I change out a lot (100+ gallons/day) of water. It has always bothered me how much warm water I have been dumping down the drain. Recently I started thinking about a DIY heat exchanger to help reduce the cost of heating all the fresh water. I have a well, so water cost and chlorine are not a problem. The water comes out between 56 and 60 degrees, which really makes my heaters work.
I run four tanks off of a central sump located in my crawl space. The sump is a 300 gallon Rubbermaid stock tank. There is a 210 gallon, heavily-stocked New World Cichlid tank in my living room. There are three tanks in the garage - a 135 with two big cats, a 25 isolation tank, and a 55 grow-out.
The cores of the heat exchanger are made of two 26" x 1" pieces of thin-wall PVC (for incoming fresh water) and about 70' of 1/4" copper refrigeration tubing (for the waste water). I wanted to use brass instead of PVC for better heat exchange, but at $340.00 for a 20' piece I decided against it.
After wrapping the PVC pieces with the copper tubing I joined the PVC with two elbows and the copper with a compression coupling. I added compression adapters and 3/8" PEX to the ends of the PVC. I connected 3/8" I.D. vinyl tubing to the copper for the waste water.
The next step was insulating. For this to be efficient it needs to be very well insulated. I started with foam pipe insulation and then wrapped the whole unit in two layers of aluminized "bubble-wrap" type insulation.
I run four tanks off of a central sump located in my crawl space. The sump is a 300 gallon Rubbermaid stock tank. There is a 210 gallon, heavily-stocked New World Cichlid tank in my living room. There are three tanks in the garage - a 135 with two big cats, a 25 isolation tank, and a 55 grow-out.
The cores of the heat exchanger are made of two 26" x 1" pieces of thin-wall PVC (for incoming fresh water) and about 70' of 1/4" copper refrigeration tubing (for the waste water). I wanted to use brass instead of PVC for better heat exchange, but at $340.00 for a 20' piece I decided against it.
After wrapping the PVC pieces with the copper tubing I joined the PVC with two elbows and the copper with a compression coupling. I added compression adapters and 3/8" PEX to the ends of the PVC. I connected 3/8" I.D. vinyl tubing to the copper for the waste water.
The next step was insulating. For this to be efficient it needs to be very well insulated. I started with foam pipe insulation and then wrapped the whole unit in two layers of aluminized "bubble-wrap" type insulation.