It’s a bitterly cold day outside. The outside temperature is around 0°F, 20-30 mph winds, wind chill close to -30°F and I couldn’t feel toastier! Oh how I love the passive solar effect! Sunshine streaming in through the windows, a concrete floor soaking up the radiant heat, and thermostats in the 75-81°F range without a bit of help from our furnace.
To give you a little better idea what’s going on, how about a few pictures:
Look how low the sun’s angle is.
At this time of the year, when we need heat the most, it’s very close to the winter solstice and the sun is at its lowest angle it will be for the entire year.
Notice how deep into the room the sun’s rays strike, radiating onto the dark tile, heating the concrete underneath as it absorbs hundreds of thousands of BTUs from the sun. This energy will go into the concrete floor instead of overheating the house and gradually reradiate into the house later this evening.
The really awesome thing about passive solar heat is it works best when you need it the most! Say in the middle of the winter when it’s cold, especially on these bitterly cold subzero days. Don’t know if you ever taken a moment to step back, and really think about these supercold days, but any time it’s freezing out, like below zero, it’s always sunny. You see, air can only hold so much precipitation depending on its temperature, and the colder it gets the less it can hold, so any time it’s really cold that means it’ll be bluebird sunshine outside! Great thing because this means any time in the winter when we really need heat the most we get it for free!
Contrast this to the middle of the summer when it’s hot outside, the days are long, and the sun is high overhead, and the sun’s rays aren’t creeping into the house even a bit. Yes, it’s still bright/sunshiny inside, but no direct impact from the sun’s rays keep things from overheating. Even more, you can reverse the heat storage effects of the concrete in the summer by opening the windows at night to cool down the slab, and then closing the windows during the day to use the cooled slab to keep everything comfy. Considerable free heat in the winter, some cooling in the summer… Can somebody please tell me why more people don’t build their homes this way?
Really, it’s that amazing! I read about passive solar, researched it, incorporated it into my house design and WOW… what a difference! You really have to feel/experience it to completely appreciate the difference, and let me tell you, anyone who steps inside my house on a freezing cold day will instantly feel the sunny warmth and know what coziness is all about. Ahh… I love the sun!
Even Caleb enjoys it!
This is a gorgeous passive solar home. I’ve been reading through your website and can’t stop! Thank you for writing and sharing.
Hey Keya, just jumped over to your Green Passive Solar blog in your signature link and love all the information/pictures you have there. Will definitely have to give it a close read in the next few days when I have a bit more time. Thanks for the message!
Nicely done! You are well past the analysis/design phase, but we have a suite of DIY passive solar calculators on our website that you may nevertheless find interesting:
We have also been using an Omni Pro automation in our Seattle home. You can see a photo of it here, along with our DIY diesel engine/generator that use vegetable oil for fuel:
Thanks Bob! Some excellent information! Wish I would have found this before everything was all built! Most certainly overglazed a bit on the south side, but the view is incredible and I wanted to bring the outside in as much as possible during the winter so a little overheating is worth it!
Checked out the pictures of your Seattle home with the OmniPro; wondering what you’re using the PC for? Is this just to communicate with the OmniPro, or do you have an additional higher-level home automation software?
What about solar hot water heating? Thinking about integrating a slightly oversized system that could provide some supplementary heat to the radiant slab. Ever mess around with blending passive solar with active solar in a radiant slab? Thinking it could be a fun/economically worthwhile project.
This PC is used to interface HAL2000 voice recognition software and the Internet to the OmniPro. This allows us to speak a command from any room in our home to control everything controlled by the OmniPro. This also allows us to solicit info from the Internet from any room such as stock prices, weather reports, traffic reports, sport scores, etc. This PC also serves as our TV entertainment center (i.e., it has TV tuners and has DVR capabilty) and interfaces with the other TVs in out home. I built this system back in 2002 and it has performed flawlessly since then.
