Active solar heating and cooling systems may not be assessed at more than the value of a conventional system for property tax purposes. This law applies only to active solar systems and does not include any land or structural elements of buildings, such as walls and roofs, or other equipment ordinarily contained in a building. Specifically, a "system" includes all controls, tanks, pumps, heat exchangers and other equipment used directly and exclusively for the conversion of solar energy for heating or cooling. Systems placed on residential, commercial and industrial property are eligible for this exclusion.