Refrigeration To Reduce Battery Size / Overall Energy Storag

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is HVAC. The rest of the house doesn't need so much power and only requires a small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the ice at night. Maybe 2/3rds of the solar power goes to running the conventional AC or heat pump during the day and 1/4 goes to freezing water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the power from the PV is temporarily reduced by clouds the freezer unit would cut off while the heat pump would remain running. The clouds should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time heating.


Bret Cahill

 

[Tim Wescott]

On Wed, 22 Jun 2016 16:14:18 -0700, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the
ice at night. Maybe 2/3rds of the solar power goes to running the
conventional AC or heat pump during the day and 1/4 goes to freezing
water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the
power from the PV is temporarily reduced by clouds the freezer unit
would cut off while the heat pump would remain running. The clouds
should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it 'needs'
to be -- so it may be more efficient to find a substance that freezes at
60 degrees F or so, is cheap, easy to handle, has a significant heat of
fusion, and isn't something that would turn the entire neighborhood into
a superfund site if the tank leaks. Maybe some other wax, from the same
place you're getting your 80-degree (or 100 degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

 

[Jim Thompson]

On Wed, 22 Jun 2016 18:41:59 -0500, Tim Wescott
<seemywebsite@myfooter.really> wrote:

On Wed, 22 Jun 2016 16:14:18 -0700, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the
ice at night. Maybe 2/3rds of the solar power goes to running the
conventional AC or heat pump during the day and 1/4 goes to freezing
water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the
power from the PV is temporarily reduced by clouds the freezer unit
would cut off while the heat pump would remain running. The clouds
should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it 'needs'
to be -- so it may be more efficient to find a substance that freezes at
60 degrees F or so, is cheap, easy to handle, has a significant heat of
fusion, and isn't something that would turn the entire neighborhood into
a superfund site if the tank leaks. Maybe some other wax, from the same
place you're getting your 80-degree (or 100 degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

If it was a good idea someone would be already doing it. Daytime
power is at ON-Peak rates. You'd be better off to use night-time
OFF-peak rates to freeze some ice for you to sit on during the daytime
;-)

Since I'm now chief cook and bottle-washer while my wife recuperates
from 5 hours of back surgery, I do all clothes and dish-washing in the
early morning... (summer) ON-Peak here is 1PM to 9PM.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I'm looking for work... see my website.

 

[Tim Wescott]

On Wed, 22 Jun 2016 16:47:45 -0700, Jim Thompson wrote:

On Wed, 22 Jun 2016 18:41:59 -0500, Tim Wescott
seemywebsite@myfooter.really> wrote:

On Wed, 22 Jun 2016 16:14:18 -0700, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is
HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When
the power from the PV is temporarily reduced by clouds the freezer
unit would cut off while the heat pump would remain running. The
clouds should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it
'needs' to be -- so it may be more efficient to find a substance that
freezes at 60 degrees F or so, is cheap, easy to handle, has a
significant heat of fusion, and isn't something that would turn the
entire neighborhood into a superfund site if the tank leaks. Maybe some
other wax, from the same place you're getting your 80-degree (or 100
degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

If it was a good idea someone would be already doing it. Daytime power
is at ON-Peak rates. You'd be better off to use night-time OFF-peak
rates to freeze some ice for you to sit on during the daytime ;-)

Since I'm now chief cook and bottle-washer while my wife recuperates
from 5 hours of back surgery, I do all clothes and dish-washing in the
early morning... (summer) ON-Peak here is 1PM to 9PM.

...Jim Thompson

I think Bret was thinking of off-grid stuff.

But yes, freeze over night, melt during the day if that's what's
favorable.

Do they buy energy back during on-peak at on-peak pricing?

