Designing A House HVAC and other considerations

[Watermonkey 0]

For those who don't know, HVAC is Heating Ventilation, and Air Conditioning.

Some day in the next few years I fully intend to design, with an architect, a new house and shop for my wife and I. I've given it a lot of thought over the past years and there are literally a million things to consider. You may ask why I don't just buy a pre-existing home. The answer is I'm tired of living in other people's mistakes so I want to carefully research and plan the "perfect" home. It won't be cheap, and maybe we won't be able to afford it right away, so we'll pay off the land first. We're looking for 10 to 50 acres to live on and we'd prefer to butt up against public land so our neighbors would be limited and far away from us to hear or see. In real estate they always tell you, "location, location, location!". There's no way to underscore that phrase enough. We didn't place the weight we should have when we bought the place we live in now, but we've learned our lesson. So we've picked out our location, bought the land, picked the prime location to build the building on (we haven't yet, actually, I'm just jumping to the chase so I can discuss the topic), put in a well and ran electricity and phone to a nearby pedestal and transformer box. The requirements, which I'm sure I'll add on to as time goes by because I don't have them written down, that follow are based upon my own philosophy of minimal environmental impact with maximum self-sustainment and comfort. At some point, when a million bucks magically appears in my bank account, I'd like to add an olympic-sized swimming pool so I'd make sure the building site could accommodate that along with a waterfall water feature. Flowing water is one of the most peaceful sounds in nature and should be incorporated in the landscaping whenever possible, preferably through a natural mechanism because machinery equals maintenance.

First off, the shop. Why, you say, would someone want to build a shop/garage before building the main house? First, above the shop will be an ample-sized apartment with a balcony, solar panels on the long axis of the south-facing roof and a solar water heater to aid in the radiant heating system as well as assist the multi-fuel water heater for hot domestic water. A basic design found here, would provide a comfortable amount of living area while also providing space for our vehicles (Full sized truck, SUV, and sedan) and room for an office, utility room, and shop. I'd probably eliminate the overhead doors on the left in favor of the utility room and shop and I'd have to modify the design to raise the garage door and ceiling height on the wide bay to the right to accommodate a larger vehicle or RV. The utility room would need to accommodate a hydrogen station and storage of both hydrogen and bio-diesel for back-up electricity and heat for when the grid goes down as it inevitably does in rural America. I'd sell any extra electricity back to the utility too. All those solar panels would probably take 25 years to pay for themselves! The utilities coming in to the shop would feed the house, too, when it's built. The second reason for building the shop/garage first is to live in it while the house is being built. Theft of building supplies is the number one reason new construction is so expensive and if we're on-site 24/7 with sensors and such, we'd be able to manage loss much better, possibly preventing it altogether. This could conceivably save thousands of dollars. Further, with the new living space, we'd then be able to sell our present home and have somewhere to immediately go to when the time comes to get out. I'd have the second floor consist of a perlite/concrete mix to maintain strength while lowering the load the load-bearing poles and walls would need to handle and that would allow me to include a multi-zone radiant heating system in the floor. Using a geo-thermal heat pump, I'd also run coolers in the ceiling to remove heat in the summer thereby virtually eliminating the high cost of AC and the geo-thermal system would dramatically lower the cost of heating in the winter, especially when used in tandem with the roof-mounted solar water heater(s). For water, I don't have any better idea at this time then to go with a conventional well and AC pump with two thousand gallons of water storage in pressure tanks in the utility room. Entertainment would be piped in via a satellite dish under a south eve extended especially to accommodate several dishes and internet would be piped in, if not available via fiber optics, through our Wildblue dish that would be coming with us when we move.

