[Greenbuilding] Passive Solar and HVR/ERV systems

[Ian Albinson]

On Feb 23, 2007, at 12:17 PM, Corwyn wrote:

> I heat my house with just a woodstove.  However, before I had the  
> basement slab poured, I put PEX tubing down.  It was relatively  
> easy (I spent a day wrestling two 300 foot long snakes). cheap (~ 
> $600)  and allowed for lots of future improvements (and is  
> impossible to accomplish later).  First floor radiant can be put in  
> any time, if you design carefully.  When my mortgage company told  
> me I needed a 'furnace', I hooked up a cheap water heater to those  
> tubes (for an additional ~$600).  Now the plan is to run surplus  
> solar heated water through them and get the basement up to 68ºF.   
> This lets me take advantage of the 13000 BTU/ºF of thermal mass in  
> the foundation.  That said, I wouldn't take money from the window  
> budget for it.

I take it your basement is windowless? That's why you'll being using  
radiant to bring the temp up?

With the current design, I looking at no basement, but the master  
bedroom, spare/storage and utility rooms
are on the first floor level, ie. on slab level. I do worry with  
passive though, even with a wide bank of windows
to those rooms, that the concrete will be cold underfoot without  
radiant heat.

If I cover the concrete with rugs or a wood floor, I'm going to lose  
a lot of my thermal mass though.

> take a look at http://www.thermotechfiberglass.com/index.htm

Yup, I was looking at that site yesterday evening, after researching  
Passive House on Wikipedia.

>> Great, I was hoping for some positive feedback on that.
>> Does it make more sense, since solar may only provide me with a  
>> certain percentage of my hot water needs,
>> to pair the system with an on-demand unit?
>
> Yes it does.

How would a storage tank system work, instead of an on-demand unit?
The tank system will be there anyway because of the solar, so would it
be better to have a 2nd active tank to heat the remaining temp  
difference,
or the instant system?

Thanks!