太たい陽よう熱ねつ温おん水すい器き

• 太たい陽よう光こう発はつ電でん

  Refers to solar photovoltaic power generation, not water heating.

• 給きゅう湯とう器き

  A general water heater, often gas or electric, not necessarily solar.

Compound of 太陽 (sun), 熱 (heat), 温水 (warm water), and 器 (device).