--
Tim Wescott
Control systems, embedded software and circuit design
I'm looking for work! See my website if you're interested
http://www.wescottdesign.com

 

[Jim Thompson]

On Wed, 22 Jun 2016 20:43:33 -0500, Tim Wescott <tim@seemywebsite.com>
wrote:

On Wed, 22 Jun 2016 16:47:45 -0700, Jim Thompson wrote:

On Wed, 22 Jun 2016 18:41:59 -0500, Tim Wescott
seemywebsite@myfooter.really> wrote:

On Wed, 22 Jun 2016 16:14:18 -0700, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is
HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When
the power from the PV is temporarily reduced by clouds the freezer
unit would cut off while the heat pump would remain running. The
clouds should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it
'needs' to be -- so it may be more efficient to find a substance that
freezes at 60 degrees F or so, is cheap, easy to handle, has a
significant heat of fusion, and isn't something that would turn the
entire neighborhood into a superfund site if the tank leaks. Maybe some
other wax, from the same place you're getting your 80-degree (or 100
degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

If it was a good idea someone would be already doing it. Daytime power
is at ON-Peak rates. You'd be better off to use night-time OFF-peak
rates to freeze some ice for you to sit on during the daytime ;-)

Since I'm now chief cook and bottle-washer while my wife recuperates
from 5 hours of back surgery, I do all clothes and dish-washing in the
early morning... (summer) ON-Peak here is 1PM to 9PM.

...Jim Thompson

I think Bret was thinking of off-grid stuff.

But yes, freeze over night, melt during the day if that's what's
favorable.

Do they buy energy back during on-peak at on-peak pricing?

I don't do solar... solar is for fairies >:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I'm looking for work... see my website.

 

[Dan Coby]

On 6/22/2016 4:41 PM, Tim Wescott wrote:

On Wed, 22 Jun 2016 16:14:18 -0700, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the
ice at night. Maybe 2/3rds of the solar power goes to running the
conventional AC or heat pump during the day and 1/4 goes to freezing
water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the
power from the PV is temporarily reduced by clouds the freezer unit
would cut off while the heat pump would remain running. The clouds
should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it 'needs'
to be -- so it may be more efficient to find a substance that freezes at
60 degrees F or so, is cheap, easy to handle, has a significant heat of
fusion, and isn't something that would turn the entire neighborhood into
a superfund site if the tank leaks. Maybe some other wax, from the same
place you're getting your 80-degree (or 100 degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

I worked on several projects during the late 70's and early 80's that
were making and storing cold water at night and then using it to cool
buildings during the day. The largest was an IBM facility near Tucson
that was 14 buildings and around 1.5 million sq ft. If my memory is
correct, it had 13 large storage tanks. I forget how many millions of
gallons of water.

Dan

 

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the
ice at night. Maybe 2/3rds of the solar power goes to running the
conventional AC or heat pump during the day and 1/4 goes to freezing
water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the
power from the PV is temporarily reduced by clouds the freezer unit
would cut off while the heat pump would remain running. The clouds
should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it 'needs'
to be -- so it may be more efficient to find a substance that freezes at
60 degrees F or so, is cheap, easy to handle, has a significant heat of
fusion, and isn't something that would turn the entire neighborhood into
a superfund site if the tank leaks. Maybe some other wax, from the same
place you're getting your 80-degree (or 100 degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

I worked on several projects during the late 70's and early 80's that
were making and storing cold water at night and then using it to cool
buildings during the day.

Evaporative cooling is popular in AZ. Even though it wastes precious water a binary system can cut energy costs by 80% except in August. MasterKool swamp cools air before it enters the condenser. Hard & salty Colorado River water eats through Al and fouls everything up so unless they were on a well with a water softener most residential customers went back to high delta T high energy consumption AC.

The largest was an IBM facility near Tucson
that was 14 buildings and around 1.5 million sq ft. If my memory is
correct, it had 13 large storage tanks.

Probably a cooling tower + storage tanks. They ran the cooling tower at night with off peak power from the coal powered plant

I forget how many millions of
gallons of water.

