Solar Hot Water "Batch Collector"

Solar Hot Water "Batch Collector":

These installations provide year-round domestic water heating using our abundant Southwest sunshine. A system such as the one pictured above can reduce your electric, natural gas or propane consumption and your monthly bill or greatly extend your propane tank refill interval. Why doesn't everyone have one?

Use as Pre-heater, Stand-Alone, or Both:

A solar batch collector provides ample hot water during the warmer months for most families with zero back-up heating from gas, propane or electricity. In the winter months, depending on your family's habits and needs, a double-tank collector like the one pictured above may also provide enough hot water for stand-alone use. Alternatively, for large families or early morning showers, a batch collector can be used to pre-heat the water going into your conventional or tankless hot water heater.

Our experience is that a single-tank batch collector usually doesn't provide warm enough water during the coolest months for stand-alone use. The double-tank design, however, provides the sufficient boost without adding much complexity to the insulated box housing or to the installation. A client recently reported running two hot baths, back-to-back during a blizzard over New Years from one of our stand-alonedouble tank installations.   

Construction and Installation Services:Construction and installation of a batch collector is a project most DIY folk can handle and we encourage to try it! Please feel free to copy our design in whole or part and let us know how your project goes. If you don't feel up to the job, you can hire us or your favorite handy-man to build it for you. Below is a general description of our process. We salvage the steel tanks from discarded conventional hot water heaters, usually 30gal or 40gal units. The sheet metal skin, insulation, and old fittings are removed and the tanks cleaned inside and out and painted flat black. We purchase double-pane windows from a used construction materials center and design the insulated box to fit thetanks and the windows. The box is constructed of 2x4s and plywood with 1x2 furring strips used to frame in the windows. We create our own insulation sheets by laminating multiple layers of corrugated cardboard (R-value 4 to 5 per inch!) and then cutting to size to fit the box. We use three inches thickness of corrugated cardboard on the back-side and 1 1/2" along the side walls of the box. The interior surface of the cardboard insulation is lined with heavy duty aluminum foil to reflect sunlight onto the backsides of the tanks for optimal efficiency. The two tanks are plumbed together using PEX fittings and PEX tubing. The plumbing of the tanks takes advantage of natural thermal stratification inside each of the tanks (hot water rises to the top) to ensure that the hottest water gets delivered to your domestic faucets.

We will visit your site to determine optimum placement of the batch collector for solar gain and access to your existing plumbing. We need a pressurized cold water line to feed the batch collector, and a way to get the hot water into your house, usually near your existing hot water heater. If you are doing new construction, you may want to consider stub-outs through the foundation wall for a batch collector!

We generally build the box and prepare the tanks at our workshop, which takes about 18-24 hours of work. Installation takes another 4-12 hours, depending