Fast-Payback Polymeric Solar Water Heaters with Controlled Heat Transfer

Solar water heaters are an efficient means to harvest energy from the sun to heat water for domestic use (i.e. bathing, washing dishes, etc.). However, the current solar water heating systems cost approximately $133/ft2 and have a payback period of 7-10 years, including incentives and rebates, which is prohibitively expensive for most homeowners. The initial expense is largely attributed to the solar collector (30%) and installation and labor costs (70%). The solar collectors for these systems are made mostly out of copper, which adds significant weight to the solar collector and increases its installation costs. The creation of a lighter weight, less expensive solar collector will help reduce the payback period while taking advantage of renewable solar water heating technologies. The overall objective of the Phase I and Phase II program is to develop and demonstrate a fully-glazed polymeric solar water heater with enhanced overheat protection. The proposed innovation will provide passive measures for enhanced heat transfer during dry stagnation, thus reducing the maximum temperature to a safe limit for polymer materials. Replacing metal components with polymeric materials will reduce the material and production costs of solar collectors and the overall weight of the solar collector. More importantly, the weight reduction will increase the ease of installation, thus reducing the largest portion of the system cost, the installation and labor. The proposed polymeric solar collector is expected to reduce the installed cost of solar water heating systems to $50/ft2 and the payback period to less than 5 years, excluding incentives and rebates. Advanced Cooling Technologies, Inc. (ACT) will partner with AET Solar, LLC. to create a first of its kind fully-glazed polymeric solar water heater. Tri-State Plastics, Inc. will serve as consultants for polymer selection and processing/manufacturing. Currently 13% of the energy usage in homes is to heat water for showering, washing clothes and dishes, and preparing food. In 2010, residential buildings in the United States used 840 billion kWh of energy for water heating at a cost of $97 billion. Solar water heating can alleviate 80% of this energy demand and reduce energy consumption by 673 billion kWh, saving $78 billion annually in the United States. Reducing the initial installation cost of solar water heating systems by incorporating polymer materials will enable more homeowners to participate in solar technologies, which reduce CO2 emissions and foreign fuel consumption.