That's one reason to go with a higher delta T [lower COP] and freeze water: It reduces the size of the heat storage by an order of magnitude.

Another reason is ice making equipment is off the shelf, cheaper than battery storage by an order of magnitude on a / joule basis.

A 3rd reason is the blower at night doesn't need to draw as much power.

There are more issues here than pure thermo and heat exchange.


Bret Cahill

 

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is HVAC..
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the
ice at night. Maybe 2/3rds of the solar power goes to running the
conventional AC or heat pump during the day and 1/4 goes to freezing
water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the
power from the PV is temporarily reduced by clouds the freezer unit
would cut off while the heat pump would remain running. The clouds
should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water?

A lot of swimming pools in SoCal are empty because of lack of water so the question isn't "got room" but "got water?"

Just stick the ice maker in the empty pool, the PV on the roof and call it a day.

IIRC, there's energy
losses involved in pushing a given amount of heat farther than it 'needs'
to be -- so it may be more efficient to find a substance that freezes at
60 degrees F or so, is cheap, easy to handle, has a significant heat of
fusion, and isn't something that would turn the entire neighborhood into
a superfund site if the tank leaks.

If an idea requires tweaking from the git go, get another idea.

There's way too much low hanging fruit on the ground to tweak.

Maybe some other wax, from the same
place you're getting your 80-degree (or 100 degree, or whatever) paraffin..

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

I'm real big on back of envelope calculations when I wake up at 2 am.

I woke up at 1 am a couple of weeks ago wondering, "hey, I just happened to coincidentally wake up in the middle of an earth quake! What are the odds of that?" I looked up at the massive ceiling fan and tried to detect any wobble, to calculate the stresses that any change in angular momentum would put on whatever was keeping it from falling on my left foot.

Finally I got up, turned off the fan and went back to sleep.

Problem solved!

 

Il giorno giovedĂŹ 23 giugno 2016 06:08:32 UTC+2, Dan Coby ha scritto:

I worked on several projects during the late 70's and early 80's that
were making and storing cold water at night and then using it to cool
buildings during the day. The largest was an IBM facility near Tucson
that was 14 buildings and around 1.5 million sq ft. If my memory is
correct, it had 13 large storage tanks. I forget how many millions of
gallons of water.

Dan

The CSCS (Swiss National Supercomputing Center) uses water from the lake to cool down the computers and the building:
http://cscs.ch/cscs/an_innovative_centre/cooling_system/index.html

Bye Jack

 

[default]

On Wed, 22 Jun 2016 19:58:36 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Wed, 22 Jun 2016 20:43:33 -0500, Tim Wescott <tim@seemywebsite.com
wrote:

On Wed, 22 Jun 2016 16:47:45 -0700, Jim Thompson wrote:

On Wed, 22 Jun 2016 18:41:59 -0500, Tim Wescott
seemywebsite@myfooter.really> wrote:

On Wed, 22 Jun 2016 16:14:18 -0700, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is
HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When
the power from the PV is temporarily reduced by clouds the freezer
unit would cut off while the heat pump would remain running. The
clouds should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it
'needs' to be -- so it may be more efficient to find a substance that
freezes at 60 degrees F or so, is cheap, easy to handle, has a
significant heat of fusion, and isn't something that would turn the
entire neighborhood into a superfund site if the tank leaks. Maybe some
other wax, from the same place you're getting your 80-degree (or 100
degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

If it was a good idea someone would be already doing it. Daytime power
is at ON-Peak rates. You'd be better off to use night-time OFF-peak
rates to freeze some ice for you to sit on during the daytime ;-)

Since I'm now chief cook and bottle-washer while my wife recuperates
from 5 hours of back surgery, I do all clothes and dish-washing in the
early morning... (summer) ON-Peak here is 1PM to 9PM.

...Jim Thompson

I think Bret was thinking of off-grid stuff.

