Wellstone Apartments Solar Thermal Solar Evaluation

The Wellstone is a 49-unit apartment building located just south of downtown Minneapolis that serves the affordable housing market. The project's solar domestic hot water system is designed with the intention of providing between 30% and 50% of the building's hot water demand during a typical year. In addition to the renewable systems, the project was built with low-consumption water fixture to reduce the total water demand.

The solar domestic hot water system consists of 24 4'x10' Solar Skies collectors, mounted in a fixed position on the roof of the four story apartment building. A glycol loop and heat exchanger transfer the heat collected on the roof into two 505-gallon water storage tanks located in the basement. Conventional natural gas fired hot water heaters supplement the solar system in order to satisfy the building's hot water demands.

The cost of the solar thermal system was approximately $125,000. Hope Communities received a $10,000 Minnesota Solar Hot Water rebate and expects a simple payback of 7-9 years.

In order to build a detailed record of system performance, CSBR has installed data loggers at the Wellstone to record minute-by-minute data on the performance of the system. This data will be collected for a minimum of a calendar year and will be analyzed with respect to weather conditions to determine how the system is functioning in different environments. The monitoring equipment is installed in order to track both supply and demand sides of the hot water system. This will provide information to assist in the design and sizing of future systems.