "good" spray-in insulations have an R-Value of 7. A double-paned window, standard, has an R-Value approaching 1. There is a company that produces windows with a layer of Aerogel, which I will again mention is nearly transparent, sandwiched between two standard panes of glass. I think the R-Value of these windows approaches 8. Again, you lose a bit more sunlight to the interference of the Aerogel layer, but this might be completely made up for by how slowly your house would lose heat at night. If you plan to have plants in the inner area, along the inner side of the inner partition of the greenhouse, you might consider leafy dark green plants like spinach, chard, and kale. They grow well in less magnificent sunlight.

C) Preventing temperature and humidity equalization with the atmosphere and the greenhouse. Use airlocks. Have an airlock that you walk into before walking into the living area, and have an airlock between the greenhouse and the living area. This idea is straight out of the ZED book.

D) More ideas for controlling temperature. Increase the height of the windows in front of the greenhouse, use the largest panes of glass possible to minimize frame shading, and depress the living area three feet below ground level. If you get the angle of the entire design just right, you will have more sunlight entering the living area, providing more heat in the wintertime. The depressed living area will take advantage of the constant temperatures of the Earth's surface. If you use a dark color motif for the floor, the building will absorb sunlight in the daytime. Have an engineer or architect (a good passive solar architect) take a look at this idea while you're designing your home.

E) A couple of awesome ideas from ZED about air-conditioning. Don't forget to avoid slanted glass for the greenhouse. Vertical only. You can tilt the house so its slightly running northeast to southwest to get more sunlight in the winter mornings, when it will be coldest during the day, and to avoid hot western sunlight in the summer. You should have a retractable black overhang, something you can adjust depending on variations, to block high-angle sunlight in the summer. This will mean your greenhouse won't be getting sunlight during the summer (a bit counter-intuitive from a horticultural perspective), so you might want to install a bunch of LED bulbs in your greenhouse and run them off the solar panels in the summer. Also, check out the ZED book to learn about absorption-chiller air-conditioning. If you are looking for a reliable way to generate the high temperatures needed to fire the absorption-chiller, take a look at Home Power magazine and the various articles there about parabolic solar troughs, which I've heard work great all year round and in low-light environments, too. The only electricity required would be that needed for the fluid pumps, probably less than 3KW a day. Very green, too. The main ingredient is ammonia, which can be recycled easily, and glycol, same. You could use your hot water system as a heatsink for the absorption-chiller, and use the parabolic troughs for hot water and supplemental heating in the winter.


B) Batteries. There hasn't been much in the way of new batteries since 2009, when the LIFEPO4 batteries hit the market. If you don't want to manage a giant armored personnel carrier-sized set of lead acid batteries, you might want to consider Winston or Sonopoly. These are the main batteries on the market for DIY lithium-seekers, and can be used for stationary applications as well as electric vehicles. I don't know when newer, better batteries will become available. You might want to consider the Kolibri AlphaPolymer batteries, but I have been unable to contact the company that claims to make them. If they are real, and anything like reasonably priced, they would be a good 20-year solution.

Increasing horticultural food output. Consider aquaponics for the greenhouse. They use 90-95% less water and produce spectacular results. While I'm at it, consider a Clivus Multrum toilet to conserve water and produce AAAAA++ fertilizer for your plants not growing in the aquaponic system. Also, since your greenhouse would ideally be completely partitioned from the living space, consider carbon-boosting. If anyone shows interest in this post reply, I will dig up all my links for carbon-boosting, Aerogel windows, and the Kolibri batteries, etc. If you're interested in a supergreen toilet, visit the Clivus Multrum website (it might be CLIVIS).

Looking forward to continuing the discussion.

I like the solarwall/chimney idea, particularly since the house is not facing south. You can use the south face for the solarwall. Earth tubes can be added to the living space and you can put the draw at or above ceiling height in the south corner. A solarwall in the west corner would not be as effective but could architecturally balance the front of the house and provide draft when you need it most. When you get enough ventilation the humidity should be at ambient in the living space. I think I would put in ceiling fans because when I visited the Taos Earthships they seemed a bit stuffy. If anyone needs help tag me, I figure I will need to help at least 100 people before I build my earthship. regards