Building Design for Going Off the Grid

What is the usable area of the building's roof?

Worst-case electric-power requirements?

I will have to measure it. I am assuming 10,000 square feet. I will get an estimate together for the expected power usage in a day or two. This is a stripped shell with no systems installed. We have total control of all of the systems for lighting, HVAC, water heating and electrical. I will be walking the building this weekend and can be more specific then. G

What's the estimated load?

Why do you want/need an off-grid solution (trying to 'go green' or just plain located in the middle of nowhere)?

Do you not have a local utility connection (or is it so unreliable that you are trying to go off-grid to avoid power quality issues)?

If you had no viable alternative, solar and wind turbine are potential solutions as are gas turbines, but there is too little information given to say.

Please provide more information.

Load estimates will be determined by the systems we install more than the tenant loads. I will try to get an estimate together over the weekend. We do have access to the grid but would prefer to produce more than we need if possible. There will be a cloud on site that needs a guaranteed independent supply of electricity. This is an opportunity to retrofit an office building to be independent of the grid using all the green technologies we can imagine. I have already planned on passive solar, Low e glass, spray foam insulation, water recovery, etc. I appreciate any ideas in making these ideas work together with the other systems to have as low a footprint as possible. G

You may also want to look at creating a green roof.

http://en.wikipedia.org/wiki/Green_roof

May be a viable 'green' initiative from a company environmental marketing point of view.

Solar hot water heating works really well and can save lots of electricity and money, but may not be viable for an office with de-centralized water heaters. A good option to consider.

http://en.wikipedia.org/wiki/Solar_water_heating

Where is the building located? What sort of typical weather patterns are experienced? What sort of clientele are anticipated?

G - Look seriously at a Solyndra solar installation if solar electric is suitable for the location. Their panel technology is particularly suitable for flat roofs and can take advantage of a white roof covering to improve cell efficiency. Also their panel designs offer some installation cost advantages. (in the interest of full disclosure I have a connection to this Fremont, California, company.)

Ed Weldon

You said historical. Are there any restrictions on exterior changes? My building is in a historical district, and all changes must be approved by the historical society. Does the building have a steel frame? Is there a basement? Elevators? Do you have a parking lot that you own the land it's on?

You may want to contact these guys. They did what you are planning on doing right here in the St. Louis Area.

Alberici

60 minuites did a peice on a company called BloomEnergy. I watched it. I was pretty impressed. I'm not a Designer, or an Engineer, so I'm not sure if it would work in your application. But maybe someday, we'll all be off the grid .

http://www.bloomenergy.com/

http://www.cbsnews.com/stories/2010/02/18/60minutes/main6221135.shtml

It's not a commercial space, and it was originally designed and built to be energy efficient, but here is a link to the Waldsee BioHaus. I know it's not directly related, but maybe you could look at some of the concepts and put together a wish list.

http://waldseebiohaus.typepad.com/

A good stiff dose of reality...

I might suggest you check out Greensburg kansas, they were wiped out by tornado a few years ago and are rebuilding the town for maximum efficiency, largely to leed platinum.

Friends, I appreciate every comment and lead, as all have been helpful. I will send more details as they become available and would welcome your participation and continued input. G

Without knowing where you are located exactly and using my personal place as a reference to real life working energy numbers here is what I came up with.

My house with both heat and electricity factored into kilowatt hours works out to need about 500 watt hours per square foot per day in the worst parts of winter. In the summer the cooling works out to around 100 watt hours per square foot per day. To be fully off grid I would need a electrical storage system capable of holding around 700 KWH's of electricity with a peak output capacity of around 40 KW's at any point in time. I have a wood and coal fired boiler for my alternative fuel based heating system that supplies my 1.2 million BTU hours per day on those bad days which saves me a load of money on heating. The electrical side is the biggest problem I would have to deal with being I would need about 700 KWH's of battery back up at certain times of the year and also some way to recharge all of that in two or three days which is just not realistic. I have good wind but still there are many times where I can have near no usable wind for two weeks or more and solar electric is just not cost effective in my region.

