Fuel is Fuel.... An alternative view to economy

[freebeard]

The lighting is bad, the reflection is unnecessary. It looks like it's floating on a ring and standing on five legs at the same time. I forget.

The decks that pivot up to cover the doors and windows would work for a wilderness cabin.

I've saved some other models from before but I'm trying to migrate to different software, and I'm having to relearn materials and lighting.

Heat and humidity can be controlled with an enthalpy wheel

[redpoint5]

I've thought it would be neat to have an interior wall of water to absorb excess heat of the day and release it at night to stabilize temperature.

My favorite idea is an infrared light with tracking to follow people in a room, heating individual people rather than a whole mass of air.

The house temps dipped down to about 68F today, and I found my fingers weren't keeping warm. I'm still adapted to summer temperatures.

Originally Posted by aardvarcus

My issue with the phase change material is that they tend to loose their effectiveness over time.

Which materials lose their effectiveness? I mean, water never gets better or worse and converting between solid, liquid, and gas.

[aardvarcus]

Teoman,
I have built two. Another one of my hobbies. All you really need to do is achieve very high R values in the floor, walls, and ceiling and do good air sealing. Stay away from scam products that lie about R values. Radiant barriers and air sealing products are bad about this, they work but their effects can’t be quantified in terms of an R value. You don’t need fancy products, just add more of the same insulation for what is usual in your area for construction which keeps the cost affordable. I had to quit posting on energy efficient housing forums as this advice is contrary to what lines the pockets of the forum sponsors.

They look just like normal houses, except the exterior walls usually end up very thick. For example my brick faced double stud wall is 21 ¾” thick and has a true R-67 after discounting for thermal bridging. Insulated with Recycled (used) polyisocyanurate foam (unbelievably cheap, get fiber faced not foil faced for moisture reasons) between the stud walls and fiberglass. The internet is full of wisdom here (search Passive House), you just have to shovel through the garbage. In order to transplant a design from one climate to another you must pay attention to humidity and moisture. Do not just grab a design from up north and build it down south.

Use fewer larger windows (save cost for same amount of light) and spring for triple panes or better. (Vinyl replacement triple panes are affordable, only 10-20% more than similar double.) Get the R values high enough and all you need to condition the space is one or two mini split air conditioners. Lighter exterior colors and cool roofing products reduce the temperature of the outside surface, aka if you want a dark exterior you need even more insulation to get the same performance.


Redpoint5,
I was talking about phase change solutions, usually waxes or salts, sold in packets and marketed as PCM. I can’t explain it either, but the data sheets show a drop of in performance after a number of cycles. I assume the chemistry degrades over time? Obviously normal materials don’t normally stop absorbing heat when they phase change…

The problem being is that if you need a specific temperature of phase change there are relatively few options other than those solutions. I purchased a quantity of PCM packets that change phase at like 40 degrees for my refrigerator due to the monthly power outages in my rural area. Got to keep the fridge cold until I have time to start the generator.

[teoman]

I believe you were responding to my link of the amazon instant heat packs.

Yes they do lose « performance » over time.

[freebeard]

Originally Posted by redpoint5

I've thought it would be neat to have an interior wall of water to absorb excess heat of the day and release it at night to stabilize temperature.

Passive Solar Design Guide page 13

[redpoint5]

It's been getting down to low 50s, high 40s at night here, and we still haven't run the heat yet. Every few days the sun will break out long enough for me to open the shades and soak up the heat, which will get us by a couple more days without running the heat.

This summer I ran the AC about 2hrs each day that was above about 85 degrees. Just dehumidifying the air made a big difference. I set the temp to 78 degrees for cooling.

[owly]

Originally Posted by aardvarcus

Why not just design the house to use such little energy that supplemental heating is very minimal?

I utilize what you are suggesting when I need to work on my car in the winter, make sure it is nice and warm before pulling into the garage for the free heating.

What we really need is an exhaust heated oven to cook our dinner on our drive home. Simple heat exchanger... Or how about a engine coolant heated crock pot.

My issue with the phase change material is that they tend to loose their effectiveness over time.

Toyota had the vacuum insulated canister to store heated coolant to preheat the engine for the next trip, it would be cool to see that idea on steroids.

It frustrates me in the winter to see industrial cooling towers running expelling waste heat from industrial process water, and then to see the same plants burning natural gas to heat water for building heat. Not even trying...