But yes, freeze over night, melt during the day if that's what's
favorable.

Do they buy energy back during on-peak at on-peak pricing?

I don't do solar... solar is for fairies >:-}

...Jim Thompson

 

[Dan Coby]

On 6/22/2016 10:48 PM, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the
ice at night. Maybe 2/3rds of the solar power goes to running the
conventional AC or heat pump during the day and 1/4 goes to freezing
water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the
power from the PV is temporarily reduced by clouds the freezer unit
would cut off while the heat pump would remain running. The clouds
should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it 'needs'
to be -- so it may be more efficient to find a substance that freezes at
60 degrees F or so, is cheap, easy to handle, has a significant heat of
fusion, and isn't something that would turn the entire neighborhood into
a superfund site if the tank leaks. Maybe some other wax, from the same
place you're getting your 80-degree (or 100 degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

I worked on several projects during the late 70's and early 80's that
were making and storing cold water at night and then using it to cool
buildings during the day.

Evaporative cooling is popular in AZ. Even though it wastes precious water a binary system can cut energy costs by 80% except in August. MasterKool swamp cools air before it enters the condenser. Hard & salty Colorado River water eats through Al and fouls everything up so unless they were on a well with a water softener most residential customers went back to high delta T high energy consumption AC.

The largest was an IBM facility near Tucson
that was 14 buildings and around 1.5 million sq ft. If my memory is
correct, it had 13 large storage tanks.

Probably a cooling tower + storage tanks. They ran the cooling tower at night with off peak power from the coal powered plant

Actually the cooling was done via 'chillers' which are industrial size
heat pumps.

I forget how many millions of
gallons of water.

That's one reason to go with a higher delta T [lower COP] and freeze water: It reduces the size of the heat storage by an order of magnitude.

However the higher the delta T that you are trying to create the less
efficient the system will be. Like any system there are trade offs. A
smaller temperature difference requires more storage but it takes less
total energy. Like many cases, you are trading off the initial cost of
the storage system versus operating costs.

Another reason is ice making equipment is off the shelf, cheaper than battery storage by an order of magnitude on a / joule basis.

A 3rd reason is the blower at night doesn't need to draw as much power.

The major reason for running the chillers at night is that it is much
easier to make cold water when it is cooler outside. In Tucson, there
can be major differences between day and night time temperatures. That
was the main reason that the cold water storage system was able to save
on energy costs. Now there is probably a different price for night time
versus day time energy use. However I do not know if that was true in
1979 when we were building this system.

There are more issues here than pure thermo and heat exchange.


Bret Cahill

 

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the
ice at night. Maybe 2/3rds of the solar power goes to running the
conventional AC or heat pump during the day and 1/4 goes to freezing
water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the
power from the PV is temporarily reduced by clouds the freezer unit
would cut off while the heat pump would remain running. The clouds
should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it 'needs'
to be -- so it may be more efficient to find a substance that freezes at
60 degrees F or so, is cheap, easy to handle, has a significant heat of
fusion, and isn't something that would turn the entire neighborhood into
a superfund site if the tank leaks. Maybe some other wax, from the same
place you're getting your 80-degree (or 100 degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

I worked on several projects during the late 70's and early 80's that
were making and storing cold water at night and then using it to cool
buildings during the day.

Evaporative cooling is popular in AZ. Even though it wastes precious water a binary system can cut energy costs by 80% except in August. MasterKool swamp cools air before it enters the condenser. Hard & salty Colorado River water eats through Al and fouls everything up so unless they were on a well with a water softener most residential customers went back to high delta T high energy consumption AC.

The largest was an IBM facility near Tucson
that was 14 buildings and around 1.5 million sq ft. If my memory is
correct, it had 13 large storage tanks.

Probably a cooling tower + storage tanks. They ran the cooling tower at night with off peak power from the coal powered plant

Actually the cooling was done via 'chillers' which are industrial size
heat pumps.