Basically using what I have as a rough estimate for your square footage and assuming you have similar winter and summer energy loads and better insulation you would be likely looking at needing an electrical power generation, storage and conversion system capable of around 30,000+ KWH's with probably a peak power output capacity of around 500 KW's and an alternative fuel based heating system capable of around 50+ million BTU hours per day for peak times.

Thats roughly a battery bank the size of 25 semi trailers and a heating system that burns about 6 -10 tons of wood per day assuming a good but realistic system efficiency. Plus you also need a few acres of solar panels and/or a 500 - 750 KW wind generator to charge those batteries in a reasonable time frame as well.

Best guess for the whole system would be around $3 - 4+ million installed with all new factory built off the shelf equipment.

Simply put a full AE/RE based system is not cheap, low maintenance, or low effort on your scale of application and usage.

The building is located in downtown Houston, Texas. I love people who have taken the time to log their results and I respect your opinion and findings very much. This building is stripped. I have the ability to insulate, install systems from plumbing to lighting, hvac to solar. In South Central Texas, heat and humidity are our major problem. Heat, we have enough of. My heater went out at the beginning of this winter and I can warm my house with a toaster oven and a pot of beans on the stove despite the coldest winter we have had in a long time. It helps that I recycled the home, beefed up the insulation and utilize passive solar in it's orientation. The morning sun usually raises the temp 20 degrees and we are opening windows by mid afternoon. We are trying to assure a supply of continuous energy apart from dependence on the grid, not generate 100% of our electricity from any one supply or storage method. This allows a great deal more innovation in recovery of all sources of energy with very few limiting conditions. I hope you will add input as I am able to give more specific information on this project and again I love that you have used your experience with your home to extrapolate a worst case scenario for this venture. Gary

Houston is a good place for this sort of thing. I think you should be thinking in terms of roof-top solar. Your high ceilings are very important for cooling (in fact, this suggests the building may have been built before air conditioning was so prevalent)- what you need is lots of air circulation. Conventional air conditioning will most likely be 60% of a modern building's energy consumption, so if you can maintain a comfortable environment without it, you are ahead of the game. Next to consider is lighting. The most energy-efficient is going to be LED lighting, but it is not clear that the technology has reached the point where LED lighting can replace more conventional lighting, especially in an office or other commercial establishment. What would be ideal would be a DC-powered lighting system powered primarily by a solar voltaic installation. You could also power your laptop computers from the DC system- actually, with the exception of the monitor, you could power a desktop PC from a DC system- all of the juice used inside the computer is DC provided by that big, heat generating inverter power supply mounted in the case. You could also most likely charge all of your small electronic devices directly off DC as well- a lot of them come with chargers for plugging in to a cigarette lighter socket in an automobile.

You may want to consider natural-gas powered refrigerators- available through RV suppliers or boat chandleries.

What is the building going to be used for?

The building will house a state of the art recording facility along with a business generator for high tech music enterprises. I have a full appreciation for the high ceilings and rooftop generation. I am not sure yet what I can get away with given the constraints of the Historical Society that has say in such matters. I like Huvco's solution for natural lighting via fiber optics and supplemented with low cost light fixture such as you suggest should work well for our location. Please keep the ideas coming! Gary

Well, so much for roof-top solar...I find it difficult to believe you will have sufficient energy available for such an energy-intensive application. How about a mini-nuclear plant? Don't laugh- they are on the horizon. Toshiba is trying to get licensing to install a new design in Alaska right now, and there is an outfit in New Mexico promoting their "bathtub-sized" nuclear power plant. These units are buried deep in the ground and you essentially forget about them for 40 years. Then the supplier (assuming they are still around) comes back and replaces the core...The Toshiba unit is probably too big for your application, but the guys in New Mexico (a spin-off from one of the national labs) may have something about the right size...

