I guess I could work the valves idea; how do you propose it might work? Use with valves open during warm ups I know have heat left in the wax and close them off until after the car is fully warmed up?
When the engine is completely cold (been off for 12+ hours) keep coolant flow from reaching the wax heat sink. Drive it until until the coolant gauge shows that the coolant is up to operating temp and then open the valve that allows hot coolant to circulate through the wax thermal storage device (this heat would have been dissipated out the radiator anyway).
When you restart after sitting for just minutes or up to 6 or so hours, let the coolant circulate through the wax device for the first 60 seconds after start up (hopefully heating the coolant up somewhat) then shut off flow to the device (so it doesn't slow down the remainder of the warm up). Open flow to it back up once you get all the way to operating temp.
Ideally, you would have a thermometer in the wax. You start the engine after it had been sitting just a few hours. As it runs, you note the time that the wax temp has stops falling (that would tell you that it has warmed the coolant up as much as it can) and then you would shut off flow to the wax device to prevent it from absorbing heat during the last part of the warm up period.
Well, in this scenario, all I would need would be two t-connectors for the heater core lines. When I did not want coolant to circulate through the wax exchanger, I'd have to plumb in a shut off valve right after one of those t's. Preferably for practical purposes, that valve needs to be inside the cab. I wonder how I might run that... drilling holes in the firewall sucks. There are some existing holes for wiring, but nothing really big enough that I can see. (or can take the 200df temps)
I don't think I'd need a venturi to help flow into the unit, but I'm not sure about that. I wonder how much flow would go through it? Maybe I could use a larger diameter coolant line than feeds the heater core to run my storage unit with. That might help coolant flow through it instead of the heater core.
Any thoughts on this?
I plan to monitor temperature inside this device. It would be much more efficient with a simple valve, I think you are right. I could also monitor coolant temp going into the heat exchanger too. When the temp is greater going in than it is inside the unit, off goes the valve. This way it would be effective even if the temp inside was just 10 or 20df greater.
If I'm going to put a valve in, I could put a spring loaded type one-way valve in on the other side. That would further isolate the warmer coolant from the cooling off coolant. It would be a trick to get flow to go through it and not through the heater core when I want it to.... hmm. Maybe a 3-way valve? Instead of a T? Is there such a thing as a T-valve that doesn't shut off but re-directs flow from one outlet to the other? Time for a trip to the plumbing section.....
It's going to require a few more bits...
Two digital thermometers
Two plastic T's/clamps
25' of hose or so
Black iron pipes/caps
Rigid foam/tape to hold it together while the great stuff sets up
A shut off valve (which would also help to isolate the warmer coolant)
Non-flammable fiberglass type pipe insulation/tape
As I recall from my old shorty 2 ton school bus I had, there were heater shut off valves under the hood. This was because the rear heaters were in the bypass loop but added like 10 gallons or more to the system.
The temp selector knob on my 87 civic is connected by a cable (like a lawnmower throttle cable) to a heater hose valve under the hood. You could likely get a few of these valves and not have to drill any big holes through the firewall (just a few 1/4" holes).
I don't know if I have ever seen a three way bypass type valve, you may just have to use two valves one either side of a T and wire them so that when one opens, the other closes.
There are backflow preventing valves- some have a metal housing and and have a one way metal flapper door that closes by gravity.
Good idea on the cable valve... my volvo wagon has a vacuum operated one.... Maybe I can scarf that one (or one from the scrap yard) and control it with vacuum provided by me.....
Or something else.
All good ideas. I'll scower the yards and see if I can find a civic/crx like that. Then all I would need is a lawnmower choke assembly cable thingy.
Maybe I'll even scarf some of the other parts I need for the project in the yard. There's a yard near me that charges dirt for things not in their inventory. (sometimes even free) Maybe some t's, stainless clamps, some brackets....
My favorite place to be is the scrap yard.
If you really want to warm up then put the wax storage inside the passenger compartment like under the seat where the heat loss would warm the car where YOU are as it looses some heat. Just run heater hose through the wax so you don't have to worry about the cooling wax crushing anything - I don't think it has that kind of strength anyway - and you can pinch off the hose when the wax is cold to stop the coolent from heating the wax during engine warmup. You could also add a small electric coolent pump to transfer the heat from the wax to the engine before you start it up. Simple test of the phase change energy content would be to just heat up some wax and put a bottle of cold water to it and see how hot the water gets per volume of hot wax.