Evaporative cooling will only get you down so far. Then you need ac or heat pump.

I forget how many millions of
gallons of water.

That's one reason to go with a higher delta T [lower COP] and freeze water: It reduces the size of the heat storage by an order of magnitude.

However the higher the delta T that you are trying to create the less
efficient the system will be.

The delta T is 60 degrees C in the summer afternoon desert sun so maybe a 100,000 BTU/hr refrigeration unit freezing a high latent heat phase change material at 50 degrees might be better than a icemaker freezing 2 tons water/day.

But what is that material?

If you have an empty swimming pool you might try using sensible heat like IBM.

Like any system there are trade offs. A
smaller temperature difference requires more storage

Storage goes up mostly because any material with the right freezing point, say, 50 C, will probably have a much lower latent heat of fusion than H2O.

but it takes less
total energy. Like many cases, you are trading off the initial cost of
the storage system versus operating costs.

Another reason is ice making equipment is off the shelf, cheaper than battery storage by an order of magnitude on a / joule basis.

A 3rd reason is the blower at night doesn't need to draw as much power.

The major reason for running the chillers at night is that it is much
easier to make cold water when it is cooler outside. In Tucson, there
can be major differences between day and night time temperatures.

As opposed to Phoenix which is still over 40 C when they close the bars.

That
was the main reason that the cold water storage system was able to save
on energy costs. Now there is probably a different price for night time
versus day time energy use. However I do not know if that was true in
1979 when we were building this system.

Back then it was definitely cheaper at night so IBM found a nice dove tail, lower rates & lower temperatures.

Soon power will be cheaper during the day because solar is so cheap.

Most off-grid homes have a smaller % of roof area paneled than the SDG&E or SoCal Edison deals which are supplying energy to the rest of the neighborhood during peak usage.

So there is plenty of room to add more panels to power the ice maker as well as the AC.

This would save some money even if you stayed on the grid because you wouldn't draw much energy from the grid at night.

With off grid solar it would really save a lot of money. Off grid homes typically have a shed full of batteries + a propane engine for back up power.

If you wanted to go off grid in hot areas it would be much cheaper to trade most of the batteries and/or the engine for an ice maker and more solar panels.


Bret Cahill

 

[Jasen Betts]

On 2016-06-22, Bret Cahill <bretcahill@aol.com> wrote:

90% of the electric bill in the desert at this time of the year is
HVAC. The rest of the house doesn't need so much power and only
requires a small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

What makes you think active cooling is needed at night?



--
This email has not been checked by half-arsed antivirus software

 

[Jasen Betts]

On 2016-06-23, Bret Cahill <bretcahill@aol.com> wrote:

I woke up at 1 am a couple of weeks ago wondering, "hey, I just
happened to coincidentally wake up in the middle of an earth quake!
What are the odds of that?"

A massive earthquake is almost guaranteed to wake you.
(there's a small chance that it will kill you instead)


--
This email has not been checked by half-arsed antivirus software

 

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is
HVAC. The rest of the house doesn't need so much power and only
requires a small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

What makes you think active cooling is needed at night?

Most people sleep better below 38 C.


Bret Cahill

 

On Wednesday, June 22, 2016 at 7:14:22 PM UTC-4, Bret Cahill wrote:

90% of the electric bill in the desert at this time of the year is HVAC. The rest of the house doesn't need so much power and only requires a small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the ice at night. Maybe 2/3rds of the solar power goes to running the conventional AC or heat pump during the day and 1/4 goes to freezing water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the power from the PV is temporarily reduced by clouds the freezer unit would cut off while the heat pump would remain running. The clouds should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time heating.


Bret Cahill

Another benifit: ice ready for your drinks!

 

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is HVAC. The rest of the house doesn't need so much power and only requires a small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into the ice at night. Maybe 2/3rds of the solar power goes to running the conventional AC or heat pump during the day and 1/4 goes to freezing water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When the power from the PV is temporarily reduced by clouds the freezer unit would cut off while the heat pump would remain running. The clouds should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time heating.