Yes, integrating passive solar with hydronic radiant floor heating is precisely what our company does (in addition to water work project engineering/contruction). Our integrated designs allow excess passive solar heat in one area of the building (e.g., southern exposure areas) to be conveyed via the hydronic floor heating system to other areas of building where this heat is needed (e.g., northern areas), stored until required, or simply rejected if this heat is not needed. This is discussed somewhat in the calculator instructions on our website.
Very interesting to hear you’re using HAL2000 to control your home. That software seems to be one that many with spinal cord injuries used to automate their homes by voice. I thought about going with HAL myself, but after looking at their website was a little concerned about the dated appearance of the product and their rate of development. As a user, do you feel like they’re keeping up with the times, or stuck back in the early 2000s?
I’d be very interested to talk to you further about integrating solar hot water heating into my radiant slab. I’ve been brainstorming the best way to make a feature/showcase project, where I could really highlight the solar hot water heating panels and water storage tanks of a manufacturer, and through a partnership with the local community college get a really impressive system installed that could act as a real world teaching tool for the students. Not sure the best way to approach this, but through Quadomated and the college I think it be a great way to really educate the public on the incredible benefits of solar hot water heating.
I’ll drop you a personal email in the next day or two and see if we can collaborate further.
Looking forward to chatting further,
I entered my personal email address into your entry box. We are heading out of town for a long weekend, but we will be back on 30 Jan.
You are correct in characterizing HAL2000 as being dated now-a-days. However, I have not researched this area in many years, so I don’t know if there are better products available now…likely so. HAL2000 did have a very good forum with out-spoken participants calling for more development when I use to hang out there several years ago.
I have not actually done anything associated with solar hot water panels. My related experience is more associated with hydronic floor heating and passive solar heating. I have also been an aerospace engineer at Boeing for many years and now manage their flight operations engineering department. Nevertheless, I would be happy to assist you with your project. My undergraduate degree was in mechanical engineering, so I always get excited about opportunities to apply fluid dynamics and heat transfer!
I did post some info about concrete tanks that could be used for heat storage on this site today:
You might find this website interesting just in general too.
Wow! You sound like a very busy man!
Found your suggestion about using a large capacity, cast concrete tank for water and energy storage to be extremely interesting. Too bad I hadn’t thought of that ahead of time and placed a large super insulated tank directly within my slab, inside the building envelope. I think without that, I’ll probably stick to building a smaller (but still large) 500+ gallon tank inside my garage to store a few 100,000 BTUs of energy throughout the sunny days for release during the night. Still have lots of sizing calculations to do, but this seems like it could really work, especially with the low 85°F design temperature of my radiant slab. I’ll touchdown with an email in the next few.
Thanks for getting me looking at Green Building Talk again!
Probably the wrong place for this question… but are those Bowers & Wilkens 801 speakers I see?
They sure are buddy… I take it you’ve played around a little bit in the audio world?!?
That speaker is one speaker I have always been interested in. From what I read, it is one of the most accurate speakers ever built, the point of exposing weaknesses in recordings that were otherwise though to be flawless. Do you have the optional “bass alignment filter” (equalizer)? I also understand that they are best mounted on the optional (of course) 11″ stands to get the tweeter to ear height.
Guess you are a speaker geek! I searched for much of last year for these bad boys, browsing eBay, losing out on numerous auctions, until I finally captured this pair for WAY less than the rest of the auctions had been going for. They started life as the recording/mastering speakers in a Sony Recording Studio that was closed down, and were repurchased/resold by an individual who went in and bought everything from the studio. They were listed on eBay with spectacularly crappy pictures, and I took a chance. LUCKY ME!!! When they arrived on the back of the trailer truck packaged on a pallet I was instantly overwhelmed by their awesome condition!
I’ve been searching for the base alignment filter for what seems like forever! They’re either extremely pricey on places like Audiogon or just hard to find. Someday I’ll get lucky or shell out for a set of aftermarket crossovers. I don’t have the optional stands, but they arrived installed on a set of 4 inch risers!
Oh this audio hobby is addictive and expensive!
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Using the latest WordPress 3.8… Seems to provide an easy platform with lots of customization and functionality. Not experiencing much for security issues here, what sort of problems are you having on your site?
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