There is also going to be a problem with air circulation. I don't think you want a lot of moving air in a recording studio. That technique can work in the other spaces, but I think you are going to have to air-condition the studio itself...

Any estimates of what a typical recording studio would consume in energy?

I couldn't help it, I laughed anyway! Maybe, I simplify things too much. I would embrace nuclear as an option. I believe, through the combination of multiple energy generation technologies and creative thinking, a near zero renovation of this small size can be accomplished. I rule nothing out! Thank you for you response and I hope you will contribute more ideas as specific details about the building are announced. Gary

Given the hot region this building is located in and the heat generating properties of a cloud system and other heat generating equipment, what are your thoughts on a TES system such as the one www.fafco.com has done for CBS? Gary

In as much as this building does have an antique water tank on the roof, what are your thoughts on a Water Battery? I think PV awnings could generate enough power to move the recovered water to the roof tank and gravity and micro hydro could generate enough electricity to see a profit in the system. Gary

I think the FAFCO system may be worth investigating, but without more information about the actual structure and cooling loads, it is difficult to estimate the potential economic benefits. As to the water battery idea, I think it would mostly be a waste of money. You would be talking a very complicated system that requires a much larger scale to be economically feasible. Direct solar votaic is more suitable for this scale- especially if you can use the DC voltage for lights and such. I think it is also a whole lot easier to get roof-mounted flat panels past the historical society, since they should not be all that visible from the ground. But I don't think you are going to have enough roof area to meet all your energy needs. Solar hot water heating is very viable, but I do not know how much hot water you would be using (anyone taking showers? Restaurant/cafeteria to be included?). If all you are doing is washing your hands, solar hot water may not be appropriate.

Understood, there are some interesting PV products out and combined with rooftop gardening and the cafeteria could be a great contribution. The water battery concept came into play as a concept for a waterfall in the atrium that offers tranquility and some offset of the negative vs positive ion concept when using so much computer equipment. Gary

Properly designed, the water fall in the atrium could be a significant part of the air conditioning system, probably cheaper than the ice storage concept...

Do tell? I agree cooling tower effect could be incorporated into the atrium waterfall, however energy or cooling storage is a major component in independence. Gary

Run up to San Antonio and have a look at the Marriot on the Riverwalk. Of course, it's been 30 years since I was there, but that's the sort of thing I am thinking of.

You/we need to look at the Load, how many people and where will they be in the building; # of computers, servers, lights etc which create heat from energy loss. Where is the building located exactly, Sun and Overcast days, Times building is in use or not in use. Send me you prints with the load added and we can be serious Tom@GetESS.com

Kudos to gcoffing for this thread. More people should support this kind of thinking. If everybody becomes power conscious, we can reduce our dependence on foreign oil.

For this project, I think saving on air conditioning will make the most difference. Geo thermal is not all that expensive, few moving parts, and efficient. Combine that with a solar/ammonia package and you just might cut air conditioning costs right down.

PV panels to run the electrics, when the sun is shining, the system is working.

Geothermal is most likely not going to be an option for down town Houston, Texas- and he might run in to problems with the Historical Society over that sort of approach. I have seen some ideas for direct solar air conditioning using an ammonia absorption cycle, but I do not know of anyone doing anything commercial along these lines...

So far I see two overwhelming limitations to any practical level of self sufficiency. Down town Huston Texas location and the "hysterical society" limitations on changing anything.

Odds are the location will prevent any thermal well drilling or external off building power system installation that does not fit on the roof. The "hysterical society" will probably have some limitations on how much external anything can be changed for air conditioners or other equipment that could be added plus likely some limitations on the buildings internal updates and changes as well.