Bret Cahill

Another benifit: ice ready for your drinks!

Several patents cover PV on motor vehicles powering a small freezer for instant cold ac. Shorter trips are very common so it would save a considerable amount of fuel. The regular ac would only draw power from the engine on longer trips.

There should always be a cold non alcoholic drink at the ready near the front seat.


Bret Cahill

 

[Jasen Betts]

On 2016-06-24, Bret Cahill <bretcahill@aol.com> wrote:

90% of the electric bill in the desert at this time of the year is
HVAC. The rest of the house doesn't need so much power and only
requires a small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

What makes you think active cooling is needed at night?

Most people sleep better below 38 C.

You don't get that at night time in a desert.

--
This email has not been checked by half-arsed antivirus software

 

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is
HVAC. The rest of the house doesn't need so much power and only
requires a small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

What makes you think active cooling is needed at night?

Most people sleep better below 38 C.

You don't get that at night time in a desert.

Phoenix is always over 40C in August when high humidity traps heat. Stucco and the rest of the building heat up so much it takes all night for the interior to cool off the rest of the summer. If you try to hose down a wall or sidewalk in California they'll geotag you with the water stazi app.

Last year I took out a bad attic fan. The high temp. limit, 70C, was marked on the motor. The new motor will be dead in another year or so.

Wood shake is a popular roof cover here because it doesn't evaporate like asphalt composition w/ a dead attic fan.

It might be years before you know you have a leak.


Bret Cahill

 

[Bret Cahill]

90% of the electric bill in the desert at this time of the year is
HVAC.
The rest of the house doesn't need so much power and only requires a
small low cost battery for night time.

Freeze about 2 tons of water during the day and then sink heat into
the ice at night. Maybe 2/3rds of the solar power goes to running
the conventional AC or heat pump during the day and 1/4 goes to
freezing water for evening and night time cooling.

Load level with the freezer unit and the much smaller battery. When
the power from the PV is temporarily reduced by clouds the freezer
unit would cut off while the heat pump would remain running. The
clouds should cool things off anyway.

In winter the heat pump would melt a tank of paraffin for night time
heating.


Bret Cahill

Sounds good. You got room for that much water? IIRC, there's energy
losses involved in pushing a given amount of heat farther than it
'needs' to be -- so it may be more efficient to find a substance that
freezes at 60 degrees F or so, is cheap, easy to handle, has a
significant heat of fusion, and isn't something that would turn the
entire neighborhood into a superfund site if the tank leaks. Maybe some
other wax, from the same place you're getting your 80-degree (or 100
degree, or whatever) paraffin.

Note that I managed to dodge taking thermodynamics in school -- so go do
your own math on this.

If it was a good idea someone would be already doing it. Daytime power
is at ON-Peak rates. You'd be better off to use night-time OFF-peak
rates to freeze some ice for you to sit on during the daytime ;-)

Since I'm now chief cook and bottle-washer while my wife recuperates
from 5 hours of back surgery, I do all clothes and dish-washing in the
early morning... (summer) ON-Peak here is 1PM to 9PM.

...Jim Thompson

I think Bret was thinking of off-grid stuff.

But yes, freeze over night, melt during the day if that's what's
favorable.

You can freeze during the day - there is a less popular heat pump
refrigeration type that uses ammonia and no moving parts - it simply has a
thermostatically controlled heating element at a specific point in the
plumbing.

Cut out the moving mechanical part from a refrigerator, the compressor, and a heat engine, the expander, and splice together what is remaining of each loop.

A small array of curved reflectors/collectors would suffice to focus a beam
of sunlight on the bit that needs to get hot.

Instead of CHP (combined heating and power) here's CCP:

http://www.sciencedirect.com/science/article/pii/S187770581202005X


Bret Cahill