An enclosure temperature control system utilizes a renewable power source and a thermal sink to reduce the overall power requirements from a power grid. A renewable power source, such as a solar panel may provide power that drives the components required to maintain the greenhouse temperature within upper and lower limits, including a HVAC system and/or a heat transfer system coupled with a thermal sink. The thermal sink includes a phase change material that releases heat when it solidifies and this heat can be used to heat the greenhouse. Likewise, the phase change material absorbs heat during the day to reduce the temperature within the greenhouse. A heat transfer system may be coupled with the phase change material and a solid conductor component within the tank of a phase change material may increase thermal transfer rate.