I call BS on the statement about phase change materials losing their effectiveness over time. The melt point and freeze point of a chemical does not change over time, nor does the amount of energy required for phase change....Water of course being the obvious example......... of course if an eutectic material is not chemically stable and breaks down, or reacts with itself to produce something entirely different this would not be the case. Otherwise there is no possible change in the heat of fusion of a chemical. If an eutectic material is not stable by itself, it should never be sold for that application. If it reacts to it's environment (containment), then it needs to be contained with something that is not reactive to it. It's that simple.

H.W.

[owly]

Originally Posted by aardvarcus

Teoman,
I have built two. Another one of my hobbies. All you really need to do is achieve very high R values in the floor, walls, and ceiling and do good air sealing. Stay away from scam products that lie about R values. Radiant barriers and air sealing products are bad about this, they work but their effects can’t be quantified in terms of an R value. You don’t need fancy products, just add more of the same insulation for what is usual in your area for construction which keeps the cost affordable. I had to quit posting on energy efficient housing forums as this advice is contrary to what lines the pockets of the forum sponsors.

They look just like normal houses, except the exterior walls usually end up very thick. For example my brick faced double stud wall is 21 ¾” thick and has a true R-67 after discounting for thermal bridging. Insulated with Recycled (used) polyisocyanurate foam (unbelievably cheap, get fiber faced not foil faced for moisture reasons) between the stud walls and fiberglass. The internet is full of wisdom here (search Passive House), you just have to shovel through the garbage. In order to transplant a design from one climate to another you must pay attention to humidity and moisture. Do not just grab a design from up north and build it down south.

Use fewer larger windows (save cost for same amount of light) and spring for triple panes or better. (Vinyl replacement triple panes are affordable, only 10-20% more than similar double.) Get the R values high enough and all you need to condition the space is one or two mini split air conditioners. Lighter exterior colors and cool roofing products reduce the temperature of the outside surface, aka if you want a dark exterior you need even more insulation to get the same performance.


Redpoint5,
I was talking about phase change solutions, usually waxes or salts, sold in packets and marketed as PCM. I can’t explain it either, but the data sheets show a drop of in performance after a number of cycles. I assume the chemistry degrades over time? Obviously normal materials don’t normally stop absorbing heat when they phase change…

The problem being is that if you need a specific temperature of phase change there are relatively few options other than those solutions. I purchased a quantity of PCM packets that change phase at like 40 degrees for my refrigerator due to the monthly power outages in my rural area. Got to keep the fridge cold until I have time to start the generator.

Oops........ I didn't read this before posting. It should have been a "qualified" statement from the start.


H.W.

[owly]

Originally Posted by aardvarcus

Why not just design the house to use such little energy that supplemental heating is very minimal?

I utilize what you are suggesting when I need to work on my car in the winter, make sure it is nice and warm before pulling into the garage for the free heating.

What we really need is an exhaust heated oven to cook our dinner on our drive home. Simple heat exchanger... Or how about a engine coolant heated crock pot.

My issue with the phase change material is that they tend to loose their effectiveness over time.

Toyota had the vacuum insulated canister to store heated coolant to preheat the engine for the next trip, it would be cool to see that idea on steroids.

It frustrates me in the winter to see industrial cooling towers running expelling waste heat from industrial process water, and then to see the same plants burning natural gas to heat water for building heat. Not even trying...

I used to cook on the manifold when traveling....... There are vacuum insulated containers for cooking........ called of all things "thermal cookers"..... Isn't all cooking "thermal".... Kind of an absurd term. But it's like a thermos..... you heat it to cooking temp, and it holds that temp within a few degrees for hours, cooking your food. Ideal in an RV or sailboat. I use Sous Vide extensively in cooking, most often at a mere 130F for meat. A super insulated container would be perfect for this........... Heat a piece of chuck steak to 130, and hold it for 48 hours, and it is as tender as rib eye... or more, and a perfect pink medium rare all the way through, requiring just a minute or two of searing on the outside to make a perfect steak such as you cannot possibly do on a grill... it tenderizes while never exceeding a medium rare state, rich pink and juicy. Many things can be cooked to perfection this way.
Precision temp control is the challenge... With 180F coolant, how do you regulate temp at 130F in your water bath? The food is sealed in a food saver or zip lock, submerged in closely regulated water. Veggies can be cooked to the perfect crispness / softness, eggs to a perfect custard yoke.......... an awesome tool if you haven't tried it yet!
H.W.

[cRiPpLe_rOoStEr]

Sounds too complicated trying to store thermal energy instead of converting it into chemical or electrical. Well, maybe a good alternative would be recovering exhaust heat, repurposing an old absorption fridge to serve as an air conditioner, and then if you use the moisture taken out of the interior of your vehicle as a source of water for supplemental injection you'd be able to go leaner and using that moisture to avoind knocks and keep the temperature under control.