Enough with the data and entertainment, and on to the HVAC! Anyone knows that a home (even a shop/garage/apartment) must have new air coming in and old air exhausted to maintain a healthy environment to live in. So what I thought is this air should be tightly controlled. Like it would be in a lab or something. I'd dig a nice long trench, maybe even zig-zag it so it wouldn't have to be a real long straight line, and at the far end build a small shed. Inside this shed would be one large 8-12 inch diameter metal tube leading back to the building(s). On the top of this, like on an older car, would be many round cloth air filters that can be easily gotten at any auto supplier. It'd basically be functionally identical to an air cleaner for a large engine, but the air would be for human consumption, not for the fuel-air mixture needed on an engine. On the top of the air cleaner, with solar back-up (of course) would be a large "squirrel cage" style rotary fan that would spin all the time, forcing air down the pipe. All of this, except for the solar panels that would be "shingles" on the small roof, would be completely contained in the shed so as not to attract attention. The positive pressure in the buildings would need to be managed by venting it to the outside via special air vents that would open when the air pressure became too high, but would act manually, just like turning on the fan in the bathroom -without the noisy fan! With a long enough pipe buried deep enough (15 feet?) it would act like a geo-thermal system and perhaps the pipe could have some kind of feature (copper fins?) that would make this more effective like radiators that would act to cool or warm the air as it moves through. The doors to the buildings would have to be specially designed to accommodate this type of system, but there are many advantages. First, from a house-cleaning perspective, the dust problem 99% of us face would be a thing of the past. Next, I can't think of a better way to keep bugs, pollen, and pollutants out of the building, though the apartment would need to be well sheltered from the garage below (with its own exhaust vents) because when you first start a car is when you'll get the worst pollution from it. These things would need to be worked out, but this system, I'd think, would be pretty maintenance free, don't you think? I can't afford to ask a high-end architect what people like Paul Allen (co-founder of Microsoft and one of the wealthiest people in the world today. I've actually been inside of two buildings in two very different locations he owns and lives in at various times, and I've been inspired to say the least) do with their HVAC systems when their homes are on the drawing board, so if anyone who reads this has ideas, suggestions, feed-back of any kind, please add to this topic and together we can engineer the perfect HVAC (and other systems) system for the not-so-modest but very humble residence.

[Yratorm, LightMage 0]

You've certainly put a lot of work into this, watermonkey. it's fascinating.However, my ideal home would be preferably on a mountain, a stone castle whose cold chambers extend into the mountains itself. No air-conditioning and no heating. Just stone walls, a landscaped garden, and a view that ranges over several mountain chains. Sure, it's short on comfort, but it suits me, somehow. A landscaped garden within the castle walls, and wild leopards ranging outside would sort of complete the interesting and unique aspects of the place. A few friends to whom creature comforts matter little (I have plenty of these) would provide human company, both with conversation and at pursuits like archery and swordplay and other forms of entertainment. And of course, the sunsets in the mountains are awesome, as are the cherry blossoms in bloom. Beauty and austerity. They make a subtle and truly interesting combination. Electricity, television, the internet, etc. I can live without (and have).Well, not many would care for this plan. However, it's unique to me, and I kind of like it.

[Watermonkey 0]

The more I think about it, the more I think the air intake temperature could be controlled or stabilized by integrating the intake into the geo-thermal system somehow, maybe by encorporating the air duct inside the water piping allowing it to be completely surrounded by water, but there would be corrosion and condensation to consider there too. I'm sure this design or idea isn't unique, but I can find nothing on it so far doing internet searches... Another thought I had was to just blow the air through underground water and pick it up again above the water line. That would be the most effective way to control the air temp, but it'd also result in air that was high in humidity, which would need to be removed at some point. Maybe I just need to go take some architect classes at the local community college...

[jlhaslip 4]

Using a thermal mass such as rock and sand is an excellent way to store excess heat from the daytime and draw on this reserve through the night or cloudy days and it has been done this way for years. Lining the "reservoir" with an impervious membrane (6 mil poly) should reduce the humidity of the storage area as well. I have seen where the air is forced through a series of "tubes" (concrete blocks positioned to act as tubes) to pick up or deliver the heat and also embedding waterlines in the sand bed also allows you to generate heat from roof mounted panels during warm, sunny periods.As for payback, the consensus would be that the passive Solar heat is quite cost effective and the payback period is shorter than you imagine. Geo thermal might cost more to install, but the reduced energy costs in operating the system will be to your advantage in a relatively short period, afaik.Additionally, using a "panel" form of insulation in the construction has advantages, too. Less thermal bridging and therefore, more effective insulating qualities. The weak spot in most roof systems is the lumber material bridging between the warm and cold spots. Panels reduce the bridging of the tmperature zones. if you ever see a roof with "frost lines" in spring and fall seasons, that house has serious "thermal bridging" happening.

[Watermonkey 0]

Additionally, using a "panel" form of insulation in the construction has advantages, too. Less thermal bridging and therefore, more effective insulating qualities. The weak spot in most roof systems is the lumber material bridging between the warm and cold spots. Panels reduce the bridging of the tmperature zones. if you ever see a roof with "frost lines" in spring and fall seasons, that house has serious "thermal bridging" happening.

Well that describes our house. I'll remember that bit about the panels. Now that's good information. I just wish all replies were so informative...
Sadly, I'm seeing nothing but absolutely insane asking prices for land around here and in the county to the east. I don't know how we'll be able to afford to build a shed let alone a project on this scale if we spend all our money on the land. I don't get why people suddenly think their land is worth so much...

I've gotten a preliminary estimate on the cost of the building and after all is said and done including landscaping and road work, I can expect this one building to cost upwards of $400k USD. I hate to think of how much the actual residence would cost to build when the time comes...
Edited April 2, 2007 by Watermonkey (see edit history)