Methods and apparatuses for cultivating phototropic microorganisms

Abstract

Method and apparatus for biomass cultivation (preferably using algae) incorporating photo bio-reactor (PBR) technology coupled with a heat sink to increase energy efficiency. An external PBR array is coupled to an indoor storage tank system with a volume equal to or greater than the volume of the PBR array. A controller can be used to optimize the growth of biomass by optimizing three key growth parameters: exposure to sunlight, temperature and nutrients. The indoor tank system serves as a reservoir where algae can be protected from harsh ambient conditions, minimizing the cost of energy for heating and cooling that would normally be incurred to accommodate ambient temperature swings caused by weather if the biomass is always stored in an outdoor PBR array. During cold winter nights, the biomass can be brought indoors to conserve thermal energy. High energy efficiency can be achieved when the heat sink consists of a second holding tank and a second tubing array, and the swings in the ambient temperature are exploited to add or reject energy from the biomass cultivation.