From what I see you are in a overall bad location for any practical level AE/RE power or energy saving systems and are under the control of one of the bigger nutter organizations that is against any general change as well. This seems like a poor plan and poor location to try such an endeavor in general. Odds are you could spend a fortune on consultants and bureaucratic paper work and likely still be right where you are now a year or two from now and have less than nothing to show for that efforts on top of all of that.

To put in geothermal, you just drill a bunch of holes in the parking lot and run some pipes underground. Once the drill rig is gone, there won't be anything visible for the H.S. to be upset about.

I would think you could use solar to heat the ammonia, and geo to cool it. PV to pump it, and at least the air conditioning is off grid.

Getting the AC off grid is probably the best way to bring power costs down- but at what cost? This is a pretty complicated scheme, and most likely all custom. What would be the payback period on this?

Most of the systems we are discussing will qualify for the minimum Federal Tax Credit of 30% plus State and Local Utility incentives. This is certainly going to be a custom installation with technologies being interconnected in ways not before tried. The payback for most of these systems is already estimated at 18 to 30 months without tax incentives. If our collaboration accomplishes it's goal, we would have bragging rights far more valuable than the monetary gain. The Hickory House (in one of the Carolinas) actually produces more electricity than it uses. The local Habitat for Humanity uses it as an office and example of what can be done. Our building is intended to be a high tech business incubator and I can think of no finer way to challenge others to think out of the box than accomplishing a Zero footprint commercial building. I believe it would be the first. Gary

These comments are starting to really show the thought put into them! I wonder if the Ice Storage system could be oversized to allow the Geo thermal to spend some of its energy? Gary

This is Geo thermal heating an coolings dirty little secret that they seem to not want the average pubic buyer to know. If you don't balance what goes in VS what comes out over the year the system eventually becomes thermally saturated or drained at some point in time.

Only or especially if the management overrides engineering when the system size is spec'd.

Houston enjoys a fairly high water table though it would not preclude the advantages realized from vertical geo-therm systems. Oversize the system 30% to offset the thermal saturation ratio to your benefit.

I've often wondered about those sink sizing issues vs geothermal north. I'm thinking the way to get seasonal balance in the north, is to build a solar heat collector and maximize what you have to store for the winter..

For Houston, obviously you will want to minimize your solar heat gain, make your building a "cool sink" to the extent that it's possible, by insulating max and by including storage mass in your interior design- stone is very moderating, cw wood or other mass in my experience. Water, of course, is a brilliant storage mass with great design possibilities for interiors but there are maintenance issues no matter how you use it.

Lot of good ideas here. I'll throw in a few:

R-200 roof. Solar water heat panels and PV panels to shade most of the roof surface from summer sun.

R-100 walls. Mass on outside, insulation on inside.

Triple pane operable windows with custom, hinged, foam-insulated shutters. I'm thinking 2 or 3" thick Polyisocyanurate-insulated shutters. If not hinged shutters then moveable foam window covers.

PV covered awnings above the windows to shield windows from summer sun.

Laptop computers for low power useage.

Dry cooler for producing cool water for cooling.

Possibly more task lighting and less general lighting. If budget allows go LED lights but I think they are spendy.

Building temps to be higher than normal if needed to meet energy goals. Tenants will be allowed relaxed dress codes to allow tee shirts, shorts, bikinis, etc. Solar hot water heat. Possibly solar hot water cooling (absorption chillers).

Use of ventilation instead of mechanical cooling when possible.

May need to limit tenants to low power/heat generators/users.

Possibly subcool building at night and allow temp to creep up during the day to limit size of HVAC mechanical cooling system. Tenants start off with sweat shirt/pants and gradually TAKE IT ALL OFF as the day wears on.

May need to put PV panels EVERYWHERE. Aesthetics may have to go bye bye. Who cares if you can get to total off-grid status.

If you have seen some of these musician types naked you would not sweat their clothes off! Thanks for the input. The building is in negotiation and may actually close by the end of the year. That should give us this winter to plan for the remodel. I promise I will share the details when they are available. Gary