Connor Macreno

"Where are you getting a 25+% loss from without having a design?"
When I had read up on zeolite heat pumps and heat storage I read that the efficiencies achieved with zeolite heat pumps were 10 to 60% and the highest efficiency that could be achieved (with the types of zeolite they were using in the zeolite heat storage system I was reading about) was 75%. My understanding is there are inherent loses converting thermal energy to chemical and back (probably less than the 75% before other loses,but I was accepting this as a reasonable best case).

"I thought Zeolite performed best in a vacuum closed loop system."
I thought the advantage of the vacuum was that it allows the zeolite to be regenerated at a lower temperature. That only helps for half the problem I'm trying to overcome.

"What grade of Zeolite are you referring to or can you source? Post some material properties and a system design so we can look at it."
I don't even know if zeolite is the best choice. I don't have enough material properties data.

"Lots of different grades and varying material properties out there, both natural and synthetic."
Yep, but so far I haven't had much luck finding useful information on the different materials.

Right now I have a general idea and lots of questions; nothing close to a design yet.

I don't want a system where the compressor has to run continuously while heat is being extracted.
I'm thinking of zeolite in a pressure vessel, where the pressure is adjusted down before the heat is stored and back up before it's extracted. Like a solar zeolite heat pump, but upping the pressure and extracting the heat at a higher temperature than the solar collector originally provided; possibly even using a lower temperatures heat source (I'm thinking compost heat) to regenerate the desiccant.
I'm not sure how low the temperature can be for regenerating zeolite and at what pressure, or what other desiccant material may work better for lower regeneration temperatures.

I know there are materials that release water when heated and produce heat when water is added. I understand that it normally requires higher heat to dry/regenerate the materials than the heat released when the materials are saturated, but the heat required can be reduced by lowering the air pressure.

I'm wondering, if you lower the pressure while heating the material, then raise the pressure before saturating, can you extract heat at a higher temperature than the heat it was regenerated at?

I know the total energy out will be less than the energy in. Iirc the best you can achieve with zeolite is 75% (or less) of the heat applied. I'm thinking that heating it slowly at low pressure and then saturating it quickly at high pressure could produce higher heat for a shorter duration.

"Personally I think there is a future in compost energy generation, but I am not sure it would be in microhydro. I think the future lies in using the heat of compost for the heat side of a Stirling Engine, and ground temperature for the cool side"
I like this idea, but we can do better than ground temperature for the cool/cold side.
Check out passive ice boxes and zeolite ice makers.

A solar recharging zeolite system should be able to provide hot water and ice.
With heat exchangers that should handle heating, cooling, and refrigeration.
The temperature difference should be more than enough to run a sterling pump for the heat exchange.

I'm thinking it'd be fun to build a small scale system to try this out. Maybe just big enough to use for a crock pot and chest cooler?

http://www.solaripedia.com/13/389/5545/solar_zeolite_ice_maker_diagram.html

http://m.rimg.geoscienceworld.org/content/45/1/589.short

Disappearing link...

I had put in a link to an article about zeolite heat storage.

One of my neighbors owns this beauty. So envious...

Sigh. Just got to make do with my BikeE for now.

Google downhill handcycle. Tilting trike front ends are well developed and capable of handling rough terrain (and snow). Open Source Ecology is combining the tilting front end with a simple sturdy box beam long wheelbase recumbent.

I have a BikeE that I've greatly enjoyed, but probably wouldn't do much with off road. The extra stability with a trike and a fatter rear tire would probably be enough to change that. I'm eager to try something like this.