Solar Heating and Car Radiator Cooling

[Shaun Sweeney]

Lookout everybody. I found the "new post" button.
I use solar evacuated tubes to provide hot water for heating my house so on my recent upgrade (to 2 140 gallon 1/2 pipe tanks) I decided to use my hot water reservoir to heat my salt water system and save on heater electricity. Also decided to use a car radiator for cooling. Here are the details:

A feed from the solar reservoir (740 gallon) is circulated thru a small metal tank that sits under my primary filtration tank. Heat radiates up into the tank. That same circuit continues on thru two home made PVC heat exchange units. One sits in the main sump (just before the return pumps) and the other sits in my skimmer tank (under my Vertex 250 skimmer).

As the water exits the skimmer heat exchange, it encounters a "T" that allows water to flow back to the solar reservoir or on and thru the car radiator. The car radiator has a simple house fan pointed at it. There is no valve at this point so water could really go either way.

The line to the solar reservoir has no valve either however, where the water is allowed to flow happens at two points. The line returning from the radiator has a "normally closed" electric valve and it returns upstream of the circulating pump. There is also an additional "normally open" electric upstream of the pump.

The heating/cooling system is controlled by my Apex and uses two outlets and here is the logic:

If the fish tank system needs heat, the power to the circulating pump is on but power to the valves is off. In this mode, water from the solar reservoir is pushed thru the small tank and two heat exchange units but it is unable to go thru the radiator. The fan is on the same circuit as the pump so it is on but having no effect on water temp.

If the fish tank system is up to temp with no heat needed, power to the circulating pump is off and power to the electric valves is on. There is zero circulation.

If the fish tank system needs cooling, the power to the circulating pump is on as is power to electric valves is on. Water from the solar reservoir is blocked (the normally open valve is now closed) and water is circulated thru the heat exchange system and the car radiator. Since the circulating pump is on, the fan is on and heat is taken from the radiator.

How "cool" is all of that ....

 

[Shaun Sweeney]

Ooops ... the first sentence says "cooling" but should say "heating".

 

[Kershaw]

How are you running the water through the car radiator? Is the tank water directly exposed to the metal of the radiator?

 

[dbl]

Ooops ... the first sentence says "cooling" but should say "heating".

Not any more.

 

[Shaun Sweeney]

None of the solar heating reservoir water comes in contact with the aquarium water. Similarly, no metal (from the radiator tank under the primary filtration tank or radiator) touches any aquarium water.

 

[Kershaw]

I have thought about doing somthing like this in the future for a cold saltwater pond. The idea was to lay pvc piping a few feet down in the ground where the tempature is always the same. Would be allot cheaper then running a chiller. Post some pictures. I would like to see how you are doing this

 

[JamesP]

I dont think the wife would let me put part of a car in the living room lol. Its cool dont get me wrong, and i would love to see pics, but i think throwing in a $20 heater may have been more for me.

 

[Shaun Sweeney]

Pics from my "boiler room" would just scare you folks so I'll do a schematic and post it asap. Today was a bit of a medical emergency (literally off to the emergency room) but maybe tomorrow. Meanwhile, got to thinking about it (and reviewing electrical bills) and I'm betting that it would be cheaper to use a small hot water tank to heat the aquarium rather than those power sucking heaters - which sometimes explode. The hot water tank would just be substituted for my reservoir.

 

[Shaun Sweeney]

I dont think the wife would let me put part of a car in the living room lol. Its cool dont get me wrong, and i would love to see pics, but i think throwing in a $20 heater may have been more for me.

Yeah, I had the same problem until I figured out I should take the rad out of the car ...

 

[JamesP]

Pics from my "boiler room" would just scare you folks so I'll do a schematic and post it asap. Today was a bit of a medical emergency (literally off to the emergency room) but maybe tomorrow. Meanwhile, got to thinking about it (and reviewing electrical bills) and I'm betting that it would be cheaper to use a small hot water tank to heat the aquarium rather than those power sucking heaters - which sometimes explode. The hot water tank would just be substituted for my reservoir.

I hope you're feeling better Shaun. I just saw a post the other day of an exploding heater.

 

[Shaun Sweeney]

Thanks for asking James. It was my wife who had the problem but she's dealing with it. I saw the exploding heater post as well and scared the crap out of me. What a disaster that would be. I've got my solar heating tweaked now so that the heater never come on. Each tank has a single heater that should only come on in the case of an emergency power outage where no warm water is getting circulated. Even if they don't explode, they sure get pricey to operate.

 

[reefwiser]

I have seen this type of set up on aquariums before it works its just not something everyone would have the space to do.

 

[Shaun Sweeney]

Quite right about the space - particularly the heating loop - but less so if you can get some plumbing run outside and into the ground for cooling.