SunCache pre-heats cold water before it enters a conventional backup water heater.
When a hot water tap is opened inside the house, water moves through the circuit. No pumps or controls are necessary.
The amount of heat added to the cold water by the SunCache system depends on weather, time of day, season, and recent hot water usage.
Because the backup water heater maintains the desired temperature set-point, occupant comfort is never compromised.
SunCache is compatible with all water heaters.
SIMPLIFIED PLUMBING SCHEMATIC
As cold water enters the SunCache collector, it passes through a copper heat exchanger inside the polyethylene panel. The heat exchanger is placed inthe mold along with the raw plastic resin at the start of each molding cycle, and the panel is rotationally molded around the copper tubing, creating a "ship-in-bottle" design.
CUT-AWAY ILLUSTRATION OF SUNCACHE COLLECTOR
With the copper heat exchanger containing the potable water, the water inside the polyethylene panel can be unpressurized, making it possible for the panel walls to be thin enough to tranfser solar energy, but strong enough to provide a Factor of Safety of 10:1.
After installtion, the panel is filled 50 gallons of water using a garden hose. Anti-freeze is not necessary. The water in the panel is static thermal storage, collecting solar energy and then transferring heat to the potable water inside the copper heat exchanger during hot water draws. The water in the panel never enters the domestic piping system, and only needs to be "topped-off" once every five years to replace the water lost to permeation through the panel walls.
Above the panel is a thermoformed glazing made from impact-modified acrylic. The glazing creates a semi-sealed air gap to reduce convective heat loss to the atmosphere. The glazing helps the panel to hold heat through the night, but like all ICS systems, SunCache works best with hot water draw patterns biased toward afternoon and evening usage. The glazing has a double-wall perimeter frame made from extruded aluminum by a major manufacturer of commercial skylights. Corners are MIG welded and the exterior extrusion has a durable brown baked enamel finish.
Stainless steel mounting hardware and fasteners tie the glazing frame and panel to three rafters or trusses, securing the system against wind uplift forces. In testing, SunCache glazing assemblies survived uplift forces equipvalent to winds of 105 MPH (34 PSF). The panel rests directly on the roof surface, spreading its 520 lb weight (filled) across five rafters/trusses and 35 square feet of roof. At less than 15 PSF, the weight of the SunCache collector is less than the 20 PSF dead load that most roofs are built to withstand.
To meet plumbing codes and SRCC requirements, every SunCache system shall include a variety of plumbing components. To ensure compliance, reduce cost, and simplify installation, the SunCache system includes a pre-assembled valve package with the following components:
Isolation valve (for cold water inlet)
Bypass valve (to bypass the SWH system during repairs)
Pressure-relief valve
Drain valve
Thermometer (to verify operation)
Four solderless Sharkbite™ fittings (to make connections between the copper stubs on the collector and valve package and the PEX piping of the supply and return lines, also compatible with all-copper plumbing)
The installer provides only the PEX tubing (length depending on installation) and a tempering valve (aka thermostatic mixing valve) to provide protection against scalding water. Depending on cold-in and mixing valve connections, it may be possible to perform the SunCache installation without any solder connections.
